A pterodactyloid pterosaur from the Upper Cretaceous Lapurr sandstone, West Turkana, Kenya

An isolated pterosaurian caudal cervical (~ postcervical) vertebra was recovered from the Upper Cretaceous Lapurr sandstone ofWest Turkana, northwestern Kenya. The vertebral centrum is short, wide, and dorsoventrally compressed. Although the specimen is lightly built similar to most pterosaurs, it is here referred to Pterodactyloidea and tentatively to the Azhdarchidae in that it lacks pneumatic features on both the centrum and neural arch. This represents one of the few pterosaurs recovered from the entirety of Afro-Arabia, the first pterosaur recovered from the Cretaceous of East Africa, and, significantly, a specimen that was recovered from fluvial deposits rather than the near-shore marine setting typical of most pterosaur discoveries.Uma vértebra cervical caudal isolada de pterossauro (~ pós-cervical) foi recuperada do Cretáceo Superior do arenito de Lapurr do Oeste de Turkana, noroeste do Quênia. O centro vertebral é curto, largo e comprimido dorsoventralmente. Embora o espécime seja leve como grande parte dos pterossauros, ele é aqui referido a Pterodactyloidea e tentativamente a Azhdarchidae no que diz respeito à ausência de características pneumáticas tanto no centro quanto no arco neural. Este representa um dos poucos pterossauros recuperados do conjunto Afro-Arábia, o primeiro pterossauro proveniente do Cretáceo do Leste da África e, significativamente, um espécime que foi recuperado de depósitos fluviais e não do cenário marinho próximo da costa típico da maioria das descobertas de pterossauros

A description of a Denazinemys nodosa specimen (Testudinata, Baenidae) from the Late Cretaceous Kaiparowits Formation of southern Utah

Denazinemys nodosa is a Late Cretaceous representative of the North American turtle clade Baenidae diagnosed, among others, by a shell surface texture consisting of raised welts. We provide a detailed description of a partial skeleton from the late Campanian Kaiparowits Formation of Utah, USA, including bone-by-bone analysis of its cranium based on images obtained using micro-computed tomography. A revised phylogenetic analysis confirms placement of Denazinemys nodosa close to Eubaena cephalica and Boremys spp. within the clade Eubaeninae. Comparison with a second skull from the Kaiparowits Formation previously assigned to Denazinemys nodosa questions its referral to this taxon. An assortment of specimens from the Early to Late Campanian of Mexico and the USA had previously been referred to Denazinemys nodosa based on shell surface texture alone, even though this characteristic is known to occur in other baenids. Our review of all available material concludes that Denazinemys nodosa is currently only known from the Late Campanian of New Mexico and Utah

Overview of the discovery, distribution, and geological context of Simosuchus clarki (Crocodyliformes: Notosuchia) from the late cretaceous of madagascar

Simosuchus clarki is a bizarre, pug-nosed notosuchian crocodyliform known only from the Upper Cretaceous (Maastrichtian) Maevarano Formation in the Mahajanga Basin of northwestern Madagascar. When originally named and described in 2000, S. clarki was based entirely on a single specimen that included a nearly complete skull and lower jaw preserved in articulation with the anterior and mid-trunk portions of the postcranial skeleton, as well as several associated elements from the posterior region. The species is now represented by three additional partial and nearly complete articulated skeletons, as well as numerous isolated elements (mostly teeth), that permit detailed description of its entire bony anatomy, the primary subject of other chapters in this volume. These specimens were discovered as part of the \u27Mahajanga Basin Project,\u27 initiated in 1993 and conducted jointly by Stony Brook University and the Université d\u27Antananarivo, in the Berivotra and Masiakakoho study areas. The best-preserved specimens of S. clarki were entombed in massive, poorly sorted, clay-rich debris flow deposits (facics 2 of the Anembalemba Member) that accumulated in channel belts in response to exceptional rainfall events. Simosuchus, along with its contemporaries in the Maevarano assemblage, lived in a strongly seasonal, semi-arid climate some 20 million years after Madagascar separated from the India/Seychelles block and became an island isolated in the Indian Ocean. © 2010 by the Society of Vertebrate Paleontology

Overview of the discovery, distribution, and geological context of Simosuchus clarki (Crocodyliformes: Notosuchia) from the late cretaceous of madagascar

Simosuchus clarki is a bizarre, pug-nosed notosuchian crocodyliform known only from the Upper Cretaceous (Maastrichtian) Maevarano Formation in the Mahajanga Basin of northwestern Madagascar. When originally named and described in 2000, S. clarki was based entirely on a single specimen that included a nearly complete skull and lower jaw preserved in articulation with the anterior and mid-trunk portions of the postcranial skeleton, as well as several associated elements from the posterior region. The species is now represented by three additional partial and nearly complete articulated skeletons, as well as numerous isolated elements (mostly teeth), that permit detailed description of its entire bony anatomy, the primary subject of other chapters in this volume. These specimens were discovered as part of the \u27Mahajanga Basin Project,\u27 initiated in 1993 and conducted jointly by Stony Brook University and the Université d\u27Antananarivo, in the Berivotra and Masiakakoho study areas. The best-preserved specimens of S. clarki were entombed in massive, poorly sorted, clay-rich debris flow deposits (facics 2 of the Anembalemba Member) that accumulated in channel belts in response to exceptional rainfall events. Simosuchus, along with its contemporaries in the Maevarano assemblage, lived in a strongly seasonal, semi-arid climate some 20 million years after Madagascar separated from the India/Seychelles block and became an island isolated in the Indian Ocean. © 2010 by the Society of Vertebrate Paleontology

