uu.seUppsala universitets publikationer
Ändra sökning
Avgränsa sökresultatet
1 - 48 av 48
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.
  • 1.
    Ahlberg, Per. E.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för fysiologi och utvecklingsbiologi, Evolutionär organismbiologi.
    Blom, H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Clack, J. A.
    The axial skeleton of the Devonian Tetrapod Ichthyostega2003Ingår i: The Gross Symposium 2. Advances in Palaeoichthyology. Riga, Latvia., 2003, s. 7-8Konferensbidrag (Refereegranskat)
  • 2.
    Ahlberg, Per E.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för fysiologi och utvecklingsbiologi, Evolutionär organismbiologi.
    Clack, J. A.
    Blom, H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    The axial skeleton of the Devonian Tetrapod Ichthyostega.2003Ingår i: 51st symposium of vertebrate palaeontology and comparative anatomy, Oxford University Museum of Natural History, Oxford, 2003, s. 3-Konferensbidrag (Refereegranskat)
  • 3.
    Andersson, Ki
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleontologigruppen.
    Aspects of locomotor evolution in the Carnivora (Mammalia)2003Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    In this thesis, the shape of the distal humerus trochlea is analysed using landmark-based morphometrics and multivariate methods, with the aim of exploring locomotor evolution in carnivorans. Elbow joint morphology is used together with body size and craniodental morphology to characterize past and present carnivorans. Evolutionary implications are studied at the ordinal, familial, and species levels, testing specific hypotheses about scaling, morphological constraints, evolutionary trajectories, and potential for social pack-hunting behaviour. The circumference of the distal humerus trochlea is found to be highly correlated with body mass, and appears to scale similarly throughout the order Carnivora. A general predictive model for carnivoran bodymass is presented (a=0.601; b= 2.552; r2=0.952, SEE=0.136, p<0001, n=92), which removes the need for the investigator to actively choose between the diverging estimates that different predictors and their equations often produce. At the elbow joint, manual manipulation and locomotion appear to be conflicting functions, thus suggesting mutually exclusive lifestyles involving either forelimb grappling or pursuit. At large body sizes, carnivorans are distributed over a strongly dichotomised pattern (grappling or locomotion), a pattern coinciding with the postulated threshold in predator-prey size ratio at 21.5-25 kg. This pattern is compared to that of two carnivoran faunas from the Tertiary. In the Oligocene (33.7-23.8 Myr BP), the overall pattern is remarkably similar to that observed for extant Carnivora. In the Miocene (23.8-11.2 Myr BP) carnivores show a similarly dichotomised pattern as the Oligocene and Recent, although the whole pattern is shifted towards larger body sizes. This difference is suggested to be a reflection of the extraordinary species richness of browsing ungulates in the early Miocene of North America. Such an increase in prey spectrum would create a unique situation, in which large carnivores need not commit to a cursorial habitus in order to fill their nutritional requirements. Finally, the elbow joints and craniodental morphology (14 measurements) of fossil canids were examined with the aim of assessing the potential for pack-hunting in fossil canids. It is clear that small and large members of the Recent Caninae share similar craniodental morphologies. However, this pattern is not present in Borophaginae and Hesperocyoninae. In the latter, large representatives are characterized by being short-faced, with reduced anterior premolars and enlarged posterior premolars, thus approaching a “pantherine-like” craniodental configuration. These traits are interpreted as an adaptation for killing prey with canine bites. It is similarly determined that, unlike recent Caninae, all analyzed species of borophagines and hesperocyonines have retained the ability to supinate their forearms. It is therefore likely that manual manipulation was part of their hunting behaviour, thus removing an essential part of the argument for social pack-hunting in these forms, as the benefits of such a strategy become less obvious.

