Probainognathidae
| Probainognathidae Temporal range:
| |
|---|---|
| |
| Bonacynodon skull | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Synapsida |
| Clade: | Therapsida |
| Clade: | Cynodontia |
| Clade: | Probainognathia |
| Family: | †Probainognathidae Romer, 1973 |
| Genera | |
Probainognathidae is an extinct
Dinodontosaurus Assemblage Zone of Brazil. Probainognathids were closely related to the clade Prozostrodontia, which includes mammals
and their close relatives.
Description
Members of Probainognathidae were relatively small-bodied animals, with skull lengths of around 6–7 centimetres (2.4–2.8 in). The temporal region (area behind the
insectivorous.[1]
Based on the shape of the maxillary canal, a 2020 paper by Benoit et al. suggested that Probainognathus was among the first cynodonts to possess a mobile rhinarium with whiskers.[2]
Classification
Probainognathidae was erected in a 1973 paper by the American palaeontologist
Dinodontosaurus Assemblage Zone of Brazil, was named in a 2016 paper by Martinelli et al.[1][3] This paper also provided a phylogenetic definition of Probainognathidae, as "the clade including the most recent common ancestor of Probainognathus jenseni and Bonacynodon schultzi, and all its descendants".[1]
Phylogenetic analyses have generally found probainognathids to be relatively early-diverging members of Probainognathia, a clade that includes all cynodonts closer to mammals than to Cynognathia. The exact placement of probainognathids relative to other basal probainognathians varies between analyses. Some analyses find probainognathids to be very close relatives of Prozostrodontia, a group of advanced probainognathians that includes mammals and their close relatives.[1] Some analyses alternatively find Ecteniniidae, a group of large predatory cynodonts, to be closer to prozostrodontians than the probainognathids.[4][5]
Cladogram from Martinelli et al. (2016)[1]
Cladogram from Stefanello et al. (2023)[5]