Wyniki wyszukiwania

1

Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik

The phylogenetic position of the ornithischian dinosaur Stenopelix valdensis from the Lower Cretaceous of Germany and the early fossil record of Pachycephalosauria

100%

Butler R. J., Sullivan R. M.

Acta Palaeontologica Polonica

|

2009

|

tom 54

|

nr 1

21-34

The holotype of Stenopelix valdensis is the most completely known dinosaur specimen from the “Wealden” (Lower Cretaceous) of northwestern Germany, but its phylogenetic position has remained highly controversial. Most recent authors have suggested affinities with the ornithischian clade Marginocephalia, and most commonly to the marginocephalian subclade Pachycephalosauria. A pachycephalosaurian identity would make Stenopelix the only confirmed pre−Late Cretaceous member of this clade, breaking up an extensive ghost lineage which extends to the inferred origin of Pachycephalosauria in the Middle–Late Jurassic. Based upon re−examination of the holotype we here review the characters that have previously been used to assign Stenopelix to either Pachycephalosauria or Ceratopsia. All of these characters are problematic, being based upon inaccurate anatomical interpretations, or having more widespread distributions within Ornithischia than previously realised. We conclude that although the overall anatomy of Stenopelix is consistent with marginocephalian affinities, there is insufficient evidence to support referral to either Pachycephalosauria or Ceratopsia; we consider Stenopelix ?Marginocephalia. A brief review indicates that there is no compelling fossil evidence for pachycephalosaurs prior to the Late Cretaceous.

2

New partial dentaries of amphitheriid mammal Palaeoxonodon ooliticus from Scotland, and posterior dentary morphology in early cladotherians

81%

Panciroli E., Benson R. B. J., Butler R. J.

Acta Palaeontologica Polonica

|

2018

|

tom 63

|

nr 2

We describe two partial dentaries of mammals from the Middle Jurassic of Scotland. They belong to the early cladotherian Palaeoxonodon ooliticus. These dentaries comprise the first specimen of P. ooliticus ever found—although its significance was initially unrecognised so it remained undescribed until now—and the most recently discovered specimen, found during fieldwork in 2017. The new specimen preserves part of the coronoid process of the dentary, previously unknown for P. ooliticus, demonstrating the presence of a deep masseteric fossa, with a prominent crest enclosing the fossa anteriorly, and a masseteric foramen, located in the masseteric fossa on the buccal surface of the dentary. On the lingual surface, the mandibular foramen is offset from the Meckel’s sulcus, and positioned below the alveolar plane. These morphologies allow an updated analysis of the phylogenetic position of P. ooliticus, confirming a sister-taxa relationship between Palaeoxonodon and Amphitherium. The position of the mandibular foramen, and the slight extension of the masseteric fossa into the body of the dentary are new autapomorphies for Palaeoxonodon.

3

The last erythrosuchid - a revision of Chalishevia cothurnata from the late Middle Triassic of European Russia

81%

Butler R. J., Sennikov A. G., Ezcurra M. D., Gower D. J.

Acta Palaeontologica Polonica

|

2019

|

tom 64

|

nr 4

Erythrosuchidae is a clade of early archosauriform reptiles that were large-bodied, hypercarnivorous, possibly apex predators in late Early and Middle Triassic ecosystems following the Permo-Triassic mass extinction. Chalishevia cothurnata from the late Middle Triassic (Ladinian) of Russia, is the stratigraphically youngest known erythrosuchid species, but the holotype and referred material of this taxon has received little study. Here, we provide the first detailed anatomical description of C. cothurnata, including comparisons to other erythrosuchids. Although known from relatively fragmentary material, the anatomy of C. cothurnata is distinctive, including an autapomorphic strongly slanted ventral border of the antorbital fossa. The presence of a large accessory opening (the “accessory antorbital fenestra”) in the skull between the premaxilla, nasal and maxilla, together with the inferred presence of a narrow postnarial process of the premaxilla that articulated with a slot on the nasal, provides strong evidence for a sister taxon relationship between C. cothurnata and the erythrosuchid Shansisuchus shansisuchus from the early Middle Triassic (Anisian) of China. The inferred basal skull length of C. cothurnata was approximately 80 cm, making it one of the largest erythrosuchids known.