    Delarbeten
    1. Predicting carnivoran body mass from a weight bearing joint
    Öppna denna publikation i ny flik eller fönster >>Predicting carnivoran body mass from a weight bearing joint
    2004 (Engelska)Ingår i: Journal of Zoology, ISSN 0952-8369, E-ISSN 1469-7998, Vol. 262, nr 2, s. 161-172Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Predictors used to calculate the body mass of extinct carnivorans often scale differently between different taxa, thus yielding body mass estimates that diverge considerably depending on which predictive equation is used. This requires the investigator to choose the ones most suitable, a procedure that is best avoided if possible. The carnivoran elbow joint is here explored with the aim of producing a single general body mass predictor that can be used over a broad range of terrestrial and arboreal carnivorans. The circumference of the distal humerus trochlea is found to be highly correlated with body mass, and trochlea circumference seems to scale similarly throughout the order Carnivora. This scaling is not as theoretically predicted by elastic similarity and is slightly higher than that predicted by geometric similarity, indicating a slight positive allometry for the latter. Some degree of differential scaling between carnivoran families and between animals of large and small size cannot be ruled out, but this result is inconclusive. A predictive model that allows mass estimations for a broad range of carnivorans is presented (a=0.601; b=2.552; r2=0.952, SEE=0.136, P<0001, n=92). Body mass for eight extinct carnivoran species are calculated and these generally conform to earlier mass predictions.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-90745 (URN)10.1017/S0952836903004564 (DOI)
    Tillgänglig från: 2003-09-01 Skapad: 2003-09-01 Senast uppdaterad: 2017-12-14Bibliografiskt granskad
    2. Elbow-joint morphology as a guide to forearm function and foraging behaviour in mammalian carnivores
    Öppna denna publikation i ny flik eller fönster >>Elbow-joint morphology as a guide to forearm function and foraging behaviour in mammalian carnivores
    2004 (Engelska)Ingår i: Zoological Journal of the Linnean Society, ISSN 0024-4082, E-ISSN 1096-3642, Vol. 142, nr 1, s. 91-104Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Among the hunting strategies employed by members of the order Carnivora (Mammalia), two, stalk and ambush and sustained pursuit, are particularly prevalent among larger species of the order. It has been difficult to identify morphological traits that support this distinction and ecological observations have shown that most carnivorans adopt a continuum of strategies, depending on available habitat and prey. In this paper, the shape of the distal humerus articulation is analysed, with the aim of exploring the use of the forelimb in prey procurement, and as a guide to such behaviour among fossil carnivorans. The results suggest that manual manipulation and locomotion are conflicting functions. Elbow-joint morphology supports a division between grapplers (i.e. ambushers) and nongrapplers (i.e. pursuers). Joints of the former are characterized by being relatively wide and the latter, by being relatively narrow and box-like with pronounced stabilizing features. At intermediate and large body sizes, carnivorans show a pattern suggesting mutually exclusive feeding strategies that involve either grappling with prey or sustained pursuit. The former allows for large body sizes, such as pantherine felids and ursids; the latter includes species of only moderate size, such as hyenids and canids. Elbow-joint morphology is closely linked to phylogeny, but the morphology of the cheetah converges with that of nongrapplers, showing that strong selective forces may override the phylogenetic component. Two taxa of giant mustelids from the Miocene were analysed to test whether this sort of analysis is applicable to carnivorans of the past. The African Late Miocene species Ekorus ekakeran has a joint morphology comparable to that of modern-day nongrapplers. Two joint morphologies were found in the North American Late Oligocene-Early Miocene Megalictis ferox. The first morphology is comparable to that of modern pantherine cats and the second forms  an  intermediate  between  grapplers  and  nongrapplers  that  is  not  present  in  the  modern  carnivoran  fauna.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-90746 (URN)10.1111/j.1096-3642.2004.00129.x (DOI)
    Tillgänglig från: 2003-09-01 Skapad: 2003-09-01 Senast uppdaterad: 2017-12-14Bibliografiskt granskad
    3. The evolution of cursorial carnivores in the Tertiary: implications of elbow-joint morphology
    Öppna denna publikation i ny flik eller fönster >>The evolution of cursorial carnivores in the Tertiary: implications of elbow-joint morphology
    2003 Ingår i: Biology letters, Vol. Published online 6 AugustArtikel i tidskrift (Refereegranskat) Published
    Identifikatorer
    urn:nbn:se:uu:diva-90747 (URN)
    Tillgänglig från: 2003-09-01 Skapad: 2003-09-01Bibliografiskt granskad
    4. Potential for pack-hunting in Tertiary canids (Canidae, Carnivora)
    Öppna denna publikation i ny flik eller fönster >>Potential for pack-hunting in Tertiary canids (Canidae, Carnivora)
    Manuskript (Övrigt vetenskapligt)
    Identifikatorer
    urn:nbn:se:uu:diva-90748 (URN)
    Tillgänglig från: 2003-09-01 Skapad: 2003-09-01 Senast uppdaterad: 2010-01-13Bibliografiskt granskad
  • 4.
    Andersson, Ki
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Elbow-joint morphology as a guide to forearm function and foraging behaviour in mammalian carnivores2004Ingår i: Zoological Journal of the Linnean Society, ISSN 0024-4082, E-ISSN 1096-3642, Vol. 142, nr 1, s. 91-104Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Among the hunting strategies employed by members of the order Carnivora (Mammalia), two, stalk and ambush and sustained pursuit, are particularly prevalent among larger species of the order. It has been difficult to identify morphological traits that support this distinction and ecological observations have shown that most carnivorans adopt a continuum of strategies, depending on available habitat and prey. In this paper, the shape of the distal humerus articulation is analysed, with the aim of exploring the use of the forelimb in prey procurement, and as a guide to such behaviour among fossil carnivorans. The results suggest that manual manipulation and locomotion are conflicting functions. Elbow-joint morphology supports a division between grapplers (i.e. ambushers) and nongrapplers (i.e. pursuers). Joints of the former are characterized by being relatively wide and the latter, by being relatively narrow and box-like with pronounced stabilizing features. At intermediate and large body sizes, carnivorans show a pattern suggesting mutually exclusive feeding strategies that involve either grappling with prey or sustained pursuit. The former allows for large body sizes, such as pantherine felids and ursids; the latter includes species of only moderate size, such as hyenids and canids. Elbow-joint morphology is closely linked to phylogeny, but the morphology of the cheetah converges with that of nongrapplers, showing that strong selective forces may override the phylogenetic component. Two taxa of giant mustelids from the Miocene were analysed to test whether this sort of analysis is applicable to carnivorans of the past. The African Late Miocene species Ekorus ekakeran has a joint morphology comparable to that of modern-day nongrapplers. Two joint morphologies were found in the North American Late Oligocene-Early Miocene Megalictis ferox. The first morphology is comparable to that of modern pantherine cats and the second forms  an  intermediate  between  grapplers  and  nongrapplers  that  is  not  present  in  the  modern  carnivoran  fauna.

  • 5.
    Andersson, Ki
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleontologigruppen.
    Potential for pack-hunting in Tertiary canids (Canidae, Carnivora)Manuskript (Övrigt vetenskapligt)
  • 6.
    Andersson, Ki
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Predicting carnivoran body mass from a weight bearing joint2004Ingår i: Journal of Zoology, ISSN 0952-8369, E-ISSN 1469-7998, Vol. 262, nr 2, s. 161-172Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Predictors used to calculate the body mass of extinct carnivorans often scale differently between different taxa, thus yielding body mass estimates that diverge considerably depending on which predictive equation is used. This requires the investigator to choose the ones most suitable, a procedure that is best avoided if possible. The carnivoran elbow joint is here explored with the aim of producing a single general body mass predictor that can be used over a broad range of terrestrial and arboreal carnivorans. The circumference of the distal humerus trochlea is found to be highly correlated with body mass, and trochlea circumference seems to scale similarly throughout the order Carnivora. This scaling is not as theoretically predicted by elastic similarity and is slightly higher than that predicted by geometric similarity, indicating a slight positive allometry for the latter. Some degree of differential scaling between carnivoran families and between animals of large and small size cannot be ruled out, but this result is inconclusive. A predictive model that allows mass estimations for a broad range of carnivorans is presented (a=0.601; b=2.552; r2=0.952, SEE=0.136, P<0001, n=92). Body mass for eight extinct carnivoran species are calculated and these generally conform to earlier mass predictions.

