Uca typhoni Crane, 1975

Shih, Hsi-Te, Ng, Peter K. L., Fang, Shou-Hua, Chan, Benny K. K. & Wong, Kingsley J. H., 2010, Diversity and distribution of fiddler crabs (Brachyura: Ocypodidae: Uca) from China, with new records from Hainan Island in the South China Sea, Zootaxa 2640, pp. 1-19 : 13-15

Uca typhoni Crane, 1975

( Figs. 4 A, B, 5A, C)

Uca (Deltuca) demani typhoni Crane, 1975: 41 , pl. 4E–H, fig. 61C [type locality Manila, Luzon]. Uca (Tubuca) typhoni —Ng et al. 2008: 242 [list].

Material examined. Hainan: 1 Ƥ (30.75 mm) (NCHUZOOL 13371), Sanya, Hainan, coll. H.-T. Shih & R.- H. Lee, 28 Jun. 2004; 1 Ƥ (20.64 mm) (MBMCAS 166269), Qinglan Harbor, Wenchang, 5 Dec. 1990.

Comparative material. Uca demani Ortmann, 1897: 2 3 (16.70, 20.54 mm), 3 ƤƤ (17.92–26.53 mm) (NCHUZOOL 13372), Cebu, Philippines, coll. L. Liao et al., 2 Sep. 2003; 1 3 (19.09 mm) (NCHUZOOL 13373), Zamboanga, Philippines; 2 3 (27.45, 28.04 mm) ( ZRC 2000.1731), Sulawesi, Indonesia, coll. C.D. Schubart, 19 Jan. 2000.

Live coloration. The Chinese female specimen (NCHUZOOL 13371) has purple carapace and legs, except that two legs and the left minor cheliped are bright red ( Fig. 4 A, B). This asymmetry is anomalous, and may be the result of these appendages having been lost and regenerated.

Ecology. The Chinese specimen (NCHUZOOL 13371) was collected from the mangrove area at the southern tip of Hainan Island ( Fig. 4 C). It occurred sympatrically with other species including Uca crassipes , U. annulipes , U. vocans , Mictyris brevidactylus Stimpson, 1858 , and Macrophthalmus sp. (see Shih et al. 2009, 2010; Davie et al. 2010).

Distribution. Northern Philippines and Hainan in China. It is a new record both for China and East Asia.

Remarks. Crane (1975) reported three subspecies under U. demani , viz. U. demani demani Ortmann, 1897 , U. demani typhoni Crane, 1975 , and U. demani australiae Crane, 1975 . Uca australiae was published based on a single specimen from Broome, Australia ( Crane 1975) and its taxonomic validity is considered doubtful ( George & Jones 1982). Crane (1975) identified the specimens from northern Philippines (Negros, Panay, Lubang, Samar, and Luzon) as U. typhoni (type locality Manila), and specimens from southern Philippines (Zamboanga and Gulf of Davao in Mindanao) and Indonesia (Java, Sumbawa, and Sulawesi) as U. demani (lectotype locality Sulawesi). For this study, we compared specimens from Hainan, Cebu (next to Negros), Zamboanga, and Sulawesi (see Comparative material).

The specimens from southern Philippines and Indonesia agree well with the description of U. demani , especially with regard to the form of the male major cheliped ( Crane 1975: 39; Yamaguchi 1994: fig. 4). The freshly preserved specimens show the reddish purple on the posterior carapace, and the degrees of gray blotching on the anterior part, and the gray legs ( Fig. 4 E, F), conform well with Crane’s (1975: 42) description. Crane (1975: 41–42) mentioned the relative development of tubercles on the floor of the orbit is important to separate the three subspecies, e.g., tubercles of U. demani typhoni are 12–18 and U. demani demani 18–22. However, we found the number of tubercles on the orbital floor to be variable and unreliable. The tubercles on U. demani are 0–24 for males and 5–18 for females (cf. Fig. 5 B), and large specimens tend to have more tubercles, although the tubercles are weak or lacking on either side of the orbits for some specimens ( Table 2). The females from Hainan have 16–28 tubercles on the orbits ( Fig. 5 A), a similar number or more than those from Philippines and Indonesia ( Table 2). The large variation of the tubercle number on the orbital floor makes this character not very unsuitable for separating these species.

However, there are substantial differences in the gonopore morphology between the females from Hainan and Cebu ( Fig. 5 C, D). Although Crane (1975: 40) noted that the subspecies of U. demani can be differentiated by the form of the gonopores, she also admitted that the “[Female] Material is insufficient for a satisfactory comparison in either d. demani or d. typhoni ”. For the gonopore of the Hainan specimen, the depression is deep, with lateral-external margin surrounded by a low raised rim, and the angle of the lateral margin is subparallel to the longitudinal line ( Fig. 5 C). For the gonopore of U. demani from Cebu, the depression is shallow with a median tubercle, the anterior and posterior rims are relatively more prominent and more raised, with the angle of the lateral margin directed slightly towards the postero-external part ( Fig. 5 D).

tubercle number on floor

species sex CW left orbit right orbit locality museum cat. no.

Uca typhoni Ƥ 20.64 16 16 Hainan MBMCAS 166269 Ƥ 30.75 28 26 Hainan NCHUZOOL 13371

Uca demani 3 16.70 1 2 Cebu NCHUZOOL 13372 3 19.09 13 16 Zamboanga NCHUZOOL 13373 3 20.54 7 8 Cebu NCHUZOOL 13372 3 27.45 13 24 Sulawesi ZRC 2000.1731 3 28.04 0 13 Sulawesi ZRC 2000.1731 Ƥ 17.92 5 6 Cebu NCHUZOOL 13372 Ƥ 22.54 16 17 Cebu NCHUZOOL 13372 Ƥ 26.53 17 18 Cebu NCHUZOOL 13372 In addition, the genetic differences also support their separation as species. The Philippine and Indonesian specimens form a distinct clade, while the Hainan specimen belongs to another clade, with the basepair differences 1.9% of 16S rRNA and 4.1% of COI (Shih et al. unpublished data). In conclusion, based on the morphology, distribution, and genetic data, we are confident that the female specimens from Hainan are U. typhoni . The occurrence of U. typhoni in southern Hainan extends its range westwards. It is also a new record for China and East Asia.

Figures

FIGURE 4. Specimens of Uca typhoni Crane, 1975 from Hainan, China (A – B, NCHUZOOL 13371, CW 30.75 mm) and U. demani Ortmann, 1897 from Cebu, Philippines (D – F, NCHUZOOL 13372, D, E, CW 20.54 mm; F, CW 17.92 mm). A, B, photographs in life of U. typhoni; C, the mangrove habitat of U. typhoni in Sanya, Hainan; D, E, a fresh preserved adult male specimen of U. demani; E, the female U. demani specimen.

FIGURE 5. The floor of orbits and right gonopore of female specimens of Uca typhoni from Hainan, China (NCHUZOOL 13371, CW 30.75 mm) and U. demani from Cebu, Philippines (NCHUZOOL 13372, CW 17.4 mm). A, B, floor of left orbit of U. typhoni and U. demani, respectively, showing the tubercles (arrowed); C, D, the right gonopore and its position on sternum of U. typhoni and U. demani, respectively.