Boreosignum, Just & Wilson, 2007

Just, Jean & Wilson, George D. F., 2021, Redescriptions and new species in the ‘ Austrosignum-Munnogonium’ complex sensu Just & Wilson (2007), mainly from the Southern Hemisphere (Crustacea Isopoda: Paramunnidae), Zootaxa 4952 (3), pp. 401-447 : 408

Boreosignum specimens

( Fig. 5 )

Material examined. ♂, 0.85 mm, (lacking all pereiopods), Jervis Bay , New South Wales, Australia, AM P68211 ; ♀, 1.1 mm, Maston Point , American River, Kangaroo Island, South Australia, 35°46.30’S, 137°46.50’E, 4–5 m, clumps of sponge in channel below wharf, P. Hutchings, 2 March 1979, AM P68210 .

Remarks. The male from Jervis Bay could be referred to Boreosignum orientale ( Shimomura & Mawatari, 2000) on account of the unique double-bump dorsoanteriorly on the head. The Australian and Japanese males, however, show subtle differences, in particular the shape of the lateral lobes of pleopod I. The lack of all pereiopods makes definitive identification impossible. The female from Kangaroo Island lacks head ornamentation, but Shimomura & Mawatari (2000: 223) in their description of Boreosignum orientale state only ‘ Female: Similar to male in morphology of all pereional appendages’. Hence, we do not know if head morphology is sexually dimorphic in Boreosignum orientale , and cannot, therefore, refer the two Australian specimens to the same species. This is the first report of the genus from Australia.

Figures

FIGURE 5. Boreosignum specimens. M, ♂ from Jervis Bay; F, ♀ from Kangaroo Island. a, antenna; au, antennula; cvv, head ventral view; p1, pereiopod I; pl1, pleopod I; up, uropod. Scale for habitus (both), 0.5 mm.