Squalus bucephalus Last, Séret & Pogonoski, 2007: 23-29 Squalus Squalus rancureli Fourmanoir, 1979, a new junior synonym of the blacktailed spurdog S. melanurus Fourmanoir, 1979, and updated diagnosis of S. bucephalus Last, Séret & Pogonoski, 2007 from New Caledonia (Squaliformes, Squalidae) Viana, Sarah T. F. L. De Carvalho, Marcelo R. Zoosystema 2018 2018-05-09 40 9 159 177 6ZDW5 Last, Seret & Pogonoski, 2007 Last, Seret & Pogonoski 2007 [860,1408,727,754] Elasmobranchii Squalidae Squalus Animalia Squaliformes 11 168 Chordata species bucephalus  Bighead spurdog; Aiguillat à grosse tête  ( Figs 9-15; Tables 2-3)    Squalus bucephalus Last, Séret & Pogonoski, 2007: 23-29(original description; illustrated. Typeby original designation. Typelocality Norfolk Ridge, south of New Caledonia, 405-411 mdepth). — Ebert et al.2013: 78, 86 (cited, description; Southwest Pacific Ocean). — Weigmann 2016: 903(listed; Southwestern Pacific Ocean). — Bernot & Boxshall 2017: 275-276, 288 (cited, listed; New Caledonia).   Squalussp. – Séret 1994: 7(listed; New Caledonia).   MATERIAL EXAMINED. — MNHN-IC-1997-3634, juvenile ♂, 520 mmTL, Norfolk Ridge, New Caledonia, 24°43’1”S, 168°6’0”E,  500-600 mdepth; MNHN-IC-1997-3635, juvenile ♀, 476 mmTL, Norfolk Ridge, New Caledonia, 24°43’1”S, 168°6’0”E,  500- 600 mdepth; MNHN-IC-1997-3636, juvenile ♀, 495 mmTL, Norfolk Ridge, New Caledonia, 24°43’1”S, 168°6’0”E,  500-600 mdepth; MNHN-IC-1997-3641 ( paratypeof  S. bucephalus), juvenile ♀, 430 mmTL, Norfolk Ridge, New Caledonia, 23°39’0”S, 167°43’59”E,  420-470 mdepth; MNHN-IC-1997-3657, adult ♂, 705 mmTL, New Caledonia, 23°43’1”S, 168°15’0”E,  405-411 mdepth; MNHN-IC-1997-3659, adult ♂, 805 mmTL, Stylaster Seamount, Norfolk Ridge, New Caledonia, 23°37’1”S, 167°39’0”E,  486-962 mdepth; MNHN-IC-1997-3662, adult ♂, 795 mmTL, Stylaster Seamount, Norfolk Ridge, New Caledonia, 23°36’0”S, 167°40’59”E,  448-880 mdepth; MNHN-IC-1998-1017, adult ♂, 810 mmTL, New Caledonia, 23°43’1”S, 168°15’0”E,  405-411 mdepth; MNHN-IC-2006-1754 ( holotypeof  S. bucephalus), juvenile ♂, 550 mmTL, Norfolk Ridge, south of New Caledonia, 23°43’S, 168°16’E,  405-411 mdepth, collected on  28.XI.1993;  NMNZP 34030 ( paratypesof  S. bucephalus), two adult ♂, 787-802 mmTL, Stylaster Seamount, Norfolk Ridge, New Caledonia, 23°35’S, 167°42’E,  448-880 mdepth.  GEOGRAPHICAL DISTRIBUTION. —  Squalus bucephalusis endemic to New Caledoniain the Southwestern Pacific Ocean ( Fig. 15).  DIAGNOSIS. — Short-snouted dogfish shark from New Caledoniathat it is distinguished from its congeners by: head conspicuously humped dorsal-posteriorly and wide, its width at mouth 13.5% (12.1-13.9%) TL; anterior margin of nostrils conspicuously bilobate and broad; mouth straight and wide, its width 8.7% (7.6-8.8%) TL; caudal fin very slender on upper and lower lobes; caudal fin elongate, its dorsal caudal margin length 24.2% (21.7-23.9%); smaller pelvic-caudal space 24.9% (23.1-  FIG. 9. —  Squalus bucephalus Last, Séret & Pogonoski, 2007in lateral view: A, MNHN-IC-1998-1017, adult male, 810 mm TL; B, MNHN-IC-1997-3636, juvenile female, 495 mm TL. Scale bars: 50 mm.  FIG. 10. — Detail of head in anterior dorsal view ( A) and right nostrils ( B) of holotype of  Squalus bucephalus Last, Séret & Pogonoski,2007(MNHN-IC-2006-1754, juvenile male, 550 mm TL). Scale bar: A, 20 mm; B, not to scale. 26.3%) TL. It is clearly separated from  S. melanurusby snout conspicuously short, its prenarial length 1.0-1.1 times distance nostril-upper labial furrow (vs snout conspicuously elongate, its prenarial length 1.4-1.7 times distance nostril-upper labial furrow in  S. melanurus), prespiracular length (12.2-14.0% TL for  S. bucephalusvs 14.7-16.8% TL for  S. melanurus), and preoral length (9.2-10.9% TL for  S. bucephalusvs 12.6-14.3% TL for  S. melanurus). It is further distinct from this species by having lower caudal lobe conspicuously white (vs conspicuously black), and dermal denticles unicuspidate and lanceolate (vs tricuspidate and rhomboid).  Squalus bucephalusis also separated from  S. melanurusby number of monospondylous (49 vs 41 for  S. melanurus), caudal (31 vs 26-29 for  S. melanurus), and total vertebrae (124 vs 114-120 for  S. melanurus).  REMARKS   Squalus bucephalusis a deep-water dogfish shark that occurs in the continental slope between 405-962 mdepth, although it is often caught at depths between 405-600 meters. It is a species with very restrict geographical distribution and whose biology is totally unknown. Females are rarely caught in New Caledonia, arousing attention for conservation and fisheries management. Studies on population size and trends, maturation, feeding and reproduction are imperative for threatened assessments of this species. 2594760060 Norfolk Island 550 -24.716946 Ridge 21 168.1 11 168 2 1 1 Ridge 2594760055 Norfolk Island 550 -24.716946 Ridge 21 168.1 11 168 2 1 1 Ridge 2594760057 Norfolk Island 550 -24.716946 Ridge 21 168.1 11 168 2 1 1 Ridge 2594760062 Norfolk Island 445 -23.65 Ridge 21 167.73305 11 168 2 1 1 Ridge paratype 2594760054 New Caledonia 408 -23.716946 New Caledonia 21 168.25 11 168 2 1 1 Ridge 2594760071 Norfolk Island 724 -23.616945 Stylaster Seamount 21 167.65 11 168 2 1 1 Stylaster Seamount 2594760056 Norfolk Island 664 -23.6 Stylaster Seamount 21 167.68306 11 168 2 1 1 Stylaster Seamount 2594760051 New Caledonia 408 -23.716946 New Caledonia 21 168.25 11 168 2 1 1 Stylaster Seamount 2594760074 1993-11-28 Norfolk Island 408 -23.716667 Ridge 1254 168.26666 11 168 2 1 1 Ridge holotype 2594760052 NMNZ Norfolk Island 664 -23.583334 Stylaster Seamount 1255 167.7 11 168 2 1 1 Stylaster Seamount paratype