Clarkcomanthus exilis (Rowe, Hoggett, Birtles & Vail, 1986)

Obuchi, Masami, 2020, Shallow-water Comatulids (Echinodermata: Crinoidea: Comatulida) of the Ashizuri-Uwakai Sea, Shikoku Island, Southern Japan, Species Diversity 25, pp. 309-328 : 315-316

14. Clarkcomanthus exilis

( Rowe, Hoggett, Birtles, and Vail, 1986) [Japanese name: Hige-kushi-umishida]

Morphology. Centrodorsal small, thin discoidal, 2.2– 2.6 mm across; polar area flat 0.7–0.9 times of centrodorsal diameter. Cirri less developed, up to XII, 13 segments, 6.0 mm long, arranged in single rows with gap; c4–7 longest, L/ W 1.4; distal 3–5 segments with weak aboral process. Radials exposed, length up to 20% of centrodorsal diameter. IBr series composed of 2 ossicles, IIBr of 2 or 4(3+4), and IIIBr of 4(3+4); each second ossicles fused by thin epidermis. Arms 20–30, up to 90 mm long; anterior arms sometimes distinct, up to 1.8 times longer than posterior; first arm syzygy at br 3+4; distal intersyzygial intervals 4. Comparative pinnule m PD > P 1 >>P 2 =P 3 =P 4 =P 5; PD and P 1 enlarged; segments finely spinose . Terminal combs present to P 1, rarely to P 2, consisting of 6–14 segments; tooth single, non-confluent, straight, widely spaced from adjacent one; terminal segments fused to sharp tip. Disk four to six times as wide as centrodorsal.

Posture. Nocturnal. Hiding under overhangs or between foliose corals. Anterior arms extended in multidirectional posture at nighttime.

Coloration in life. Rays banded with red and white, sometimes yellow in distal part.

Distribution. Sagami Bay, Japan ( Kogo and Fujita 2014) to southern Queensland, Australia, and to Fiji ( Rowe et al. 1986). Guam ( Kirkendale and Messing 2003).

Remarks. This species is recognizable by its small size, restricted distribution of the terminal combs to only P 1, and the combs with pointed tip.