  • 7.
    Andersson, Ki
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleontologigruppen.
    Werdelin, Lars
    The evolution of cursorial carnivores in the Tertiary: implications of elbow-joint morphology2003Ingår i: Biology letters, Vol. Published online 6 AugustArtikel i tidskrift (Refereegranskat)
  • 8.
    Blom, H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Book review: Encyclopedia of Paleoherpetology, Part 3B: Stereospondyli. Schoch R. R. & Milner A. R.2002Ingår i: The Palaeontological Association Newsletter, Vol. 49, s. 108-110Artikel, recension (Övrig (populärvetenskap, debatt, mm))
  • 9.
    Blom, H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    How many four-legged fishes? The diversity and distribution of Ichthyostega.2001Ingår i: Palaeontological Association 45th Annual Meeting. Geological Musuem, University of Copenhagen., 2001, s. 4-Konferensbidrag (Refereegranskat)
  • 10.
    Blom, H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    IGCP project 406:"Circum-Arctic Lower-Middle Palaeozoic Vertebrate Palaeontology and Biostratigraphy"- Preliminary results from the Greenland Working Group.1997Ingår i: Lundadagarna i Historisk Geologi och Paleontologi. Lund University, Lund., 1997, s. 4-Konferensbidrag (Refereegranskat)
  • 11.
    Blom, H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    IGCP: Workshop1996Konferensbidrag (Refereegranskat)
  • 12.
    Blom, H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Paedomorphism in the Late Devonian tetrapod Ichthyostega from East Greenland.2002Ingår i: Palaeontological Association 46th Annual Meeting, Cambridge, 2002, s. 84-85Konferensbidrag (Refereegranskat)
  • 13.
    Blom, H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Silurian vertebrate remains from the Franklinian Basin, North Greenland1997Konferensbidrag (Refereegranskat)
  • 14.
    Blom, H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Silurian vertebrate remains from the Franklinian Basin, North Greenland1996Ingår i: The James Hall Symposium: Second international symposium on the Silurian System., 1996, s. 33-Konferensbidrag (Refereegranskat)
  • 15.
    Blom, H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Tetrapod diversity in the Late Devonian basin of East Greenland2002Ingår i: Geological Society of Australia, 2002, s. 19-20Konferensbidrag (Refereegranskat)
  • 16.
    Blom, H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    The Dermal skeleton of Birkeniid anaspis: a clue to their evolution?2000Ingår i: 9th International Symposium, Early Vertebrates/Lower Vertebrates. Flagstaff, Arizona., 2000, s. 2-Konferensbidrag (Refereegranskat)
  • 17.
    Blom, H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Vertebrate remanis from the Chester Bjerg Formation (Late Silurian?), Hall Land, North Greenland.1995Ingår i: Lundadagarna i Historisk Geologi och Palaeontologi. Lund University, Lund., 1995, s. 5-Konferensbidrag (Refereegranskat)
  • 18.
    Blom, H.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Clack, J. A.
    Ahlberg, Per E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för fysiologi och utvecklingsbiologi, Evolutionär organismbiologi.
    The forelimb of the Devonian tetrapod Ichthyostega.2003Ingår i: 51st symposium of vertebrate palaeontology and comparative anatomy, Oxford University Museum of Natural History, Oxford., 2003, s. 6-Konferensbidrag (Refereegranskat)
  • 19.
    Blom, H.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Clack, J. A.
    Ahlberg, Per E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för fysiologi och utvecklingsbiologi, Evolutionär organismbiologi.
    Friedman, M.
    Devonian vertebrates from East Greenland: a review of faunal composition and distribution2003Ingår i: The Gross Symposium 2. Advances in Palaeoichthyology. Riga, Latvia., 2003, s. 13-Konferensbidrag (Refereegranskat)
  • 20.
    Blom, H.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Goujet, D.
    Thelodont scales from the Lower Devonian Red Bay Group, Spitsbergen.2000Ingår i: 9th International Symposium, Early Vertebrates/Lower Vertebrates. Flagstaff, Arizona., 2000, s. 2-Konferensbidrag (Refereegranskat)
  • 21.
    Blom, H.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Märss, T.
    Miller, G. C.
    Affinity, classification and distribution of Silurian and lowermost Devonian birkeniid anaspid scales in the Circum-Arctic, Baltoscandia and Britain.1999Ingår i: Lower-Middle Palaeozoic Events Across the Circum-Arctic., 1999, s. 12-13Konferensbidrag (Refereegranskat)
  • 22.
    Blom, H.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Märss, T.
    Miller, G. C.
    Silurian birkeniid anaspids from Britain.1999Ingår i: Palaeontological Association 43rd Annual Meeting. Manchester., 1999Konferensbidrag (Refereegranskat)
  • 23.
    Blom, Henning
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Vertebrate remains from the Chester Bjerg Formation (Late Silurian?), Hall Land, North Greenland.1995Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
  • 24.
    Blom, Henning
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Vertebrate remains from the Upper Silurian-Lower Devonian of North Greenland1998Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
  • 25. Clack, J. A.
    et al.
    Ahlberg, Per E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för fysiologi och utvecklingsbiologi, Evolutionär organismbiologi.
    Blom, H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    A new genus of tetrapod from the Devonian of East Greenland.2004Ingår i: Paleaontological Association Annual Meeting Lille, 2004, s. 8-9Konferensbidrag (Refereegranskat)
  • 26. Clack, J. A.
    et al.
    Ahlberg, Per E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för fysiologi och utvecklingsbiologi, Evolutionär organismbiologi.
    Blom, H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    A new tetrapod taxon from the Devonian of East Greenland2004Ingår i: 52nd Symposium of Vertebrate Paleontology and Comparative Anatomy, 2004, s. 10-Konferensbidrag (Refereegranskat)
  • 27. Clack, J. A.
    et al.
    Ahlberg, Per E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för fysiologi och utvecklingsbiologi, Evolutionär organismbiologi.
    Blom, H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Ichthyostega: the makeover.2003Ingår i: Palaeontological Association 47th Annual Meeting, 2003Konferensbidrag (Refereegranskat)
  • 28. Clack, J. A.
    et al.
    Blom, H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Ahlberg, Per E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för fysiologi och utvecklingsbiologi, Evolutionär organismbiologi.
    New insights into the forelimb skeleton of Ichthyostega2003Ingår i: The Gross Symposium 2. Advances in Palaeoichthyology. Riga, Latvia, 2003, s. 17-Konferensbidrag (Refereegranskat)
  • 29. Clement, G.
    et al.
    Blom, H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    A Famennian vertebrate assemblage from Belgium: How different from East Greenland?2004Ingår i: 52nd Symposium of Vertebrate Palaeontology and Comparative Anatomy, 2004, s. 10-Konferensbidrag (Refereegranskat)
  • 30.
    Egerquist, Eva
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleontologigruppen.
    New brachiopods from the Lower-Middle Ordovician (Billingen-Volkhov stages) of the East Baltic2003Ingår i: Acta Palaeontologica Polonica, ISSN 0567-7920, Vol. 48, nr 1, s. 31-38Artikel i tidskrift (Refereegranskat)
  • 31.
    Egerquist, Eva
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Ordovician (Billingen and Volkhov stages) Brachiopod Faunas of the East Baltic2004Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Lower-Middle Ordovician (Arenig) successions in the East Baltic have been investigated for more than one hundred and fifty years. Nevertheless detailed sampling still yields new species and better knowledge of the environment in which these organisms lived. The successions are well suited for bed by bed sampling because of the lack of tectonic disturbance and because the sequences are well documented.

