Iconometra japonica ( Hartlaub, 1890 )

Obuchi, Masami, 2020, Shallow-water Comatulids (Echinodermata: Crinoidea: Comatulida) of the Ashizuri-Uwakai Sea, Shikoku Island, Southern Japan, Species Diversity 25, pp. 309-328 : 321

26. Iconometra japonica ( Hartlaub, 1890) [Japanese name: Shimofuri-umishida]

Morphology. Centrodorsal low hemispherical to thick discoidal, 3.4–3.6 mm across; polar area flat, more than 0.9 times of centrodorsal diameter. Cirri stout, XVII–XXVI, up to 28 segments, 14.5 mm long, arranged in single row; all segments short, L/W up to 0.6; aboral transverse bar present near distal end in proximal segments, and located at median in distal segments. Radials invisible. IBr series composed of 2 ossicles, with synarthrial tubercles. Arms 10, up to 95 mm long; brachials shorter than broad; first arm syzygy at br 3+4; distal intersyzygial intervals 5–9. Comparative pinnule length P 1 <P 2>P 3>P 4 =P 5; P 2 longest, but sometimes same length as P 1 and P 3, with smooth segments; pinnules beyond P 3 with segments spinose on distal ends. Disk flat, stellate, two to three times wide of centrodorsal.

Posture. Fully exposed on gorgonian perches, forming radial fan.

Coloration in life. Various. Rays black, red-purple, or yellow, with white spots, sometimes banded with brown and cream.

Distribution. Endemic to Japan: Noto Peninsula ( Kohtsuka and Kogo 2001) to Ashizuri-Uwakai Sea (this study).

Remarks. Genus Iconometra A. H. Clark, 1929 includes small ten-armed species with enlarged but not spine-like proximal pinnules, of which P 2 is the longest. This species is distinguishable by its aboral transverse bars on the cirrus segments located at distal ends in early segments.