Refined geochronology and revised stratigraphic nomenclature of the Upper Cretaceous Wahweap Formation, Utah, U.S.A. and the age of early Campanian vertebrates from southern Laramidia

The Western Interior of North America preserves one of the most complete successions of Upper Cretaceous marine and non-marine strata in the world; among these, the Cenomanian-Campanian units of the Kaiparowits Plateau in southern Utah are a critical archive of terrestrial environments and biotas. Here we present new radioisotopic ages for the Campanian Wahweap Formation, along with lithostratigraphic revision, to improve the geological context of its fossil biota. The widely accepted informal stratigraphic subdivisions of the Wahweap Formation on the Kaiparowits Plateau are herein formalized and named the Last Chance Creek Member, Reynolds Point Member, Coyote Point Member, and Pardner Canyon Member (formerly the lower, middle, upper, and capping sandstone members respectively). Two high-precision U-Pb zircon ages were obtained from bentonites using CA-ID-TIMS, supported by five additional bentonite and detrital zircon LA-ICP-MS ages. Improved geochronology of the Star Seep bentonite from the base of the Reynolds Point Member via CA-ID-TIMS demonstrates that this important marker horizon is over a million years older than previously thought. A Bayesian age-stratigraphic model was constructed for the Wahweap Formation using the new geochronologic data, yielding statistically robust ages and associated uncertainties that quantifiably account for potential variations in sediment accumulation rate. The new chronostratigraphic framework places the lower and upper formation boundaries at 82.17 +1.47/-10.63 Ma and 77.29 +0.72/-0.62 Ma, respectively, thus constraining its age to the first half of the Campanian. Additionally, a holistic review of known vertebrate fossil localities from the Wahweap Formation was conducted to better understand their spatio-temporal distribution including revised ages for early members of iconic dinosaur lineages such as Tyrannosauridae, Hadrosauridae, and Centrosaurinae. Chronoand lithostratigraphic refinement of the Wahweap Formation and its constituent biotic assemblages establishes an important reference for addressing questions of Campanian terrestrial paleoecology and macroevolution, including dinosaur endemism and diversification throughout western North America

The evolution of mammal-like crocodyliforms in the\ud Cretaceous Period of Gondwana

Fossil crocodyliforms discovered in recent years have revealed a level of morphological and ecological diversity not exhibited by extant members of the group. This diversity is particularly notable among taxa of the Cretaceous Period (144–65 million years ago) recovered from former Gondwanan landmasses. Here we report the discovery of a new species of Cretaceous notosuchian crocodyliform from the Rukwa Rift Basin of southwestern Tanzania. This small-bodied form deviates significantly from more typical crocodyliform craniodental morphologies, having a short, broad skull, robust lower jaw, and a dentition with relatively few teeth that nonetheless show marked heterodonty. The presence of morphologically complex, complementary upper and lower molariform teeth suggests a degree of crown–crown contact during jaw adduction that is unmatched among known crocodyliforms, paralleling the level of occlusal complexity seen in mammals and their extinct relatives. The presence of another small-bodied mammal-like crocodyliform in the Cretaceous of Gondwana indicates that notosuchians probably filled niches and inhabited ecomorphospace that were otherwise occupied by mammals on northern continents

Data from: A new species of trionychid turtle from the Upper Cretaceous (Campanian) Fruitland Formation of New Mexico, U.S.A.

New shell material of a trionychid turtle from the Upper Cretaceous (upper Campanian) Fossil Forest Member of the Fruitland Formation of northwestern New Mexico represents a new species, Gilmoremys gettyspherensis. The material consists of right costals I–III, V, VI, and VIII, left costals V, VII, and VIII, the left half of the entoplastron, the right hypo- and xiphiplastron, and the left hyo-, hypo-, and xiphiplastron. The specimen shows great similarities with the Late Cretaceous (Maastrichtian) trionychid Gilmoremys lancensis by having a relatively thin shell, carapacial sculpturing consisting of fine pits combined with extended sinusoidal ridges or grooves, free costal rib ends, presence of a preneural, a distally constricted costal I and distally expanded costal II, two lateral hyoplastral processes, low hyoplastral shoulders, and full midline contact of the elongate xiphiplastra, but differs by being smaller, having raised sinusoidal ridges on the carapace instead of grooves, less distally expanded costals II, and less elongate xiphiplastra. Phylogenetic analysis places Gilmoremys gettyspherensis as sister to Gilmoremys lancensis near the base of the clade Plastomenidae. Like the majority of previously described plastomenid materials, the type specimen of Gilmoremys gettyspherensis was collected from a mudstone horizon, suggesting a preference for ponded environments