Petruca Shih, Ng & Christy, 2015

Shih, Hsi-Te, Ng, Peter K. L., Davie, Peter J. F., Schubart, Christoph D., Türkay, Michael, Naderloo, Reza, Jones, Diana & Liu, Min-Yun, 2016, Systematics of the family Ocypodidae Rafinesque, 1815 (Crustacea: Brachyura), based on phylogenetic relationships, with a reorganization of subfamily rankings and a review of the taxonomic status of Uca Leach, 1814, sensu lato and its subgenera, Raffles Bulletin of Zoology 64, pp. 139-175 : 156

Petruca Shih, Ng & Christy, 2015 , status nov.

( Fig. 10F )

Petruca Shih, Ng & Christy, 2015: 476 . Type species: Gelasimus panamensis Stimpson, 1859 , by original designation. Gender feminine.

Diagnosis. Medium-sized species (carapace width about 15 mm in adults); carapace widest between tips of anterolateral angles; dorsal carapace surface almost flat, smooth, with posterolateral striae; front broad; cornea round; eyestalks slender; orbital floor with spinous tubercle near inner corner; adult male major cheliped very large, right- or left-handed, pollex without ventral carina, major chela smooth in inner or outer surfaces, with posterior extension of manus; tips of minor fingers of both sexes with brush of long setae; male pleonites free; pleonal locking mechanism absent; gastric mill with 2 large brownish setae at base of posterior tooth plate. Confined to the East Pacific coasts of the Americas.

Species included:

Petruca panamensis ( Stimpson, 1859) .

Remarks. Gelasimus panamensis Stimpson, 1859 , has been placed either in Minuca or Leptuca , but Shih et al. (2015) established a new subgenus for it based on a number of unusual characters, e.g., the relatively flat dorsal carapace surface, the posterior extension of the major manus, the smooth inner and outer surfaces of the major chela, the brush of long stiff setae on the finger tips of the minor cheliped, the armature at the inner corner of the orbital floor, and the characteristic urocardiac ossicles of the gastric mill. In addition, its ecology and behavior are peculiar for fiddler crabs, e.g. lives on cobble beaches rather than sandy-muddy substrates, has no deep or permanent burrows, and swallow food particles directly (see Shih et al., 2015). The distribution is limited to the Pacific side of Central America and northern South America ( Fig. 4 ).

Figures

Fig. 10. Photographs of some species of the genera Minuca, Paraleptuca, Petruca and Tubuca. A, M. herradurensis (Panama); B, M. rapax (Brazil); C, Pa. chlorophthalmus (East Africa); D, Pa. crassipes (Donghsa, Taiwan); E, Pa. splendida (Penghu, Taiwan); F, Pe. panamensis (Costa Rica); G, T. arcuata (Hainan, China); H, T. bellator (Labuan, Malaysia). C, courtesy of S. Cannicci.

Fig. 4. The distribution of 11 genera of fiddler crabs, mainly based on Crane (1975) and the website (http://www.fiddlercrab.info/index. html; Rosenberg, 2014).