Basilometra boschmai A. H. Clark, 1936

Obuchi, Masami, 2020, Shallow-water Comatulids (Echinodermata: Crinoidea: Comatulida) of the Ashizuri-Uwakai Sea, Shikoku Island, Southern Japan, Species Diversity 25, pp. 309-328 : 320-321

23. Basilometra boschmai A. H. Clark, 1936 [Japanese name: Kotengu-umishida]

Morphology. Centrodorsal globular, 5.5–6.7 mm across; polar area flat, 0.3–0.4 times of centrodorsal diameter. Cirri stout, tapering, XLII–L, up to 53 segments, 33 mm long, arranged in three rows; all segments broader than long; aboral transverse bar with two apexes, gradually developing at distal half segments. Radials exposed only at distal corners. Division series slender; IBr series composed of 2 ossicles, IIBr of 4(3+4), IIIBr of 2, IV–VBr with 2 or 4(3+4); each ossicle L/W about 1.0, with tubercular lateral expansions; synarthrial tubercles on articulation; each ray well separated. Arms up to 87, 155 mm long; 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; P 1–3 enlarged, stiffened, spine-like, with segments spinose on distal ends; Pa and often Pb absent; P 2 and sometimes P 1 absent on arms arising inner side of bifurcation. Disk flat, stellate, two times as wide as centrodorsal, paved with small calcareous plates.

Posture. Fully exposed on gorgonian perches, forming multi-layered radial fan.

Coloration in life. Uniformly dark brown; arms sometimes striped with yellow; disk sometimes white.

Distribution. Kii Peninsula ( Kohtsuka and Kato 2012) to Western Australia ( Rowe and Gates 1995), and to Gulf of Thailand ( Lane et al. 2000).

Remarks. This species is recognizable by the numerous arms, IIBr composed of four ossicles, and stiffened pinnules. Genus Basilometra A. H. Clark, 1936 is monospecific.