Postcranial remains of Teraterpeton hrynewichorum (Reptilia: Archosauromorpha) and the mosaic evolution of the saurian postcranial skeleton (project)

SynopsisIn a previous paper (Andrews and Westoll 1970) the postcranial skeleton of the best known rhipidistian, Eusthenopteron, was described, and its bearing on the origin of the tetrapod postcranial skeleton discussed. The postcranial remains of other Rhipidistia are now described as far as they are known, and comparisons are made with Eusthenopteron and other forms where relevant. Possible modes of function are considered in relation to the habitats in which these fishes may have lived. These studies have made it necessary to revise rhipidistian classification; the Family Rhizodontidae is re-defined and placed alone in a third Order of Rhipidistia (the Rhizodontida, alongside the better known Osteolepidida and Holoptychiida). Fresh insight has been gained into the following morphological problems: the composition of the osteolepid ring-like centrum, the origin of the tetrapod scapular blade and the diphyletic origin of the tetrapods.

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The postcranial skeleton of Cerrejonisuchus improcerus (Crocodyliformes: Dyrosauridae) and the unusual anatomy of dyrosaurids

PeerJ ◽

10.7717/peerj.11222 ◽

2021 ◽

Vol 9 ◽

pp. e11222

Author(s):

Isaure Scavezzoni ◽

Valentin Fischer

Keyword(s):

Principal Coordinate Analysis ◽

Thoracic Vertebra ◽

Aquatic Environments ◽

Postcranial Skeleton ◽

Rib Cage ◽

Lateral Process ◽

Distal Surface ◽

Postcranial Remains ◽

Functional Analog ◽

Postcranial Anatomy

Dyrosauridae is a clade of neosuchian crocodyliforms that diversified in terrestrial and aquatic environments across the Cretaceous-Paleogene transition. The postcranial anatomy of dyrosaurids has long been overlooked, obscuring both their disparity and their locomotive adaptations. Here we thoroughly describe of the postcranial remains of an unusually small dyrosaurid, Cerrejonisuchus improcerus, from the middle-late Paleocene Cerrejón Formation of Colombia, and we provide a wealth of new data concerning the postcranial anatomy of the key dyrosaurids: Congosaurus bequaerti and Hyposaurus rogersii. We identify a series of postcranial autapomorphies in Cerrejonisuchus improcerus (an elliptic-shaped odontoid laterally wide, a ulna possessing a double concavity, a fibula bearing a widely flattened proximal end, a pubis showing a large non-triangular distal surface) as well as functionally-important traits such as a relatively long ulna (85% of the humerus’ length), short forelimb (83% of hindlimb’s length), or thoracic vertebra bearing comparatively large lateral process (with widened parapophysis and diapophysis) along with strongly arched thoracic ribs allowing a more sturdy and cylindrical rib cage. These indicate a more terrestrial lifestyle for Cerrejonisuchus compared to the derived members of the clade. We also built a dataset of 187 traits on 27 taxa, that extensively samples the cranial and postcranial architectures of exemplar crocodyliforms. We analyze these data in via Principal Coordinate Analysis (PCoA) to visualize the postcranial morphospace occupation of Dyrosauridae, Thalattosuchia, and Crocodylia. Our data reveal the existence of a distinctive postcranial anatomy for Dyrosauridae that is markedly distinct from that of crocodylians. As a result, modern crocodylians are probably not good functional analog for extinct crocodyliformes. Postcranial data should also be more widely used in phylogenetic and disparity analyses of Crocodyliformes.

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The postcranial skeleton ofBoreogomphodon(Cynodontia: Traversodontidae) from the Upper Triassic of North Carolina, USA and the comparison with other traversodontids

PeerJ ◽

10.7717/peerj.3521 ◽

2017 ◽

Vol 5 ◽

pp. e3521 ◽

Cited By ~ 5

Author(s):

Jun Liu ◽

Vincent P. Schneider ◽

Paul E. Olsen

Keyword(s):

