The functional significance of aberrant cervical counts in sloths: insights from automated exhaustive analysis of cervical range of motion.

Besides manatees, the suspensory extant 'tree sloths' are the only mammals that deviate from a cervical count (CC) of seven vertebrae. They do so in opposite directions in the two living genera (increased versus decreased CC). Aberrant CCs seemingly reflect neck mobility in both genera, suggesting adaptive significance for their head position during suspensory locomotion and especially increased ability for neck torsion in three-toed sloths.

Conical and sabertoothed cats as an exception to craniofacial evolutionary allometry.

Among evolutionary trends shaping phenotypic diversity over macroevolutionary scales, CREA (CRaniofacial Evolutionary Allometry) describes a tendency, among closely related species, for the smaller-sized of the group to have proportionally shorter rostra and larger braincases. Here, we used a phylogenetically broad cranial dataset, 3D geometric morphometrics, and phylogenetic comparative methods to assess the validity and strength of CREA in extinct and living felids. To test for the influence of biomechanical constraints, we quantified the impact of relative canine height on cranial shape evolution.

Revisiting proboscidean phylogeny and evolution through total evidence and palaeogenetic analyses including ancient DNA.

The extinct Gomphotheriidae is the only proboscidean family that colonized South America. The phylogenetic position of the endemic taxa has been through several revisions using morphological comparisons. Morphological studies are enhanced by paleogenetic analyses, a powerful tool to resolve phylogenetic relationships; however, ancient DNA (aDNA) preservation decreases in warmer regions.

Deep classification of cut-marks on bones from Arroyo del Vizcaíno (Uruguay).

The earliest widely accepted presence of humans in America dates to approximately 17.5 cal kyr BP, at the end of the Last Glacial Maximum (LGM). Among other evidence, this presence is attested by stone tools and associated cut-marks and other bone surface modifications (BSM), interpreted as the result of the consumption of animals by humans.

Phylogeny, Macroevolutionary Trends and Historical Biogeography of Sloths: Insights From a Bayesian Morphological Clock Analysis.

Sloths, like other xenarthrans, are an extremely interesting group of mammals that, after a long history of evolution and diversification in South America, became established on islands in the Caribbean and later reached North America during the Great American Biotic Interchange. In all three regions, they were part of the impressive Pleistocene megafauna. Most taxa became extinct and only two small, distantly related tree-dwelling genera survived.