Diversity, systematics and phylogeny of sand-bubbler crabs Scopimera (Crustacea: Decapoda: Dotillidae) in East Asian waters
Date Issued
2010
Date
2010
Author(s)
Jin-Ho Wong, Kingsley
Abstract
Crabs of the genus Scopimera De Haan, 1833, commonly known as sand-bubbler crabs, are abundant on sandy shores of the Indo-West Pacific region. Taxonomy of Scopimera in the Indo-West Pacific region was confused and one of the issues centered on the identity of S. globosa De Haan, 1835 and S. tuberculata Stimpson, 1858, and the latter was considered as a synonym with S. globosa. Type material of S. tuberculata was lost and controversies centered on whether S. globosa and S. tuberculata belong to the same species. In the present study taxonomic status of S. globosa and S. tuberculata were revealed from fresh specimens and museum collections from Taiwan, South China and Japan and the two are verified to be conspecific. A specimen of S. globosa was designated as the neotype of S. tuberculata. Two additional species from Ryukyus, Japan and Panay, Philippines are each found to be new and discussed herein (as S. ryukyuensis Wong, Chan et Shih, 2010 and S. philippinensis sp. nov. respectively).
The present study reviewed the diagnostic morphological character of 6 East Asian Scopimera species: S. globosa, S. bitympana Shen, 1930, S. longidactyla Shen, 1932, S. intermedia, S. curtelsona Shen, 1936 and S. ryukyuensis, using quantitative multivariate morphological analysis. 175 morphological characters were measured from a total of 60 crabs belonging to 6 species. Parameters contributing significantly to species variation include relative length of external maxilliped merus to ischium, relative length of cheliped carpus, relative length of 1st ambulatory leg carpus and propodus, and total length of 2nd ambulatory leg. A revised identification scheme and taxonomical treatment of the Asian species is provided based on quantitative and qualitative data.
The present study further examines the phylogeny of Scopimera in the Indo-West Pacific region using partial sequences of two mitochondrial genes: the large subunit (16S) ribosomal (r)RNA and cytochrome oxidase subunit I (COI). Gene sequences of 8 Indo-Pacific species were obtained. Results do not support the monophyly of the genus, with buddhist crab Tmethypocoelis ceratophora Koelbel, 1897 nested within. Among the four defined groupings, the “normal form” group, containing S. globosa, S. longidactyla, S. intermedia, S. curtelsona, S. ryukyuensis and S. philippinensis sp. nov. is found monophyletic. Within the “normal form” group the species are subdivided into 2 sub-clades: S. intermedia and S. sp. nov. distribute from Southeast Asia to South China, and S. globosa, S. longidactyla, S. curtelsona and S. ryukyuensis confined to East Asia (the Japanese archipelago, Taiwan and the Mainland Chinese coast).
Subjects
Scopimera
biodiversity
taxonomy
biogeography
phylogeny
SDGs
Type
thesis
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