uu.seUppsala universitets publikationer
Ändra sökning
Avgränsa sökresultatet
1234567 51 - 100 av 349
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 51.
    Chen, Donglei
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Janvier, Philippe
    Département Histoire de la Terre, Muséum National d'Histoire Naturelle,.
    Ahlberg, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Blom, Henning
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Scale morphology and squamation of the Late Silurian osteichthyan Andreolepis from Gotland, Sweden2012Ingår i: Historical Biology, ISSN 0891-2963, E-ISSN 1029-2381, Vol. 24, nr 4, s. 411-423Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The origin of osteichthyans (bony fishes and tetrapods) dates back to the Late Silurian, but the early evolution of the group is poorly understood. Andreolepis is one of the oldest known osteichthyans, but exclusively documented by detached and fragmentary dermal microremains. A large data-set of Andreolepis scales from the Silurian of Gotland has been used to explore the scale morphology on different parts of the body. Landmark-based geometric morphometrics together with comparative anatomy and functional morphology has allowed 10 morphotypes to be identified and incorporated into a squamation model, in which scales are allocated to anterior-mid lateral flank scales, posterior lateral flank scales, caudal peduncle scales, pectoral peduncle scales, dorsal flank scales, dorsal fulcral scales, caudal fulcral scales, ventral flank scales, medioventral scales and cranial scales. The scale morphology and squamation pattern ofAndreolepis may be primitive for the Osteichthyes and thus informative about the acquisition of the osteichthyan body plan.

  • 52.
    Cheng, Xinlai
    et al.
    Institut für Pharmazie und Molekulare Biotechnologie, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 364, 69120, Heidelberg, Germany.
    Peuckert, Christiane
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Wölfl, Stefan
    Institut für Pharmazie und Molekulare Biotechnologie, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 364, 69120, Heidelberg, Germany.
    Essential role of mitochondrial Stat3 in p38MAPK mediated apoptosis under oxidative stress2017Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, nr 1, artikel-id 15388Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Stat3 is an oncogene, frequently associated with malignant transformation. A body of evidence implicates that phospho-Stat3(Y705) contributes to its nucleic translocation, while phospho-Stat3(S727) leads to the accumulation in mitochondria. Both are of importance for tumor cell proliferation. In comparison to well-characterized signaling pathways interplaying with Stat3(Y705), little is known about Stat3(S727). In this work, we studied the influence of Stat3 deficiency on the viability of cells exposed to H2O2 or hypoxia using siRNA and CRISPR/Cas9 genome-editing. We found dysregulation of mitochondrial activity, which was associated with excessive ROS formation and reduced mitochondrial membrane potential, and observed a synergistic effect for oxidative stress-mediated apoptosis in Stat3-KD cells or cells carrying Stat3(Y705F), but not Stat3(S727D), suggesting the importance of functional mitochondrial Stat3 in this context. We also found that ROS-mediated activation of ASK1/p38(MAPK) was involved and adding antioxidants, p38(MAPK) inhibitor, or genetic repression of ASK1 could easily rescue the cellular damage. Our finding reveals a new role of mitochondrial Stat3 in preventing ASK1/p38(MAPK)-mediated apoptosis, wich further support the notion that selective inhibition mitochondrial Stat3 could provide a primsing target for chemotherapy.

  • 53.
    Choo, Brian
    et al.
    Chinese Acad Sci, Key Lab Vertebrate Evolut & Human Origins, Inst Vertebrate Paleontol & Paleoanthropol, Beijing, Peoples R China.;Flinders Univ S Australia, Sch Biol Sci, Adelaide, SA, Australia..
    Zhu, Min
    Chinese Acad Sci, Key Lab Vertebrate Evolut & Human Origins, Inst Vertebrate Paleontol & Paleoanthropol, Beijing, Peoples R China.;Univ Chinese Acad Sci, Coll Earth Sci, Beijing, Peoples R China..
    Qu, Qinming
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi. Univ Ottawa, Ctr Adv Res Environm Genom, Ottawa, ON, Canada..
    Yu, Xiaobo
    Chinese Acad Sci, Key Lab Vertebrate Evolut & Human Origins, Inst Vertebrate Paleontol & Paleoanthropol, Beijing, Peoples R China.;Kean Univ, Dept Biol Sci, Union, NJ USA..
    Jia, Liantao
    Chinese Acad Sci, Key Lab Vertebrate Evolut & Human Origins, Inst Vertebrate Paleontol & Paleoanthropol, Beijing, Peoples R China..
    Zhao, Wenjin
    Chinese Acad Sci, Key Lab Vertebrate Evolut & Human Origins, Inst Vertebrate Paleontol & Paleoanthropol, Beijing, Peoples R China.;Univ Chinese Acad Sci, Coll Earth Sci, Beijing, Peoples R China..
    A new osteichthyan from the late Silurian of Yunnan, China2017Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, nr 3, artikel-id e0170929Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Our understanding of early gnathostome evolution has been hampered by a generally scant fossil record beyond the Devonian. Recent discoveries from the late Silurian Xiaoxiang Fauna of Yunnan, China, have yielded significant new information, including the earliest articulated osteichthyan fossils from the Ludlow-aged Kuanti Formation. Here we describe the partial postcranium of a new primitive bony fish from the Kuanti Formation that represents the second known taxon of pre-Devonian osteichthyan revealing articulated remains. The new form, Sparalepis tingi gen. et sp. nov., displays similarities with Guiyu and Psarolepis, including a spine-bearing pectoral girdle and a placoderm-like dermal pelvic girdle, a structure only recently identified in early osteichthyans. The squamation with particularly thick rhombic scales shares an overall morphological similarity to that of Psarolepis. However, the anterior flank scales of Sparalepis possess an unusual interlocking system of ventral bulges embraced by dorsal concavities on the outer surfaces. A phylogenetic analysis resolves Sparalepis within a previously recovered cluster of stem-sarcopterygians including Guiyu, Psarolepis and Achoania. The high diversity of osteichthyans from the Ludlow of Yunnan strongly contrasts with other Silurian vertebrate assemblages, suggesting that the South China block may have been an early center of diversification for early gnathostomes, well before the advent of the Devonian "Age of Fishes".

  • 54.
    Chylenski, Maciej
    et al.
    Adam Mickiewicz Univ, Fac Hist, Inst Archaeol, Umultowska 89D, PL-61614 Poznan, Poland..
    Juras, Anna
    Adam Mickiewicz Univ, Fac Biol, Inst Anthropol, Dept Human Evolutionary Biol, Umultowska 89, PL-61614 Poznan, Poland..
    Ehler, Edvard
    Adam Mickiewicz Univ, Fac Biol, Inst Anthropol, Dept Human Evolutionary Biol, Umultowska 89, PL-61614 Poznan, Poland.;Charles Univ Prague, Fac Educ, Dept Biol & Environm Studies, Magdaleny Rettigove 4, Prague 11639, Czech Republic..
    Malmström, Helena
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Piontek, Janusz
    Adam Mickiewicz Univ, Fac Biol, Inst Anthropol, Dept Human Evolutionary Biol, Umultowska 89, PL-61614 Poznan, Poland..
    Jakobsson, Mattias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Marciniak, Arkadiusz
    Adam Mickiewicz Univ, Fac Hist, Inst Archaeol, Umultowska 89D, PL-61614 Poznan, Poland..
    Dabert, Miroslawa
    Adam Mickiewicz Univ, Fac Biol, Mol Biol Techn Lab, Umultowska 89, PL-61614 Poznan, Poland..
    Late Danubian mitochondrial genomes shed light into the Neolithisation of Central Europe in the 5th millennium BC2017Ingår i: BMC Evolutionary Biology, ISSN 1471-2148, E-ISSN 1471-2148, Vol. 17, artikel-id 80Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Recent aDNA studies are progressively focusing on various Neolithic and Hunter-Gatherer (HG) populations, providing arguments in favor of major migrations accompanying European Neolithisation. The major focus was so far on the Linear Pottery Culture (LBK), which introduced the Neolithic way of life in Central Europe in the second half of 6th millennium BC. It is widely agreed that people of this culture were genetically different from local HGs and no genetic exchange is seen between the two groups. From the other hand some degree of resurgence of HGs genetic component is seen in late Neolithic groups belonging to the complex of the Funnel Beaker Cultures (TRB). Less attention is brought to various middle Neolithic cultures belonging to Late Danubian sequence which chronologically fall in between those two abovementioned groups. We suspected that genetic influx from HG to farming communities might have happened in Late Danubian cultures since archaeologists see extensive contacts between those two communities. Results: Here we address this issue by presenting 5 complete mitochondrial genomes of various late Danubian individuals from modern-day Poland and combining it with available published data. Our data show that Late Danubian cultures are maternally closely related to Funnel Beaker groups instead of culturally similar LBK. Conclusions: We assume that it is an effect of the presence of individuals belonging to U5 haplogroup both in Late Danubians and the TRB. The U5 haplogroup is thought to be a typical for HGs of Europe and therefore we argue that it is an additional evidence of genetic exchange between farming and HG groups taking place at least as far back as in middle Neolithic, in the Late Danubian communities.

  • 55. Clack, Jennifer A.
    et al.
    Ahlberg, Per E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Blom, Henning
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Finney, Sarah M.
    A new genus of Devonian tetrapod from North-East Greenland, with new information on the lower jaw of Ichthyostega2012Ingår i: Palaeontology, ISSN 0031-0239, E-ISSN 1475-4983, Vol. 55, nr 1, s. 73-86Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new genus and species of Devonian tetrapod has been identified from material collected in 1947 from the southern slope of Mt. Celsius, Ymer phi, North-East Greenland. The specimen preserves both lower jaws, partial palate, premaxillae and maxillae, with a natural mould of parts of the shoulder girdle. The new taxon, Ymeria denticulata, shows differences in dentition, skull ornament and lateral line expression from both Acanthostega and Ichthyostega, but it shows a closer resemblance to the latter. A cladistic analysis not only suggests that Ymeria lies adjacent to Ichthyostega on the tetrapod stem, but also reveals substantial topological instability. As the third genus and the fifth species of tetrapod identified from North-East Greenland, it demonstrates the high diversity of Devonian tetrapods in that region.

