Parathelphusa H. Milne Edwards, 1853

Ng, Oliver K. S. Chia Peter K. L., 2006, The Freshwater Crabs Of Sulawesi, With Descriptions Of Two New Genera And Four New Species (Crustacea: Decapoda: Brachyura: Parathelphusidae), Raffles Bulletin of Zoology 54 (2), pp. 381-428 : 384

Parathelphusa H. Milne Edwards, 1853

Parathelphusa H. Milne Edwards, 1853: 213 ; 1854: 171; A. Milne-Edwards, 1869: 161, 163; Wood-Mason, 1871: 192; 1875: 230; 1876: 120; Hilgendorf, 1898: 20; Rathbun, 1905: 228; Alcock, 1909: 376; 1910: 70; Roux, 1915: 363; Colosi, 1919: 12; Balss, 1934: 231; 1937: 144; Fernando, 1960: 191; Bishop, 1963: 220; Bott, 1969a: 365; 1970b: 332, 335; 1970c: 117-118; Ng & Goh, 1987: 315; Ng, 1988a: 96.

Telphusa (Parathelphusa) - von Martens, 1868: 19; Wood-Mason, 1876: 121.

Potamon (Parathelphusa) - Rathbun, 1905: 228 (part).

Paratelphusa (Paratelphusa) - Alcock, 1909: 376; 1910: 70, 254 (spelling erroneous).

Parathelphusa (Parathelphusa) - Bott, 1970c: 118.

Paratelphusa (Mesotelphusa) Roux, 1915: 24 , 247 (part); Balss, 1937: 144; 1969a: 365; 1970c: 124 (type species Telphusa celebensis De Man, 1892 , by original designation).

Palawanthelphusa Bott, 1969a: 365 ; 1970c: 129 (type species Potamon (Parathelphusa) tridentata var. pulcherrima De Man, 1902 , by original designation).

Type species. – Parathelphusa tridentata H. Milne Edwards, 1853 ; subsequent designation by Rathbun (1905). Gender of genus: feminine.

Diagnosis. – Carapace transverse, smooth, glabrous, regions distinct. Frontal margin with distinct and well developed median triangle. Anterolateral margin with 2 epibranchial teeth and an external orbital angle, all of which may be reduced. Posterior margin of epistome with distinctly triangular median lobe. Third maxilliped exopod with long flagellum extending beyond width of merus. Chelipeds unequal in large adult males. Male abdomen distinctly Tshaped, narrow, with proximal segments broader but narrowing sharply from segment 5 onwards, G1 stout, simple, terminal and subterminal segments indistinctly or cannot be demarcated; terminal segment conical to subtruncate; G2 shorter than G1, basal segment subequal to or longer than well developed distal segment.

Remarks. – Parathelphusa H. Milne Edwards, 1853 , is a speciose genus of freshwater crabs with members mainly Sundaic in distribution with outliers in the Philippines, Sulawesi, Bali and Lombok. Excluding the species presently treated in this study, 42 species have been recognised thus far ( Bott, 1970c; Chia & Ng, 1998; Ng, 1988a, 1990, 1992, 1993, 1995b, 1997; Ng & Goh, 1987; Ng & Takeda, 1992, 1993; Freitag & Yeo, 2004). The genus Parathelphusa was first established by H. Milne Edwards, 1853, for two new species: P. tridentata and P. sinensis . No type species was indicated. Subsequently, Rathbun (1905) identified P. tridentata as the type of Parathelphusa . Her designation of the type species is valid under Article 69(a) of the International Code of Zoological Nomenclature (ICZN, 1999). The genus has a very confused taxonomic history. Two synonyms are Palawanthelphusa Bott, 1969 , and Mesothelphusa De Man, 1892 (see Ng, 1988a). Palawanthelphusa was established by Bott (1969a) for three species from Northern Borneo and Palawan Islands and it was eventually regarded as a junior synonym of Parathelphusa by Ng and Goh (1987). Mesothelphusa was use for P. celebensis by De Man (1892), but subsequently Ng (1988a) commented that the subgeneric characters cited by Bott (1970b, c) to distinguish it from Parathelphusa sensu stricto were vague and in many instances, overlapping, and he synonymised both taxa.

A new genus, Syntripsa , is here established for Potamon (Parathelphusa) matannensis Schenkel, 1902 , as there are several diagnostic characters which distinguish it from both Nautilothelphusa Balss, 1933 , and Parathelphusa (see also Ng, 1988a). Of the five species of Parathelphusa from Sulawesi, Ng (1993) regarded the taxonomy of P. celebensis and P. pallida as difficult despite Bott’s (1970c) conclusions, and Ng (1993) contends that there are more than two species in what he referred to as the P. celebensis - P. pallida complex. This study confirms that the complex contains seven species (see below). This means that the genus Parathelphusa now contains 47 known species (Table 1).