Rostratoverruca krugeri (Broch, 1922)

Figures 2 H, 27, 28

Verruca krügeri Broch, 1922: 295, figs 43–44.

Verruca (Rostratoverruca) krügeri Broch, 1931: 46 .

Rostratoverruca koehleri . — Liu & Ren, 2007: 273, fig. 119 (non R. koehleri (Gruvel, 1907)) .

Material examined. NMNS 0003328-00076, 55 specimens, benthic trawl at Donggang, on spines of the sea urchin Stylocidaris renei (17 Jan. 2000), BD 2.25–6.45 mm.

Diagnosis. Operculum parallel to basis; rostrum patelliform, apex of rostrum removed from opercular margin; fixed scutum without myophore; movable tergum and scutum with 4 articular ribs; rostrum and carina with prominent rounded ribbing.

Description. Shell white, basis membranous; rostrum patelliform, apex removed from opercular margin; carina with apex produced, extending beyond basitergal angle of tergum; carina and rostrum with prominent rounded ribbing, interlocking with 3 ribs (Fig. 2 H); movable scutum triangular, apex produced, incurved, 4 ribs on tergal margin, 3 ribs in occludent region, interlocking with rostrum at scutal basal margin; (Fig. 2 H); movable tergum quadrangular; apex produced, incurved towards movable scutum, 3 secondary ribs interlocking with movable scutum, 3 ribs on occludent margin interlocking with carina. Maxilla globular, dense setae on margin (Fig. 27 A); maxillule notched, 2 large and 2 small cuspidate setae above notch, several fine setae in notch, ~ 10 setae below notch (Fig. 27 B); mandible with 3 teeth (Fig. 27 C, G), lower margin strongly pectinated with sharp teeth, inferior angle ending in 4 cuspidate setae (Fig. 27 E); mandibular palp subtriangular, with setae on superior margin (Fig. 27 D); labrum not strongly concave, fine teeth on cutting edge, some bidentate (Fig. 27 H). Cirrus I with rami subequal, outer ramus 14-segmented, inner ramus 10- segmented (Fig. 28 A); cirrus II with rami subequal, outer ramus 15-segmented, inner ramus 11-segmented (Fig. 28 B); caudal appendage long, 1/2 length of cirrus VI, 18-segmented (Fig. 28 C).

Distribution. East China Sea, South China Sea, Taiwan, western Pacific.

Remarks. This is a new record for Taiwanese waters. The species has often been reported attached to the spines of sea urchins, suggesting a commensal relationship. Buckeridge (1994) concluded Rostratoverruca koehleri (Gruvel, 1907) was morphologically close to R. krugeri (Broch, 1922) . When compared to R. koehleri, the fixed tergum of R. krugeri has a more prominent apex and there is more ribbing on the movable plates. Liu & Ren (2007), however, consider R. krugeri to be a subjective synonym of R. koehleri . In the present study, we consider R. krugeri and R. koehleri to be separate species and the illustration in Liu & Ren (2007) suggested their specimen is R. krugeri .