The postcranial skeleton of Brasilodon, a near relative of mammals

[Halichoeres]

The skull of Brasilodon quadrangularis is well-known, and based on its anatomy the species is regarded as the sister-group to the Mammaliaformes. This paper describes a large quantity of postcranial material, giving a fairly complete picture of its anatomy and posture, and helping to place the acquisition of traits in a phylogenetic context. Here, for example, is a figure mapping several forelimb traits on a cladogram:


The forelimb was semi-sprawling, whereas the hindlimb gait was parasagittal (parallel to the spine, like a modern mammal).

Also featuring a nice reconstruction by Jorge Blanco. The fossorial animal whose head and forelimbs are visible is Riograndia guaibensis.


Paper is open access: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0216672