  • 56. Clack, Jennifer A.
    et al.
    Ahlberg, Per Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Sarcopterygians: From Lobe-Finned Fishes to the Tetrapod Stem Group2016Ingår i: Evolution of the Vertebrate Ear: Evidence from the Fossil Record / [ed] Jennifer A. Clack, Richard R. Fay, Arthur N. Popper, Springer Publishing Company, 2016, s. 51-70Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    The sarcopterygians or lobe-finned fishes is the group that gave rise to tetrapods, and they were the dominant bony fishes of the Devonian period. Their otic regions were constructed similarly to those of both the actinopterygians and chondrichthyans, their structure being the common inheritance of all jawed vertebrates. One distinguishing feature of the primitive sarcopterygian braincase was that the division between the anterior ethmosphenoid and posterior otoccipital section sof the braincase was marked by a flexible hinge joint, which is seen today in the modern coelacanth, Latimeria. The hyomandibular was long and projected ventrally with an opercular process that contacted the opercular bone and with the distal end associated indirectly with the jaw joint. It was a key component of the buccal pumping mechanism for breathing and feeding. The braincases of dipnoans (lungfishes) were the most highly modified of sarcopterygian braincases with consolidated fore and aft portions and reduction or loss of the hyomandibula. The utricle was enlarged in several fossil dipnoans, although the reason for this is not clear. The braincases of tetrapodomorph sarcopterygians differed little from the primitive condition in the group. The main modifications were to the more crownward and tetrapod-like forms from the Late Devonian. In these fishes, the hyomandibula was reduced in length, its contact with the opercular bone lost and, ultimately, the opercular bone itself disappeared. The spiracular notch and associated cleft increased in width and volume respectively, possibly resulting in increased air-breathing capacity and reduced use of the gill system.

  • 57.
    Clarac, Francois
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi. Sorbonne Univ, CNRS, Inst Sci Terre Paris, UMR 7193, 4 Pl Jussieu,BC 19, F-75005 Paris, France;Sorbonne Univ, Dept Hist Terre, Museum Natl Hist Nat, Ctr Rech Paleontol Paris,CNRS,UMR 7207, Batiment Geol Paris, F-75231 Paris 05, France.
    Goussard, Florent
    Sorbonne Univ, Dept Hist Terre, Museum Natl Hist Nat, Ctr Rech Paleontol Paris,CNRS,UMR 7207, Batiment Geol Paris, F-75231 Paris 05, France.
    de Buffrenil, Vivian
    Sorbonne Univ, Dept Hist Terre, Museum Natl Hist Nat, Ctr Rech Paleontol Paris,CNRS,UMR 7207, Batiment Geol Paris, F-75231 Paris 05, France.
    Sansalone, Vittorio
    Univ Paris Est, Lab Modelisat & Simulat Multi Echelle, MSME LIMR 8208, CNRS, 61 Ave Gen Gaulle, F-94010 Creteil, France.
    The function(s) of bone ornamentation in the crocodylomorph osteoderms: a biomechanical model based on a finite element analysis2019Ingår i: Paleobiology, ISSN 0094-8373, E-ISSN 1938-5331, Vol. 45, nr 1, s. 182-200Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper aims at assessing the influence of the bone ornamentation and, specifically, the associated loss of bone mass on the mechanical response of the crocodylomorph osteoderms. To this end, we have performed three-dimensional (3D) modeling and a finite element analysis on a sample that includes both extant dry bones and well-preserved fossils tracing back to the Late Triassic. We simulated an external attack under various angles on the apical surface of each osteoderm and further repeated the simulation on an equivalent set of smoothed 3D-modeled osteoderms. The comparative results indicated that the presence of an apical sculpture has no significant influence on the von Mises stress distribution in the osteoderm volume, although it produces a slight increase in its numerical score. Moreover, performing parametric analyses, we showed that the Young's modulus of the osteoderm, which may vary depending on the bone porosity, the collagen fiber orientation, or the calcification density, has no impact on the von Mises stress distribution inside the osteoderm volume. As the crocodylomorph bone ornamentation is continuously remodeled by pit resorption and secondary bone deposition, we assume that the apical sculpture may be the outcome of a trade-off between the bone mechanical resistance and the involvement in physiological functions. These physiological functions are indeed based on the setup of a bone superficial vessel network and/or the recurrent release of mineral elements into the plasma: heat transfers during basking and respiratory acidosis buffering during prolonged apnea in neosuchians and teleosaurids; compensatory homeostasis in response to general calcium deficiencies. On a general morphological basis, the osteoderm geometric variability within our sample leads us to assess that the global osteoderm geometry (whether square or rectangular) does not influence the von Mises stress, whereas the presence of a dorsal keel would somewhat reduce the stress along the vertical axis.

  • 58.
    Clarac, Francois
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi. Sorbonne Univ, CNRS, MNHN, CR2P,UMR 7207,Ctr Rech Paleobiodiversite & Paleoe, Paris, France.
    Quilhac, A.
    Sorbonne Univ, CNRS, MNHN, CR2P,UMR 7207,Ctr Rech Paleobiodiversite & Paleoe, Paris, France.
    The crocodylian skull and osteoderms: A functional exaptation to ectothermy?2019Ingår i: Zoology (Jena), ISSN 0944-2006, E-ISSN 1873-2720, Vol. 132, s. 31-40Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The crocodylians are ectothermic semi-aquatic vertebrates which are assessed to have evolved from endothermic terrestrial forms during the Mesozoic. Such a physiological transition should have involved modifications in their cardio-vascular system allowing to increase the heat transfers with the surrounding environment by growing a peripheral vascularization which would be mainly located in the dermal skeleton: the dermatocranium and the osteoderms. In order to assess the implication of these anatomical regions in thermal exchanges, we have recorded the temperature above a set of representative skin areas in order to draw comparisons between the skull, the osteoderms, and the rest of the body parts which present either none or residual dermal ossification. We computed the data after the specimens were successively laid in different stereotyped environmental conditions which involved significant variations in the environmental temperature. Our results show that the osteoderms collect the external heat during the basking periods as they become significantly warmer than the surrounding skin; they further release the heat into the core of the organism as they turn out to be colder than the surrounding skin after a significant cooling period. In disregard of the environmental temperature variations, the skull table (which encloses the braincase) remains warmer than the rest of the cranial regions and shows less temperature variations than the osteoderms; a result which has lead us to think that the braincase temperature is monitored and controlled by a thermoregulatory system. Therefore, as hypothesized by previous authors regarding the ectothermic diapsids, we assume that the crocodylian skull possesses shunting blood pathways which tend to maintain both the braincase and the main sensory organs at the nearest to the optimal physiological temperature depending on the external temperature variations. Concerning the skin vascularization, the study of an albino Alligator mississippiensis specimen permitted to observe the repartition of the superficial blood vessels by transparency through the skin. We thus testify that the skin which covers either the skull or the osteoderms is more vascularized than the skin which does not present any subjacent dermal ossification. We consequently deduce that the significant contrast in the thermal behavior between the dermal skeleton and the rest of the body is indeed correlated with a difference in the relative degree of skin vascularization. This last assessment confirms that the development of the dermal skeleton should have played a functional role in the crocodylian transition from endothermy to ectothermy through the set-up of a peripheral vessel network.

  • 59.
    Clement, Alice
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Ahlberg, Per Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    The First Virtual Cranial Endocast of a Lungfish (Sarcopterygii: Dipnoi)2014Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, nr 11, artikel-id 0113898Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lungfish, or dipnoans, have a history spanning over 400 million years and are the closest living sister taxon to the tetrapods. Most Devonian lungfish had heavily ossified endoskeletons, whereas most Mesozoic and Cenozoic lungfish had largely cartilaginous endoskeletons and are usually known only from isolated tooth plates or disarticulated bone fragments. There is thus a substantial temporal and evolutionary gap in our understanding of lungfish endoskeletal morphology, between the diverse and highly variable Devonian forms on the one hand and the three extant genera on the other. Here we present a virtual cranial endocast of Rhinodipterus kimberleyensis, from the Late Devonian Gogo Formation of Australia, one of the most derived fossil dipnoans with a well-ossified braincase. This endocast, generated from a Computed Microtomography (µCT) scan of the skull, is the first virtual endocast of any lungfish published, and only the third fossil dipnoan endocast to be illustrated in its entirety. Key features include long olfactory canals, a telencephalic cavity with a moderate degree of ventral expansion, large suparaotic cavities, and moderately enlarged utricular recesses. It has numerous similarities to the endocasts of Chirodipterus wildungensis and Griphognathus whitei, and to a lesser degree to 'Chirodipterus' australis and Dipnorhynchus sussmilchi. Among extant lungfish, it consistently resembles Neoceratodus more closely than Lepidosiren and Protopterus. Several trends in the evolution of the brains and labyrinth regions in dipnoans, such as the expansions of the utricular recess and telencephalic regions over time, are identified and discussed.

  • 60.
    Clement, Alice
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi. Flinders Univ S Australia, Coll Sci & Engn, Adelaide, SA, Australia;Museum Victoria, Dept Sci, Melbourne, Vic, Australia.
    King, Benedict
    Flinders Univ S Australia, Coll Sci & Engn, Adelaide, SA, Australia;Nat Biodivers Ctr, Leiden, Netherlands.
    Giles, Sam
    Univ Oxford, Dept Earth Sci, Oxford, England.
    Choo, Brian
    Flinders Univ S Australia, Coll Sci & Engn, Adelaide, SA, Australia.
    Ahlberg, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Young, Gavin C.
    Australian Natl Univ, Res Sch Phys & Engn, Dept Appl Math, Canberra, ACT, Australia;Australian Museum, Res Inst, Sydney, NSW, Australia.
    Long, John A.
    Flinders Univ S Australia, Coll Sci & Engn, Adelaide, SA, Australia;Museum Victoria, Dept Sci, Melbourne, Vic, Australia.
    Neurocranial anatomy of an enigmatic Early Devonian fish sheds light on early osteichthyan evolution2018Ingår i: eLIFE, E-ISSN 2050-084X, Vol. 7, artikel-id e34349Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The skull of 'Ligulalepis' from the Early Devonian of Australia (AM-F101607) has significantly expanded our knowledge of early osteichthyan anatomy, but its phylogenetic position has remained uncertain. We herein describe a second skull of 'Ligulalepis' and present micro-CT data on both specimens to reveal novel anatomical features, including cranial endocasts. Several features previously considered to link 'Ligulalepis' with actinopterygians are now considered generalized osteichthyan characters or of uncertain polarity. The presence of a lateral cranial canal is shown to be variable in its development between specimens. Other notable new features include the presence of a pineal foramen, the some detail of skull roof sutures, the shape of the nasal capsules, a placoderm-like hypophysial vein, and a chondrichthyan-like labyrinth system. New phylogenetic analyses place 'Ligulalepis' as a stem osteichthyan, specifically as the sister taxon to 'psarolepids' plus crown osteichthyans. The precise position of 'psarolepids' differs between parsimony and Bayesian analyses.

