Pristidae Bonaparte, 1835

Last, Peter R., Séret, Bernard & Naylor, Gavin J. P., 2016, A new species of guitarfish, Rhinobatos borneensis sp. nov. with a redefinition of the family-level classification in the order Rhinopristiformes (Chondrichthyes: Batoidea), Zootaxa 4117 (4), pp. 451-475 : 473

Family Pristidae Bonaparte, 1835

Type genus. Pristis Linck, 1790 (inferred from stem).

Description. Large to very large rays (adults up to 7 m TL) with snout greatly extended to form a hard, flattened blade armed along each edge with a row of sharp, robust, hypertrophied tooth-like denticles. Pectoral fins relatively small, separate, not fused to head or forming an obvious disc. Head slightly flattened, projecting well forward of pectoral fins. Eyes positioned very close to sides of head; well removed from spiracles. Spiracles lacking folds. Mouth broad, lacking oral grooves. Nostrils variably developed, short to relatively elongate, well separated, located well anterior to mouth and posterior to toothed part of rostrum; mouth broad and transverse. Tail elongate, more or less subcylindrical anteriorly; lateral skin folds weak anteriorly but more expanded posteriorly to form a welldefined keel; keels extending well onto caudal fin (their posterior extremities not almost joined adjacent origin of ventral lobe of fin). Two dorsal fins similar in shape, rather tall, with first located fully or partly above pelvic fins; pectoral fins well separated from pelvic fins. Pelvic fins short-based, subtriangular. Caudal fin variably developed, its ventral lobe weak or short ( Pristis ), or present as a long lobe ( Anoxypristis ). Dorsal coloration plain yellowish, brownish, greyish or greenish. Two genera: Anoxypristis and Pristis .

Remarks. No other batoid has a heavily modified, blade-like snout armed with enlarged tooth-like denticles. The shark family Pristiophoridae also has a modified saw-like snout but otherwise possesses characteristics of sharks (e.g. gill slits lateral rather than ventral on head). In most recent morphology-based classifications, pristids have been placed alone in the order Pristiformes (e.g. McEachran et al., 1996; van der Laan, et al., 2014), but recurrent recovery of the group as being monophyletic within the Rhinopristiformes based on molecular data is compelling evidence. Apart from their snout morphology, they share many key characters with other rhinopristiform families, notably the rhinids.