    This study analyses collections of Billingen-Volkhov age mainly from the St. Petersburg region, but also from Estonia. A great deal of the material was obtained from the marly to clayey, soft sediment that intercalates the compact packstones and wackestones in the succession. Twenty-nine of these clay horizons were used for diversity estimates on the fauna through the succession. The most thoroughly investigated groups for this investigation were rhynchonelliformean brachiopods, conodonts and ostracodes. The results indicate that variances in diversity and abundance levels for these groups were not correlated, either to each other or to the small-scale sea level fluctuations that have been suggested for the region. However, diversity dynamics of brachiopods and ostracodes confirm the large-scale upward shallowing of the basin into the Upper Volkhov. Comparison with fossils from the limestones did not reveal any differences in faunal composition between the two preservation modes.

    The detailed sampling, coupled with sampling of the recently described mud mounds that occur in several outcrops, yielded large numbers of specimens. This enabled revision of earlier poorly known rhynchonelliformean genera such as Ujukella Andreev, as well as better known genera such as Porambonites Pander. In total the examined faunas include 31 genera assigned to 53 species of rhynchonelliformean brachiopods. Of these Leoniorthis and Eoporambonites are defined as new genera, and the following new species are described: Neumania paucicostata, Ranorthis rotunda, Orthidium gambolovensis, Orthidium lavensis, Skenidioides minutus, Tetralobula peregrina, Idiostrophia prima and Idiostrophia tenuicostata.

    Delarbeten
    1. Spatial variations in faunal composition, Middle Ordovician, Volkhov Stage, East Baltic
    Öppna denna publikation i ny flik eller fönster >>Spatial variations in faunal composition, Middle Ordovician, Volkhov Stage, East Baltic
    2001 (Engelska)Ingår i: GFF, ISSN 1103-5897, Vol. 123, nr 2, s. 65-72Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Small-scale lateral variations in faunal skeletal composition and taphonomic characters were analysed at five successive levels containing soft clay layers in the Middle Ordovician (Middle and Upper Volkhov Stage) of the Putilovo quarry in the East Baltic region of Russia. At the studied levels, the relative abundance of faunal elements (mainly brachiopods, ostracodes, and conodonts) generally shows high spatial homogeneity. This even faunal composition is probably due to major time averaging, leading to equalisation of the composition of the assemblages within the units. Differences in taphonomic characters between the sub-samples are also mostly minor; variation in the degree of shell breakage is most probably the result of intensive bioturbation rather than of hydraulic transportation. Changes in the relative abundance of taxa either spatially or temporally, can be considered reliable only if they exceed the small-scale spatial heterogeneity of faunal composition as well as the errors related to the sample size and laboratory treatment of the samples. The relative error in the relative abundance of conodont taxa connected with the laboratory treatment is rather high (approximately 12%).

    Nyckelord
    Conodonts, brachiopods, ostracodes, diversity, taphonomy, Ordovician, Russia
    Nationell ämneskategori
    Geovetenskap och miljövetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-91909 (URN)
    Tillgänglig från: 2004-05-14 Skapad: 2004-05-14 Senast uppdaterad: 2013-04-29Bibliografiskt granskad
    2. Faunal composition and dynamics in unconsolidated sediments: a case study from the Middle Ordovician of the East Baltic
    Öppna denna publikation i ny flik eller fönster >>Faunal composition and dynamics in unconsolidated sediments: a case study from the Middle Ordovician of the East Baltic
    Visa övriga...
    2003 (Engelska)Ingår i: Geological Magazine, ISSN 0016-7568, Vol. 140, nr 1, s. 31-44Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The Volkhov Regional Stage (Middle Ordovician) in the East Baltic preserves diverse fossil assemblages dominated by epibenthic suspension feeders. Brachiopods, ostracodes, conodonts, echinoderms and bryozoans are the main components of palaeocommunities obtained from clay horizons in the Putilovo section (St Petersburg region, Russia), whereas trilobites, machaeridians, hyolithids, graptolites, benthic foraminifers and gastropods are rare or occur sporadically. Brachiopod bioclasts volumetrically dominate the debris of the studied sediments. Quantitative faunal data are used to assess species diversity patterns, as expressed by the species richness (total number of species in the standardized sample size) and by the evenness or equitability of the community. The numerical abundance of particular taxa in each standardized sample was used to evaluate the density of the fauna. The communities in the Volkhov Stage in Putilovo Quarry reveal a remarkable stability throughout the studied interval and are characterized by high density (1000–6000 specimens per 100 g), relatively moderate species richness (10–15 species) and a moderately variable equitability (0.3–0.7) for the dominant fossil groups (conodonts, ostracodes and brachiopods). Ostracodes significantly increase in numbers within the upper part of the section. This confirms a shallowing of the basin during the late Volkhov interval. Small-scale variability of the diversity estimates does not correlate with the small-scale sea-level changes reconstructed for this part of the basin. It may be connected with error in diversity measurement, or the result of undetected environmental parameters. Variability estimates for different faunal groups are poorly correlated because particular groups have different environmental tolerances.