  • 61.
    Clement, Alice M.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi. Flinders Univ S Australia, Sch Biol Sci, Adelaide, SA, Australia.;Museum Victoria, Dept Sci, Melbourne, Vic, Australia..
    Challands, Tom J.
    Univ Edinburgh, Sch Geosci, Edinburgh, Midlothian, Scotland..
    Long, John A.
    Flinders Univ S Australia, Sch Biol Sci, Adelaide, SA, Australia..
    Ahlberg, Per E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    The cranial endocast of Dipnorhynchus sussmilchi (Sarcopterygii: Dipnoi) and the interrelationships of stem-group lungfishes2016Ingår i: PeerJ, ISSN 2167-8359, E-ISSN 2167-8359, Vol. 4, artikel-id e2539Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The first virtual cranial endocast of a lungfish from the Early Devonian, Dipnorhynchus sussmilchi, is described. Dipnorhynchus, only the fourth Devonian lungfish for which a near complete cranial endocast is known, is a key taxon for clarifying primitive character states within the group. A ventrally-expanded telencephalic cavity is present in the endocast of Dipnorhynchus demonstrating that this is the primitive state for "true" Dipnoi. Dipnorhynchus also possesses a utricular recess differentiated from the sacculolagenar pouch like that seen in stratigraphically younger lungfish (Dipterus, Chirodipterus, Rhinodipterus), but absent from the dipnomorph Youngolepis. We do not find separate pineal and para-pineal canals in contrast to a reconstruction from previous authors. We conduct the first phylogenetic analysis of Dipnoi based purely on endocast characters, which supports a basal placement of Dipnorhynchus within the dipnoan stem group, in agreement with recent analyses. Our analysis demonstrates the value of endocast characters for inferring phylogenetic relationships.

  • 62.
    Clement, Alice M.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi. Flinders Univ S Australia, Sch Biol Sci, GPO Box 2100, Adelaide, SA 5001, Australia..
    Long, J. A.
    Flinders Univ S Australia, Sch Biol Sci, GPO Box 2100, Adelaide, SA 5001, Australia..
    Tafforeau, P.
    Flinders Univ S Australia, Sch Biol Sci, GPO Box 2100, Adelaide, SA 5001, Australia.;European Synchrotron Radiat Facil, 71 Ave Martyrs, F-38043 Grenoble, France..
    Ahlberg, Per E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi. Flinders Univ S Australia, Sch Biol Sci, GPO Box 2100, Adelaide, SA 5001, Australia..
    The dipnoan buccal pump reconstructed in 3D and implications for air breathing in Devonian lungfishes2016Ingår i: Paleobiology, ISSN 0094-8373, E-ISSN 1938-5331, Vol. 42, nr 2, s. 289-304Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lungfishes are known for, and indeed take their name from, their bimodal respiratory abilities. All three extant genera can use their lungs to extract oxygen from the atmosphere, although their reliance upon this capability differs among taxa. Lungs are considered primitive for the Osteichthyes, however the distinctive buccal pump mode of air gulping exhibited by extant lungfishes appears to be a specialization. It is associated with a number of derived skeletal characters (cranial ribs, long parasphenoid stalk, midline gap between palatal tooth plates) that first appeared during the Devonian. These have been described individually, but in no Devonian lungfish has their three-dimensional (3D) spatial relationship been reconstructed and analyzed. Here we present the 3D morphology of Rhinodipterus, a Mid-Late Devonian lungfish from Australia and Europe, based on synchrotron tomography and conventional microtomography scans. Unlike less crownward contemporaneous lungfishes such as Griphognathus and Chirodipterus, Rhinodipterus has a full set of skeletal buccal pump components that can be directly compared to those of extant lungfishes, suggesting that it made more extensive use of air breathing than other Gogo or Bergisch Gladbach genera. This is interesting in relation to the environmental context as Gogo and Bergisch Gladbach are both marine, contrasting with the frequently hypoxic tropical to subtropical fresh water environments inhabited by modern lungfishes. The evolution of buccal pump-supported lung ventilation was evidently not necessarily associated with a transition to non-marine habitats.

  • 63.
    Clement, Alice M.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Nysjö, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Strand, Robin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Ahlberg, Per E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Brain – Endocast relationship in the Australian lungfish, Neoceratodus forsteri, elucidated from tomographic data (Sarcopterygii: Dipnoi)2015Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, nr 10, artikel-id e0141277Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Although the brains of the three extant lungfish genera have been previously described, the spatial relationship between the brain and the neurocranium has never before been fully described nor quantified. Through the application of virtual microtomography (mu CT) and 3D rendering software, we describe aspects of the gross anatomy of the brain and labyrinth region in the Australian lungfish, Neoceratodus forsteri and compare this to previous accounts. Unexpected characters in this specimen include short olfactory peduncles connecting the olfactory bulbs to the telencephalon, and an oblong telencephalon. Furthermore, we illustrate the endocast (the mould of the internal space of the neurocranial cavity) of Neoceratodus, also describing and quantifying the brain-endocast relationship in a lungfish for the first time. Overall, the brain of the Australian lungfish closely matches the size and shape of the endocast cavity housing it, filling more than four fifths of the total volume. The forebrain and labyrinth regions of the brain correspond very well to the endocast morphology, while the midbrain and hindbrain do not fit so closely. Our results cast light on the gross neural and endocast anatomy in lungfishes, and are likely to have particular significance for palaeoneurologists studying fossil taxa.

  • 64.
    Clement, Alice M.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Strand, Robin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Nysjö, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Long, John A.
    Ahlberg, Per E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    A new method for reconstructing brain morphology: Applying the brain-neurocranial spatial relationship in an extant lungfish to a fossil endocast2016Ingår i: Royal Society Open Science, E-ISSN 2054-5703, Vol. 3, nr 7, artikel-id 160307Artikel i tidskrift (Refereegranskat)
  • 65. Clemente, Florian J
    et al.
    Cardona, Alexia
    Inchley, Charlotte E
    Peter, Benjamin M
    Jacobs, Guy
    Pagani, Luca
    Lawson, Daniel J
    Antão, Tiago
    Vicente, Mário
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Mitt, Mario
    DeGiorgio, Michael
    Faltyskova, Zuzana
    Xue, Yali
    Ayub, Qasim
    Szpak, Michal
    Mägi, Reedik
    Eriksson, Anders
    Manica, Andrea
    Raghavan, Maanasa
    Rasmussen, Morten
    Rasmussen, Simon
    Willerslev, Eske
    Vidal-Puig, Antonio
    Tyler-Smith, Chris
    Villems, Richard
    Nielsen, Rasmus
    Metspalu, Mait
    Malyarchuk, Boris
    Derenko, Miroslava
    Kivisild, Toomas
    A Selective Sweep on a Deleterious Mutation in CPT1A in Arctic Populations.2014Ingår i: American Journal of Human Genetics, ISSN 0002-9297, E-ISSN 1537-6605, Vol. 95, nr 5Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Arctic populations live in an environment characterized by extreme cold and the absence of plant foods for much of the year and are likely to have undergone genetic adaptations to these environmental conditions in the time they have been living there. Genome-wide selection scans based on genotype data from native Siberians have previously highlighted a 3 Mb chromosome 11 region containing 79 protein-coding genes as the strongest candidates for positive selection in Northeast Siberians. However, it was not possible to determine which of the genes might be driving the selection signal. Here, using whole-genome high-coverage sequence data, we identified the most likely causative variant as a nonsynonymous G>A transition (rs80356779; c.1436C>T [p.Pro479Leu] on the reverse strand) in CPT1A, a key regulator of mitochondrial long-chain fatty-acid oxidation. Remarkably, the derived allele is associated with hypoketotic hypoglycemia and high infant mortality yet occurs at high frequency in Canadian and Greenland Inuits and was also found at 68% frequency in our Northeast Siberian sample. We provide evidence of one of the strongest selective sweeps reported in humans; this sweep has driven this variant to high frequency in circum-Arctic populations within the last 6-23 ka despite associated deleterious consequences, possibly as a result of the selective advantage it originally provided to either a high-fat diet or a cold environment.

