scholarly journals New information on the early Permian lanthanosuchoid Feeserpeton oklahomensis based on computed tomography

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7753 ◽  
Author(s):  
Mark J. MacDougall ◽  
Anika Winge ◽  
Jasper Ponstein ◽  
Maren Jansen ◽  
Robert R. Reisz ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Phylogenetic Analyses ◽  
Lower Permian ◽  
Early Permian ◽  
Mandibular Ramus ◽  
Cave Deposits ◽  
New Information ◽  
The Many ◽  
Anatomical Information ◽  
Tomography Data

The cave deposits of the Lower Permian Richards Spur locality in Oklahoma, USA, have produced an incredible number of terrestrial tetrapod taxa, many of which are currently only known from this locality. One of the many recent taxa to be described from the locality was the small lanthanosuchoid parareptile Feeserpeton oklahomensis. Represented by a well-preserved, near complete skull, F. oklahomensis would have been a small predatory reptile, likely preying upon arthropods, and contributes to the extensive tetrapod fauna that was present at Richards Spur. New computed tomography data of the holotype and only specimen has allowed us to visualize and describe previously obscured and inaccessible anatomy of this taxon. These areas include the mandibular ramus, the palate, the sphenethmoid, the epipterygoids, and the braincase. Furthermore, this new anatomical information allowed formerly unknown character codings to be updated, thus we also performed new phylogenetic analyses that incorporated this new information. The results of these updated phylogenetic analyses are very similar to those of past studies, with F. oklahomensis being found as the sister taxon to all other lanthanosuchoids.

Aspects of the postcranial skeleton of the Lower Permian lungfish, Gnathorhiza

1989 ◽  
Vol 63 (6) ◽  
pp. 919-930 ◽  
Author(s):  
Walter W. Dalquest ◽  
M. John Kocurko ◽  
John V. Grimes
Keyword(s):  
Axial Skeleton ◽  
Lower Permian ◽  
Fish Scales ◽  
Early Permian ◽  
Postcranial Skeleton ◽  
Caudal Fin ◽  
North Central ◽  
New Information ◽  
Central Texas ◽  
Median Fins

A newly discovered locality of aestivation burrow casts containing the lungfish, Gnathorhiza serrata, is reported from the early Permian Arroyo Formation of Wilbarger County, north-central Texas. Remains preserved in the burrow casts provide sections of mummified Gnathorhiza and new information about the postcranial skeleton of this fish. Scales of Gnathorhiza resemble those of the modern lungfishes such as Lepidosiren in their microanatomy. No traces of paddle-like pectoral or pelvic fins were found and paired fins of Gnathorhiza may have resembled those of Lepidosiren. The axial skeleton and median fins of Gnathorhiza seem to resemble those of Lepidosiren except that the tail area and caudal fin of Gnathorhiza were stout and strong rather than slender and tapering. Gnathorhiza, which aestivated tail-down in its burrow, may have required a stout tail for support.

Rediscovery and redescription of Marmosa (Stegomarmosa) andersoni Pine (Mammalia: Didelphimorphia: Didelphidae), an endemic Peruvian mouse opossum, with a reassessment of its affinities

Zootaxa ◽  
2008 ◽  
Vol 1756 (1) ◽  
pp. 49 ◽  
Author(s):  
SERGIO SOLARI ◽  
RONALD H. PINE
Keyword(s):  
Natural History ◽  
Type Species ◽  
Phylogenetic Analyses ◽  
Morphological Characters ◽  
Geographic Range ◽  
Single Specimen ◽  
New Information ◽  
History Of ◽  
The Many ◽  
Detailed Diagnosis

