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Triassic strata of the Economy Member of the Wolfville Formation (Newark Supergroup) exposed along the shorelines in Colchester County, Nova Scotia, have yielded an assemblage of continental tetrapods that is clearly different from other Triassic tetrapod communities in eastern North America, including the Late Triassic (Carnian) one from the overlying Evangeline Member of the Wolfville Formation. Although dissociated and fragmentary, the skeletal elements document the presence of a lonchorhynchine trematosaurid and at least two taxa of capitosauroid temnospondyls, procolophonid parareptiles, several taxa of archosauromorph reptiles, and a kannemeyeriiform dicynodont synapsid. Particularly noteworthy is the first definite record of the long-necked archosauromorph Tanystropheus from eastern North America. The strata of the Economy Member were deposited in a semiarid setting but the presence of various temnospondyls indicates the existence of perennial bodies of water. The age of this unit has long been regarded as Middle Triassic (Anisian to Ladinian) based on the tetrapod record, and the present study supports this assessment. The tetrapod assemblage most closely resembles those from the upper Moenkopi Formation of the American Southwest and the upper Middle to Upper Buntsandstein of Germany. The Economy Member is the oldest known Triassic tetrapod-bearing stratigraphic unit as well as the first occurrence of Middle Triassic continental tetrapods in eastern North America. [ABSTRACT FROM AUTHOR]

A new taxon of sphenodontian reptile, Micromenodon pitti new genus new species is described from the Upper Triassic (Carnian) Vinita Formation of the Richmond basin of the Newark Supergroup in Virginia. It is diagnosed by a dorsoventrally deep facial process of the maxilla that extends for almost the entire anteroposterior length of the bone and by obtusely conical, strongly ribbed additional teeth in the maxilla that comprise a greatly enlarged tooth followed by smaller teeth posteriorly. Phylogenetic analysis found Micromenodon pitti n. gen. n. sp. as an early-diverging sphenodontian with fully acrodont tooth implantation. The maxillary dentition appears functionally suited for processing hard arthropod exoskeletons and snail shells. UUID: http://zoobank.org/40ed7cb6-4867-464b-8bfb-db07febfe97c [ABSTRACT FROM AUTHOR]

The origin of the unique body plan of turtles has long been one of the most intriguing mysteries in evolutionary morphology. Discoveries of several new stem‐turtles, together with insights from recent studies on the development of the shell in extant turtles, have provided crucial new information concerning this subject. It is now possible to develop a comprehensive scenario for the sequence of evolutionary changes leading to the formation of the turtle body plan within a phylogenetic framework and evaluate it in light of the ontogenetic development of the shell in extant turtles. The fossil record demonstrates that the evolution of the turtle shell took place over millions of years and involved a number of steps. [ABSTRACT FROM AUTHOR]

Teraterpeton hrynewichorum is an unusual archosauromorph reptile from the Upper Triassic (Carnian) Evangeline Member of the Wolfville Formation in Nova Scotia (Canada). Its long snout has transversely broad, cusped 'molariform' teeth posteriorly and lacks teeth anteriorly. The temporal region of the cranium is 'euryapsid' with large upper and closed lower temporal fenestrae. A previously undescribed specimen referable to Teraterpeton includes a nearly complete pelvic girdle and both hind limbs. The ilium has a long, dorsoventrally deep anterior process similar to that of derived rhynchosaurs. The pelvis has a well-developed thyroid fenestra, a feature shared only by Tanystropheidae among Archosauromorpha. Metatarsal V is proximodistally short, resembling the condition in Tanystropheidae. The pedal unguals of Teraterpeton are strongly flattened mediolaterally, dorsoventrally deep and weakly curved, much like the manual unguals. We performed a phylogenetic analysis of a matrix comprising 61 taxa of Permo-Triassic diapsid reptiles and 337 characters, which supports the position of Teraterpeton as the sister-taxon of Trilophosaurus + Spinosuchus. In the current phylogeny, parsimony-based character optimization of the aforementioned character-states in Teraterpeton indicate that all were acquired independently from other saurian lineages. The unusual combination of postcranial features in Teraterpeton underscores the critical importance of comprehensive taxon sampling for understanding the mode of character change among Triassic diapsid reptiles and careful apomorphy-based identifications to faunal analyses. [ABSTRACT FROM AUTHOR]

In the present paper, we provide a comprehensive revision of the large-sized neosuchians Kansajsuchus and ' Turanosuchus ' from the Late Cretaceous of Central Asia. Kansajsuchus extensus from the Kansai locality of the Yalovach Formation, Tadzhikistan, is confirmed as a valid taxon. Previously hypothesized goniopholidid affinities of Kansajsuchus are not supported. Our phylogenetic analyses found this taxon as a derived member of the family-level taxon Paralligatoridae. With a dorsal cranial length of 70–80 cm and a total body length reaching 5–7 m, Kansajsuchus extensus is among the largest known paralligatorids and derived neosuchians in general. The large-sized neosuchian from the Shakh Shakh locality of the Bostobe Formation, Kazakhstan, previously identified as Kansajsuchus spp. ' Turanosuchus aralensis ', or Neosuchia indet. with allegedly goniopholidid affinities, is a paralligatorid closely related to K. extensus. The taxonomic composition, internal relationships and geographical distribution of Paralligatoridae are reconsidered. Paralligatoridae is an endemic clade from the Cretaceous of Asia comprising four recognized genera (Paralligator, Shamosuchus, Rugosuchus and Kansajsuchus), which is characterized by the unique suite of osteodermal features (paravertebral osteoderms with high dorsal keels restricted to posterior margins, arranged in more than two rows and lacking anterolateral processes). [ABSTRACT FROM AUTHOR]

Pappochelys extends the fossil record of Triassic stem-turtles back by some 20 million years, and provides important new insights into how and in what sequence the key features of turtles arose. It shares various derived features with the early Late Triassic stem-turtle Odontochelys, such as T-shaped ribs, a short trunk, and features of the girdles and limbs. At the same time, it is more plesiomorphic in retaining a fully diapsid skull and in lacking both neurals and a plastron with plate-like elements. Pappochelys provides important new evidence that the carapace and plastron of turtles are distinct moieties that evolved independently from each other. The skull of Pappochelys is more or less triangular in plan view. The marginal dentition comprises peg-like teeth with subthecodont implantation. Whereas the upper temporal fenestra is relatively small and rounded, the lower temporal opening is large and ventrally open. The slender vomers are fused. The vertebral column of Pappochelys comprises probably eight cervical, probably nine dorsal, two sacral, and more than 24 caudal vertebrae. The dorsal ribs have asymmetrical anterior and posterior flanges and their external surfaces are heavily ornamented. The gastralia form pairs of robust elements, one per vertebral segment. The scapula has a slender dorsal shaft and a rounded ‘acromial’ flange. The humerus has a slightly dorsally raised proximal head and a gently sigmoidal curvature. The pubis closely resembles that of Odontochelys in overall shape and has a well-developed lateral process. We performed a phylogenetic analysis using a modified character-taxon matrix (272 characters, 50 taxa) from a recent study to assess the placement of Pappochelys among amniotes. Pappochelys was found to nest among Pantestudines with Eunotosaurus and the more derived Odontochelys and Proganochelys. The diapsid affinities of turtles are well supported but it is still unresolved whether turtles are saurians or only related to the latter. [ABSTRACT FROM AUTHOR]

The Legacy of the Mastodon: The Golden Age of Fossils in America. Keith Thomson. Yale University Press, New Haven, CT, 2008. 424 pp., illus. $35.00 (ISBN 9780300117042 cloth). Keith Stewart [...]