Nannastacus unguiculatus

(Bate, 1859)

Description
Anterolateral angles of carapace prominent, especially in the female. Eyes, when present, divided into two separate groups. Maxilliped 2 with 6 segments. Endopod of the uropods longer than the exopod. Exopodites may be lacking from maxilliped 3 and pereiopods l and 2 but are usually present.
Body short and broad. Integument calcified, with many small tubercles and scattered hairs in the female, which is often covered with particles of the deposit. Female with pseudorostral lobes fairly short, upturned, their edges broadly serrate, meeting below the branchial orifice. The anterolateral margins are concave and acutely projecting forwards on either side, with the lower margins coarsely serrated. There are a number of rows of spines on the carapace and these are large and flattened behind the branchial region, while some similar spines occur at the sides of the outstanding sideplates of the pereion somites. Many of these spines, however, may be wholly broken off. There are two rows of smaller spines on the pereion and pleon somites. The eyes are wide apart, each with several lenses.
Uropods longer than the last two pleonites together, the peduncle less than half as long as the endopod, which is about three times as long as the exopod. Male with scattered hairs. Pseudorostral lobes shorter and thicker, less upturned, anterolateral corners quadrate. Carapace without flattened spines.

Size
Length up to 2 mm.

Ecology
Shelf.

Depth range
Down to about 40 m.

Distribution in the North Sea
Unknown.

World distribution
A Mediterranean-Boreal species, found on coarser substrates in shallow water found the British Isles and from north of Shetland to the Bay of Biscay and also in the Mediterranean and Black Sea.

[After Jones, 1976]

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