Earliest Palaeocene purgatoriids and the initial radiation of stem primates.

Plesiadapiform mammals, as stem primates, are key to understanding the evolutionary and ecological origins of Pan-Primates and Euarchonta. The Purgatoriidae, as the geologically oldest and most primitive known plesiadapiforms and one of the oldest known placental groups, are also central to the evolutionary radiation of placentals and the Cretaceous-Palaeogene biotic recovery on land. Here, we report new dental fossils of Purgatorius from early Palaeocene (early Puercan) age deposits in northeastern Montana that represent the earliest dated occurrences of plesiadapiforms. We constrain the age of these earliest purgatoriids to magnetochron C29R and most likely to within 105-139 thousand years post-K/Pg boundary. Given the occurrence of at least two species, Purgatorius janisae and a new species, at the locality, we provide the strongest support to date that purgatoriids and, by extension, Pan-Primates, Euarchonta and Placentalia probably originated by the Late Cretaceous. Within 1 million years of their arrival in northeastern Montana, plesiadapiforms outstripped archaic ungulates in numerical abundance and dominated the arboreal omnivore-frugivore niche in mammalian local faunas.

A new tyrannosaur with evidence for anagenesis and crocodile-like facial sensory system.

A new species of tyrannosaurid from the upper Two Medicine Formation of Montana supports the presence of a Laramidian anagenetic (ancestor-descendant) lineage of Late Cretaceous tyrannosaurids. In concert with other anagenetic lineages of dinosaurs from the same time and place, this suggests that anagenesis could have been a widespread mechanism generating species diversity amongst dinosaurs, and perhaps beyond. We studied the excellent fossil record of the tyrannosaurid to test that hypothesis. Phylogenetic analysis places this new taxon as the sister species to Daspletosaurus torosus. However, given their close phylogenetic relationship, geographic proximity, and temporal succession, where D. torosus (~76.7-75.2 Ma) precedes the younger new species (~75.1-74.4 Ma), we argue that the two forms most likely represent a single anagenetic lineage. Daspletosaurus was an important apex predator in the late Campanian dinosaur faunas of Laramidia; its absence from later units indicates it was extinct before Tyrannosaurus rex dispersed into Laramidia from Asia. In addition to its evolutionary implications, the texture of the facial bones of the new taxon, and other derived tyrannosauroids, indicates a scaly integument with high tactile sensitivity. Most significantly, the lower jaw shows evidence for neurovasculature that is also seen in birds.

The Evolution of Diapsid Reproductive Strategy with Inferences about Extinct Taxa.

Diapsids show an extremely wide range of reproductive strategies. Offspring may receive no parental care, care from only one sex, care from both parents, or care under more complex regimes. Young may vary from independent, super-precocial hatchlings to altricial neonates needing much care before leaving the nest. Parents can invest heavily in a few young, or less so in a larger number. Here we examine the evolution of these traits across a composite phylogeny spanning the extant diapsids and including the limited number of extinct taxa for which reproductive strategies can be well constrained. Generalized estimating equation(GEE)-based phylogenetic comparative methods demonstrate the influences of body mass, parental care strategy and hatchling maturity on clutch volume across the diapsids. The influence of polygamous reproduction is not important despite a large sample size. Applying the results of these models to the dinosaurs supports the hypothesis of paternal care (male only) in derived non-avian theropods, previously suggested based on simpler analyses. These data also suggest that sauropodomorphs did not care for their young. The evolution of parental-care occurs in an almost linear series of transitions. Paternal care rarely gives rise to other care strategies. Where hatchling condition changes, diapsids show an almost unidirectional tendency of evolution towards increased altriciality. Transitions to social monogamy from the ancestral state in diapsids, where both sexes are polygamous, are common. In contrast, once evolved, polygyny and polyandry are very evolutionarily stable. Polygyny and maternal care correlate, as do polyandry and paternal care. Ancestral-character estimation (ACE) of these care strategies with the character transition likelihoods estimated from the original data gives good confidence at most important nodes. These analyses suggest that the basalmost diapsids had no parental care. Crocodilians independently evolved maternal care, paternal care evolved in the saurischian line, prior to derived theropod dinosaurs, and the most basal neognaths likely exhibited biparental care. Overall, the evolution of parental care among diapsids shows a persistent trend towards increased care of offspring, and more complex care strategies and behaviors with time. Reversions to reduced care are infrequent.

Assessing the Control of Preservational Environment on Taphonomic and Ecological Patterns in an Oligocene Mammal Fauna from Badlands National Park, South Dakota.

