RESUMEN
The Placerias/Downs' Quarry complex in eastern Arizona, USA, is the most diverse Upper Triassic vertebrate locality known. We report a new short-faced archosauriform, Syntomiprosopus sucherorum gen. et sp. nov., represented by four incomplete mandibles, that expands that diversity with a morphology unique among Late Triassic archosauriforms. The most distinctive feature of Syntomiprosopus gen. nov. is its anteroposteriorly short, robust mandible with 3-4 anterior, a larger caniniform, and 1-3 "postcanine" alveoli. The size and shape of the alveoli and the preserved tips of replacement teeth preclude assignment to any taxon known only from teeth. Additional autapomorphies of S. sucherorum gen. et sp. nov. include a large fossa associated with the mandibular fenestra, an interdigitating suture of the surangular with the dentary, fine texture ornamenting the medial surface of the splenial, and a surangular ridge that completes a 90° arc. The external surfaces of the mandibles bear shallow, densely packed, irregular, fine pits and narrow, arcuate grooves. This combination of character states allows an archosauriform assignment; however, an associated and similarly sized braincase indicates that Syntomiprosopus n. gen. may represent previously unsampled disparity in early-diverging crocodylomorphs. The Placerias Quarry is Adamanian (Norian, maximum depositional age ~219 Ma), and this specimen appears to be an early example of shortening of the skull, which occurs later in diverse archosaur lineages, including the Late Cretaceous crocodyliform Simosuchus. This is another case where Triassic archosauriforms occupied morphospace converged upon by other archosaurs later in the Mesozoic and further demonstrates that even well-sampled localities can yield new taxa.
Asunto(s)
Dinosaurios , Fósiles , Animales , Arizona , Dinosaurios/anatomía & histología , Cabello , Cráneo/anatomía & histologíaRESUMEN
Fossil hominin footprints preserve data on a remarkably short time scale compared to most other fossil evidence, offering snapshots of organisms in their immediate ecological and behavioral contexts. Here, we report on our excavations and analyses of more than 400 Late Pleistocene human footprints from Engare Sero, Tanzania. The site represents the largest assemblage of footprints currently known from the human fossil record in Africa. Speed estimates show that the trackways reflect both walking and running behaviors. Estimates of group composition suggest that these footprints were made by a mixed-sex and mixed-age group, but one that consisted of mostly adult females. One group of similarly-oriented trackways was attributed to 14 adult females who walked together at the same pace, with only two adult males and one juvenile accompanying them. In the context of modern ethnographic data, we suggest that these trackways may capture a unique snapshot of cooperative and sexually divided foraging behavior in Late Pleistocene humans.
Asunto(s)
Fósiles/anatomía & histología , Hominidae/fisiología , Animales , Femenino , Pie/anatomía & histología , Pie/crecimiento & desarrollo , Pie/fisiología , Fósiles/historia , Marcha , Historia Antigua , Hominidae/crecimiento & desarrollo , Locomoción , Masculino , Tanzanía , CaminataRESUMEN
BACKGROUND: Alemtuzumab is a humanized anti-CD52 monoclonal antibody that is increasingly used in solid organ transplantation. OBJECTIVE: The novel mechanism by which alemtuzumab works was used to provide an understanding of its clinical efficacy and adverse effects. METHODS: Human studies of alemtuzumab in adult renal and pancreas transplantation were reviewed. These studies looked at the role of alemtuzumab as a tolerogenic and induction agent as well as its role in the treatment of acute rejection. RESULTS/CONCLUSIONS: Overall, alemtuzumab induction resulted in patient and graft outcomes comparable to other induction strategies but studies failed to show development of true tolerance. Economic benefit is a major attraction for alemtuzumab use. Future studies will further identify the optimal use of alemtuzumab.