uu.seUppsala University Publications
Change search
Link to record
Permanent link

Direct link
BETA
Alternative names
Publications (10 of 120) Show all publications
Qvarnström, M., Vikberg Wernström, J., Piechowski, R., Talanda, M., Ahlberg, P. E. & Niedzwiedzki, G. (2019). Beetle-bearing coprolites possibly reveal the diet of a Late Triassic dinosauriform. Royal Society Open Science, 6(3), Article ID 181042.
Open this publication in new window or tab >>Beetle-bearing coprolites possibly reveal the diet of a Late Triassic dinosauriform
Show others...
2019 (English)In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 6, no 3, article id 181042Article in journal (Refereed) Published
Abstract [en]

Diets of extinct animals can be difficult to analyse if no direct evidence, such as gut contents, is preserved in association with body fossils. Inclusions from coprolites (fossil faeces), however, may also reflect the diet of the host animal and become especially informative if the coprolite producer link can be established. Here we describe, based on propagation phase-contrast synchrotron microtomography (PPC-SRμCT), the contents of five morphologically similar coprolites collected from two fossil-bearing intervals from the highly fossiliferous Upper Triassic locality at Krasiejow in Silesia, Poland. Beetle remains, mostly elytra, and unidentified exoskeleton fragments of arthropods are the most conspicuous inclusions found in the coprolites. The abundance of these inclusions suggests that the coprolite producer deliberately targeted beetles and similar small terrestrial invertebrates as prey, but the relatively large size of the coprolites shows that it was not itself a small animal. The best candidate from the body fossil record of the locality is the dinosauriform Silesaurus opolensis Dzik, 2003, which had an anatomy in several ways similar to those of bird-like neotheropod dinosaurs and modern birds. We hypothesize that the beak-like jaws of S. opolensis were used to efficiently peck small insects off the ground, a feeding behaviour analogous to some extant birds.

Keywords
coprolites, palaeoecology, Dinosauromorpha, beetle elytra, insectivore
National Category
Geosciences, Multidisciplinary Other Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:uu:diva-383880 (URN)10.1098/rsos.181042 (DOI)000465470300008 ()31031991 (PubMedID)
Funder
Swedish Research Council, 2017-05248
Available from: 2019-06-11 Created: 2019-06-11 Last updated: 2019-06-11Bibliographically approved
Kundrát, M., Nudds, J., Kear, B. P., Lu, J. & Ahlberg, P. (2019). The first specimen of Archaeopteryx from the Upper Jurassic Mornsheim Formation of Germany. Historical Biology, 31(1), 3-63
Open this publication in new window or tab >>The first specimen of Archaeopteryx from the Upper Jurassic Mornsheim Formation of Germany
Show others...
2019 (English)In: Historical Biology, ISSN 0891-2963, E-ISSN 1029-2381, Vol. 31, no 1, p. 3-63Article in journal (Refereed) Published
Abstract [en]

From an initial isolated position as the oldest evolutionary prototype of a bird, Archaeopteryx has, as a result of recent fossil discoveries, become embedded in a rich phylogenetic context of both more and less crownward stem-group birds. This has prompted debate over whether Archaeopteryx is simply a convergently bird-like non-avialan theropod. Here we show, using the first synchrotron microtomographic examination of the genus, that the eighth or Daiting specimen of Archaeopteryx possesses a character suite that robustly constrains it as a basal avialan (primitive bird). The specimen, which comes from the Mornsheim Formation and is thus younger than the other specimens from the underlying Solnhofen Formation, is distinctive enough to merit designation as a new species, Archaeopteryx albersdoerferi sp. nov., but is recovered in close phylogenetic proximity to Archaeopteryx lithographica. Skeletal innovations of the Daiting specimen, such as fusion and pneumatization of the cranial bones, well vascularized pectoral girdle and wing elements, and a reinforced configuration of carpals and metacarpals, suggest that it may have had more characters seen in flying birds than the older Archaeopteryx lithographica. These innovations appear to be convergent on those of more crownward avialans, suggesting that Bavarian archaeopterygids independently acquired increasingly bird-like traits over time. Such mosaic evolution and iterative exploration of adaptive space may be typical for major functional transitions like the origin of flight.

