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Per E. Ahlberg
Uppsala University
105Publications
36H-index
3,770Citations
Publications 105
Newest
#1Martin Qvarnström (Uppsala University)H-Index: 5
#2Per Ahlberg (Uppsala University)H-Index: 24
Last.Grzegorz Niedźwiedzki (Uppsala University)H-Index: 16
view all 3 authors...
Here we present evidence for osteophagy in the Late Triassic archosaur Smok wawelski Niedźwiedzki, 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 ...
#1Martin Qvarnström (Uppsala University)H-Index: 5
#2Piotr SzrekH-Index: 4
Last.Grzegorz Niedźwiedzki (Uppsala University)H-Index: 16
view all 4 authors...
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, desp...
#1Jonathan E. Jeffery (UoB: University of Bristol)H-Index: 12
#2Glenn W. Storrs (Cincinnati Museum Center)H-Index: 16
Last.Per E. Ahlberg (Uppsala University)H-Index: 36
view all 5 authors...
All living tetrapods have a one-to-two branching pattern in the embryonic proximal limb skeleton, with a single element at the base of the limb (the humerus or femur) that articulates distally with two parallel radials (the ulna and radius or the tibia and fibula). This pattern is also seen in the fossilized remains of stem-tetrapods, including the fishlike members of the group, in which despite the absence of digits, the proximal parts of the fin skeleton clearly resemble those of later tetrapo...
#1Robert W. Gess (Rhodes University)H-Index: 9
#2Per E. Ahlberg (Uppsala University)H-Index: 36
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 tetrapod...
#1Alice M. Clement (Uppsala University)H-Index: 6
#2Benedict King (Flinders University)H-Index: 4
Last.John A. Long (Flinders University)H-Index: 30
view all 7 authors...
All animals can be classified as either vertebrate (those that have a spine) or invertebrate (those that do not). About 98% of all living vertebrate species belong to a group called Osteichthyes, otherwise known as bony fish. Despite the name, this group also includes all four-limbed vertebrates – amphibians, reptiles, birds and mammals – since they evolved from prehistoric bony fish millions of years ago. The oldest known bony fish can be traced back to around 425 million years. These ancient b...
#1Martin Qvarnström (Uppsala University)H-Index: 5
#2Grzegorz Niedźwiedzki (Uppsala University)H-Index: 16
Last.Per E. Ahlberg (Uppsala University)H-Index: 36
view all 5 authors...
Coprolites (fossil faeces) reveal clues to ancient trophic relations, and contain inclusions representing organisms that are rarely preserved elsewhere. However, much information is lost by classical techniques of investigation, which cannot find and image the inclusions in an adequate manner. We demonstrate that propagation phase-contrast synchrotron microtomography (PPC-SRμCT) permits high-quality virtual 3D-reconstruction of coprolite inclusions, exemplified by two coprolites from the Upper T...
#1Min Zhu (CAS: Chinese Academy of Sciences)H-Index: 21
#2Per E. Ahlberg (Uppsala University)H-Index: 36
Last.Liantao Jia (CAS: Chinese Academy of Sciences)H-Index: 11
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The fossils assigned to the tetrapod stem group document the evolution of terrestrial vertebrates from lobe-finned fishes. During the past 18 years the phylogenetic structure of this stem group has remained remarkably stable, even when accommodating new discoveries such as the earliest known stem tetrapod Tungsenia and the elpistostegid (fish–tetrapod intermediate) Tiktaalik. Here we present a large lobe-finned fish from the Late Devonian period of China that disrupts this stability. It combines...
#1Gerard D. Gierliński (Delta Air Lines)H-Index: 3
#2Grzegorz Niedźwiedzki (Uppsala University)H-Index: 16
Last.Per E. Ahlberg (Uppsala University)H-Index: 36
view all 9 authors...
Abstract We describe late Miocene tetrapod footprints (tracks) from the Trachilos locality in western Crete (Greece), which show hominin-like characteristics. They occur in an emergent horizon within an otherwise marginal marine succession of Messinian age (latest Miocene), dated to approximately 5.7 Ma (million years), just prior to the Messinian Salinity Crisis. The tracks indicate that the trackmaker lacked claws, and was bipedal, plantigrade, pentadactyl and strongly entaxonic. The impressio...
#1Jason D. PardoH-Index: 8
#2Matt SzostakiwskyjH-Index: 4
Last.Jason S. AndersonH-Index: 20
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Detailed micro-computed tomography analysis of the skull of Lethiscus stocki places it much earlier in the tetrapod lineage that was previously thought, showing that early tetrapods were more morphologically diverse than has been believed.
#1Dong Lei Chen (Uppsala University)H-Index: 1
#2Henning Blom (Uppsala University)H-Index: 13
Last.Per E. Ahlberg (Uppsala University)H-Index: 36
view all 6 authors...
The numerous cushion-shaped tooth-bearing plates attributed to the stem-group osteichthyan Lophosteus superbus, which are argued here to represent the ancient form of inner dental arcade, display a ...
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