Uca (Xeruca), a new subgenus for the Taiwanese fiddler crab Uca formosensis Rathbun, 1921 (Crustacea: Decapoda: Ocypodidae), based on morphological and molecular evidence

Abstract

The fiddler crab Uca formosensis Rathbun, 1921 (Crustacea: Decapoda: Ocypodidae), restricted to the western part of Taiwan and the offshore Penghu (Pescadores) Islands in the Taiwan Strait, has been placed under the subgenus Uca (Gelasimus) Latreille, 1817 (= Uca (Thalassuca) Crane, 1975) based on only less than a dozen specimens, but later suggested under the subgenus Tubuca Bott, 1973 because the similarity of external morphology. A suite of characters of carapace, major cheliped, gastric mill, male first gonopod, and chela handedness, as well as the phylogenic relationships (mitochondrial 16S rDNA and cytochrome oxidase subunit I, and nuclear 28S rDNA), nevertheless support this species belongs to its own subgenus. A new subgenus Uca (Xeruca) subgen. nov. is herein established for U. formosensis.

Uca (Petruca), a new subgenus for the rock fiddler crab Uca panamensis <br />(Stimpson, 1859) from Central America, with comments on some species of the American broad-fronted subgenera

“…The relationships of the IWP subgenera ( Fig. 9) generally agree with Shih et al (2013b) and Shih (2015) and are not repeated here. The American broad-fronted species form a highly-supported main clade by three methods, with three distinct clades corresponding to three subgenera with high support at least by the BI method.…”

“…Fiddler crabs are abundant in marine wetlands in tropical and subtropical zones (Crane 1975). There are currently 102 species belonging to 11 subgenera, one from West Africa, three from the Americas, and seven from the Indo-West Pacific (IWP) (Ng et al 2008;Shih et al 2013a;Rosenberg 2014;Shih 2015). With regard to the American subgenera, one contains all the species with narrow fronts (relative width between the bases of the eyestalks) (Uca Leach, 1814), whereas the other two (Minuca Bott, 1954, andLeptuca Bott, 1973) include the broad-fronted taxa (Rosenberg 2001;Beinlich & von Hagen 2006;Ng et al 2008).…”

Morphology of the gastric mill teeth in dotillid crabs (Crustacea: Brachyura: Dotillidae) from Indonesia

“…These findings are in consensus with those of Shih (2015) and Shih, Ng, et al (2015), who found that the characteristics of the median tooth plate in the gastric mill, particularly the urocardiac ossicles, are sufficient and useful for distinguishing species. Moreover, variation in the number of teeth on the propyloric ossicles have been detected in the Austruca lactea species complex, with numbers ranging from 5 in A. perplexa to 8 in A. albimana (Naderloo et al, 2010).…”

“…The morphology of the gastric mill is often considered species‐specific (Allardyce & Linton, 2010; Brösing, 2010; Carvalho et al, 2018; Naderloo et al, 2010) and sometimes used for the purpose of distinguishing between families, genera, species including even cryptic species (Brösing, 2010; Brösing et al, 2007; Felgenhauer & Abele, 1989; Naderloo et al, 2010; Shih, 2015). Therefore, it may be reflected by crab's phylogeny in addition to their feeding ecology.…”

Species diversity of fiddler crabs, genus Uca Leach, 1814 (Crustacea: Ocypodidae), from Taiwan and adjacent islands, with notes on the Japanese species

“…Fiddler crabs, genus Uca Leach, 1814 (Decapoda: Ocypodidae) are dominant among the intertidal benthos of tropical and subtropical mudflats (Crane 1975). The fiddler crab fauna of Taiwan and Japan was listed by Crane (1975) but some new records, new species, and a new subgenus have been added from this region during the decades (see Shih 1994Shih , 2015Yoshigou 2001;Shih et al 2010aShih et al , b, 2012. Five species of Uca had been recorded from Taiwan before 1945, viz.…”