Place, publisher, year, edition, pages
TAYLOR & FRANCIS LTD, 2019
Keywords
Aves, Avialae, Tithonian, origin of birds, flight, evolution, development, phylogeny, synchrotron microtomography
National Category
Evolutionary Biology
Identifiers
urn:nbn:se:uu:diva-369376 (URN)10.1080/08912963.2018.1518443 (DOI)000448258500002 ()
Funder
Swedish Research Council
Available from: 2019-01-15 Created: 2019-01-15 Last updated: 2019-01-15Bibliographically approved
Qvarnström, M., Ahlberg, P. & Niedzwiedzki, G. (2019). Tyrannosaurid-like osteophagy by a Triassic archosaur. Scientific Reports, 9, Article ID 925.
Open this publication in new window or tab >>Tyrannosaurid-like osteophagy by a Triassic archosaur
2019 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 925Article in journal (Refereed) Published
Abstract [en]

Here we present evidence for osteophagy in the Late Triassic archosaur Smok wawelski Niedzwiedzki, Sulej and Dzik, 2012, a large theropod-like predator from Poland. Ten medium to large-sized coprolites are matched, by their dimensions and by association with body fossils and footprints, to S. wawelski. The coprolites contain fragments of large serrated teeth as well as up to 50 percent by volume of bone fragments, with distinct fragmentation and angularity, from several prey taxa. This suggests pronounced osteophagy. Further evidence for bone-crushing behaviour is provided by isolated worn teeth, bone-rich regurgitalites (fossil regurgitates) and numerous examples of crushed or bite-marked dicynodont bones, all collected from the same bone-bearing beds in the Lipie Slaskie clay-pit. Several of the anatomical characters related to osteophagy, such as a massive head and robust body, seem to be shared by S. wawelski and the tyrannosaurids, despite their wide phylogenetic separation. These large predators thus provide evidence of convergence driven by similar feeding ecology at the beginning and end of the age of dinosaurs.

National Category
Evolutionary Biology
Identifiers
urn:nbn:se:uu:diva-377342 (URN)10.1038/s41598-018-37540-4 (DOI)000457128700002 ()30700743 (PubMedID)
Funder
Swedish Research Council, 2017-05248Knut and Alice Wallenberg Foundation
Available from: 2019-02-25 Created: 2019-02-25 Last updated: 2019-02-25Bibliographically approved
Chen, D. L., Alavi, Y., Brazeau, M. D., Blom, H., Millward, D. & Ahlberg, P. E. (2018). A partial lower jaw of a tetrapod from "Romer's Gap". Earth and environmental science transactions of the Royal Society of Edinburgh, 108(1), 55-65
Open this publication in new window or tab >>A partial lower jaw of a tetrapod from "Romer's Gap"
Show others...
2018 (English)In: Earth and environmental science transactions of the Royal Society of Edinburgh, ISSN 1755-6910, E-ISSN 1755-6929, Vol. 108, no 1, p. 55-65Article in journal (Refereed) Published
Abstract [en]

The first half of the Mississippian or Early Carboniferous (Tournaisian to mid-Visean), an interval of about 20 million years, has become known as "Romer's Gap" because of its poor tetrapod record. Recent discoveries emphasise the differences between pre-"Gap" Devonian tetrapods, unambiguous stem-group members retaining numerous "fish" characters indicative of an at least partially aquatic lifestyle, and post-"Gap" Carboniferous tetrapods, which are far more diverse and include fully terrestrial representatives of the main crown-group lineages. It seems that "Romer's Gap" coincided with the cladogenetic events leading to the origin of the tetrapod crown group. Here, we describe a partial right lower jaw ramus of a tetrapod from the late Tournaisian or early Visean of Scotland. The large and robust jaw displays a distinctive character combination, including a significant mesial lamina of the strongly sculptured angular, an open sulcus for the mandibular lateral line, a non-ossified narrow Meckelian exposure, a well-defined dorsal longitudinal denticle ridge on the prearticular, and a mesially open adductor fossa. A phylogenctic analysis places this specimen in a trichotomy with Crassigyrinus and baphetids + higher tetrapods in the upper part of the tetrapod stem group, above Whatcheeria, Pederpes, Ossinodus, Sigournea and Greererpeton. It represents a small but significant step in the gradual closure of "Romer's Gap".

