Rhinochimaera africana,a new longnose chimaera from southern Africa,with comments on the systematics and distribution of the genus Rhinochimaera Garman, 1901 (Chondrichthyes,Chimaeriformes, Rhinochimaeridae)

Rhinochimaera africana, a new species (Chondrichthyes, Chimaeriformes, Rhinochimaeridae), is described from five specimens from the Western Cape and KwaZulu coasts of southern Africa and from the Moçambique Channel between South-Western Madagascar and Europa Island. Two more specimens are known from off the Agulhas Bank, South Africa. It differs from the partially sympatric R. atlantica Holt and Byrne, 1909, and the Pacific R. pacifica (Mitsukuri, 1895) in its darker coloration, longer, broader, paddle-shaped snout, tooth plates of different shape, a more elongate-oval clasper glans, a shorter caudal fin with very short filament, and possibly a smaller dorsal fin and longer interdorsal space. R. africana males are mature at 568 mm body length (BDL), females adolescent at 476 mm BDL. A large, probably adult female of 650 mm BDL is larger than any recorded R. atlantica or R. africana. Wounds on two specimens indicate possible "cookie-cutter" bites by squaloid sharks, and one has a possible bite by another Rhinochimaera. Data on R. pacifica and R. atlantica, including 45 specimens from off Namibia and South Africa, are presented for comparison with R. africana. Caudal tubercle counts of R. africana (40–46) are intermediate between those of R. atlantica (most with 19–33, rarely up to 43) and of R. pacifica (41–68, rarely as low as 25–34). Southern African R. atlantica agree with North Atlantic R. atlantica in having few caudal tubercles, but there is slight overlap with R. pacifica in the case of higher counts recorded for R. africana. The systematics and distribution of the genus Rhinochimaera are reviewed, a terminology and abbreviation system for morphometries presented, and a key to species provided. The separation of R. atlantica and R. pacifica on caudal tubercle counts is provisionally accepted but considered problematical until adequate samples of both species can be critically compared. Proportional measurements and counts of caudal tubercles were highly variable in Rhinochimaera, with much allometry in proportions with growth and much individual variation. Selected morphometrics are plotted to show allometric trends in proportions that separate R. africana from other species.