Kinmen, 22 Aug 2006: 125 specimens (BD 15.74-35.94 mm) (CEL-BB-118).
Parietes and operculum grey, purple, or brown, with 4 plates, plates tubiferous, base membranous. Scutum triangular, occludent margin with strong teeth, adductor muscle scar deep; tergum higher than wide, basi scutal angle protruding, spur sharp. Serrulate setae present on cirri I and II; cirrus III with multicuspidate setae. Labrum cutting edge smooth, with sparse small teeth; mandible with 4 teeth, 2nd and 3rd teeth containing double teeth on edge, lower margin of mandible consisting of 10-12 spines; maxillule notched, 3 large setae on upper region and 10-13 setae on lower region; mandibulatory palps and maxilla clothed with fine serrulate setae.
Coloration.—Parietes purple, grey, or brown.
BD to 40 mm.
Chan et al. (2001) showed that the distribution of T. japonica in Hong Kong waters was related to high-salinity waters. Settlement and recruitment of T. japonica in Hong Kong occur in summer, with heat and desiccation stress being major factors controlling the mortality of settlers and recruits (Chan & Williams, 2003, 2004; Chan et al., 2006). (also see remarks in T. japonica formosana).
Japan, mainland China, Kinmen and Matsu (Taiwan).
Mid-shore of exposed intertidal rocky shores.