Keywords
Early Carboniferous, fossil, palaeontology, Tantallon Castle
National Category
Other Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:uu:diva-375860 (URN)10.1017/S1755691018000099 (DOI)000456089700006 ()
Funder
EU, European Research Council, 233111Knut and Alice Wallenberg Foundation
Available from: 2019-02-01 Created: 2019-02-01 Last updated: 2019-02-01Bibliographically approved
Gess, R. & Ahlberg, P. (2018). A tetrapod fauna from within the Devonian Antarctic Circle. Science, 360(6393), 1120-1124
Open this publication in new window or tab >>A tetrapod fauna from within the Devonian Antarctic Circle
2018 (English)In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 360, no 6393, p. 1120-1124Article in journal (Refereed) Published
Abstract [en]

Until now, all known fossils of tetrapods (limbed vertebrates with digits) and near-tetrapods (such as Elpistostege, Tiktaalik, and Panderichthys) from the Devonian period have come from localities in tropical to subtropical paleolatitudes. Most are from Laurussia, a continent incorporating Europe, Greenland, and North America, with only one body fossil and one footprint locality from Australia representing the southern supercontinent Gondwana. Here we describe two previously unknown tetrapods from the Late Devonian (late Famennian) Gondwana locality of Waterloo Farm in South Africa, then located within the Antarctic Circle, which demonstrate that Devonian tetrapods were not restricted to warm environments and suggest that they may have been global in distribution.

National Category
Geology
Identifiers
urn:nbn:se:uu:diva-357682 (URN)10.1126/science.aaq1645 (DOI)000434635500046 ()29880689 (PubMedID)
Funder
Knut and Alice Wallenberg Foundation
Available from: 2018-08-20 Created: 2018-08-20 Last updated: 2018-08-20Bibliographically approved
Kuratani, S. & Ahlberg, P. E. (2018). Evolution of the vertebrate neurocranium: problems of the premandibular domain and the origin of the trabecula. ZOOLOGICAL LETTERS, 4, Article ID 1.
Open this publication in new window or tab >>Evolution of the vertebrate neurocranium: problems of the premandibular domain and the origin of the trabecula
2018 (English)In: ZOOLOGICAL LETTERS, ISSN 2056-306X, Vol. 4, article id 1Article, review/survey (Refereed) Published
Abstract [en]

The subdivision of the gnathostome neurocranium into an anterior neural crest-derived moiety and a posterior mesodermal moiety has attracted the interest of researchers for nearly two centuries. We present a synthetic scenario for the evolution of this structure, uniting developmental data from living cyclostomes and gnathostomes with morphological data from fossil stem gnathostomes in a common phylogenetic framework. Ancestrally, vertebrates had an anteroposteriorly short forebrain, and the neurocranium was essentially mesodermal; skeletal structures derived from premandibular ectomesenchyme were mostly anterior to the brain and formed part of the visceral arch skeleton. The evolution of a one-piece neurocranial 'head shield' in jawless stem gnathostomes, such as galeaspids and osteostracans, caused this mesenchyme to become incorporated into the neurocranium, but its position relative to the brain and nasohypophyseal duct remained unchanged. Basically similar distribution of the premandibular ectomesenchyme is inferred, even in placoderms, the earliest jawed vertebrates, in which the separation of hypophyseal and nasal placodes obliterated the nasohypophyseal duct, leading to redeployment of this ectomesenchyme between the separate placodes and permitting differentiation of the crown gnathostome trabecula that floored the forebrain. Initially this region was very short, and the bulk of the premandibular cranial part projected anteroventral to the nasal capsule, as in jawless stem gnathostomes. Due to the lengthening of the forebrain, the anteriorly projecting 'upper lip' was lost, resulting in the modern gnathostome neurocranium with a long forebrain cavity floored by the trabeculae.

