Proceratosaurus bradleyi, (WOODWARD, 1910)

Rauhut, Oliver W. M., Milner, Angela C. & Moore-Fay, Scott, 2010, Cranial osteology and phylogenetic position of the theropod dinosaur Proceratosaurus bradleyi (Woodward, 1910) from the Middle Jurassic of England, Zoological Journal of the Linnean Society 158 (1), pp. 155-195 : 157-158

PROCERATOSAURUS BRADLEYI ( WOODWARD, 1910)

Holotype: NHM R 4860 , partial skull and mandibles, hyoid, and fragments of cervical ribs. The only known specimen.

Type locality: Minchinhampton, Gloucestershire, England.

Horizon and age: Great Oolite, Late Bathonian, Middle Jurassic.

Emended diagnosis: Small to medium-sized theropod dinosaur (body length approximately 3 m) characterized by the following autapomorphies: anterior nasal process of the premaxilla inclined slightly anterodorsally, and nasal horn core overhanging the premaxillary internarial bar anteriorly; internarial bar of the premaxilla bifurcating posteriorly into a posteriorly directed ramus and a dorsally directed ramus; anterior end of the maxillary antorbital fossa placed considerably anterior and ventral to the promaxillary foramen; anteriormost dentary tooth curved anteriorly, and with the carinae oriented labiolingually. Furthermore, Proceratosaurus bradleyi can be distinguished from all other theropods by the following unique combination of characters: length of external nares more than 20% of skull length, and nares inclined posterodorsally; promaxillary foramen higher dorsoventrally than maxillary fenestra; presence of a midline crest on the nasals that begins at slightly less than one-third of the length of the external nares, from the anterior end; strongly expanded, sheet-like quadratojugal process of the squamosal; angular extends to the posterior end of the retroarticular process of the mandible; large, medially directed pendant process on the articular posterior to the jaw articulation; premaxillary teeth considerably smaller than maxillary teeth; premaxillary teeth with slight longitudinal striations; anteriormost teeth of the dentary procumbent; teeth with pronounced size difference between mesial and distal denticles.

Remarks: The differential diagnosis given above is purely taxonomic, i.e. a unique combination of characters to identify the taxon, even if the autapomorphic characters are not preserved or visible. Likewise, the apomorphic characters listed are autapomorphic for Proceratosaurus only, and have thus not been included in the phylogenetic analysis. We prefer to separate the taxonomic and phylogenetic diagnoses, as the former should help to identify the taxon independent of its phylogenetic placement. As all characters in the phylogenetic analysis have to be parsimony informative, their taxonomic utility depends on the tree topology recovered. For further possible apomorphies of Proceratosaurus recovered from the phylogenetic analysis, see below.

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