We used isotopic and genomic data to explore the ecological and social context of cultural practices associated with the mummification of crocodiles in ancient Egypt. Ancient DNA was recovered from four mummified crocodile hatchlings held in the collections of the Peabody Museum of Natural History, Yale University. Previous genetic analyses of crocodile mummies have indicated that most mummies represent the newly resurrected taxon, Crocodylus suchus Geoffroy Saint-Hilaire, 1807. However, mitogenomic data for the Yale Peabody Museum mummies indicates that these specimens represent the first genomically authenticated representatives of the Nile crocodile (Crocodylus niloticus Laurenti, 1768) in museum collections. We explore these findings within the broader context of modern and historical distributions of both crocodile species and the potential implications for our understanding of funerary practices involving crocodiles in ancient Egypt.

Pterygotid eurypterids are the most speciose eurypterid clade, accounting for almost a fifth of the approximately 250 known species, although it is unclear whether this increase in diversity is due to their increased dispersal ability, shift in predation style to cheliceral-driven prey capture, or some other factor. Determining if the development of their characteristic large chelicerae represents a key trait facilitating increased diversification is hindered by uncertainty regarding the form of the chelicerae in Slimonia, the sister taxon to Pterygotidae. Here I report the discovery of a specimen of Slimonia acuminata preserving the chelicerae in detail and corroborate reports from the 1800s suggesting that the chelicerae of Slimonia were short and robust. The evidence from the new specimen, taken in concert with the morphology of the rest of the animal, indicates that Slimonia was an active predator that captured prey with its robust prosomal appendages. The apparent increase in pterygotid species diversity therefore does indeed seem to be associated with the development of the large chelicerae; however, further work is needed to determine whether taphonomic biases in preservation due to increased sclerotization of the chelicerae or taxonomic oversplitting due to minor changes in denticle morphology are driving this phenomenon.

We describe tooth implantation, replacement, and attachment in a specimen of the procolophonid Scoloparia glyphanodon. Though an earlier description of the specimen made mention of the dentary, splenial, and coronoid, we identify a small sliver of the angular that is also present. We observe two modes of tooth implantation (protothecodonty and acrodonty) and no tooth replacement, though it is likely teeth were added posteriorly over time. Previous interpretations of tooth implantation in procolophonids were conflated with replacement patterns and mode of implantation. Additionally, the combination of dental characters of the specimen suggests Scoloparia glyphanodon had an herbivorous diet.