Accepted by J. Mendoza: 5 Mar. 2019; published: 12 Apr. 2019 ZOOTAXA ISSN 1175-5326 (print edition) ISSN 1175-5334 (online edition) Copyright © 2019 Magnolia Press Zootaxa 4585 (2): 315–331 https://www.mapress.com/j/zt/ Article 315 https://doi.org/10.11646/zootaxa.4585.2.5 http://zoobank.org/urn:lsid:zoobank.org:pub:6E61D5EE-E3AD-44EC-9AB3-C7B3E303BF92 On the identity of Sundathelphusa philippina (von Martens, 1868) (Decapoda: Brachyura: Gecarcinucidae) from the Philippines, with descriptions of two new species DANIEL EDISON M. HUSANA 1,3 & PETER K.L. NG 2 1 Environmental Biology Division, Institute of Biological Sciences, College of Arts and Sciences, University of the Philippines Los Baños, College, Laguna 4031, Philippines. E-mail: dmhusana@up.edu.ph 2 Lee Kong Chian Natural History Museum, Faculty of Science, National University of Singapore, 2 Conservatory Drive, 117377, Republic of Singapore. E-mail: peterng@nus.edu.sg 3 Corresponding author Abstract The taxonomy of the Sundathelphusa philippina (von Martens, 1868) species group (Brachyura; Gecarcinucidae) from the Philippines is revised, and two new species are described. Sundathelphusa philippina sensu stricto is here restricted to the Bicol Peninsula of southern Luzon, and to the islands of Samar and Leyte. It is one of the largest freshwater crabs in the archipelago, reaching carapace widths of more than 53 mm. Sundathelphusa cebu sp. nov. from Cebu Island is super- ficially similar to S. philippina in morphology but can be separated by a suite of carapace characters. Sundathelphusa quirino sp. nov. from northern Luzon is the most distinct of the three taxa, with a distinctly more swollen carapace, rela- tively wider male pleon and a straighter male first gonopod. Sundathelphusa spelaeophila Stasolla, Abbarchi & Innocenti, 2015, is also shown to be a junior synonym of S. philippina sensu stricto. Key words: Freshwater crab, taxonomy, revision, Sundathelphusa quirino sp. nov., Sundathelphusa cebu sp. nov. Introduction One of the largest and more commonly reported freshwater crabs in the Philippines is the gecarcinucid, Sundathelphusa philippina (von Martens, 1868). Described from the islands of Samar and Luzon, the species has been widely reported in the literature from several Philippine islands. The taxonomy of S. philippina has long been confused because it was only briefly described and without figures, and this has resulted in its misidentification in various studies. For example, the name S. philippina has appeared in many works, including parasitology, as the species is associated with the lung fluke disease, Paragonimiasis, as an intermediate host of the Paragonimus parasite in the Philippines. Tubangui (1946) reported Paragonimus from a species of “Potamon” from Camarines Sur in southern Luzon, which was later reidentified as Sundathelphusa philippina in Cabrera (1975). The parasite has also been reported from S. philippina collected from other parts of Luzon ((Tubangui et al. 1950; Yogore et al. 1957; Cabrera & Valeza 1979; Zhong et al. 1982) and Leyte (Cabrera 1973; Cabrera & Vajrasthira 1973; Miyazaki 1978; Miyazaki & Habe 1979) (see reviews by Cabrera 1984; Kawashima 1987b). Takeda (1987) reported on the crab material from which parasites were obtained by Kawashima (1987a), identifying material from Camarines Sur in southern Luzon as S. philippina. On the basis of the material on hand and a re-examination of Takeda’s (1987) specimens, the records of S. philippina from southern Luzon in Camarines Sur, Sorsogon, Leyte and Samar are correct. Those from other parts of Luzon may belong to other species. Takeda (1987: 102) also noted that he also had “many specimens from Cebu in the collections of the National Science Museum” belonging to “S. philippina”. His material has been examined and they are here determined to belong to S. cebu sp. nov. instead. The identity of the specimens identified as S. philippina and used by Klaus et al. (2013b) for his studies on spermatophore formation and sperm ultrastructure is uncertain since they were collected from an unspecified part of Luzon Island.