Mouse opossums of the genus Marmosa Gray (Didelphidae) represent a complex of taxa with poorly understood affinities. Species now placed within this genus are mostly the leftovers from previous taxonomic arrangements. Even the most recent and complete revisions have not fully resolved the relationships among Marmosa and the many taxa previously included in Marmosa or listed as synonyms of it. Herein, we review and discuss one of these taxa, Stegomarmosa, based on new specimens that significantly increase our knowledge of the morphological diversification of the group. Until recently, this genus/subgenus has been known only from a single specimen taken more than 50 years ago in southeastern Peru. In 1997-1998, six additional specimens were collected at two little-separated localities almost 200 km NW of the type locality. We include a detailed diagnosis of the genus-group Stegomarmosa and its type species, M. andersoni, and update the distribution for and provide new information on the natural history of the latter. We also discuss published claims, concerning geographic range, that may be inaccurate and misleading. Finally, we scored the morphological characters used in the most recent phylogenetic analyses of the didelphids, in order to explore the affinities of M. andersoni and to determine the distinctiveness of the taxon Stegomarmosa.

scholarly journals The braincase, brain and palaeobiology of the basal sauropodomorph dinosaur Thecodontosaurus antiquus

2020 ◽  
Author(s):  
Antonio Ballell ◽  
J Logan King ◽  
James M Neenan ◽  
Emily J Rayfield ◽  
Michael J Benton
Keyword(s):  
Computed Tomography ◽  
Foramen Magnum ◽  
Lateral View ◽  
Late Triassic ◽  
Bipedal Stance ◽  
New Information ◽  
Tomography Data ◽  
Basal Position

Abstract Sauropodomorph dinosaurs underwent drastic changes in their anatomy and ecology throughout their evolution. The Late Triassic Thecodontosaurus antiquus occupies a basal position within Sauropodomorpha, being a key taxon for documenting how those morphofunctional transitions occurred. Here, we redescribe the braincase osteology and reconstruct the neuroanatomy of Thecodontosaurus, based on computed tomography data. The braincase of Thecodontosaurus shares the presence of medial basioccipital components of the basal tubera and a U-shaped basioccipital–parabasisphenoid suture with other basal sauropodomorphs and shows a distinct combination of characters: a straight outline of the braincase floor, an undivided metotic foramen, an unossified gap, large floccular fossae, basipterygoid processes perpendicular to the cultriform process in lateral view and a rhomboid foramen magnum. We reinterpret these braincase features in the light of new discoveries in dinosaur anatomy. Our endocranial reconstruction reveals important aspects of the palaeobiology of Thecodontosaurus, supporting a bipedal stance and cursorial habits, with adaptations to retain a steady head and gaze while moving. We also estimate its hearing frequency and range based on endosseous labyrinth morphology. Our study provides new information on the pattern of braincase and endocranial evolution in Sauropodomorpha.

scholarly journals Revised Description of the Early Permian Recumbirostran “Microsaur” Nannaroter mckinziei Based on New Fossil Material and Computed Tomographic Data

2021 ◽  
Vol 9 ◽  
Author(s):  
Mark J. MacDougall ◽  
Robert Seeger ◽  
Bryan Gee ◽  
Jasper Ponstein ◽  
Maren Jansen ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Early Permian ◽  
Computed Tomographic ◽  
Lower Jaw ◽  
Fossil Material ◽  
New Information ◽  
Ct Analysis ◽  
Tomographic Data ◽  
Ct Data ◽  
Phylogenetic Character

The early Permian Richards Spur locality of Oklahoma has produced abundant material of numerous terrestrial fossil tetrapods, including various “microsaurs,” several of which are considered to belong to the clade Recumbirostra. We present a new partial skull of the recumbirostran “microsaur” Nannaroter mckinziei; through computed tomography (CT) analysis of both this new specimen and the holotype, we provide an updated description of the taxon. This new description provides novel information regarding several regions that could not be examined previously due to either being absent in the holotype or difficult to access. This includes missing and obscured aspects of the skull roof, braincase, lower jaw, and the palatal region. Furthermore, the new information obtained from this description was used to update phylogenetic character codings of Nannaroter, and a revised phylogenetic analysis was conducted. The results of this updated analysis are congruent with those of other recent phylogenetic analyses of recumbirostran “microsaurs.” This new information adds to the ever-growing body of early tetrapod CT data, which has been, and will continue to be, important in revealing details regarding early tetrapod anatomy, interrelationships, paleoecology, and evolution.

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