Zoology Publications from Victoria University of Wellington—Nos. 54 to 57
Whitley (1931, p. 310) proposed the new species Heptranchias dakini on the basis of an earlier account (McCulloch, 1911, p. 2) of seven specimens from Victoria, Australia, which McCulloch identified as H. perlo. Whitley noted that the specimen in McCulloch's figure "appears to differ in having the head 4½ in total length and anal originating below middle of dorsal, with its base shorter than that of dorsal", and he selected as holotype of H. dakini the specimen figured by McCulloch (1911, pl. 1, fig. 1).
No definitive account of H. dakini has appeared since the original description. In fact, there have apparently never been any measurements taken from a specimen; those of Whitley (1931) were, as far as we can determine (see below), taken straight from McCulloch's illustration. Although this illustration has been republished several times, no new illustrations of the species have appeared.page 2
Several Australian workers have referred briefly to the Sharpsnouted Sevengill shark. Whitley (1940, 1968), Munro (1956), Scott (1962) and Lynch (1963) treated it as H. dakini, while Stead (1963) treated it as H. perlo, stating, without supporting evidence, that "Whitley's Heptranchias dakini is identical with this species".
Heptranchias was first recorded from New Zealand in 1953 from one specimen (DM 2745) which was referred to H. dakini by McCann (1953) and to H. perlo (mis-spelt parlo in title) by Parrott (1953). The same specimen was discussed in Parrott (1958). No further specimens are recorded in the literature, although several were received and catalogued by the Dominion and Canterbury Museums from 1953 onwards. Whitley (1956, 1968) listed the New Zealand species as H. dakini. Richardson and Garrick (1953) mentioned that both dakini and perlo might occur in the New Zealand area.
Bigelow and Schroeder (1948) listed the two species as distinct, but with some reservations, viz. (p. 92): Heptranchias perlo "is represented in Australian waters by a relative (dakini) so close to perlo that it might finally prove identical". Garrick and Schultz (1963) implied in their account of H. perlo— "almost worldwide in distribution", with no mention of a related species H. dakini—that only one species existed.
Early brief accounts and listings of Heptranchias indicus, Notidanus indicus and Notorynchus indicus, sometimes named as the "Perlon Shark", in New Zealand literature (e.g. Hutton, 1872: 79; 1904: 54; Sherrin, 1886: 121; Waite, 1907: 6; Hamilton, 1908: 30; Thomson, 1913: 235; Thomson and Anderton, 1921: 68) are inadequate and confusing. We suspect, from the context of the brief accounts, that they refer to the more commonly caught Broadsnouted Sevengill Notorynchus. We have not checked the early Australian literature, but the same situation may well occur there.