A review of the varunid crab genus Parapyxidognathus Ward, 1941 (Decapoda: Brachyura: Varunidae), with descriptions of two new species

Abstract

Abstract Species of Parapyxidognathus Ward, 1941 are distributed across tropical Indo-West Pacific to temperate downstream rivers and in estuaries. The genus previously included only one species, Parapyxidognathus deianira (De Man, 1888). We examined specimens from Parapyxidognathus and its closely related genus, Pyxidognathus A. Milne-Edwards, 1879 from the eastern Indian Ocean and western Pacific, focusing on their morphological characters. The results also support the reclassification of Pyxidognathus fluviatilis Alcock, 1900 into Parapyxidognathus, as well as the establishment of two new species from the western Pacific, Pa. tshiansuesp. nov. and Pa. ongiasp. nov. The identity of the species is supported by evidence from mitochondrial 16S rDNA and cytochrome oxidase subunit 1 (COI) genes. There are now four species in Parapyxidognathus distinguishable by the characters of the anterolateral teeth of the carapace, the pleon, and the first gonopods of the male, and the female vulvae.