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Functional morphology and biomechanics of the cynodont Trucidocynodon riograndensis from the Triassic of Southern Brazil: Pectoral girdle and forelimb

100%
de Oliveira T. V., Schultz C. L.
Acta Palaeontologica Polonica
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2016
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tom 61
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nr 2
Non-mammalian cynodonts provide insights on several points about mammalian evolution, such as the postural change and locomotory advances within the group. Unfortunately, complete skeletons of Triassic cynodonts are rather uncommon and where more complete specimens are found they can offer a global vision on some traits not available from partial specimens. This is the case of the cynodont Trucidocynodon riograndensis, from the Triassic of Brazil, that has preserved its forelimbs providing some insights into locomotory properties. The movements between interclavicle and clavicle must have been limited, as such as those occurring between the latter and the scapulocoracoid although the long acromion process of this should have permitted a greater degree of freedom. Some of the more significant movements were those on the shoulder joint, in which the maximum adduction should have been ca. 35º relative to the parasagittal plane and the greater abduction ca. 55º. The maximum adduction occurred when the humerus was in the more retracted position during stride and the variation in the adduction/abduction should have been significant to the limb posture during its recovery stroke. The long olecranon and the distal overlapping between radius and ulna suggest the predominance of simple flexion/extension on the forearm without significant pronation/supination. The poorly preserved hand suggests that Trucidocynodon could have evolved a slight semidigitigrad condition in its forelimbs. All these features give to this cynodont an important role in the evolution of the mammalian locomotory properties indicating that some features, such as the possibility of greater humeral adduction, evolved early in cynodont lineage.
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The skull anatomy and cranial endocast of the pseudosuchid archosaur Prestosuchus chiniquensis from the Triassic of Brazil

81%
Mastrantonio B. M., Von Baczko M. B., Desojo J. B., Schultz C. L.
Acta Palaeontologica Polonica
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2019
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tom 64
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nr 1
Prestosuchus chiniquensis is the most famous “rauisuchian” described by Friedrich von Huene, eight decades ago, and several specimens have been assigned to this taxon since then. In the present contribution, we provide the first detailed description of a complete and very well preserved skull (including the braincase) assigned to Prestosuchus chiniquensis from the Dinodontosaurus Assemblage Zone of the Santa Maria Supersequence of southern Brazil. The detailed description of the skull of Prestosuchus chiniquensis, besides increasing the knowledge about this taxon, may help elucidate the taxonomic relationships of pseudosuchians even further, since most of the characters used in phylogenetic analyzes are cranial. The presence of the subnarial fenestra, a controvertial extra opening on the skull of “rauisuchians”, is thoroughly discussed considering the evidence provided by this new specimen. We consider that the small slit-opening between the premaxilla and the maxilla in Prestosuchus chiniquensis, can not safely be considered a true fenestra, but indicates more likely the existence of some degree of cranial kinesis between these elements which can result in different relative positions of the bones after definitive burial and fossilization, so that the size and shape of this opening is taphonomically controlled. Complementarily, the digital reconstruction of its cranial endocast was developed both from the observation of the preserved braincase and from CT scan images, which resulted in obtaining the first endocast known for a “rauisuchian”. The endocast of Prestosuchus chiniquensis exhibited some remarkable convergences with that of theropod dinosaurs, which could be a reflection of the similar niches they occupied, since “rauisuchians” were the top predators at the end of the Late Triassic, before the extinction of all non-crocodylomorph pseudosuchians.
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Tooth microstructure of the Early Permian aquatic predator Stereosternum tumidum

81%
Pretto F. A., Cabreira S. F., Schultz C. L.
Acta Palaeontologica Polonica
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2014
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tom 59
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nr 1
A histological investigation of the feeding apparatus of a Stereosternum specimen revealed a great number of adaptations in the structure and insertion of teeth, to deal with breakage risks. The tooth wall is composed of different layers of dentine, varying in orientation and composition. This mixed arrangement may have increased tooth resistance to lateral tension. The tooth insertion also involves more than one mechanism. The teeth are located inside shallow tooth sockets and are held in place by a tripartite periodontium (composed of alveolar bone, cementum and possibly soft periodontal tissue) and accessory structures, here termed anchorage trabeculae (mainly composed of cementum). Fully grown teeth are ankylosed to the bottom of the tooth socket. The recognition of alveolar bone and cementum (and the possible presence of a soft periodontal ligament) reinforces the idea that these tissues were widespread among Amniota, not being exclusive to mammals and archosaurs. The adaptations identified here reinforce the hypothesis that Stereosternum was an active aquatic predator.
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New information on the pterosaur Tupandactylus imperator, with comments on the relationships of Tapejaridae

71%
Pinheiro F. L., Fortier D. C., Schultz C. L., Andrade,de J. A. F. G., Bantim R. A. M.
Acta Palaeontologica Polonica
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2011
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tom 56
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nr 3
A new specimen of Tupandactylus imperator, comprising an incomplete skull with associated lower jaw, is described. The material is the best preserved specimen of this species known so far and provides new information on the anatomy of this pterodactyloid pterosaur, especially with respect to the morphology of the lower jaw, the first one formally described for the species. Also, the new specimen shows an extensive preservation of soft tissues such as the soft−tissue component of the headcrest, ramphoteca associated with the premaxillae and lower jaw, as well as probable pycnofibres. A phylogenetic analysis was performed in order to test the relationships of the taxon within Tapejaridae. The results of the analysis support Tapejaridae, as well as monophyly of Tapejarinae and Thalassodrominae.
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Tanystropheid archosauromorphs in the Lower Triassic of Gondwana

71%
De Oliveira T. M., Oliveira D., Schultz C. L., Kerber L., Pinheiro F. L.
Acta Palaeontologica Polonica
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2018
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tom 63
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nr 4
Tanystropheidae is a clade of early archosauromorphs with a reported distribution ranging from the Early to the Late Triassic of Asia, Europe, and North America. Although some specimens with possible tanystropheid affinities from the Lower Triassic beds of Brazil have been previously attributed to “Protorosauria”, little is known about the tanystropheid record in Gondwana. Here, two new and one previously reported specimen from the Sanga do Cabral Formation (Induan–Olenekian) of Brazil are described and interpreted as ?Tanystropheidae. These records, together with other tetrapods previously reported for the Sanga do Cabral Formation, increase the knowledge of the biotic diversification during the beginning of the Triassic. This contribution reinforces that the archosauromorph diversification occurred shortly after the Permo-Triassic extinction, making the Sanga do Cabral Formation an important unit for the study of early Mesozoic faunas.
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Effect of nitroethane administration on ruminal VFA production and specific activity of methane production

51%
Anderson E. C., Carstens G. E., Miller R. K., Callaway T. R., Schultz C. L., Edrington T. S., Harvey R. B., Nisbet D. J.
Journal of Animal and Feed Sciences. Supplement
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2004
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tom 13
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nr 1
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