North Carolina ◽

Normal Form ◽

Anterior Margin ◽

Upper Triassic ◽

Postcranial Skeleton ◽

Allometric Growth ◽

Anterior Process ◽

Limb Bones ◽

Postcranial Remains

Postcranial remains ofBoreogomphodonfrom the Upper Triassic of North Carolina are described and compared to those of other known traversodontid cynodonts. The postcranial skeleton ofBoreogomphodonis characterized by four sacral ribs, simple ribs lacking costal plates, the extension of the scapular neck below the acromion process, a short scapular facet on the procoracoid, a concave anterior margin of the procoracoid, humerus entepicondyle with smooth corner, and the presence of a fifth distal carpal. Four types of ribs are identified among traversodontids: ‘normal’ form, tubercular rib, costal plate, and Y-shaped rib. Fossorial behavior is suggested for traversodontids with elaborate costal plates. Within Traversodontidae, the procoracoid is relatively small; the anterior process of the iliac blade extends anteroventrally to different degrees in different taxa, which facilitates retraction of the femur; and the limb bones show allometric growth in terms of length and width.

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SPIDER DRAGLINE SILK: CORRELATED AND MOSAIC EVOLUTION IN HIGH-PERFORMANCE BIOLOGICAL MATERIALS

Evolution ◽

10.1554/06-267.1 ◽

2006 ◽

Vol 60 (12) ◽

pp. 2539 ◽

Cited By ~ 6

Author(s):

Brook O. Swanson ◽

Todd A. Blackledge ◽

Adam P. Summers ◽

Cheryl Y. Hayashi

Keyword(s):

High Performance ◽

Biological Materials ◽

Dragline Silk ◽

Spider Dragline Silk ◽

Mosaic Evolution

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MOSAIC EVOLUTION IN THE MIDDLE MIOCENE PLANKTONIC FORAMINIFERA GLOBOROTALIA FOHSI LINEAGE

10.1130/abs/2016am-285252 ◽

2016 ◽

Author(s):

Weimin Si ◽

◽

William Berggren ◽

Marie-Pierre Aubry

Keyword(s):

Middle Miocene ◽

Planktonic Foraminifera ◽

Mosaic Evolution

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POSTCRANIAL REMAINS OF A SAUROPODOMORPH DINOSAUR FROM THE LOWER JURASSIC OF ANTARCTICA

10.1130/abs/2016nc-275471 ◽

2016 ◽

Author(s):

Lucas J. Ratzer ◽

Keyword(s):

Lower Jurassic ◽

Postcranial Remains

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Rhinocerotidae from the early Miocene of the Negev (Israel) and implications for the dispersal of early Neogene rhinoceroses

Journal of Paleontology ◽

10.1017/jpa.2021.64 ◽

2021 ◽

pp. 1-12

Author(s):

Luca Pandolfi ◽

Ran Calvo ◽

Ari Grossman ◽

Rivka Rabinovich

Keyword(s):

Southeast Asia ◽

South Asian ◽

North Africa ◽

Range Expansion ◽

New Records ◽

Ct Scanning ◽

Early Miocene ◽

Early Neogene ◽

Postcranial Remains

Abstract A revision of the rhinocerotid material from the Negev (Israel), dating back to the early Miocene (MN3 in the European Mammal Biochronology), highlights the presence of Brachypotherium and a taxon close to Gaindatherium in the Levantine corridor. A juvenile mandible, investigated using CT scanning, displays morphologically distinct characters consistent with Brachypotherium cf. B. snowi rather than with other Eurasian representatives of this genus. Some postcranial remains from the Negev, such as a humerus, display features that distinguish it among Miocene taxa. We attribute these postcrania to cf. Gaindatherium sp., a taxon never recorded outside the Siwaliks until now. This taxon dispersed into the Levantine region during the late early Miocene, following a pattern similar to other South Asian taxa. Brachypotherium cf. B. snowi probably occurred in the Levantine region and then in North Africa during the early Miocene because its remains are known from slightly younger localities such as Moghara (Egypt) and Jebel Zelten (Libya). The occurrence cf. Gaindatherium sp. represents a previously unrecorded range expansion out of Southeast Asia. These new records demonstrate the paleogeographic importance of the Levantine region showcasing the complex role of the Levantine corridor in intercontinental dispersals between Asia and Europe as well as Eurasia and Africa.

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