2: HEXANCHIDAE (COW SHARKS)
N
2.2 Hexanchus griseus: 97 em immature male (Namibia). N & T as in 2.1.
Genus Hexanchus Rafinesque, 1810
Two species, both in our area.
KEY TO SPECIES
la Lower jaw with 5 rows of large teeth on each side;
mouth length 1.2-1. 7 in its width ..... .. .... ..... ... ..... ........ H. vitulus
1b Lower jaw with 6 rows of large teeth on each side;
mouth length 1.6-2.7 in its width .......................... .. .... H. griseus
Sixgill shark
2.2 Hexanchus griseus
(Bonnaterre, 1788)
Seskiefhaai
Squalus griseus Bonnaterre, 1788: 9 (Mediterranean). Hexanchus
griseus: Smith, SFSA No. 1*; Bass et aI., 1975: 8*.
Snout length 4-7 % TL, 2.0-2.8 times in mouth width; Dbase 1.1-1.4 in
distance from D base to upper C lobe. Pre caudal vertebrae 57.
Head and body grey; fins with thin white trailing edges.
Ovoviviparous; litters of 22-108 pups, 70 cm at birth;
females mature at 4.0-4.5 m, males at 3.5-4.0 m; attains
5+ m, 730+ kg. A benthic species found in all oceans, usually in deep water (100 - 1 500 m). Our specimens from
Namibia, Port Elizabeth, Durban and southern Mozambique.
2.3 Hexanchus vitulus
Springer & Waller, 1969
Bigeye sixgill shark
Grootoog-seskiefhaai
Hexanchus vitulus Springer & Waller, 1969: 160, Figs. 1-4 (Bimini,
Bahamas); Bass et aI., 1975: 9*; Compagno, 1981: 2*.
Snout length 6-8% TL, 1.5-2.1 in mouth width; Dbase 1.8-2.1 in distance from D base to upper C lobe.
Brownish grey; trailing edges of fins white. Ovoviviparous; about 13 pups per litter, 42 cm at birth; females
mature at 142 cm, males at 123 cm; attains 180 cm. Previously confused with H. griseus, this species is known from
the Atlantic, southwest Indian Ocean, Taiwan and the
Philippines. A benthic species that normally inhabits deep
water (90 - 600 m), with occasional excursions towards the
surface.
----------/ '~.:,.
N
~~~q~oo-6b~
2.3 Hexanchus vitulus: 115 em immature male (Natal). N & T as in 2.1 .
46