4

Cranial anatomy of the iguanodontoid ornithopod Jinzhousaurus yangi from the Lower Cretaceous Yixian Formation of China

81%

Barrett P. M., Butler R. J., Xiao-Lin W., Xing X.

Acta Palaeontologica Polonica

|

2009

|

tom 54

|

nr 1

35-48

The Yixian Formation (Lower Cretaceous) of Liaoning Province, China, is justifiably famous for its exceptionally preserved fauna, which includes a remarkable diversity of non−avian dinosaurs. Here, we provide the first detailed description of the cranial skeleton of the iguanodontian ornithopod Jinzhousaurus yangi. Many previously unrecorded features have been recognised, permitting a new and more robust diagnosis for this taxon, which is based on a suite of autapomorphic features. Jinzhousaurus and an unnamed sauropod represent the largest, but some of the least abundant, animals in the Jehol Biota, a situation that contrasts with many other Lower Cretaceous faunas in which large dinosaurs are common faunal components. This rarity may be due to either palaeoenvironmental constraints or taphonomic bias, although it is not possible to choose between these alternatives on the basis of current data.

5

The taxonomy and anatomy of rauisuchian archosaur from the Late Triassic of Germany and Poland

81%

Brusatte S. L., Butler R. J., Sulej T., Niedzwiedzki G.

Acta Palaeontologica Polonica

|

2009

|

tom 54

|

nr 2

221-230

The German Late Triassic archosaur Teratosaurus suevicus is a historically important taxon, being the first described rauisuchian. Unfortunately the holotype is a single element, a maxilla, which is poorly preserved and incomplete. We redescribe this maxilla and identify a single potential autapomorphy. The fragmentary type specimen complicates attempts to refer additional material to this taxon, and other unassociated archosaur and rauisuchian specimens from the Mittlerer Stubensandstein of Germany cannot be referred to T. suevicus with any degree of confidence. The stratigraphically older T. silesiacus, from the upper Carnian of Poland, is represented by a much more complete and better preserved specimen. Comparison of the maxillae of T. suevicus and T. silesiacus reveals that the two are distinct taxa, contra recent suggestions, but also that they do not share any synapomorphies or a unique combination of characters relative to Postosuchus kirkpatricki and other rauisuchians. Thus, the Polish material must be transferred to a new genus, Polonosuchus gen. nov. Both Polonosuchus and Teratosaurus are very similar to Postosuchus kirkpatricki, and the three taxa are likely closely related.

Ograniczanie wyników

5 Acta Palaeontologica Polonica

5 Butler R. J.

1 Barrett P. M.

1 Benson R. B. J.

1 Brusatte S. L.

1 Ezcurra M. D.

1 Gower D. J.

1 Niedzwiedzki G.

1 Panciroli E.

1 Sennikov A. G.

1 Sulej T.

1 Sullivan R. M.

1 Xiao-Lin W.

1 Xing X.

1 2019

1 2018

3 2009

The phylogenetic position of the ornithischian dinosaur Stenopelix valdensis from the Lower Cretaceous of Germany and the early fossil record of Pachycephalosauria

New partial dentaries of amphitheriid mammal Palaeoxonodon ooliticus from Scotland, and posterior dentary morphology in early cladotherians

The last erythrosuchid - a revision of Chalishevia cothurnata from the late Middle Triassic of European Russia

Cranial anatomy of the iguanodontoid ornithopod Jinzhousaurus yangi from the Lower Cretaceous Yixian Formation of China

The taxonomy and anatomy of rauisuchian archosaur from the Late Triassic of Germany and Poland