Cilunculus

Arango, Claudia P., 2009, New species and new records of sea spiders (Arthropoda: Pycnogonida) from deep waters in Western Australia, Zootaxa 1977, pp. 1-20 : 15

Cilunculus sp.

Material: AM P73036, 1 sub-adult. 23 November 2005, Albany, Western Australia, CSIRO station 023-020, collected with Sherman sled from 35.3925S- 118.3090E to 35.4012S- 118.3060E, hard bottom, 776m.

This is a soft and clear, very fragile young specimen with a characteristic cephalic hood partially covering the chelifores as typical of the genus Cilunculus ; however, it cannot be assigned to any known species, and there is not sufficient evidence at hand to propose it as a new species.

Description: Trunk length 2.3mm, segmented, smooth, each segment with a mid-dorsal bump, no tall tubercles; very low ocular tubercle; lateral processes separated by less than their own diameter. Proboscis longer than trunk, elliptical, inflated, deep mouth commissures. Chelifore (one chelifore missing) under the cephalic hood, scape one-segmented, chela chelate. Palp segments 6–10 subequal, with ventral setae, tenth segment slender, third segment longest. Tibia 2 longest leg segment; tarsus less than ¼ as long as propodus; 3 heel spines, 7 sole spines, long setae dorsally on propodus; tiny auxiliary claws.

Remarks: Cilunculus species in Australia include C. australiensis Clark 1963 and C. hirsutus Clark 1963 known from New South Wales ( Clark 1963). They are both recognised by dorsal ornamentation on the midtrunk and lateral processes, and tubercles or horns on the anterior margin of the cephalon. None of these are present in this individual. Several Cilunculus species are known from the Indo-West Pacific, all included in Stock’s (1997) key, but the combination of very small auxiliary claws, a one-segmented scape and a totally smooth body leads nowhere in that key. The absence of tubercles, cephalic horns, and setae might be related to the early age of the animal or could be diagnostic of a new species for WA, but mature specimens are needed for confirmation.