  • 66.
    Clément, Gaël
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för fysiologi och utvecklingsbiologi, Evolutionär organismbiologi.
    Ahlberg, Per E
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    The endocranial anatomy of the early sarcopterygian Powichthys from Spitsbergen, based on CT scanning2010Ingår i: Morphology, Phylogeny and Paleobiogeography of Fossil Fishes: honoring Meemann Chang / [ed] David K. Elliott, John G. Maisey, Xiaobo Yu, Desui Miao, München: Dr. Friedrich Pfeil , 2010, s. 363-377Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 67.
    Conte, Gabriele Larocca
    et al.
    Univ Bologna, Dipartimento Sci Biol Geol & Ambientali, Alma Mater Studiorum, Via Zamboni 67, I-40126 Bologna, Italy.
    Fanti, Federico
    Univ Bologna, Dipartimento Sci Biol Geol & Ambientali, Alma Mater Studiorum, Via Zamboni 67, I-40126 Bologna, Italy;Univ Bologna, Museo Geol Giovanni Capellini, Alma Mater Studiorum, Via Zamboni 63, I-40126 Bologna, Italy.
    Trevisani, Enrico
    Museo Civ Storia Nat Ferrara, Via De Pisis 24, I-44121 Ferrara, Italy.
    Guaschi, Paolo
    Univ Pavia, Museo Storia Nat, Piazza Botta 9-10, I-27100 Pavia, Italy.
    Barbieri, Roberto
    Univ Bologna, Dipartimento Sci Biol Geol & Ambientali, Alma Mater Studiorum, Via Zamboni 67, I-40126 Bologna, Italy;Univ Bologna, Museo Geol Giovanni Capellini, Alma Mater Studiorum, Via Zamboni 63, I-40126 Bologna, Italy.
    Bazzi, Mohamad
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Reassessment of a large lamniform shark from the Upper Cretaceous (Santonian) of Italy2019Ingår i: Cretaceous research (Print), ISSN 0195-6671, E-ISSN 1095-998X, Vol. 99, s. 156-168Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To date, only a few partially articulated chondrichthyan specimens are known from the Upper Cretaceous marine fossil record of northern Italy. Here, we re-evaluate the taxonomic status and geological age of selachian remains originally discovered during the 19th century from the Castellavazzo locality. The described specimen is largely embedded in matrix with minute exposure of joined and moderately deformed sequentially stacked vertebral centra. Computed tomography (CT) image-data obtained of the specimen enabled the identification of potential cranial-cartilage elements located in close proximity to teeth and are here interpreted as remnants of the jaws. Based on tooth and vertebral morphology the specimen is in all likelihood an adult lamniform shark with a measured 3.5 m length. Using ordinary least-squares regression analysis (OLS) and proportion-based calculations, we estimated a total-length (TL) of 596.27 and 632.5-672.64 cm respectively. We prefer the size estimation derived through OLS bivariate regression; however, in the present analysis, reliance on a small sample size (n = 11) and evidence for differential scaling between taxa impose limitations on the precision of our size prediction. Planktonic foraminifera examined from the surrounding matrix of the slab preserving shark vertebral centra and teeth indicate a Santonian age (Dicarinella asymetrica zone). Although, the specimen could not confidently be assigned beyond the ordinal-level, the sheer centrum size, gross dental morphology, and depositional environment, are indicative of a pelagic apex-predator comparable to coeval lamniforms, with a specific resemblance towards cretoxyrhinids, reported from elsewhere along the peri-Tethyan shelf of Europe and Western Interior Seaway of North America. Finally, the re-emergence of this historical specimen, here re-described using cutting-edge techniques, is of great importance as it contributes to the otherwise poor record of extinct lamniform shark skeletons.

  • 68.
    Corell, Mikael
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för neurovetenskap, Genetisk utvecklingsbiologi.
    Wicher, Grzegorz
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi, Cancer och vaskulärbiologi.
    Katarzyna J., Radomska
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Trier Kjær, Marcel
    Syddansk Universitet, IMM-Neurobiology Reseach, Denmark .
    Dağlıkoca, E. Duygu
    Bogazici University, Deptartment of Molecular Biology and Genetics, Turkey .
    Fredriksson, Robert
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för neurovetenskap, Funktionell farmakologi.
    Fex Svenningsen, Åsa
    Syddansk Universitet, IMM-Neurobiology Reseach, Denmark .
    The function of GABA and its B-receptor in Schwann cell developmentManuskript (preprint) (Övrigt vetenskapligt)
  • 69. Cunningham, John A.
    et al.
    Ruecklin, Martin
    Blom, Henning
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Botella, Hector
    Donoghue, Philip C. J.
    Testing models of dental development in the earliest bony vertebrates, Andreolepis and Lophosteus2012Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 8, nr 5, s. 833-837Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Theories on the development and evolution of teeth have long been biased by the fallacy that chondrichthyans reflect the ancestral condition for jawed vertebrates. However, correctly resolving the nature of the primitive vertebrate dentition is challenged by a dearth of evidence on dental development in primitive osteichthyans. Jaw elements from the Silurian-Devonian stem-osteichthyans Lophosteus and Andreolepis have been described to bear a dentition arranged in longitudinal rows and vertical files, reminiscent of a pattern of successional development. We tested this inference, using synchrotron radiation X-ray tomographic microscopy (SRXTM) to reveal the pattern of skeletal development preserved in the sclerochronology of the mineralized tissues. The tooth-like tubercles represent focal elaborations of dentine within otherwise continuous sheets of the dermal skeleton, present in at least three stacked generations. Thus, the tubercles are not discrete modular teeth and their arrangement into rows and files is a feature of the dermal ornamentation that does not reflect a polarity of development or linear succession. These fossil remains have no bearing on the nature of the dentition in osteichthyans and, indeed, our results raise questions concerning the homologies of these bones and the phylogenetic classification of Andreolepis and Lophosteus.

  • 70.
    Defourny, Jean
    et al.
    Univ Liege, Unit Cell & Tissue Biol, GIGA Neurosci, CHU B36, B-4000 Liege, Belgium;Univ Liege, Dev Neurobiol Unit, GIGA Neurosci, CHU B36, B-4000 Liege, Belgium.
    Peuckert, Christiane
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Kullander, Klas
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för neurovetenskap.
    Malgrange, Brigitte
    Univ Liege, Dev Neurobiol Unit, GIGA Neurosci, CHU B36, B-4000 Liege, Belgium.
    EphA4-ADAM10 Interplay Patterns the Cochlear Sensory Epithelium through Local Disruption of Adherens Junctions2019Ingår i: ISCIENCE, ISSN 2589-0042, Vol. 11, s. 246-257Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The cochlear sensory epithelium contains a functionally important triangular fluid-filled space between adjacent pillar cells referred to as the tunnel of Corti. However, the molecular mechanisms leading to local cell-cell separation during development remain elusive. Here we show that EphA4 associates with ADAM10 to promote the destruction of E-cadherin-based adhesions between adjacent pillar cells. These cells fail to separate from each other, and E-cadherin abnormally persists at the pillar cell junction in EphA4 forward-signaling-deficient mice, as well as in the presence of ADAM10 inhibitor. Using immunolabeling and an in situ proximity ligation assay, we found that EphA4 forms a complex with E-cadherin and its sheddase ADAM10, which could be activated by ephrin-B2 across the pillar cell junction to trigger the cleavage of E-cadherin. Altogether, our findings provide a new molecular insight into the regulation of adherens junctions, which might be extended to a variety of physiological or pathological processes.

  • 71.
    Den Boer, Wendy
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi. Swedish Nat Hist Museum, Dept Palaeobiol, S-10405 Stockholm, Sweden.
    Campione, Nicolás E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi. Univ New England, Palaeosci Res Ctr, Sch Environm & Rural Sci, Armidale, NSW 2531, Australia.
    Kear, Benjamin P.
    Uppsala universitet, Enheten för musik och museer, Evolutionsmuseet.
    Climbing adaptations, locomotory disparity and ecological convergence in ancient stem 'kangaroos'2019Ingår i: Royal Society Open Science, E-ISSN 2054-5703, Vol. 6, nr 2, artikel-id 181617Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Living kangaroos, wallabies and rat-kangaroos (Macropodoidea) constitute the most ecologically diverse radiation of Australasian marsupials. Indeed, even their hallmark bipedal hopping gait has been variously modified for bounding, walking and climbing. However, the origins of this locomotory adaptability are uncertain because skeletons of the most ancient macropodoids are exceptionally rare. Some of the stratigraphically oldest fossils have been attributed to Balbaridae-a clade of potentially quadrupedal stem macropodoids that became extinct during the late Miocene. Here we undertake the first assessment of balbarid locomotion using two-dimensional geometric morphometrics and a correlative multivariate analysis of linear measurements. We selected the astragalus and pedal digit IV ungual as proxies for primary gait because these elements are preserved in the only articulated balbarid skeleton, as well as some unusual early Miocene balbarid-like remains that resemble the bones of modern tree-kangaroos. Our results show that these fossils manifest character states indicative of contrasting locomotory capabilities. Furthermore, predictive modelling reveals similarities with extant macropodoids that employ either bipedal saltation and/or climbing. We interpret this as evidence for archetypal gait versatility, which probably integrated higher-speed hopping with slower-speed quadrupedal progression and varying degrees of scansoriality as independent specializations for life in forest and woodland settings.

  • 72.
    Di Paolo, Antonello
    et al.
    Univ Pisa, Sect Pharmacol, Dept Clin & Expt Med, Via Roma 55, I-56126 Pisa, Italy.
    Sarkozy, Francois
    FSNB Hlth & Care, Carenity, Paris, France.
    Ryll, Bettina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi. Melanoma Patient Network Europe.
    Siebert, Uwe
    UMIT Univ Hlth Sci Med Informat & Technol, Dept Publ Hlth Hlth Serv Res & Hlth Technol Asses, Hall In Tirol, Austria.;ONCOTYROL Ctr Personalized Canc Med, Area Hlth Technol Assessment, Innsbruck, Austria..
    Personalized medicine in Europe: not yet personal enough?2017Ingår i: BMC Health Services Research, ISSN 1472-6963, E-ISSN 1472-6963, Vol. 17, artikel-id 289Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Personalized medicine has the potential to allow patients to receive drugs specific to their individual disease, and to increase the efficiency of the healthcare system. There is currently no comprehensive overview of personalized medicine, and this research aims to provide an overview of the concept and definition of personalized medicine in nine European countries. Methods: A targeted literature review of selected health databases and grey literature was conducted to collate information regarding the definition, process, use, funding, impact and challenges associated with personalized medicine. In-depth qualitative interviews were carried out with experts with health technology assessment, clinical provisioning, payer, academic, economic and industry experience, and with patient organizations. Results: We identified a wide range of definitions of personalized medicine, with most studies referring to the use of diagnostics and individual biological information such as genetics and biomarkers. Few studies mentioned patients' needs, beliefs, behaviour, values, wishes, utilities, environment and circumstances, and there was little evidence in the literature for formal incorporation of patient preferences into the evaluation of new medicines. Most interviewees described approaches to stratification and segmentation of patients based on genetic markers or diagnostics, and few mentioned health-related quality of life. Conclusions: The published literature on personalized medicine is predominantly focused on patient stratification according to individual biological information. Although these approaches are important, incorporation of environmental factors and patients' preferences in decision making is also needed. In future, personalized medicine should move from treating diseases to managing patients, taking into account all individual factors.

