Anneissia japonica ( Müller, 1841 )

Obuchi, Masami, 2020, Shallow-water Comatulids (Echinodermata: Crinoidea: Comatulida) of the Ashizuri-Uwakai Sea, Shikoku Island, Southern Japan, Species Diversity 25, pp. 309-328 : 314

10. Anneissia japonica ( Müller, 1841)

[Japanese name: Nippon-umishida]

Morphology. Centrodorsal hemispherical, approximately 10 mm across; polar area concave, 0.5–0.6 times of centrodorsal diameter. Cirri LVII – LXIX, up to 25 segments, 27.0 mm long, arranged in two to three rows; c5–8 longest, L/ W 1.3; distal ten segments with blunt aboral process . Radials invisible. IBr series composed of 2 ossicles, IIBr of 4(3+4), and IIIBr of 4(3+4). Arms 38, up to 135 mm long; brachials shorter than broad, with distal ends everted; first arm syzygy at br 3+4; distal intersyzygial intervals 4. Comparative pinnule length PD > P 1 >P 2>P 3 =P 4 =P 5; PD and P 1 enlarged; proximal segments finely spinose at distal end, with narrow keel on side toward arm tip . Terminal combs present as far as P 2–3, consisting of 4–13 segments; teeth single, nonconfluent, knob-like; terminal segments fused to sharp tip. Disk two to three times as wide as centrodorsal, smooth.

Posture. Hiding under overhangs or between foliose corals, with arms in multilayered arrays.

Coloration in life. Rays dark brown with pinnule tips orange to white. Some animals with pinnules aborally white.

Distribution. Endemic to Japan: Aomori ( Kogo and Fujita 2014) to Kagoshima ( Kogo and Fujita 2005).

Remarks. The specimens were identified by having about 40 arms and more than 50 cirri. This species is considered endemic to Japan ( Kogo and Fujita 2014). Specimens recently recorded from southern Vietnam have fewer cirri, 28–36 in number ( Mekhova and Britayev 2012), compared to previous records from Japan with at least 40 cirri ( Kogo and Fujita 2014). It is likely that they are different species, although which species they would be referred to is unclear. A specimen recorded in southern Korea seems young due to fewer arms and is difficult to identify ( Shin 2001).