Comaster schlegelii ( Carpenter, 1881 )

Mohammednowshad, B., Idreesbabu, K. K., Parameswaran, Usha V., Messing, Charles G. & Sureshkumar, S., 2020, The Shallow-water Crinoid Fauna of Lakshadweep Atolls, North-western Indian Ocean, Zootaxa 4789 (1), pp. 247-265 : 252-254

Comaster schlegelii ( Carpenter, 1881)

Actinometra schlegelii Carpenter, 1881:210 .

Actinometra nobilis Carpenter, 1884:55 ; 1888:336, pl. 65 (figs. 1–8).

Comanthus (Comanthina) nobilis: A.H. Clark, 1909c:143 .

Comanthus (Comanthina) schlegelii: A.H. Clark, 1911a:536 .

Comanthina schlegelii: A.H. Clark, 1911b:179 ; 1931:466–482, pl. 53 (fig. 158), pl. 54 (fig. 159), pl. 55 (figs. 160, 161), pl. 64 (fig. 180); A.M. Clark & Rowe, 1971:16; Rowe et al., 1986:204, 207 (fig. 2E), 242 (fig. 8C), 244–246; Sastry, 2005:4 (as C. schlegeli ).

Comanthina nobilis: Rowe et al., 1986:204 , 242 (fig. 8B), 243–244; Sastry, 2005:4.

Comaster schlegelii: Messing, 1998b:206 ; Summers et al., 2017:172 (fig. 8A–G).

Comaster nobilis: Messing, 1998b:206 ; 2001:287 (fig. 5c).

Material examined.— Western outer reef of Amini I., 11.131N, 72.717E, 15 m, 6 May 2018, Mohammed Nowshad and Khaleel, coll. (3, MTRLDST E0224, E0225, and ZSI/ WGRC /IR.INV/13964) .

Diagnosis.—A species of Comaster with cirri absent, few and weak, to well developed; division series and arm bases not tuberculate; brachials only slightly everted if at all; aboral surface variably colored (e.g., green, yellow, mottled, sometimes white with dark bluish markings, not pinkish-tan) ( Rowe et al., 1986; CGM, personal observations).

Description of survey specimens ( Figure 2A–D ).— MTRLDST E0224: ~140 arms; centrodorsal rounded pentagonal, flush with surface of radials; one cirrus 10 mm long, l4 segments; IIBr and following series all 4 (3+4) except exterior IIIBr2; synarthrial tubercles prominent; aboral surface nearly flat. ZSI/WGRC/IR.INV/13964: ~120 arms, ~ 130 mm long. Cirrus sockets numerous, all obsolete; IIIBr series typical on two rays (IIIBr2 exteriorly, 4(3+4) interiorly); third ray with only one exterior IIIBr2; remaining two rays with all series following IIBr 4(3+4). MTRLDST E0225: small specimen with ~80 arms, several arising via multiplicative regeneration. Aboral perisome plated as in adults. Centrodorsal thin discoidal with X cirri, to 10 mm long with 14 segments. Colors: broadly and irregularly banded with brown and white; entirely yellow-brown; light brown or orange-brown with large pale tan or white, midaboral blotch or spot on most ray ossicles, and arms white distally; articulations sometimes darker brown. Centrodorsal white. One specimen dark bluish-black with some scattered pinnules and some distal arms white.

Habitat.— Partly concealed under coral heads.

Distribution.— From Lakshadweep, Maldives, and Sri Lanka in the west to Palau, Chuuk Atoll ( Micronesia), and Kwajalein Atoll in the east, including the Andaman Is., and from northern Australia (Carnarvon, WA, to Solitary Is., NSW) north to Guam, Saipan, and southern Japan (A.H. Clark, 1931; Rowe et al., 1986; Meyer & Macurda 1980; Zmarzly 1984, 1985; Rowe & Gates, 1995; Kogo 1998; Messing, 1998a, 2007). Depth range: 2–92 m (Rowe, et al., 1986; Messing, 2007).

Remarks.— This is the first record of this species from Lakshadweep waters. Summers et al. (2017) returned C. nobilis ( Carpenter, 1884) as a synonym under C. schlegelii (following e.g., A.H. Clark, 1931), because specimens of both species showed <1.9% divergence in an uncorrected pairwise distance of COI, but all were>3.3% divergent from C. audax ( Rowe et al., 1986) , and the same treatment is followed here. Previously, Rowe et al. (1986) had elevated C. nobilis from synonymy under C. schlegelii based on its fewer cirri, comb distribution, color, and ecology.

Figures

FIGURE 2. A‒D. Comaster schlegelii. A–B.MTRLDST E0225, aboral view showing centrodorsal, cirri, brachitaxes, and proximal arms (A) and in situ (B). C–D. MTRLDST E0224, aboral view showing centrodorsal lacking cirri, brachitaxes, and proximal arms (C) and in situ (D). E. Himerometra robustipinna, MTRLDST E0227, in situ. F. Phanogenia typica, MTRLDST E0223, aboral view showing centrodorsal, brachitaxes and proximal arms. G. Comanthus wahlbergii, MTRLDST E0231, oblique aboral view showing centrodorsal, cirri, brachitaxes, and proximal arms.