  • 73.
    Dierker, Tabea
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinsk biokemi och mikrobiologi. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Shao, Chun
    Boston Univ, Dept Biochem, Ctr Biomed Mass Spectrometry, Med Campus, Boston, MA 02215 USA..
    Haitina, Tatjana
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Zaia, Joseph
    Boston Univ, Dept Biochem, Ctr Biomed Mass Spectrometry, Med Campus, Boston, MA 02215 USA..
    Hinas, Andrea
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för cell- och molekylärbiologi, Mikrobiologi.
    Kjellén, Lena
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinsk biokemi och mikrobiologi. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Nematodes join the family of chondroitin sulfate-synthesizing organisms: Identification of an active chondroitin sulfotransferase in Caenorhabditis elegans2016Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, artikel-id 34662Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Proteoglycans are proteins that carry sulfated glycosaminoglycans (GAGs). They help form and maintain morphogen gradients, guiding cell migration and differentiation during animal development. While no sulfated GAGs have been found in marine sponges, chondroitin sulfate (CS) and heparan sulfate (HS) have been identified in Cnidarians, Lophotrocozoans and Ecdysozoans. The general view that nematodes such as Caenorhabditis elegans, which belong to Ecdysozoa, produce HS but only chondroitin without sulfation has therefore been puzzling. We have analyzed GAGs in C. elegans using reversed-phase ion-pairing HPLC, mass spectrometry and immunohistochemistry. Our analyses included wild type C. elegans but also a mutant lacking two HS sulfotransferases (hst-6 hst-2), as we suspected that the altered HS structure could boost CS sulfation. We could indeed detect sulfated CS in both wild type and mutant nematodes. While 4-O-sulfation of galactosamine dominated, we also detected 6-O-sulfated galactosamine residues. Finally, we identified the product of the gene C41C4.1 as a C. elegans CS-sulfotransferase and renamed it chst-1 (CarboHydrate SulfoTransferase) based on loss of CS-4-O-sulfation in a C41C4.1 mutant and in vitro sulfotransferase activity of recombinant C41C4.1 protein. We conclude that C. elegans indeed manufactures CS, making this widely used nematode an interesting model for developmental studies involving CS.

  • 74.
    Dupret, Vincent
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Revision of the genus Kujdanowiaspis Stensiö, 1942 (Placodermi, Arthrodira, "Actinolepida") from the Lower Devonian of Podolia (Ukraine)2010Ingår i: Geodiversitas, ISSN 1280-9659, E-ISSN 1638-9395, Vol. 32, s. 5-63Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The genus Kujdanowiaspis Stensiö, 1942 has long been considered as the archetype of placoderms; hence, it has been often used as outgroup in phylogenetic analyses involving placoderms, or used as a representative of all the placoderms for all early vertebrate works. Nevertheless, there has been no real work on the taxonomy of this genus since Denison (1978). Here we propose a revision of the material of Kujdanowiaspis from the Old Red Sandstone of Podolia (including neurocrania, skull roofs and thoracic armours), together with the description of unpublished specimens of the genus Heightingtonaspis White, 1969. Among the available Podolian material, three species are considered valid: Kujdanowiaspis buczacziensis (Brotzen, 1934), K. podolica (Brotzen, 1934) and Erikaspis zychi (Stensiö, 1945) (K. podolica and K. buczacziensis only differ in size and in the density and size of the tuberculated ornamentation; the dermal plate pattern of E. zychi differs from that of the genus Kujdanowiaspis). The axillar area of the scapulocoracoid of K. podolica is compared with those of an osteostracan “agnathan” and of a non-tetrapod sarcopterygian. In the three cases, the articulation of the pectoral fin is of the monobasal type. An analogy with the embryonic development of the pectoral fin of the actinopterygian Danio rerio (Hamilton, 1822) suggests that the monobasal articulation would correspond to the plesiomorphic condition compared with the multibasal one of the adult actinopterygians and some derived brachythoracid placoderms. The suprasynarcual is a newly identified, chondrified element of the vertebral column, supposed to respond to the height of the median dorsal plate in Kujdanowiaspis podolica.

  • 75.
    Dupret, Vincent
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Carls, Peter
    Martinez-Perez, Carlos
    Botella, Hector
    First Perigondwanan record of actinolepids (Vertebrata: Placodermi: Arthrodira) from the Lochkovian (Early Devonian) of Spain and its palaeobiogeographic significance2011Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology, ISSN 0031-0182, E-ISSN 1872-616X, Vol. 310, nr 3-4, s. 273-282Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Different palaeogeographic models have been proposed for the position of Laurussia ( including Baltica) and Gondwana-derived microcontinents ( including Ibero-Armorica) during Ordovician to Late Carboniferous times. Principal differences concern the presence and duration of a large ocean, the Rheic Ocean, acting as a faunal barrier between these areas. The timing of the collision of Laurussia with Gondwana and/or Gondwana-derived terranes continues to be debated. Here we present new faunal data revealing close biogeographical relations between Ibero-Armorica ("Perigondwanan" or Gondwanan derivate terranes) and Podolia (SE margin of Baltica, in Laurussia). The placoderm assemblage found in the mid-late Lochkovian (Lower Devonian) of Celtiberia (north-central Spain), consisting of the 'actinolepid' species Kujdanowiaspis podolica, Erikaspis zychi and the acanthothoracid Palaeacanthaspis aff. P. vasta, is similar, both in terms of taxonomy and stratigraphic record, to that encountered in the Lochkovian of Podolia (Ukraine; Laurussia) and until now considered as endemic to this region. Moreover, vertebrate faunal links between Podolia and Celtiberia are also extended to the chondrichthyan scale-based species Seretolepis elegans and Altholepis composita previously documented exclusively from Laurussian localities (Podolia and Mackenzie Mountains in Canada), which occur together with the placoderm remains described herein. These evidences support the hypothesis that intermittent shallow neritic migration paths between Podolia (as well as "Avalonia") and Iberia existed in the late Lochkovian, agreeing with a palaeogeographic reconstruction showing close proximity between peri-Gondwanan or Gondwana-derived terranes and Laurussia. It supports the palaeogeographic model of the non-oceanic Variscan Mobile Crustal Field and it corroborates the arguments against wide oceans, acting as biogeographical relevant barriers, between Baltica and Gondwana in early Devonian times. The distribution patterns of heavy-shelled ostracods, turbidicolous brachiopods, and Rhenish trilobites also support these conclusions.

  • 76.
    Dupret, Vincent
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Martinez-Perez, Carlos
    University of Valencia, Spain.
    Botella, Hector
    University of Valencia.
    Carls, Peter
    Technische Universität Braunschweig, Germany.
    Blieck, Alain
    Université des Sciences et Technologies Lille 1, France.
    Vertebrate macroremains as stratigraphic markers: the case of the Lower Devonian “Kujdanowiaspis assemblage” from Podolia (Ukraine) and Celtiberia (Spain)2010Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The vertebrate fauna, including chondrichthyan microremains and osteostracan and placoderm macroremains encountered in the Lower Devonian (i.e. Lochkovian and Pragian) deposits from Podolia (Ukraine; see list in Voichyshyn, 2001) was considered as unique. Unfortunately, because of the Old Red Sandstone facies, the stratigraphic boundaries were very difficult to determine. Until recently, most of the units were lithologic. The occurrence of the arthrodire placoderm Kujdanowiaspis buczacziensis has since been proposed to mark the beginning of the Pragian, owing to a number of correlations between fossil distributions (i.e. the pteraspidiform Althaspis) in Western Europe and Podolia (Dupret and Blieck, 2009).

    Recently, the long time “unique” placoderm and chondrichthyan faunal assemblage from Podolia has been found in Spain (Martinez-Pérez et al., in press; Dupret et al., submitted). The absence of K. buczacziensis, nevertheless, leads us to consider an age older than Pragian, i.e. late Lochkovian. This dating confirms previous works mainly based on invertebrates and conodonts. These “double check” processes confirm the possibility of using macrovertebrate remains for stratigraphic purposes.

    The occurence of the same fauna during the Late Lochkovian in Podolia (southern margin of Laurussia) and in Spain (Armorican ”block”, part of northern margin of Gondwana or independant component), leads us to favour palaeogeographic reconstructions showing a proximity between both palaeo-provinces, allowing for the formation of, at least, punctual migratory paths. Moreover, the Old Red Sandstones have long been considered as non-marine deposits, especially in Podolia, despite the discovery of seldom brachiopod (lingulid) fragments. The similar faunal composition between Podolia and Celtiberia (the latter being clearly marine) challenges the non-marine status of the Podolian deposits.

  • 77.
    Dupret, Vincent
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Phuong, Ta Hoa
    Department of Geology, Vietnam National University, Ha Noi City.
    Thanh, Tong-Dzuy
    Department of Geology, Vietnam National University, Ha Noi City.
    Phong, Nguyen Duc
    Vietnam Institute of Geosciences and Mineral Resources.
    Janvier, Philippe
    Muséum National d'Histoire Naturelle, Paris, France.
    Clément, Gaël
    Muséum National d'Histoire Naturelle, Paris, France.
    The skull of Hagiangella goujeti Janvier, 2005, a high-crested acanthothoracid (Vertebrata, Placodermi) from the Lower Devonian of northern Vietnam2011Ingår i: Journal of Vertebrate Paleontology, ISSN 0272-4634, E-ISSN 1937-2809, Vol. 31, nr 3, s. 531-538Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The acanthothoracid Hagiangella goujeti Janvier, 2005, has been described exclusively on the basis of isolatedthoracic plates from the Lochkovian (Lower Devonian) Khao Loc Formation of Tung Vai, Ha Giang Province, northernVietnam. It is characterized by a very high, triangular median crest on the median dorsal plate, and has been referred to theAcanthothoraci on the basis of the morphology of its fused anterolateral, spinal and anterior ventrolateral plates, and thecharacteristic stellate ornamentation of the group. Isolated plates of H. goujeti are relatively abundant at Tung Vai and noother placoderm taxon from this locality seems to share the same type of ornamentation. However, the skull of this speciesremained elusive. Here we report two well-preserved skull roofs from Tung Vai, which we refer to H. goujeti. They display thesame stellate ornamentation and small size as the previously described plates of the thoracic armor of this species. This newmaterial shows that the head of H. goujeti is surprisingly short (i.e., possibly lacking dermal rostral and pineal elements), incontrast to the elongate and narrow skull of all other acanthothoracids. The combination of unique characters (e.g., presenceof two pairs of posterior pit lines, two pairs of central and paranuchal plates, etc.) suggests a possible sister group relationshipto the placoderm assemblage Petalichthyida + Ptyctodontida + Arthrodira.

