Tanaissus danica (Hansen, 1909)

Bamber, Roger N., 2011, The marine fauna and flora of the Isles of Scilly. Tanaidacea (Crustacea: Peracarida), Journal of Natural History 45 (29 - 30), pp. 1801-1815 : 1811-1812

Tanaissus danica (Hansen, 1909)

Tanaissus danica Bird, 2002 , 158–165; figs 2, 3, 5, 6 and 9.

Tanaissus elongatus Jones and Holdich, 1983 .

“ Leptognathia sp. ” Rostron, 1983; 1988?

Material

Two ♀♀ ( NMW 2009.034.5), 49 ◦ 54.68 ′ N, 06 ◦ 20.45 ′ W, coarse well-sorted clean sand, 18.7 m depth, van Veen grab, 25 June 2009 .

Remarks

The two species of Tanaissus occurring in British waters were resolved by Bird (2002). Owing to earlier records not distinguishing T. danica from the commonly recorded T. lilljeborgii (Stebbing, 1891) , it proved difficult to interpret the distribution and habitat preferences of these two species, which did on one occasion occur sympatrically; Bird (2002) concluded that T. danica was probably a more northerly species, preferring a range from clean sands to heterogeneous substrata in somewhat deeper waters, mainly 10–35 m depth (but 0–158 m overall), while T. lilljeborgii was predominantly littoral in clean medium-grained or fine-grained sands. The present records confirm the sublittoral clean-sand habitat of T. danica , but extend its distribution further south.

The four known species of Tanaissus , including T. psammophilus (Wallace, 1919) from the Bay of Fundy, and T. microthymus Bird and Bamber in Bamber et al., 2009, from Israel, are all typical inhabitants of clean-sand substrata, where they are predominantly interstitial. It is therefore to be expected that T. danica (and possibly T. lilljeborgii ) is commoner in the sublittoral sandy substrata around the Isles of Scilly than this single record suggests; none were found in the numerous littoral clean-sand samples examined here.

Not recorded previously from the Isles of Scilly.