    Nyckelord
    diversity, Conodonta, Brachiopoda, Ostracoda, Ordovician, Baltoscandia
    Nationell ämneskategori
    Geovetenskap och miljövetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-91910 (URN)10.1017/S001675680200701X (DOI)
    Tillgänglig från: 2004-05-14 Skapad: 2004-05-14 Senast uppdaterad: 2013-04-29Bibliografiskt granskad
    3. Conodonts and brachiopods from the Middle Ordovician microbial mud mound at Putilovo Quarry, north-western Russia
    Öppna denna publikation i ny flik eller fönster >>Conodonts and brachiopods from the Middle Ordovician microbial mud mound at Putilovo Quarry, north-western Russia
    2003 Ingår i: Bulletin of the Geological Society of Denmark, ISSN 0011-6297, Vol. 50, nr 1, s. 63-74Artikel i tidskrift (Refereegranskat) Published
    Identifikatorer
    urn:nbn:se:uu:diva-91911 (URN)
    Tillgänglig från: 2004-05-14 Skapad: 2004-05-14Bibliografiskt granskad
    4. New brachiopods from the Lower-Middle Ordovician (Billingen-Volkhov stages) of the East Baltic
    Öppna denna publikation i ny flik eller fönster >>New brachiopods from the Lower-Middle Ordovician (Billingen-Volkhov stages) of the East Baltic
    2003 Ingår i: Acta Palaeontologica Polonica, ISSN 0567-7920, Vol. 48, nr 1, s. 31-38Artikel i tidskrift (Refereegranskat) Published
    Identifikatorer
    urn:nbn:se:uu:diva-91912 (URN)
    Tillgänglig från: 2004-05-14 Skapad: 2004-05-14Bibliografiskt granskad
    5. Revision of the plectambonitoid brachiopod Ujukella Andreev and related genera
    Öppna denna publikation i ny flik eller fönster >>Revision of the plectambonitoid brachiopod Ujukella Andreev and related genera
    1999 Ingår i: GFF, ISSN 1103-5897, Vol. 121, nr 4, s. 325-332Artikel i tidskrift (Refereegranskat) Published
    Identifikatorer
    urn:nbn:se:uu:diva-91913 (URN)
    Tillgänglig från: 2004-05-14 Skapad: 2004-05-14Bibliografiskt granskad
    6. Ordovician (Arenig-Caradoc) Syntrophiidine brachiopods from the East Baltic Region
    Öppna denna publikation i ny flik eller fönster >>Ordovician (Arenig-Caradoc) Syntrophiidine brachiopods from the East Baltic Region
    2005 (Engelska)Ingår i: Palaeontology, ISSN 0031-0239, E-ISSN 1475-4983, Vol. 48, nr 4, s. 739-761Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Syntrophiidine brachiopods are a rare and poorly known component of Ordovician Baltoscandian faunas. They appear in the East Baltic in the Billingenian (lower Arenig) as part of the earliest known benthic assemblages dominated by elements of the Palaeozoic Evolutionary Fauna. These faunal assemblages usually include bryozoans, ostracodes, and the earliest known porambonitoids, strophomenides and endopunctate orthides, such as Idiostrophia and Orthidium, which later became characteristic of the Whiterockian brachiopod assemblages in Laurentia, but by that time had disappeared from Baltica. The superfamily Syntrophioidea reappears in Baltoscandia in the mid Caradoc. In contrast, Porambonitoidea remained the integral part of the Baltoscandian brachiopod associations through the Ordovician. Porambonites, herein redefined on the basis of restudy of the type species P. intermedius, includes only smooth porambonitoids; taxa with the distinctive ornament of radiating rows of pits first appeared in the group in the mid Arenig. The taxa Eoporambonites gen. nov., Tetralobula peregrina sp. nov., Idiostrophia prima sp. nov. and Idiostrophia tenuicostata sp. nov. are erected.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-91914 (URN)10.1111/j.1475-4983.2005.00487.x (DOI)
    Tillgänglig från: 2004-05-14 Skapad: 2004-05-14 Senast uppdaterad: 2017-12-14Bibliografiskt granskad
    7. Early-Middle Ordovician (Billingen-Volkhov stages) Orthide and Protorthide brachiopods from the East Baltic
    Öppna denna publikation i ny flik eller fönster >>Early-Middle Ordovician (Billingen-Volkhov stages) Orthide and Protorthide brachiopods from the East Baltic
    2006 (Engelska)Ingår i: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 128, nr 4, s. 339-348Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Three new orthide species: Orthidium lavensis, Orthidium gambolovensis and Ranorthis rotunda, and one new protorthide species: Skenidioides minutus, are described from the Early-Middle Ordovician (Billingen-Volkhov stages) of Estonia and north-western Russia. This is the first record of Orthidium from Baltica, whereas Skenidioides was known previously only from the Keila and Oandu stages in Estonia.

    Nyckelord
    Brachiopoda, Estonia, New species, Ordovician, Orthida, Orthidium, Protorthida, Ranorthis, Russia, Skenidioides
    Nationell ämneskategori
    Geovetenskap och miljövetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-91915 (URN)000243752400007 ()
    Tillgänglig från: 2004-05-14 Skapad: 2004-05-14 Senast uppdaterad: 2017-12-14Bibliografiskt granskad
  • 32.
    Egerquist, Eva
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleontologigruppen.
    Revision of the plectambonitoid brachiopod Ujukella Andreev and related genera1999Ingår i: GFF, ISSN 1103-5897, Vol. 121, nr 4, s. 325-332Artikel i tidskrift (Refereegranskat)
  • 33.
    Egerquist, Eva
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Holmer, Lars E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi.
    Early-Middle Ordovician (Billingen-Volkhov stages) Orthide and Protorthide brachiopods from the East Baltic2006Ingår i: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 128, nr 4, s. 339-348Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Three new orthide species: Orthidium lavensis, Orthidium gambolovensis and Ranorthis rotunda, and one new protorthide species: Skenidioides minutus, are described from the Early-Middle Ordovician (Billingen-Volkhov stages) of Estonia and north-western Russia. This is the first record of Orthidium from Baltica, whereas Skenidioides was known previously only from the Keila and Oandu stages in Estonia.

