Megaraptorans are medium- to large-bodied tetanuran theropod dinosaurs known from Cretaceous deposits in Asia, Australia, and especially South America. The megaraptoran skeleton is far from well known, and the humerus is one of the least-frequently preserved elements. Here we describe the first-documented adult humerus of a South American megaraptoran, recovered from the Upper Cretaceous (Turonian–Coniacian) Portezuelo Formation of the Neuquén Basin on the southeast coast of Lago Barreales in Neuquén Province, northern Patagonia, Argentina. The humerus is referred to the namesake megaraptoran Megaraptor namunhuaiquii Novas, 1998, based on its geographic and stratigraphic provenance as well as its morphological similarity to the corresponding element of a juvenile skeleton of the same taxon. Nevertheless, the new adult humerus exhibits osteological distinctions from that of the juvenile that we interpret as reflective of their differing ontogenetic stages. We also highlight anatomical differences between the humerus of M. namunhuaiquii and that of the enigmatic Patagonian theropod Gualicho shinyae Apesteguía et al., 2016, that show that these taxa are not closely related.

Burrowing skinks of the genus Sepsina Bocage, 1866 (Squamata: Scincidae) have a complex taxonomic history and are particularly diverse, although poorly known, in Angola. With elongated bodies and reduced limbs, the five recognized species of the genus can be diagnosed based on the presence or absence of forelimbs and the number and relative size of digits. Sepsina bayonii (Bocage, 1866) is the most distinctive species of the genus, being the only taxon without forelimbs and a single digit on the hind limbs. Revision of historical material from the collections of the California Academy of Sciences revealed the presence of two specimens without forelimbs, but differing from S. bayonii in the number of digits on each hind limb. Considering this unique combination of morphological diagnostic characters, we herein describe a new species from Angola, Sepsina caluanda. This discovery highlights the importance of natural history collections and the revision of historical material for the description of biodiversity and alerts to the threat of habitat loss due to rapid urban growth.

The demography of the northern watersnake, Nerodia sipedon sipedon (Linnaeus, 1758), was systematically studied over a 17-year period in a complex of artificial ponds on protected property in the northern Allegheny Mountains of southwestern Pennsylvania. Sexual maturity was reached by the age of three years in males and four years in females. Asymptotic body size was reached at 55 cm in five years in males and at 85 cm in seven years in females. Population size was estimated to be about 43 snakes per year, with most adult males ranging 50–59 cm in body size and adult females ranging 70–79 cm in body size. Annual survivorship, recapture probability, and population size all increased in the years after wetland renovation. Among first captures, male:female sex ratio was 0.29:1.00, and juveniles comprised 26.4% of the population. Most adults were approximately five years old, and recapture intervals indicated minimum maximum ages of eight years for both males (n = 1) and females (n = 2), with skeletochronology estimating maximum ages ranging 16–18 years among the oldest and largest females. Clutch sizes averaged 19 young. Two of the six swabbed females tested positive for Ophidiomyces but with low fungal loads. Many of the life history traits examined in our study population conformed to those of other northern watersnake populations at northern latitudes. However, our results were indicative of a large population subjected to strong selection against small individuals and conflicting rewards for increasing body size.

Assemblage structure, monthly activity, and occupancy were examined among surface-active salamanders with coverboard surveys in a mature forest from the Allegheny Mountains in southwestern Pennsylvania during February–October 2023. Among the five species detected, the Allegheny Mountain dusky salamander, Desmognathus ochrophaeus, was approximately two, four, and eight times more frequently encountered than the next three most-encountered species with at least one encounter. We found variation in the influence of both site- and survey-specific covariates among the different species, with occupancy probability being positively influenced by the distance to a major creek in two species. Detection probability covariates were more variable with survey temperature positively influencing two species and negatively for another. Comparisons with surveys conducted during 1982–1983, 2003, and 2020–2021 mirrored the highly uneven assemblage we detected in 2023. We argue that the interspecific interactions thought to shape assemblage structures in Plethodontidae may provide resiliency in the face of short-term shifts in activity and long-term climatic changes..

Dinoceratans or uintatheres are a phylogenetically enigmatic clade of extinct mammalian herbivores that were among the first eutherians to obtain truly massive body size. Uintatheres were reasonably common elements of North American mammal faunas spanning from the late Paleocene (late Tiffanian, Ti-5) through the middle Eocene (Uintan). However, prior records of North American uintatheres have been geographically restricted to the central Rockies, Texas, and California. Here, we report the first occurrence of a uintathere from the Kishenehn Formation in northern Montana, ∼750 km northwest of their previously known range. The Kishenehn uintathere is currently documented by a single upper molar bearing several characters that may indicate it pertains to a new taxon. Because various lineages of uintatheres are known to have inhabited North America and Asia, additional fossils from higher latitudes of North America could be essential in untangling their evolution, dispersal, and biogeographic history.