Halgaitosaurus gregarius is a new genus and species of araeoscelidian diapsid reptile based on numerous specimens from the Upper Carboniferous (Virgilian, Gzhelian) Birthday bonebed, Halgaito Formation, Valley of the Gods, Bears Ears National Monument, Utah, USA. An ontogenetic series is represented by juvenile to fully ossified adult specimens. halgaitosaurus gregarius is distinguished from other araeoscelidians by relative sizes of maxillary teeth, a small contribution of the jugal to the ventral margin of the skull, and eight cervical vertebrae. A phylogenetic analysis suggests that halgaitosaurus and Araeoscelis Williston, 1910, form a clade in a monophyletic Araeoscelidia, with Petrolacosaurus Lane, 1945, and Zarcasaurus Brinkman, Berman, and Eberth, 1984, forming successive sister taxa to this clade. Spinoaequalis deBraga and Reisz, 1995, places as a member of Neodiapsida. halgaitosaurus was an abundant component of the vertebrate fauna that inhabited the coastal plain on the southwestern border of the Paradox Basin in western Pangea during a relatively short period when intermittent to probable perennial streams and rivers traversed it during an otherwise semi-arid to arid climate.

The Bromacker vertebrate fossil assemblage is strikingly unique compared to those of the highly fossiliferous, widespread Early Permian deposits of the USA in exhibiting: 1) total absence of aquatic and semi-terrestrial forms, 2) greatly reduced abundance and diversity of basal synapsids (“pelycosaurs”) that fulfilled the role of apex predators, and 3) high abundance and diversity of terrestrial herbivorous taxa. That is, the composition of the Bromacker vertebrate assemblage and the relative abundances of its taxa are difficult to reconcile with current knowledge of the well-documented examples of the Early Permian mixed aquatic-to-terrestrial trophic systems in the USA. The explanation given here for these unique paleobiological features is that the vertebrate assemblage reflects an adaptation to a rarely encountered paleoenvironment, the small, far inland, isolated, internally drained Tambach Basin. It is hypothesized that the Early Permian Bromacker assemblage is unique in representing an initial stage in the evolution of the modern terrestrial trophic system or food chain.

Shrews (Mammalia: Eulipotyphla: Soricidae) reach the southern limit of their New World distribution in the Andes and eastern coastal highlands of northern South America. South of Honduras, the family is represented only by species of the genus Cryptotis Pomel, 1848. In South America, soricids are restricted to moist, high-elevation environments above 1000 m, and their distribution appears to be discontinuous. Study of specimens from a previous gap in the known geographical range of shrews in the Central Cordillera of southwestern Colombia reveals the presence of two unique populations that are distinguishable from each other and their congeners by a combination of morphological and morphometrical characters. They are described herein as, Cryptotis huttereri, n. sp. and Cryptotis andinus, n. sp. Both species are members of the Cryptotis thomasi group, one of five species groups of small-eared shrews defined partly on the basis of postcranial morphology and potential locomotor behavior. Although species in the C. thomasi group share similar postcranial architecture, as exemplified by the morphology of the forelimb, the group appears to be polyphyletic, implying convergence in locomotor behavior, possibly one uniquely adapted for Andean-type montane habitats. Recognition of C. huttereri and C. andinus brings the total number of known South American soricids to 19 species, with 11 species occurring in Colombia. Of those, seven species are endemic to that country.