  • 34. Eriksson, Mats E.
    et al.
    Frisk, Åsa M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi.
    Polychaetes from the Kukruse (early Late Ordovician) post-impact event strata of Tvären, southeastern Sweden2009Konferensbidrag (Refereegranskat)
  • 35.
    Fischer, Antje H. L.
    et al.
    European Molecular Biology Laboratory.
    Arboleda, Enrique
    Stazione Zoologica Anton Dohrn.
    Egger, Bernhard
    University College London.
    Hilbrant, Maarten
    University of Köln.
    McGregor, Alistair P.
    University of Vienna.
    Cole, Alison G.
    Stazione Zoologica Anton Cohrn.
    Daley, Allison C.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    ZOONET: perspectives on the evolution of animal form. Meeting report2009Ingår i: Journal of Experimental Zoology, ISSN 0022-104X, E-ISSN 1097-010X, Vol. 312B, nr 7, s. 679-685Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    What drives evolution? This was one of the main questions raised at the   final ZOONET meeting in Budapest, Hungary, in November 2008. The   meeting marked the conclusion of ZOONET, an EU-funded Marie-Curie   Research Training Network comprising nine research groups from all over   Europe (Max Telford, University College London; Michael Akam,   University of Cambridge; Detlev Arendt, EMBL Heidelberg; Maria Ina   Arnone, Stazione Zoologica Anton Dohrn Napoli; Michalis Averof, IMBB   Heraklion; Graham Budd, Uppsala University; Richard Copley, University   of Oxford; Wim Damen, University of Cologne; Ernst Wimmer, University   of Gottingen). ZOONET meetings and practical courses held during the   past four years provided researchers from diverse   backgrounds-bioinformatics, phylogenetics, embryology, palaeontology,   and developmental and molecular biology-the opportunity to discuss   their work under a common umbrella of evolutionary developmental   biology (Evo Devo). The Budapest meeting emphasized in-depth   discussions of the key concepts defining Evo Devo, and bringing   together ZOONET researchers with external speakers who were invited to   present their views on the evolution of animal form. The discussion   sessions addressed four main topics: the driving forces of evolution,   segmentation, fossils and phylogeny, and the future of Evo Devo.

  • 36. Friedman, M.
    et al.
    Blom, H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Ahlberg, Per E.
    New light on the lower jaw of the Devonian tetrapod Elginerpeton2003Ingår i: 51st symposium of vertebrate palaeontology and comparative anatomy, Oxford University Museum of Natural History, Oxford, 2003, s. 35-36Konferensbidrag (Refereegranskat)
  • 37.
    Frisk, Åsa M.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Harper, Dave A.T
    Shallow‐water Chonetoidea (Sericoidea) shell concentrations from the Ordovician impact crater fill in Tvären, Sweden.2009Konferensbidrag (Refereegranskat)
  • 38.
    Lagebro, Linda
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi.
    Stein, Martin
    Uppsala universitet, Museer m.m., Evolutionsmuseet.
    Peel, John Stuart
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    A new ?lamellipedian arthropod from the Early Cambrian Sirius Passet Fauna of North Greenland2009Ingår i: Journal of Paleontology, Vol. 83, nr 5, s. 820-825Artikel i tidskrift (Refereegranskat)
  • 39. Miller, C. G.
    et al.
    Blom, H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Märss, T.
    New anaspid and anaspid-like material from the Late Silurian of Man Brook and Gardner's Bank, Shropshire, UK2003Ingår i: The Gross Symposium 2. Advances in Palaeoichthyology. Riga, Latvia., 2003, s. 43-Konferensbidrag (Refereegranskat)
  • 40. Ormö, Jens
    et al.
    Hill, Andrew
    Self-Trail, Jean M.
    Frisk, Åsa M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    A method to determine the end of impact-related sedimentation at marine-target craters: geochemistry and micropaleontology of the transition from resurge to secular deposits at the Lockne, Tvären, and Chesapeake bay impact structures.2009Konferensbidrag (Refereegranskat)
  • 41. Popov, Leonid E.
    et al.
    Egerquist, Eva
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Zuykov, Michael
    Ordovician (Arenig-Caradoc) Syntrophiidine brachiopods from the East Baltic Region2005Ingår i: Palaeontology, ISSN 0031-0239, E-ISSN 1475-4983, Vol. 48, nr 4, s. 739-761Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Syntrophiidine brachiopods are a rare and poorly known component of Ordovician Baltoscandian faunas. They appear in the East Baltic in the Billingenian (lower Arenig) as part of the earliest known benthic assemblages dominated by elements of the Palaeozoic Evolutionary Fauna. These faunal assemblages usually include bryozoans, ostracodes, and the earliest known porambonitoids, strophomenides and endopunctate orthides, such as Idiostrophia and Orthidium, which later became characteristic of the Whiterockian brachiopod assemblages in Laurentia, but by that time had disappeared from Baltica. The superfamily Syntrophioidea reappears in Baltoscandia in the mid Caradoc. In contrast, Porambonitoidea remained the integral part of the Baltoscandian brachiopod associations through the Ordovician. Porambonites, herein redefined on the basis of restudy of the type species P. intermedius, includes only smooth porambonitoids; taxa with the distinctive ornament of radiating rows of pits first appeared in the group in the mid Arenig. The taxa Eoporambonites gen. nov., Tetralobula peregrina sp. nov., Idiostrophia prima sp. nov. and Idiostrophia tenuicostata sp. nov. are erected.

