Fiddler Crab Information Web Taiwanese Naturalist Wetland Crab Information Web

Zootaxa 3490: 30-47 (2012)

Gelasimus splendidus Stimpson, 1858 (Crustacea: Brachyura: Ocypodidae), a valid species of fiddler crab from the northern South China Sea and Taiwan Strait

Hsi-Te Shih, Peter K. L. Ng, Kingsley J. H. Wong & Benny K. K. Chan

The fiddler crab, Uca splendida (Stimpson, 1858) has been synonymized under Uca crassipes (White, 1847) since Crane (1975). Studies of specimens from the Hong Kong type locality and adjacent areas of China, Taiwan and Vietnam show that U. splendida is a valid species, with a characteristic suite of carapace and gonopod features as well as a distinct cytochrome oxidase I (COI) signature. Genetic work shows that U. splendida belongs to a well-supported clade and is the sister species of U. crassipes. The distribution of U. splendida is restricted to continental East and continental Southeast Asia, in contrast to the oceanic distribution of U. crassipes. Both species, however, are sympatric in Penghu Islands, western Taiwan and Dongsha Island (=Pratas Island).

Key words: Uca splendida, U. crassipes, U. chlorophthalmus, South China Sea, Taiwan Strait, cytochrome oxidase I, taxonomy.

FIGURE 1. Collection sites for specimens of Uca splendida and U. crassipes used in this study: blue triangles (nos. 9-12) for U. splendida; red solid circles (nos. 1-3, 5, 13-18) for U. crassipes; and purple squares (nos. 4, 6-8) for both species sympatrically. Red empty circles mean the additional records of U. crassipes from other references. Different lines indicate the updated ranges of the two species.

FIGURE 2. Uca splendida. G1 of neotype; A, right G1, lateral view; B, distal part of right G1, lateral view; C, distal part of right G1, mesial view.

FIGURE 3. Uca splendida. A-C, neotype. A, habitus, dorsal view; B, right major chela; C, frontal view.

FIGURE 4. Uca splendida. Live coloration of adults (A-E) and juvenile (F); C and D, the same female with different views; G, a population with high density near the bank; H, a female U. splendida (left) and a male U. crassipes (right) sympatric in one locality, with reddish eyestalks for the former and greenish eyestalks for the latter. Photos taken from Cingluo (A-E, H) and Citou (F, G), Penghu, Taiwan.

FIGURE 5. Uca crassipes. Live coloration of adults (A-D, F) and juvenile (E). Photos taken from Dongsha Island, Taiwan (A-E) and Cocos-Keeling, Australia (F).

FIGURE 6. Morphology of different sizes of Uca chlorophthalmus, U. crassipes and U. splendida males (top, middle and bottom in B-D). A, left: U. crassipes, 11.2 mm (Guam) and right: U. splendida, 11.3 mm (Hainan, China). B, 13.1 mm (Kenya), 13.1 mm (Cocos-Keeling) and 13.0 mm (New Taipei, Taiwan), respectively. C, 16.2 mm (Mayotte), 16.3 (Cocos-Keeling) and 16.2 mm (Penghu, Taiwan), respectively. D, 19.2 mm (Mayotte), 19.1 mm (Philippines), 19.2 mm (Penghu, Taiwan), respectively. E, top: U. crassipes, 23.1 mm (Dongsha, Taiwan) and bottom: U. splendida, 23.5 mm (Penghu, Taiwan). Some males¡¦ chelae are separated from the body.

FIGURE 7. The distal part of right G1 (in mesial view) of Uca chlorophthalmus (A), U. crassipes (B) and U. splendida (C), with similar carapace widths around 19.1 mm. Specimens used are the same in (D) of Fig. 6.

FIGURE 8. A Bayesian inference (BI) tree for Uca chlorophthalmus, U. crassipes and U. splendida from the Indo-West Pacific and outgroups, based on COI gene. Probability values at the nodes represent support values for BI, maximum likelihood (MI) and maximum parsimony (MP). "*" indicates specimens from the type locality of U. splendida or U. crassipes.


Fiddler Crab Information Web Taiwanese Naturalist Wetland Crab Information Web

Copyright © 2012 Hsi-Te SHIH