Catoptometra rubroflava (A. H. Clark, 1907 )

Obuchi, Masami, 2020, Shallow-water Comatulids (Echinodermata: Crinoidea: Comatulida) of the Ashizuri-Uwakai Sea, Shikoku Island, Southern Japan, Species Diversity 25, pp. 309-328 : 319-320

19. Catoptometra rubroflava (A. H. Clark, 1907) [Japanese name: Akashima-kobu-umishida]

Morphology. Centrodorsal low hemispherical, 4.7 mm across; polar area 0.6 times of centrodorsal diameter. Cirri short but stout, XXX, up to 17 segments, 15.0 mm long, arranged in two rows; all segments wider than long; opposing spine minute. Radials invisible. IBr series composed of 2(1+2). Arms 10, 180 mm long; brachials beyond proximal quarter of arms wedge shaped, L/ W 1.0; first arm syzygy at br 3+4; distal intersyzygial intervals 4–6. Comparative pinnule length P 1 <P 2 =P 3 =P 4>P 5; P 1 shortest; basal segments of proximal to middle pinnules distally everted and finely spinose, making knobby profile of pinnules. Disk flat stellate, two times wide of centrodorsal.

Posture. Attached on underside of overhangs, forming simple arm fans.

Coloration. Uniformly red; centrodorsal slightly faded.

Distribution. Noto Peninsula, Japan ( Kogo 1998) to Hong Kong (Liao and A. M. Clark 1995).

Remarks. This species is distinguished by the stout cirri with the segments wider than long. The examined specimen had only 10 arms, fewer than previous records of 11–21 arms (A. H. Clark 1941; Kogo and Fujita 2014). However, the other characters were not different from the comparative specimen from Kagoshima Bay with 13 arms.