Vol. 62, 2023

(update: 2023.6.27)

Multigene Phylogenies of the Estuarine Sesarmid Parasesarma bidens Species Complex (Decapoda: Brachyura: Sesarmidae), with Description of Three New Species

Hsi-Te Shih^1,2,§,*, Jhih-Wei Hsu^1,§, and Jheng-Jhang Li^3,4

¹Department of Life Science, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan. *Correspondence: E-mail: htshih@dragon.nchu.edu.tw (Shih).
 E-mail: rghsn550327@yahoo.com.tw (Hsu)
²Research Center for Global Change Biology, National Chung Hsing University, 250, Kuo Kuang Road, Taichung 402, Taiwan
³Department of Marine Biotechnology and Resources, National Sun Yat-sen University, 70 Lienhai Road, Kaohsiung 80424, Taiwan. E-mail: epigrapsus@gmail.com (Li)
⁴East Peak Ecological Consultants, Inc., 22 Wanggong Road, Kaohsiung 83249, Taiwan

^§HTS and JWH contributed equally to this paper.
(Received 27 October 2022 / Accepted 4 May 2023 / Published 27 June 2023)
Communicated by Benny K.K. Chan

Parasesarma bidens (De Haan, 1835) is a common intertidal sesarmid crab that inhabits the estuarine and mangrove regions of East Asia, as well as Vietnam and the Philippines. Previous studies have suggested that P. bidens is a species complex composed of several species. Our findings indicated that the P. bidens species complex is monophyletic with six clades, as shown by reconstructed phylogenies based on mitochondrial 16S rDNA and cytochrome c oxidase subunit I, as well as nuclear 28S rDNA. Specimens of each clade exhibited different characters, including the morphology of the cheliped, anterior carapace, male gonopod 1, and female vulvae, as well as the coloration. Three species in this complex have been previously described: P. bidens (De Haan, 1835), P. cricotum (Rahayu & Davie, 2002), and P. sanguimanus Li, Shih & Ng, 2019. Here, we describe three additional species: P. continentale n. sp., P. insulare n. sp., and P. chiahsiang n. sp. Biogeographically, the range of P. bidens includes the southern margin of Korea, the main islands of Japan, and the Ryukyus, with a comparatively northern distribution. P. continentale is widely distributed from the continental coasts of southeastern and southern China (including northern Hainan Island) to southern Vietnam and is occasionally found in Penghu, Taiwan. Parasesarma insulare is an insular species distributed from Taiwan main island, the central Philippines, to northern Borneo. Finally, P. chiahsiang is mainly limited to the Penghu Islands (Pescadores) but is also sometimes found in Taiwan main island and the offshore Gueishan Island.

Key words: Parasesarma bidens, P. continentale, P. insulare, P. chiahsiang, Phylogeny.

Citation: Shih HT, Hsu JW, Li JJ. 2023. Multigene phylogenies of the estuarine sesarmid Parasesarma bidens species complex (Decapoda: Brachyura: Sesarmidae), with description of three new species. Zool Stud 62:34. doi:10.6620/ZS.2023.62-34.