Place, publisher, year, edition, pages
BioMed Central, 2018
Keywords
Head mesoderm, Cranium, Cyclostomes, Neural crest, Evolution, Trabecula
National Category
Evolutionary Biology
Identifiers
urn:nbn:se:uu:diva-349317 (URN)10.1186/s40851-017-0083-6 (DOI)000419908100001 ()29340168 (PubMedID)
Funder
Knut and Alice Wallenberg FoundationSwedish Research Council, 2014-4102 15H02416 17H06385
Available from: 2018-05-02 Created: 2018-05-02 Last updated: 2018-05-02Bibliographically approved
Clement, A., King, B., Giles, S., Choo, B., Ahlberg, P., Young, G. C. & Long, J. A. (2018). Neurocranial anatomy of an enigmatic Early Devonian fish sheds light on early osteichthyan evolution. eLIFE, 7, Article ID e34349.
Open this publication in new window or tab >>Neurocranial anatomy of an enigmatic Early Devonian fish sheds light on early osteichthyan evolution
Show others...
2018 (English)In: eLIFE, E-ISSN 2050-084X, Vol. 7, article id e34349Article in journal (Refereed) Published
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.

National Category
Evolutionary Biology
Identifiers
urn:nbn:se:uu:diva-357559 (URN)10.7554/eLife.34349 (DOI)000433288300001 ()29807569 (PubMedID)
Funder
Australian Research Council, DP 140101461Australian Research Council, DE 160100247
Available from: 2018-08-20 Created: 2018-08-20 Last updated: 2018-08-20Bibliographically approved
Qvarnström, M., Szrek, P., Ahlberg, P. E. & Niedzwiedzki, G. (2018). Non-marine palaeoenvironment associated to the earliest tetrapod tracks. Scientific Reports, 8, Article ID 1074.
Open this publication in new window or tab >>Non-marine palaeoenvironment associated to the earliest tetrapod tracks
2018 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 1074Article in journal (Refereed) Published
Abstract [en]

Opinions differ on whether the evolution of tetrapods (limbed vertebrates) from lobe-finned fishes was directly linked to terrestrialization. The earliest known tetrapod fossils, from the Middle Devonian (approximately 390 million years old) of Zachelmie Quarry in Poland, are trackways made by limbs with digits; they document a direct environmental association and thus have the potential to help answer this question. However, the tetrapod identity of the tracks has recently been challenged, despite their well-preserved morphology, on account of their great age and supposedly shallow marine (intertidal or lagoonal) depositional environment. Here we present a new palaeoenvironmental interpretation of the track-bearing interval from Zachelmie, showing that it represents a succession of ephemeral lakes with a restricted and non-marine biota, rather than a marginal marine environment as originally thought. This context suggests that the trackmaker was capable of terrestrial locomotion, consistent with the appendage morphology recorded by the footprints, and thus provides additional support for a tetrapod identification.

National Category
Evolutionary Biology
Identifiers
urn:nbn:se:uu:diva-343675 (URN)10.1038/s41598-018-19220-5 (DOI)000422739300037 ()29348562 (PubMedID)
Available from: 2018-03-05 Created: 2018-03-05 Last updated: 2018-03-05Bibliographically approved
Lindgren, J., Sjövall, P., Thiel, V., Zheng, W., Ito, S., Wakamatsu, K., . . . Schweitzer, M. H. (2018). Soft-tissue evidence for homeothermy and crypsis in a Jurassic ichthyosaur. Nature, 564(7736), 359-365
Open this publication in new window or tab >>Soft-tissue evidence for homeothermy and crypsis in a Jurassic ichthyosaur
Show others...
2018 (English)In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 564, no 7736, p. 359-365Article in journal (Refereed) Published
Abstract [en]