  • 78.
    Dupret, Vincent
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi. Uppsala universitet, Science for Life Laboratory, SciLifeLab. Australian Natl Univ, Dept Appl Math, Res Sch Phys & Engn, Canberra, ACT, Australia..
    Sanchez, Sophie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi. Uppsala universitet, Science for Life Laboratory, SciLifeLab. European Synchrotron Radiat Facil, Grenoble, France..
    Goujet, Daniel
    UPMC Paris 6, CNRS, MNHN, CR2P UMR 7207,Sorbonne Univ,Museum Natl Hist Nat, Paris, France..
    Ahlberg, Per Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    The internal cranial anatomy of Romundina stellina Orvig, 1975 (Vertebrata, Placodermi, Acanthothoraci) and the origin of jawed vertebrates: Anatomical atlas of a primitive gnathostome2017Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, nr 2, artikel-id e0171241Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Placoderms are considered as the first jawed vertebrates and constitute a paraphyletic group in the stem-gnathostome grade. The acanthothoracid placoderms are among the phylogenetically most basal and morphologically primitive gnathostomes, but their neurocranial anatomy is poorly understood. Here we present a near-complete three-dimensional skull of Romundina stellina, a small Early Devonian acanthothoracid from the Canadian Arctic Archipelago, scanned with propagation phase contrast microtomography at a 7.46 mu m isotropic voxel size at the European Synchrotron Radiation Facility, Grenoble, France. This is the first model of an early gnathostome skull produced using this technique, and as such represents a major advance in objectivity compared to past descriptions of placoderm neurocrania on the basis of grinding series. Despite some loss of material along an oblique crack, most of the internal structures are remarkably preserved, and most of the missing structures can be reconstructed by symmetry. This virtual approach offers the possibility to connect with certainty all the external foramina to the blood and nerve canals and the central structures, and thus identify accurate homologies without destroying the specimen. The high level of detail enables description of the main arterial, venous and nerve canals of the skull, and other perichondrally ossified endocranial structures such as the palatoquadrate articulations, the endocranial cavity and the inner ear cavities. The braincase morphology appears less extreme than that of Brindabellaspis, and is in some respects more reminiscent of a basal arthrodire such as Kujdanowiaspis.

  • 79.
    Dupret, Vincent
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Sanchez, Sophie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Goujet, Daniel
    Muséum National D'Histoire Naturelle, Paris, France.
    Tafforeau, Paul
    European Synchrotron Radiation Facility, Grenoble, France.
    Ahlberg, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Being Romundina stellina Ørvig, 1975 (Vertebrate, Placodermi, Acanthothoraci): itracranial anatomy of one of the deepest gnathostomes revealed by synchrotron tomograpy in phase contrast protocole2012Ingår i: / [ed] Malvesy, T., Gauthrot, M., Fuchs, C., Berthoz, A., Blieck, A., Becker, D., Buffetaut, E., Mazin, J. -M.,, Montbéliard, 2012, s. 19-19Konferensbidrag (Refereegranskat)
    Abstract [en]

    Dans la peau de Romundina stellina Ørvig, 1975 (Vertebrata, Placodermi, Acanthothoraci)

    Anatomie crânienne d'un des premiers gnathostomes révélée par tomographie synchrotron en contraste de phase

     Being Romundina stellina Ørvig, 1975  (Vertebrata, Placodermi, Acanthothoraci)

    Intracranial anatomy of one of the deepest gnathostomes revealed by synchrotron tomography in phase contrast protocole

     

     

    The acanthothoracid placoderms (armored fishes) are the most basal and primitive gnathostomes (jawed vertebrates; 1). However, their endocranial morphology is poorly understood, and only one genus (Brindabellaspis) has been described thoroughly (2).

    Here we present the 3D reconstruction of a subcomplete skull of Romundina stellina Ørvig, 3, from the Lochkovian of Prince of Wales Island, Canadian Arctic Archipelago. The specimen was imaged in 3D with propagation phase contrast microtomography (4) on the ID19 beamline of the ESRF, using a 7.45 µm isotropic voxel size.

    Most features are properly preserved and most of the missing structures can be virtually rebuilt by symmetry. Another advantage of this virtual approach is the possibility of connecting with certainty all the external foramina to the blood and nerve canals and the central/internal structures, and hence to identify accurate homologies without destroying the specimen. Ørvig’s original assumptions can now be checked with confidence.

    The vasculature of the dermal bones, rendered in detail, allowed a better understanding of plate growth. It permits the visualization of dermal bone establishment over perichondral bone (5).

    The high level of details of this model reveals that between the trigeminal and vagus nerve (and the inner ears), the perichondral bone wrapping the endocranial cavity shows a “lace” pattern, unknown so far in vertebrates (presumably because of the lack of data). The significance of this character is unclear, but it is definitely not an artifact of taphonomy or scanning.

     

    References

    1          Janvier, P. Early Vertebrates. Clarendon Press edn, Vol. 1 (Oxford Science Publications, 1996).

    2          Young, G. C. A new Early Devonian placoderm from New South Wales, Australia, with a discussion of placoderm phylogeny. Palaeontographica (A) 167, 10–76 (1980).

    3          Ørvig, T. Description, with special reference to the dermal skeleton, of a new Radotinid arthrodire from the Gedinnian of Arctic Canada. Extrait des Colloques internationaux du Centre National de la Recherche Scientifique - Problèmes actuels de Paléontologie - Evolution des Vertébrés 218, 41–71 (1975).

    4          Tafforeau, P. et al. Applications of X-ray synchrotron microtomography for non-destructive 3D studies of paleontological specimens. Applied Physics A - Materials Science & Processing 83, 195–202 (2006).

    5          Dupret, V., Sanchez, S., Goujet, D., Tafforeau, P. & Ahlberg, P. Bone vascularization and growth in placoderms (Vertebrata): the example of the premedian plate of Romundina stellina Ørvig, 1975 Comptes Rendus Palevol 9, 369–375 (2010).

     

     

  • 80.
    Dupret, Vincent
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Sanchez, Sophie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Goujet, Daniel
    Muséum National D'Histoire Naturelle, Paris, France.
    Tafforeau, Paul
    European Synchrotron Radiation Facility, Grenoble, France.
    Ahlberg, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Fossil early vertebrates shed lights on the origin of the gnathostome face2013Ingår i: Program and Abstracts of the 10th International Congress of Vertebrate Morphology, Barcelona, Spain, 2013, s. 245-245Konferensbidrag (Refereegranskat)
    Abstract [en]

    Jawless cyclostomes and jawed gnathostomes show very different face patterns. Cyclostomes have a single median nasohypophysial duct, an anterior hypophysis and a short telencephalon, while gnathostomes have a pair of nasal sacs opening externally, a more posterior separate hypophysis open in the palate and a longer telencephalon.

    Embryonic processes differ as well. In cyclostomes, premandibular crest cells migrate forwards either side of the nasohypophysial placode to form the upper lip; in gnathostomes they migrate between the hypophysial and nasal placodes to form the trabecular region. Supraoptic neural crest remains posterior to the nasohypophysial duct in cyclostomes; it moves forward to create the nasal capsules in gnathostomes.

    Some fossil forms illustrate a transition between these two patterns.

    The jawless galeaspid Shuyu (-430 Ma) has a nasohypophysial duct, short telencephalon, and anteriorly oriented hypophysis, but the paired nasal sacs and hypophysis are separated by a rudimentary trabecula.

    The jawed primitive placoderm Romundina (-415 Ma) shows a cranial cavity reminiscent of that of Shuyu (anteriorly directed hypophysis, very short telencephalon). The trabecular region is long and wide, the nasal capsule is small and located far behind the tip of the snout but just in front of the orbits. We interpret these features as uniquely primitive among gnathostomes. The premandibular crest of Romundina formed a trabecular region extending as anteriorly as the tip of the snout (like in extant cyclostome and the fossil Shuyu). The position of the nasal capsule suggests that the supraoptic crest had not migrated forwards.

    We suggest that the evolutionary sequence for the creation of the extant gnathostome face from a cyclostome pattern involved 1) separation of the nasal and hypophysial placodes (galeaspids), 2) loss of the nasohypophysial duct (placoderms), and 3) lengthening of the telencephalon and the migration of the nasal capsules to the snout tip.