Comparisons of paleofaunas from different facies are often hampered by the uncertainty in the variation of taphonomic processes biasing the paleoecological parameters of interest. By examining the taphonomic patterns exhibited by different facies in the same stratigraphic interval and area, it is possible to quantify this variation, and assess inter-facies comparability. The fossil assemblages preserved in Badlands National Park (BNP), South Dakota, have long been a rich source for mammalian faunas of the White River Group. To investigate the influence of the variation of taphonomic bias with lithology whilst controlling for the influence of changes in patterns of taphonomic modification with time, taphonomic and paleoecological data were collected from four mammal-dominated fossil assemblages (two siltstone hosted and two sandstone hosted) from a narrow stratigraphic interval within the Oligocene Poleslide Member of the Brule Formation, in the Palmer Creek Unit of BNP. Previous work in the region confirmed that the two major lithologies represent primarily aeolian- and primarily fluvial-dominated depositional environments, respectively. A suite of quantifiable taphonomic and ecological variables was recorded for each of the more than 800 vertebrate specimens studied here (857 specimens were studied in the field, 9 specimens were collected and are reposited at BNP). Distinctly different patterns of taphonomic biasing were observed between the aeolian and fluvial samples, albeit with some variability between all four sites. Fluvial samples were more heavily weathered and abraded, but also contained fewer large taxa and fewer tooth-bearing elements. No quantifiable paleofaunal differences in generic richness or evenness were observed between the respective facies. This suggests that while large vertebrate taxonomic composition in the region did vary with paleodepositional environment, there is no evidence of confounding variation in faunal structure, and therefore differences between the assemblages are attributed to differing preservational environments producing a taphonomic overprint on the assemblages. The lack of apparent taphonomic bias on paleofaunal structure suggests that such paleoecological data can be compared throughout the Poleslide Member, irrespective of lithology.

TEVAR Rescue of an Embolized Edwards SAPIEN XT Valve Following TAVR.

PURPOSE: To report a successful method of managing an embolized Edwards SAPIEN XT aortic valve prosthesis using a thoracic endovascular aortic repair rescue. CASE REPORT: An 84-year-old man underwent transcatheter aortic valve replacement using a 26-mm Edwards SAPIEN XT valve, which immediately embolized into the ascending aorta. Because of the severe tapering of the patient's transverse aortic arch, the embolized valve was unable to be maneuvered further down the aorta. Therefore, a Cook 36×80-mm Zenith Dissection Endovascular System (ZDES) bare metal stent was used on a compassionate basis to append the embolized valve between the patient's coronary artery ostia and the innominate artery takeoff within the ascending aorta, with no neurological or cardiovascular complications at 12-month follow-up. CONCLUSION: A Cook ZDES bare metal stent may be successfully used to append an embolized Edwards SAPIEN XT valve within the ascending aorta.

Neuroendocrine tumors of the rectum: a 10-year review of management.

Neuroendocrine tumors of the rectum constitute approximately 19 per cent of gastrointestinal neuroendocrine tumors (NETs). The histologic characteristics of the tumor seem to be an indicative prognostic factor. Optimal treatment of NETS of the rectum has been widely debated, but more recent studies suggest that treatment depends upon the size. The medical records of 37 patients with NETS of the rectum were retrospectively reviewed. We reviewed their presentation, surgical treatment, pathology, and outcome. All pathological specimens were reviewed. Neuroendocrine tumors of the rectum were classified as either well-differentiated tumors, well-differentiated neuroendocrine carcinoma, or poorly differentiated neuroendocrine carcinoma. Evaluating tumor size, we found 35/37 patients had tumors less than 1 cm, 1 patient had a tumor between 1 and 2 cm, and one had a tumor greater than 2 cm. Pathologic evaluation of the tumors revealed that 35 of the tumors invaded the submucosa only, one invaded the muscularis propria, and one invaded the perirectal adipose tissue. The histopathologic features of the tumors revealed that 34 of the tumors were well-differentiated NETS with benign features, one tumor had invaded the submucosa, with angioinvasion, and two tumors were neuroendocrine carcinoma. Thirty-five patients underwent local excision. Eleven had reexcisions for positive margins. Two patients had local excision for recurrence, and one patient underwent low anterior resection (4 cm). Twelve patients had negative margins, 25 had positive margins. Eleven patients underwent reexcision. Six had no evidence of residual disease, and five had persistent positive margins and were offered no further treatment. Nineteen patients had positive margins and did not have reexcision. They all had tumors < 1 cm. Despite half of the lesions being resected with final pathologic positive margins, we have seen no significant influence on recurrence or overall survival. This raises the question of margin clearance in early lesions.

Avian paternal care had dinosaur origin.

The repeated discovery of adult dinosaurs in close association with egg clutches leads to speculation over the type and extent of care exhibited by these extinct animals for their eggs and young. To assess parental care in Cretaceous troodontid and oviraptorid dinosaurs, we examined clutch volume and the bone histology of brooding adults. In comparison to four archosaur care regressions, the relatively large clutch volumes of Troodon, Oviraptor, and Citipati scale most closely with a bird-paternal care model. Clutch-associated adults lack the maternal and reproductively associated histologic features common to extant archosaurs. Large clutch volumes and a suite of reproductive features shared only with birds favor paternal care, possibly within a polygamous mating system. Paternal care in both troodontids and oviraptorids indicates that this care system evolved before the emergence of birds and represents birds' ancestral condition. In extant birds and over most adult sizes, paternal and biparental care correspond to the largest and smallest relative clutch volumes, respectively.