Hyperia gaudichaudii H. Milne Edwards 1840

Hyperia gaudichaudii H. Milne Edwards

Hyperia gaudichaudii H. Milne Edwards, 1840:77.–Nicolet, 1849:245.–Bovallius, 1887b:16; 1889:175–179; pl. 10: figs. 18–24.–Stebbing, 1888:1394–1398, pl. 169; 1914:374.–Walker, 1903:40; 1907:7.–Chilton, 1912:513.–Barnard, 1916:25–286.–Dick, 1970:55–56.

Lestrigonus gaudichaudii.–Bate, 1862:289, pl. 48: fig. 3.

Hyperia galba (Montagu).–Barnard, 1930:411–412; 1932:273.–Siegfried, 1963:8.–Hurley, 1969:33.

DERIVATION OF NAME.–Presumably after the French botanist Charles Gaudichaud-Beaupré, 1789–1854, who made important collections during his voyages on the Uranis, L’Herminie, and La Bonite.

DIAGNOSIS.–Very similar to H. medusarum, hystrix form, but generally larger (10-14 mm). Confined to the southern hemisphere in antiboreal and perhaps Antarctic zones.

RELATIONSHIPS.–Illustrations are given here of specimens from the west coast of southern Africa reported as H. galba by Siegfried (1963), sent to me by R. I. Dick, University of Cape Town. A few figures are also given of a female and a male from Challenger station 312 in the Straits of Magellan, loaned to me by R. W. Ingle, British Museum (Natural History). The similarity to the hysterix form of H. medusarum is obvious, and maintaining H. gaudichaudii as a separate species is not easily defended. My reasons for doing so are largely zoogeographical. Whereas hystrix has a boreal distribution, that of gaudichaudii is antiboreal, and there is no possibility of gene flow between them. Biantitropical species among epiplanktonic Crustacea are rare and are becoming rarer as their taxonomy is examined more closely. Of the few biantitropical hyperiids the best known example is Parathemisto gaudichaudii, whose distribution is reviewed in detail by Kane (1966). The vast majority of coldwater hyperiids, however, are confined to one hemisphere; consequently I prefer to give full specific status to Hyperia gaudichaudii rather than to maintain that H. medusarum is a biantitropical species.

DISTRIBUTION.–H. gaudichaudii is known to occur along the southern coasts of Africa, Australia, and South America (Figure 10). Walker’s two records from the Ross Sea (1903, 1907) seem questionable since they are the only reported occurrences south of the Antarctic Convergence. I suspect that Walker’s specimen’s were immature Hyperia macrocephala in which the coxae of P4 had not yet developed the pointed and splayed form so characteristic of the adult of that species. Chilton’s (1912) record from Scotia station 541 (37°41′N, 29°25′W) is also unacceptable; it lies well outside the range of H. gaudichaudii but within that of H. galba and may well refer to the latter species.