Vol. 59, 2020

(update: 2020.11.20)
 

Diversity of Taiwanese Brackish Crabs Genus Ptychognathus Stimpson, 1858 (Crustacea: Brachyura: Varunidae) based on DNA Barcodes, with Descriptions of Two New Species

Jhih-Wei Hsu¹ and Hsi-Te Shih^1,2,*

¹Department of Life Science, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan. E-mail: rghsn550327@yahoo.com.tw (Hsu)
²Research Center for Global Change Biology, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan. *Correspondence: E-mail: htshih@dragon.nchu.edu.tw (Shih)

Received 18 August 2020 / Accepted 14 September 2020
Communicated by Benny K.K. Chan

Species in the brackish crab genus Ptychognathus are common in the seashore and estuary habitats with freshwater input. Due to their similar morphologies and dull colorations, it is always difficult to distinguish the species in this genus. In this study, the DNA barcode gene COI (cytochrome c oxidase subunit I) was used to help identify Ptychognathus from Taiwan. The results showed that the 10 species can be identified successfully based on COI, with intraspecific distances below 1.54% and interspecific distances of 12.2%–19.57%. In addition, two new species of Ptychognathus are described from Taiwan. Ptychognathus makii sp. nov. from southern Taiwan is similar to P. altimanus (Rathbun, 1914), and P. stimpsoni sp. nov. from southern Taiwan and the southern Philippines resembles P. aff. barbatus (A. Milne-Edwards, 1873) and P. pusillus Heller, 1865. Both species can be distinguished from other congeners by a suite of characters, including the carapace, orbital region, frontal region, telson of male pleon, male first gonopod, and setae on ambulatory legs.

Key words: Ptychognathus, P. makii, P. stimpsoni, New species, Morphology, Mitochondrial cytochrome c oxidase subunit I (COI), Barcodes.

Citation: Hsu JW, Shih HT. 2020. Diversity of Taiwanese brackish crabs genus Ptychognathus Stimpson, 1858 (Crustacea: Brachyura: Varunidae) based on DNA barcodes, with descriptions of two new species. Zool Stud 59:59. doi:10.6620/ZS.2020.59-59.