Himerometridae A. H. Clark, 1908b

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

Family Himerometridae A. H. Clark, 1908b 20. Himerometra magnipinna A. H. Clark, 1908d [Japanese name: Takanoha-umishida]

Morphology. Centrodorsal hemispherical, 9.5–13.3mm across; polar area 0.4 times of centrodorsal diameter. Cirri stout, L–LXI, up to 44 segments, 47 mm long, arranged in three, partly four rows; all segments broader than long; segments in distal quarter with aboral spine gradually developing. Radials invisible. IBr series composed of 2, IIBr of 2 or 4(3+4), III–VBr of 2 on innerside and 4(3+4) on outerside of bifurcation; division series beyond IIBr often present only in outerside of rays. Arms up to 63, 160 mm long; brachials beyond middle arms exceedingly short, W/L more than 8; first arm syzygy at br 3+4; distal intersyzygial intervals 3–20. Comparative pinnule length PD>P 1>P 2>P 3 =P 4 =P 5; PD to P 2 enlarged; all segments smooth, L/W up to 1.2. Disk flat, stellate, two times as wide as centrodorsal.

Posture. Fully exposed on rocky pinnacles, forming arcuate fan.

Coloration in life. Arms light purple; some pinnules white and others dark purple, which makes blotched pattern on rays; cirri and disk dark purple.

Distribution. Ashizuri-Uwakai Sea ( Obuchi 2013) to Great Barrier Reef ( Rowe and Gates 1995), and to Andaman Sea ( Putchakarn and Sonchaeng 2004).

Remarks. Genus Himerometra A. H. Clark, 1907 is recognized by short brachials, and the proximal pinnules are short until P 3. This species can be identified by enlarged proximal pinnules with more than 30 cylindrical segments without keels (see Obuchi 2013).