Astroboa clavata ( Lyman, 1861 )

Baker, Alan N., Okanishi, Masanori & Pawson, David L., 2018, Euryalid brittle stars from the International Indian Ocean Expedition 1963 - 64 (Echinodermata: Ophiuroidea: Euryalida), Zootaxa 4392 (1), pp. 1-27 : 9

Astroboa clavata ( Lyman, 1861)

( Fig. 5D–J )

Astrophyton clavatum Lyman, 1861: 85 .

Astroboa clavata . — Döderlein, 1911: 80. Pl. 5, figs 6,6a; 1912: 269, pl.16, figs 1, 1b, 16, pl. 18, fig. 8; 1927: 38, pl.5, figs 5,6; Putchakarn and Sonchaeng, 2004: 421; Venkatraman et al, 2013: 208.

Material Examined. Anton Bruun Cruise 9, Indian Ocean , Comoro islands, Mayotta Island, Bandeli Reef, 13° 30’ S, 045°16’ E, 23 – 26 November 1964, 1 specimen, now lost ; USNM 1072477 , Anton Bruun Cruise 9 Station 465, off NE Somalia, 11° 37’ N 51° 27’ E, 67–72 m, 18 December 1964, 1 specimen ( Fig. 5D–J ).

Remarks. This species is characterised by having prominent radial shields and a covering of minute thorny granules ( Fig. 5D, F, G ). Similar granules extend into the oral interbrachial areas.

The arm segments are separated by marked depressions with thickened edges ( Fig. 5H ). There is also a median furrow along the aboral sutures of each arm ( Fig. 5I ). Girdle bands with hooklets occur terminally on each arm ( Fig. 5J ).

A. clavata was first collected off Zanzibar, and has subsequently been found in the waters of the Persian Gulf, Bay of Bengal, Mauritius, and northwestern Australia ( Rowe & Gates, 1995).

Figures

FIGURE 5. Asteronyx luzonicus (USNM 1072474) (A–C) and Astroboa clavata (USNM 1072477) (D–J). A, aboral disc; B, lateral disc; C, basal portion of the arm; arrows indicate elongated club-shaped arm spines; D, aboral view; E, oral view; F, aboral peripheral disc; G, external ossicles on a peripheral radial shield; H, oral basal portion of the arm; I, aboral middle portion of the arm; J, aboral distal portion of the arm.