Silpholestes lends its name to Silpholestidae, a family that traditionally encompassed many small therocephalians. Silpholestidae was first named by paleontologistsD. M. S. Watson andAlfred Romer in 1956. In addition toSilpholestes, the generaIctidodraco,Scaloporhinus,Silphictidoides, andTetracynodon were all classified in Silpholestidae. Therocephalians that were once classified in this family are all very small, and have elongated and pointed snouts. Silpholestids were characterized by their short temporal openings at the back of the skull; in most therocephalians, these openings are very large and occupy much of the skull. Silpholestids were also distinguished by their wideparietal region between the temporal openings, which did not form asagittal crest as in other therocephalians. Silpholestids were also characterized by their prominentangular bones at the back of the jaw, which are very deep and covered in radiating ridges. Another traditional group of small therocephalians, the scaloposaurids, have a small angular bone that does not stand out from the curvature of the jaw. Therocephalians that were grouped in Silpholestidae all have thinzygomatic arches and complete postorbital bars that enclose the back margin of the eye sockets. Most have sixincisors, a pair of largercanines, and about ten postcanine teeth.[1]
Silpholestids and scaloposaurids comprised the larger group Scaloposauria, which included nearly all small-bodied therocephalians. Most scaloposaurians are now thought to represent juvenile forms of larger therocephalians, and both Silpholestidae and Scaloposauridae are no longer regarded as valid groupings. Most scaloposaurians, includingSilpholestes, are now regarded asbasal members of thecladeBaurioidea. Since there has never been a comprehensivephylogenetic analysis including all scaloposaurian taxa, it is unclear whether the therocephalians once classified as silpholestidae form their own clade.[2]
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