  • 42.
    Tolmacheva, Tatiana
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Egerquist, Eva
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Meidla, Tönu
    Institute of Geology, University of Tartu, Estonia.
    Holmer, Lars E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi.
    Spatial variations in faunal composition, Middle Ordovician, Volkhov Stage, East Baltic2001Ingår i: GFF, ISSN 1103-5897, Vol. 123, nr 2, s. 65-72Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Small-scale lateral variations in faunal skeletal composition and taphonomic characters were analysed at five successive levels containing soft clay layers in the Middle Ordovician (Middle and Upper Volkhov Stage) of the Putilovo quarry in the East Baltic region of Russia. At the studied levels, the relative abundance of faunal elements (mainly brachiopods, ostracodes, and conodonts) generally shows high spatial homogeneity. This even faunal composition is probably due to major time averaging, leading to equalisation of the composition of the assemblages within the units. Differences in taphonomic characters between the sub-samples are also mostly minor; variation in the degree of shell breakage is most probably the result of intensive bioturbation rather than of hydraulic transportation. Changes in the relative abundance of taxa either spatially or temporally, can be considered reliable only if they exceed the small-scale spatial heterogeneity of faunal composition as well as the errors related to the sample size and laboratory treatment of the samples. The relative error in the relative abundance of conodont taxa connected with the laboratory treatment is rather high (approximately 12%).

  • 43.
    Tolmacheva, Tatiana
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Egerquist, Eva
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Meidla, Tönu
    Institute of Geology, University of Tartu Estonia.
    Tinn, Oive
    Institute of Geology, University of Tartu Estonia.
    Holmer, Lars E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi.
    Faunal composition and dynamics in unconsolidated sediments: a case study from the Middle Ordovician of the East Baltic2003Ingår i: Geological Magazine, ISSN 0016-7568, Vol. 140, nr 1, s. 31-44Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Volkhov Regional Stage (Middle Ordovician) in the East Baltic preserves diverse fossil assemblages dominated by epibenthic suspension feeders. Brachiopods, ostracodes, conodonts, echinoderms and bryozoans are the main components of palaeocommunities obtained from clay horizons in the Putilovo section (St Petersburg region, Russia), whereas trilobites, machaeridians, hyolithids, graptolites, benthic foraminifers and gastropods are rare or occur sporadically. Brachiopod bioclasts volumetrically dominate the debris of the studied sediments. Quantitative faunal data are used to assess species diversity patterns, as expressed by the species richness (total number of species in the standardized sample size) and by the evenness or equitability of the community. The numerical abundance of particular taxa in each standardized sample was used to evaluate the density of the fauna. The communities in the Volkhov Stage in Putilovo Quarry reveal a remarkable stability throughout the studied interval and are characterized by high density (1000–6000 specimens per 100 g), relatively moderate species richness (10–15 species) and a moderately variable equitability (0.3–0.7) for the dominant fossil groups (conodonts, ostracodes and brachiopods). Ostracodes significantly increase in numbers within the upper part of the section. This confirms a shallowing of the basin during the late Volkhov interval. Small-scale variability of the diversity estimates does not correlate with the small-scale sea-level changes reconstructed for this part of the basin. It may be connected with error in diversity measurement, or the result of undetected environmental parameters. Variability estimates for different faunal groups are poorly correlated because particular groups have different environmental tolerances.

  • 44. Tolmacheva, Tatiana
    et al.
    Fedorov, Petr
    Egerquist, Eva
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleontologigruppen.
    Conodonts and brachiopods from the Middle Ordovician microbial mud mound at Putilovo Quarry, north-western Russia2003Ingår i: Bulletin of the Geological Society of Denmark, ISSN 0011-6297, Vol. 50, nr 1, s. 63-74Artikel i tidskrift (Refereegranskat)
  • 45.
    Wennberg, Sofia A
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleontologigruppen.
    Aspects of priapulid development2008Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The phylum Priapulida is a small group of marine worms that is allied with the nematodes, kinorhynchs, loriciferans and nematomorphs in a clade called the Cycloneuralia or Introverta. Together with the arthropods they are generally considered to comprise the Ecdysozoa, a clade of moulting animals. A number of recent priapulid species possess features that resemble the predicted Ecdysozoan ancestor. In addition, recent molecular studies have also shown that they are basal within the Ecdysozoa/Cycloneuralia (Garey 2001, Webster et al. 2006). Their putative basal position thus makes priapulids highly interesting research objects for understanding the evolution of Ecdysozoa.

    Earlier investigations of the early embryology of the priapulid Priapulus caudatus are critically revised with the aid of modern techniques and equipment, confirming earlier studies that the early cleavages are highly symmetrical, total, subequal, radial and stereotypical. New results show that up to the sixth cleavage, the spindles are oriented along the animal/vegetal axis at both poles. This unique cleavage pattern has only limited similarities to other animals. During the sixth cleavage two cells move inwards and gastrulation commences. If the mesoderm is derived from both cells, its origin differs from that of many other protostomes.

    Two previously undescribed larval stages of P. caudatus; the light bulb shaped hatchling and the first lorica larva are described. The second lorica larva superficially resembles the previously described type 2 lorica larva (Higgins et al 1993). Differences between the second lorica larva and the type 2 lorica larva, with respect to possible ecophenotypical variation and sub-specialization, are described.

    Preliminary data are presented on musculature development of P. caudatus. Preliminary data have also been obtained on the early development of a second priapulid, Halicryptus spinulosus. Comparison of Halicryptus and Priapulus may help to resolve developmental ground pattern of the priapulids.

    Delarbeten
    1. Early embryonic development of the priapulid worm Priapulus caudatus
    Öppna denna publikation i ny flik eller fönster >>Early embryonic development of the priapulid worm Priapulus caudatus
    2008 (Engelska)Ingår i: Evolution & Development, ISSN 1520-541X, E-ISSN 1525-142X, Vol. 10, nr 3, s. 326-338Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The early cleavage up to gastrulation is described here for the priapulid worm Priapulus caudatus, contradicting and clarifying earlier partial reports on this topic. The cleavage pattern up to gastrulation is highly symmetrical, total, subequal, radial, and stereotypical. Gastrulation is intermediate between epiboly and invagination, and the mesendoderm may be derived from both cells of the first cleavage, thus differing significantly in its origin from that of many other protostomes. Priapulids occupy an increasingly important position in studies of animal evolution as they appear to be relatively basal within the new clade Ecdysozoa (panarthropods plus cycloneuralians); and have been described as both morphological and genetic living fossils. The insights derived from priapulids combined with new data published recently on kinorhynchs and tardigrades imply a substantial developmental diversity among basal ecdysozoans, and weakens the hypothesis that irregular cleavage is plesiomorphic to the entire clade. Further study is required to reconstruct basal cleavage patterns in both this clade, and indeed, the Bilateria as a whole.