  • 81.
    Dupret, Vincent
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Sanchez, Sophie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Goujet, Daniel
    Muséum National D'Histoire Naturelle, Paris, France.
    Tafforeau, Paul
    European Synchrotron Radiation Facility, Grenoble, France.
    Ahlberg, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Fossils of early vertebrates and the evolution of the gnathostome face revealed by Synchrotron imaging2013Ingår i: Programme and Abstracts / [ed] Stig Walsh, Nick Fraser, Stephen Brusatte, Jeff Liston, Vicen Carrió, Edinburgh, U.K., 2013, s. 21-21Konferensbidrag (Refereegranskat)
    Abstract [en]

    Cyclostomes and gnathostomes have distinct face patterns. Cyclostomes possess a median nasohypophysial duct, an anterior hypophysis and a short telencephalon, contra gnathostomes possessing a pair of nasal sacs opening externally, a separate posterior hypophysis opening onto the palate and a long telencephalon. Embryonic development also differs. In cyclostomes, premandibular crest cells migrate forwards either side of the nasohypophysial placode, forming an upper lip; in gnathostomes they migrate between the hypophysial and nasal placodes forming the trabecular region. Supraoptic neural crest remains posterior to the nasohypophysial duct in cyclostomes but moves forward to create the nasal capsules in gnathostomes. Fossil stem gnathostomes illustrate a transitional sequence between these two patterns: 1) The galeaspid Shuyu (jawless stem gnathostome): nasohypophysial duct, short telencephalon, and anteriorly oriented hypophysis as in a cyclostome, but paired nasal sacs and hypophysis separated by a rudimentary trabecula. 2) The primitive placoderm Romundina (jawed stem gnathostome): short telencephalon, anteriorly directed hypophysis, trabecular region long and wide, nasal capsule located far behind the tip of the snout but just in front of the orbits. These features are interpreted as uniquely primitive among gnathostomes. The trabeculae of Romundina form an extensive precerebral region resembling the upper lip of extant cyclostomes and Shuyu. The position of the nasal capsule suggests that the supraoptic crest had not migrated forwards. 3) The arthrodire Kujdanowiapsis (a more derived placoderm): short telencephalon and vertically oriented hypophysis. The trabecula has been shortened anteriorly, making the nasal capsule terminal. These positional relationships are maintained in crown gnathostomes.

  • 82.
    Dupret, Vincent
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Sanchez, Sophie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Goujet, Daniel
    Muséum National D'Histoire Naturelle, Paris, France.
    Tafforeau, Paul
    European Synchrotron Radiation Facility, Grenoble, France.
    Ahlberg, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Internal structures of the skull of Romundina stellina Ørvig 1975 (Vertebrata, Placodermi, Acanthothoraci) revealed by phase contrast synchrotron scanning2011Ingår i: CAVEPS Perth 2011: Conference on Australasian Vertebrate Evolution Palaeontology and Systematics, Perth, April 27th-30th : programme, abstracts / [ed] Geological Survey of Western Australia, East Perth, W.A: Geological Survey of Western Australia , 2011, s. 30-30Konferensbidrag (Refereegranskat)
  • 83.
    Dupret, Vincent
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Sanchez, Sophie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Goujet, Daniel
    Muséum National D'Histoire Naturelle, Paris, France.
    Tafforeau, Paul
    European Synchrotron Radiation Facility, Grenoble, France.
    Ahlberg, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Intracranial anatomy of Romundina stellina Ørvig 1975 (Vertebrata, Placodermi, Acanthothoraci) revealed by phase contrast synchrotron imaging2011Ingår i: Abstracts: The 2nd Wiman meeting Carl Wiman's Legacy: 100 years of Swedish Palaeontology: Uppsala 17–18 November 2011 / [ed] Benjamin P. Kear, Michael Streng, 2011, s. 6-6Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Acanthothoracid placoderms are considered amongst the most basal of primitive gnathostomes. However, their endocranial morphology is poorly understood, and only one genus (Brindabellaspis) has been described in detail. Here we present a synchrotrongenerated 3D reconstruction of a nearly complete skull of Romundina stellina, a taxon established in 1975 by the Norwegian-born Swedish palaeontologist Tor Ørvig based on remains from the Lochkovian (Lower Devonian) of Prince of Wales Island, Canadian Arctic Archipelago. The specimen was imaged with propagation phase contrast microtomography on the ID19 beamline of the ESRF, using a 7.45 µm isotropic voxel size. Most structural features of the fossil are very well preserved, allowing missing elements to be virtually rebuilt by symmetry. This permitted reconnection of the external foramina and blood vessel/nerve canals, and alignment of the central/internal structures. Expanding on Ørvig’s original interpretations, our virtual models show the vasculature of the skull bones, and indicate establishment of successive dermal over perichondral bone layers. The perichondral bone wrapping the endocranial cavity, in between the trigeminal and vagus nerve (and the inner ears), shows a “lace” pattern, which is otherwise unknown in vertebrates (presumably because of the lack of data). The significance of this trait is unclear but it is not an artifact of taphonomy or scanning.

  • 84.
    Dupret, Vincent
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Sanchez, Sophie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Goujet, Daniel
    Muséum National D'Histoire Naturelle, Paris, France.
    Tafforeau, Paul
    European Synchrotron Radiation Facility, Grenoble, France.
    Ahlberg, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Structures intra-crâniennes de Romundina stellina Ørvig 1975 (Vertebrata, Placodermi, Acanthothoraci) révélé par tomographie synchrotron en contraste de phase2012Konferensbidrag (Refereegranskat)
    Abstract [fr]

    Les placodermes acanthothoracides sont parmi les vertébrés gnathostomes les plus basaux phylogénetiquement et morphologiquement. Néanmoins, une bonne connaissance anatomie crânienne fait défaut, et à ce jour un seul genre (Brindabellaspis) a été décrit en détails. Nous présentons le modèle en 3 dimensions d’un crâne presque complet de Romundina stellina, un petit acanthothoracide du Dévonien inférieur de l’Archipel Arctique Canadien, décrit originellement par Ørvig (1975). Le spécimen a été microtomographié sur la ligne de faisceau ID 19 de l’ESRF de Grenoble (European Synchrotron Radiation Facility), en protocole de contraste de phase, avec un voxel isotrope de 7,45 micromètres.

    Malgré une cassure oblique, la plupart des structures peuvent être reconstruites par symétrie. Chaque nerf crânien peut être suivi entre la cavité encéphalique et les murs du neurocrâne composés d’os périchondral. Il en est de même pour les vaisseaux sanguins. La détermination des homologies en est donc facilitée, tout en assurant la non destruction du spécimen. Les hypothèses d’homologies formulées par Ørvig peuvent être traitées en toute confidence.

    La couche d’os périchondrale entourant la cavité encéphalique n’est pas homogène mais présente un aspect en dentelle entre les nerfs trijumeaux (V) et vague (X) ; il en est de même pour les oreilles internes, dont les canaux semi-circulaires ne sont pas ossifiés du tout latéralement et dorsalement. Cet aspect en dentelle n’est ni un artefact de fossilisation, de préservation ou de modélisation, et n’a jamais été retrouvé sur aucun autre vertébré (mais l’échantillonnage à cette résolution fait encore cruellement défaut).

    Les canalicules nerveux reliés aux neuromastes de la ligne latérale permettent de retracer leur origine à une branche du nerf facial (VII). Les deux oreilles internes ont été reconstruites avec précision et montrent une morphologie primitive.

    Le réseau vasculaire de l’os dermique a été reconstruit en détails, et permet de mettre en évidence les limites de plaques du toit crânien, invisibles autrement. Ce réseau vasculaire est relié à des veines drainant la bordure de la boîte crânienne ou à une branche de la veine jugulaire. La courbure de ces vaisseaux autour de l’oreille interne pourrait démarquer la limite entre la capsule otique et l’arc hyoïdien qui s’y attachait.

    D’un point de vue général, la morphologie de la boîte crânienne et de ses structures associées paraît moins primitive (et moins extrême) que celle de Brindabellaspis, mais rappelle au contraire plus les structures observées chez le placoderme arthrodire Kujdanowiaspis, plus dérivé.

    Ces différences mettent en lumière les premiers stades de l’évolution du crâne des placodermes, donc des gnathostomes. 

  • 85.
    Dupret, Vincent
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Sanchez, Sophie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi.
    Goujet, Daniel
    Muséum National D'Histoire Naturelle, Paris, France.
    Tafforeau, Paul
    European Synchrotron Radiation Facility, Grenoble, France.
    Ahlberg, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    The cranial anatomy of Romundina stellina Ørvig, 1975 (Vertebrata, Placodermi, Acanthothoraci) revealed by phase contrast synchrotron scanning2010Konferensbidrag (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    The acanthothoracid placoderms are among the most phylogenetically basal and morphologically primitive gnathostomes. However, their endocranial anatomy is not well understood; only one genus, Brindabellaspis, has been described in detail. Here we present a near-complete three-dimensional skull of Romundina stellina, a small Early Devonian acanthothoracid from the Canadian Arctic Archipelago, scanned at the European Synchrotron Radiation Facility, Grenoble, France, at a 7.45 µm resolution using propagation phase contrast. Despite some loss of material along an oblique crack, most of the internal structures are remarkably preserved. Each postethmoid cranial and craniospinal nerve can be followed between the well-preserved endocranial cavity and the walls of the perichondrally ossified neurocranium. The minute nerve canals that supplied the neuromast organs of the sensory line system are preserved and can in the postorbital area be traced directly to a branch of the facial nerve. Both inner ears are present. The vascular mesh of the dermal bones has been reconstructed in detail, rendering visible the dermal plate boundaries of the skull roof, and is shown to connect to larger internal veins that drain to the edge of the braincase or into the jugular vein canal. The curvature of the latter vessels parallels the outer surface of the inner ear and may demarcate the boundary between otic capsule proper and applied hyoid arch material. Overall, the braincase morphology appears less extreme (and less primitive?) than that of Brindabellaspis, in some respects more reminiscent of a primitive arthrodire such as Kujdanowiaspis. These differences may illuminate the earliest stages of placoderm cranial evolution.

