Hydroides externispina Straughan, 1967b

Kupriyanova, Elena K., Sun, Yanan, Ten Hove, Harry A., Wong, Eunice & Rouse, Greg W., 2015, Serpulidae (Annelida) of Lizard Island, Great Barrier Reef, Australia, Zootaxa 4019 (1), pp. 275-353 : 281-283

Hydroides externispina Straughan, 1967b

( Fig. 3 )

Hydroides externispina Straughan, 1967b: 31 –33, fig. 3 [Heron Island, Qld; material studied].

Hydroides externispina .— Imajima 1976a: 232 [diagnosis; Japan]; 1976b: 126–127, fig. 3a–k [South-Western Japan; description]; ten Hove & Kupriyanova 2009: 53 [name only]; Sun et al. 2015: 32 –34, fig 8 [WA, Qld, Australia]. Hydroides externispinosa [in error].— Day & Hutchings 1979: 144 [Qld; name in checklist].

Material examined. AM W.45056, MI QLD 2406; AM W.45086, MI QLD 2424; MAGNT W025511, southwest of Palfrey Island, lagoon, 14°41'42"S, 145°26'50"E, coral rubble, 4 m, coll. M. Ekins, 13 Apr 2008; MAGNT W025514, lagoon southwest of Palfrey Island, 14°41'42"S, 145°26'30"E, coral rubble, 4 m, coll. M. Ekins, 15 Apr 2008.

Diagnosis. Opercular verticil with 8–10 spines, ending into sharply pointed tips, curved inwards. Two dorsal verticil spines long and curved inwards, with pair of proximal lateral spinules. Dorsal spines covering other verticil spines, the latter with one curved external spinule on 1/3 of the incurving sharp tip, with a pair of lateral spinules curving outward and a small basal spinule. Funnel with 24–36 pointed chitinized tips, base of funnel not chitinized. Grooves separating radii extending 1/3 of funnel length ( Fig. 3 ).

Remarks. Hydroides externispina is easily recognisable because of its two large, strongly curved inwards dorsal verticil spines as well as dark curved outwards lateral and external spinules. This species can be confused with H. tambalagamensis Pillai, 1961 because of similar dark curved outwards lateral spinules on the verticil spines in both species. H. externispina differs from H. tambalagamensis by the presence of two enlarged curved inwards dorsal verticil spines, whereas in H. tambalagamensis all verticil spines are of the same size. The presence of these two large inwards-curved dorsal verticil spines makes H. externispina similar to H. glasbyi Sun et al., 2015 , however, the latter species lacks conspicuous externally curved lateral spinules on smaller verticil spines.

Distribution. Indo-West Pacific: Southwestern Japan, Indonesia, New Caledonia; Qld, WA, Australia.

Figures

FIGURE 3. Hydroides externispina. A. Live animal in tube, AM W. 45056; B. Fixed specimen, various views of the same operculum. Photo: A—A. Semenov, B—E. Wong. Scale bars: A = 1 mm, B = 0.1 mm.