    Nationell ämneskategori
    Geovetenskap och miljövetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-97375 (URN)10.1111/j.1525-142X.2008.00241.x (DOI)000255552300009 ()
    Tillgänglig från: 2008-05-22 Skapad: 2008-05-22 Senast uppdaterad: 2017-12-14Bibliografiskt granskad
    2. Hatching and earliest larval stages of the priapulid worm Priapulus caudatus
    Öppna denna publikation i ny flik eller fönster >>Hatching and earliest larval stages of the priapulid worm Priapulus caudatus
    2009 (Engelska)Ingår i: Invertebrate biology., ISSN 1077-8306, E-ISSN 1744-7410, Vol. 128, nr 2, s. 157-171Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Here we describe the hatching and morphology of the earliest larval   stages of the priapulid worm Priapulus caudatus for the first time. The hatching larva differs considerably from previously described larvae  not only in its general body shape but also in its lack of a proper lorica including the typical lorica tubuli. Furthermore, no mouth opening or pharyngeal teeth have formed as yet, and the number and  arrangement of scalids differ from that of later larvae. The hatching larva molts and emerges as the first lorica larva. This larva partially   resembles earlier described lorica larvae, but there are a number of  important differences; the first lorica larva is smaller, and the mouth   opening as well as pharyngeal teeth are still yet to form. The second   lorica larva is equipped with four rings of pharyngeal teeth; it shows striking similarity to the previously described larva of P. caudatus,  i.e., the larva-type 2, only differing in the scalid pattern. We conclude that the first two larval stages of P. caudatus have not been described previously. We suggest that discrepancies between the earliest lorica larvae described here and in earlier publications might depend on sub-speciation or ecophenotypic modification of larvae collected from different localities. Our findings highlight the  importance of studying the development of non-model organisms such as priapulids under controlled laboratory conditions.

    Nyckelord
    Priapulida, Scalidophora, Cycloneuralia, Ecdysozoa, development
    Nationell ämneskategori
    Biologiska vetenskaper
    Identifikatorer
    urn:nbn:se:uu:diva-97376 (URN)10.1111/j.1744-7410.2008.00162.x (DOI)000266490400005 ()
    Tillgänglig från: 2008-05-22 Skapad: 2008-05-22 Senast uppdaterad: 2017-12-14Bibliografiskt granskad
    3. Muscle development in the priapulid worm, Priapulus caudatus
    Öppna denna publikation i ny flik eller fönster >>Muscle development in the priapulid worm, Priapulus caudatus
    Manuskript (Övrigt vetenskapligt)
    Identifikatorer
    urn:nbn:se:uu:diva-97377 (URN)
    Tillgänglig från: 2008-05-22 Skapad: 2008-05-22 Senast uppdaterad: 2010-01-13Bibliografiskt granskad
  • 46.
    Wennberg, Sofia A.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Janssen, Ralf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Budd, Graham E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi.
    Hatching and earliest larval stages of the priapulid worm Priapulus caudatus2009Ingår i: Invertebrate biology., ISSN 1077-8306, E-ISSN 1744-7410, Vol. 128, nr 2, s. 157-171Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Here we describe the hatching and morphology of the earliest larval   stages of the priapulid worm Priapulus caudatus for the first time. The hatching larva differs considerably from previously described larvae  not only in its general body shape but also in its lack of a proper lorica including the typical lorica tubuli. Furthermore, no mouth opening or pharyngeal teeth have formed as yet, and the number and  arrangement of scalids differ from that of later larvae. The hatching larva molts and emerges as the first lorica larva. This larva partially   resembles earlier described lorica larvae, but there are a number of  important differences; the first lorica larva is smaller, and the mouth   opening as well as pharyngeal teeth are still yet to form. The second   lorica larva is equipped with four rings of pharyngeal teeth; it shows striking similarity to the previously described larva of P. caudatus,  i.e., the larva-type 2, only differing in the scalid pattern. We conclude that the first two larval stages of P. caudatus have not been described previously. We suggest that discrepancies between the earliest lorica larvae described here and in earlier publications might depend on sub-speciation or ecophenotypic modification of larvae collected from different localities. Our findings highlight the  importance of studying the development of non-model organisms such as priapulids under controlled laboratory conditions.

  • 47.
    Wennberg, Sofia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleontologigruppen.
    Janssen, Ralf
    Budd, Graham
    Muscle development in the priapulid worm, Priapulus caudatusManuskript (Övrigt vetenskapligt)
  • 48.
    Wennberg, Sofia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi, Paleontologigruppen.
    Janssen, Ralf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi.
    Budd, Graham E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi.
    Early embryonic development of the priapulid worm Priapulus caudatus2008Ingår i: Evolution & Development, ISSN 1520-541X, E-ISSN 1525-142X, Vol. 10, nr 3, s. 326-338Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The early cleavage up to gastrulation is described here for the priapulid worm Priapulus caudatus, contradicting and clarifying earlier partial reports on this topic. The cleavage pattern up to gastrulation is highly symmetrical, total, subequal, radial, and stereotypical. Gastrulation is intermediate between epiboly and invagination, and the mesendoderm may be derived from both cells of the first cleavage, thus differing significantly in its origin from that of many other protostomes. Priapulids occupy an increasingly important position in studies of animal evolution as they appear to be relatively basal within the new clade Ecdysozoa (panarthropods plus cycloneuralians); and have been described as both morphological and genetic living fossils. The insights derived from priapulids combined with new data published recently on kinorhynchs and tardigrades imply a substantial developmental diversity among basal ecdysozoans, and weakens the hypothesis that irregular cleavage is plesiomorphic to the entire clade. Further study is required to reconstruct basal cleavage patterns in both this clade, and indeed, the Bilateria as a whole.

1 - 48 av 48
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