  • 86.
    Dupret, Vincent
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Sanchez, Sophie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Goujet, Daniel
    Muséum National D'Histoire Naturelle, Paris, France.
    Tafforeau, Paul
    European Synchrotron Radiation Facility, Grenoble, France.
    Ahlberg, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    The origin of the jawed vertebrate face: new insights from a synchrotron scanned skull of the primituve placoderm Romundina2013Ingår i: Program and abstracts / [ed] Maxwell, E., Miller-Camp, J., Anemone, R.,, Los Angeles, U.S.A., 2013, s. 118-118Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Jawless cyclostomes and jawed gnathostomes show very different face patterns.Cyclostomes have a single median nasohypophysial duct, an anterior hypophysis and ashort telencephalon, while gnathostomes have a pair of nasal sacs opening externally, amore posterior separate hypophysis opening in the palate and a longer telencephalon.Embryonic processes differ as well. In cyclostomes, infraorbital premandibular crest cellsmigrate forwards either side of the nasohypophysial placode to form the upper lip; ingnathostomes they migrate between the hypophysial and nasal placodes to form thetrabecular-ethmoid region. Supraoptic neural crest remains posterior to thenasohypophysial duct in cyclostomes; it moves forward to create the nasal capsules ingnathostomes. Some fossil forms illustrate a sequenced transition between these twopatterns. The Silurian galeaspid (jawless stem gnathostome) Shuyu has a nasohypophysialduct, a short telencephalon, and an anteriorly oriented hypophysis, but the paired nasalsacs and hypophysis are separated by a rudimentary trabecula. A synchrotron scannedskull of the primitive Early Devonian placoderm (jawed stem gnathostome) Romundinashows a cranial cavity reminiscent of that of Shuyu (anteriorly directed hypophysis, veryshort telencephalon). The trabecular-ethmoid region is long and wide, extending anteriorto the small nasal capsule which is located just in front of the orbits. We interpret thesefeatures as uniquely primitive among gnathostomes. In size and position the trabecularethmoidregion of Romundina resembles the upper lip of cyclostomes and Shuyu,suggesting a cyclostome-like pattern of proliferation coupled with a gnathostome-likemigration path for the premandibular crest. The position of the nasal capsule suggests thatthe supraoptic crest had not migrated forwards. A new phylogenetic analysis suggeststhat the evolutionary sequence for the creation of the extant gnathostome face from acyclostome ancestral pattern involved 1) separation of the nasal and hypophysialplacodes (galeaspids: Shuyu), 2) loss of the nasohypophysial duct (basal placoderms:antiarchs, Brindabellaspis, Romundina), 3) shortening and narrowing of the trabecularethmoidregion, the nasal capsule becoming anterior (derived placoderms such asarthrodires); 4) lengthening of the telencephalon (crown gnathostomes). Galeaspid facialanatomy appears closer to gnathostomes than that of osteostracans, but it is unclearwhether osteostracans are primitive or autapomorphic in this respect.

  • 87.
    Dupret, Vincent
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Sanchez, Sophie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Goujet, Daniel
    Muséum National D'Histoire Naturelle, Paris, France.
    Tafforeau, Paul
    European Synchrotron Radiation Facility, Grenoble, France.
    Ahlberg, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    The Placoderm Romundina and the Origin of the Gnathostome Face2013Ingår i: The Making of a Vertebrate / [ed] Toyama, Y., Ito, A., Kobe, Japan, 2013, s. 110-111Konferensbidrag (Refereegranskat)
    Abstract [en]

    Facial anatomy differs fundamentally between extant jawless and jawed vertebrates (cyclostomes and gnathostomes). Cyclostomes have a median nasohypophysial duct; gnathostomes have separate nasal sacs opening externally, and a palatal hypophysis. Premandibular crest cells migrate forwards either side of the nasohypophysial placode to form the upper lip in cyclostomes, but between the hypophysial and nasal placodes to form the trabecular region in gnathostomes1,2. Supraoptic neural crest remains posterior to the nasohypophysial duct in cyclostomes but moves forward to create the nasal capsules of gnathostomes1,2. In cyclostomes the telencephalon is much shorter than in gnathostomes and the hypophysis is relatively anterior. The galeaspid Shuyu, a 430 million year old jawless vertebrate, partly bridges the gap between these facial architectures3. Shuyu has a nasohypophysial duct, short telencephalon, and anteriorly oriented hypophysis, but the nasal sacs and hypophysis are separated by a rudimentary trabecula.

                          Here we present the placoderm Romundina, a 415 million year old jawed vertebrate that represents a further transitional step. Its cranial cavity is similar to that of Shuyu, with an anteriorly directed hypophysis and very short telencephalon. The trabecular region is exceptionally long and wide whereas the nasal capsule (demarcated by a fissure) is small and located far behind the tip of the snout. The upper jaw articulates with the side of the trabecular region to its anterior end, without contacting the nasal capsule. We interpret these features as uniquely primitive among gnathostomes. The premandibular crest of Romundina formed a trabecular region, but like the upper lip of cyclostomes and Shuyu it was a large structure reaching the tip of the snout. The position of the nasal capsule suggests that the supraoptic crest had not migrated forwards. We suggest that during the creation of the gnathostome face, separation of the nasal and hypophysial placodes was followed by loss of the nasohypophysial duct, with lengthening of the telencephalon and migration of the nasal capsules to the snout tip as the final step.

  • 88.
    Dupret, Vincent
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Sanchez, Sophie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Goujet, Daniel
    Muséum National D'Histoire Naturelle, Paris, France.
    Tafforeau, Paul
    European Synchrotron Radiation Facility, Grenoble, France.
    Ahlberg, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    The Placoderm Romundina and the Origin of the Gnathostome Face2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    Facial anatomy differs fundamentally between extant jawless and jawed vertebrates (cyclostomes and gnathostomes). Cyclostomes have a median nasohypophysial duct; gnathostomes have separate nasal sacs opening externally, and a palatal hypophysis. Premandibular crest cells migrate forwards either side of the nasohypophysial placode to form the upper lip in cyclostomes, but between the hypophysial and nasal placodes to form the trabecular region in gnathostomes1,2. Supraoptic neural crest remains posterior to the nasohypophysial duct in cyclostomes but moves forward to create the nasal capsules of gnathostomes1,2. In cyclostomes the telencephalon is much shorter than in gnathostomes and the hypophysis is relatively anterior. The galeaspid Shuyu, a 430 million year old jawless vertebrate, partly bridges the gap between these facial architectures3. Shuyu has a nasohypophysial duct, short telencephalon, and anteriorly oriented hypophysis, but the nasal sacs and hypophysis are separated by a rudimentary trabecul. Here we present the placoderm Romundina, a 415 million year old jawed vertebrate that represents a further transitional step. Its cranial cavity is similar to that of Shuyu, with an anteriorly directed hypophysis and very short telencephalon. The trabecular region is exceptionally long and wide whereas the nasal capsule (demarcated by a fissure) is small and located far behind the tip of the snout. The upper jaw articulates with the side of the trabecular region to its anterior end, without contacting the nasal capsule. We interpret these features as uniquely primitive among gnathostomes. The premandibular crest of Romundina formed a trabecular region, but like the upper lip of cyclostomes and Shuyu it was a large structure reaching the tip of the snout. The position of the nasal capsule suggests that the supraoptic crest had not migrated forwards. We suggest that during the creation of the gnathostome face, separation of the nasal and hypophysial placodes was followed by loss of the nasohypophysial duct, with lengthening of the telencephalon and migration of the nasal capsules to the snout tip as the final step.

     

    1. Kuratani, S. et al. Phil. Trans. R. Soc. Lond. B 356, 1615-1632 (2001).

    2. Kuratani, S. et al. Nature (in press, doi:10.1038/nature11794).

    3. Gai, Z. et al. Nature 476, 324-327 (2011).

  • 89.
    Dupret, Vincent
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Sanchez, Sophie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Goujet, Daniel
    Tafforeau, Paul
    Ahlberg, Per Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    A primitive placoderm sheds light on the origin of the jawed vertebrate face2014Ingår i: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 507, nr 7493, s. 500-503Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Extant vertebrates form two clades, the jawless Cyclostomata (lampreys and hagfishes) and the jawed Gnathostomata (all other vertebrates), with contrasting facial architectures(1,2). These arise during development from just a few key differences in the growth patterns of the cranial primordia: notably, the nasal sacs and hypophysis originate from a single placode in cyclostomes but from separate placodes in gnathostomes, and infraoptic ectomesenchyme migrates forward either side of the single placode in cyclostomes but between the placodes in gnathostomes(3-8). Fossil stem gnathostomes preserve cranial anatomies rich in landmarks that provide proxies for developmental processes and allow the transition from jawless to jawed vertebrates to be broken down into evolutionary steps(7,9-12). Here we use propagation phase contrast synchrotron microtomography to image the cranial anatomy of the primitive placoderm (jawed stem gnathostome) Romundina(13), and show that itcombines jawed vertebrate architecture with cranial and cerebral proportions resembling those of cyclostomes and the galeaspid (jawless stem gnathostome) Shuyu(11). This combination seems to be primitive for jawed vertebrates, and suggests a decoupling between ectomesenchymal growth trajectory, ectomesenchymal proliferation, and cerebral shape change during the origin of gnathostomes.

  • 90.
    Dupret, Vincent
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Sanchez, Sophie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Goujet, Daniel
    Muséum National D'Histoire Naturelle, Paris, France.
    Tafforeau, Paul
    European Synchrotron Radiation Facility, Grenoble, France.
    Ahlberg, Per Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Bone vascularization and growth in placoderms (Vertebrata): The example of the premedian plate of Romundina stellina Ørvig, 19752010Ingår i: Comptes rendus. Palevol, ISSN 1631-0683, E-ISSN 1777-571X, Vol. 9, nr 6-7, s. 369-375Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Placodermi (armored jawed fishes), which appeared during the Lower Silurian and disappeared without leading any descendants at the end of the Famennian (Latest Devonian), have the highest diversity of known Devonian vertebrate groups. As phylogenetically basal gnathostomes (jawed vertebrates), they are potentially informative about primitive jawed vertebrate anatomy and origins. Until recently, the study of their internal or histological structures has required destructive methods such as sectioning or serial grinding. Recent advances in tomography and imaging technologies, especially through the increasing use of synchrotron phase contrast imaging for the study of fossils, allow us to reveal the inner structures of the fossil nondestructively and with unprecedented three-dimensional level of detail. Here, we present for the first time the prerostral anatomy of the small acanthothoracid Romundina stellina, one of the earliest and most basal placoderms. Phase contrast imaging allows us to reconstruct the vascularization and nerve canals of the premedian plate and adjacent parts of the skeleton three-dimensionally in great detail, providing important clues to the growth modes and biology of the animal.

  • 91.
    Dupret, Vincent
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi. Chinese Acad Sci, Inst Vertebrate Paleontol & Paleoanthropol, Key Lab Vertebrate Evolut & Human Origins, Xizhimenwai Dajie 142, Beijing 100044, Peoples R China.;Australian Natl Univ, Res Sch Phys & Engn, Dept Appl Math, Mills Rd, Acton, ACT 2601, Australia..