Editing Probainognathidae (section)

== Description ==
[[File:Bonacynodon witout visible ears.png|thumb|left|Restoration of ''Bonacynodon'']]

Members of Probainognathidae were relatively small-bodied animals, with skull lengths of around {{Convert|6|-|7|cm|in}}. The temporal region (area behind the [[eye socket]]s) was rather wide, and longer than the snout. The [[secondary palate]] was well-developed compared to earlier cynodonts, and the portion made up by the [[maxilla]] was larger than the part made from the [[palatine bone]]. The [[Dentary bone|dentary]], the tooth-bearing bone of the lower jaw, was quite tall when seen from the side. The [[mandibular symphysis]] (the joint between the two halves of the dentary) was fused in ''Probainognathus'', but unfused in ''Bonacynodon''. In addition to the ancestral [[Quadrate bone|quadrate]]-[[Articular bone|articular]] jaw joint found in most non-mammalian cynodonts, probainognathids also had an incipient contact between the [[squamosal]] and [[surangular]] bones. The [[canine teeth]] were large and labio-lingually compressed, and in ''Bonacynodon'' they bore a [[serrated]] edge. The [[postcanine]]s had a typical "triconodont" shape, with four main cusps placed in a straight line. Unlike in other basal probainognathians like ''[[Chiniquodon]]'', the cusps were not recurved. The lower postcanines bore a discontinuous [[Cingulum (tooth)|cingulum]] which was restricted to the mesiolingual and distolingual sides of the teeth. The shape of the postcanines indicates that probainognathids most likely were [[insectivorous]].<ref name="Martinelli2016" />

Based on the shape of the [[Infraorbital canal|maxillary canal]], a 2020 paper by Benoit ''et al.'' suggested that ''Probainognathus'' was among the first cynodonts to possess a mobile [[rhinarium]] with [[whiskers]].<ref name="Benoit2020" />