Tiwaripotamon edostilus Ng & Yeo, 2001

Shih, Hsi-Te & Do, Van Tu, 2014, A new species of Tiwaripotamon Bott, 1970, from northern Vietnam, with notes on T. vietnamicum (Dang & Ho, 2002) and T. edostilus Ng & Yeo, 2001 (Crustacea, Brachyura, Potamidae), Zootaxa 3764 (1) : -

Tiwaripotamon edostilus Ng & Yeo, 2001

( Fig. 7 )

Tiwaripotamon edostilus Ng & Yeo, 2001: 282 , figs. 4, 5.—Ng et al. 2008: 167.— Dang & Ho 2012: 214, fig. 77.

Material examined. 1 male (26.1× 21.4 mm), 4 females (33.0× 26.2 mm –38.5× 30.7 mm) (IEBR-FC TE01); 1 male (42.0× 33.9 mm), 4 females (34.7× 27.9 mm –43.2× 34.9 mm) (NCHUZOOL 13613); Cat Ba Island, Hai Phong City, Vietnam, 15–170 m, coll. V. T. Do, 18–19 March 2013.

Coloration. Carapace and legs scarlet red, chela pink ( Fig. 7 C–E). Some females with purple ambulatory legs ( Fig. 7 C). Freshly preserved specimens dark red ( Fig. 7 A, B).

Ecological notes. This species inhabits in the limestone formations, living inside and outside the caves, as well as the crevices on the outside of the mountains ( Fig. 7 E, F). There are many caves that are large, long and deep at Cat Ba Island. These caves are almost dry and dark near the openings, and it was difficult to observe if there was water inside for these crabs.

Remarks. The carapace is about 1.2 times broader than long (n = 10). Ambulatory legs are smooth, conspicuously long and slender; the merus of the fouth pair is about 5.6 times longer than wide for larger specimens (CW ≥ 55 mm, n = 4), or 5.0 times for smaller ones (CW ≤ 51 mm, n = 6). The ratio is different from the holotype measurements, which has the ratio of 6.4 (Ng & Yeo 2001: 285). An estimation derived from a photograph of holotype (Ng & Yeo 2001: fig. 4) obtains a value of 5.1, which agrees with the ratios of our study, although the difference may be caused by the measurement on different positions or the unevenness of legs in the photograph.

Figures

FIGURE 7. Tiwaripotamon edostilus Ng & Yeo, 2001. A, B, male (CW 42.0 mm), NCHUZOOL 13613, dorsal and ventral views, respectively; C, female (43.2 mm), NCHUZOOL 13613, frontodorsal view; D, female (CW 33.9 mm), IEBR-FC TE 01, frontodorsal view; E, female (CW 42.6 mm), NCHUZOOL 13613, staying on the limestone surface of a cave; F, a habitat of a cave in Cat Ba Island, Hai Phong City, Vietnam.