Ichthyosaurs are extinct marine reptiles that display a notable external similarity to modern toothed whales. Here we show that this resemblance is more than skin deep. We apply a multidisciplinary experimental approach to characterize the cellular and molecular composition of integumental tissues in an exceptionally preserved specimen of the Early Jurassic ichthyosaur Stenopterygius. Our analyses recovered still-flexible remnants of the original scaleless skin, which comprises morphologically distinct epidermal and dermal layers. These are underlain by insulating blubber that would have augmented streamlining, buoyancy and homeothermy. Additionally, we identify endogenous proteinaceous and lipid constituents, together with keratinocytes and branched melanophores that contain eumelanin pigment. Distributional variation of melanophores across the body suggests countershading, possibly enhanced by physiological adjustments of colour to enable photoprotection, concealment and/or thermoregulation. Convergence of ichthyosaurs with extant marine amniotes thus extends to the ultrastructural and molecular levels, reflecting the omnipresent constraints of their shared adaptation to pelagic life.

Place, publisher, year, edition, pages
NATURE PUBLISHING GROUP, 2018
National Category
Evolutionary Biology
Identifiers
urn:nbn:se:uu:diva-372886 (URN)10.1038/s41586-018-0775-x (DOI)000453834900050 ()30518862 (PubMedID)
Funder
Swedish Research Council, 642-2014-3773
Available from: 2019-01-09 Created: 2019-01-09 Last updated: 2019-01-09Bibliographically approved
Bazzi, M., Kear, B. P., Blom, H., Ahlberg, P. & Campione, N. E. (2018). Static Dental Disparity and Morphological Turnover in Sharks across the End-Cretaceous Mass Extinction. Current Biology, 28(16), 2607-2615
Open this publication in new window or tab >>Static Dental Disparity and Morphological Turnover in Sharks across the End-Cretaceous Mass Extinction
Show others...
2018 (English)In: Current Biology, ISSN 0960-9822, E-ISSN 1879-0445, Vol. 28, no 16, p. 2607-2615Article in journal (Refereed) Published
Abstract [en]

The Cretaceous-Palaeogene (K-Pg) mass extinction profoundly altered vertebrate ecosystems and prompted the radiation of many extant clades [1, 2]. Sharks (Selachimorpha) were one of the few larger-bodied marine predators that survived the K-Pg event and are represented by an almost-continuous dental fossil record. However, the precise dynamics of their transition through this interval remain uncertain [3]. Here, we apply 2D geometric morphometrics to reconstruct global and regional dental morphospace variation among Lamniformes (Mackerel sharks) and Carch-arhiniformes (Ground sharks). These clades are prevalent predators in today's oceans, and were geographically widespread during the late Cretaceous-early Palaeogene. Our results reveal a decoupling of morphological disparity and taxonomic richness. Indeed, shark disparity was nearly static across the K-Pg extinction, in contrast to abrupt declines among other higher-trophic-level marine predators [4, 5]. Nevertheless, specific patterns indicate that an asymmetric extinction occurred among lamniforms possessing lowcrowned/triangular teeth and that a subsequent proliferation of carcharhiniforms with similar tooth morphologies took place during the early Paleocene. This compositional shift in post-Mesozoic shark lineages hints at a profound and persistent K-Pg signature evident in the heterogeneity of modern shark communities. Moreover, such wholesale lineage turnover coincided with the loss of many cephalopod [6] and pelagic amniote [5] groups, as well as the explosive radiation of middle trophic-level teleost fishes [1]. We hypothesize that a combination of prey availability and post-extinction trophic cascades favored extant shark antecedents and laid the foundation for their extensive diversification later in the Cenozoic [7-10].

Place, publisher, year, edition, pages
CELL PRESS, 2018
National Category
Evolutionary Biology
Identifiers
urn:nbn:se:uu:diva-363937 (URN)10.1016/j.cub.2018.05.093 (DOI)000442111300030 ()30078565 (PubMedID)
Funder
Knut and Alice Wallenberg FoundationThe Royal Swedish Academy of Sciences, GS2017-0018
Available from: 2018-10-23 Created: 2018-10-23 Last updated: 2018-10-23Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9054-2900

Search in DiVA

Show all publications