Taxonomy and Distribution of Thalassinidea (Crustacea: Decapoda) from Taiwan

• Main Authors: Feng-Jiau Lin, 林鳳嬌
• Other Authors: Hsiang-Ping Yu
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/82927303775912119454

博士 === 國立海洋大學 === 環境生物與漁業科學學系 === 92 === Abstract Eight species (with 5 species having holotypes from the Taiwan material) of mud shrimps (Thalassinidea) belonging to four genera were reported from Taiwan before. In the present study 28 more species, including 20 new species of 18 genera are found from Taiwan. All these thalassinid species are described in details and accompanied with illustrations. The Taiwanese thalassinid material was used to evaluate the classification schemes proposed by previous authors. It is found that thalassinids are very distinct from the Anomura, Palinura and Astacidea in morphology, mainly by the separated 7th and 8th thoracic sternites, the fifth pereiopod, abdomen and tail-fan all well-developed, and with the abdominal pleura rather reduced. In the present morphological phylogenetic analysis, the thalassinids are well separated from the Astacidea. However, the many synplesiomorphys and few autoapomorphys resulted in the thalassinids are not well separated from the Anomura. Nevertheless, it is still considered here that Thalassinidea is a distinct Infraorder as proposed by Poore (1994). The present phylogenetic analysis also supports the classification scheme of Poore (1994) and under such scheme the Taiwanese thalassinids have 2 superfamilies, 9 families, 21 genera and 36 species. The thalassinid families have clear vertical zonations in Taiwan, a phenomenon similar to the other parts of the world. However, about 2/3 of the Taiwanese thalassinid species are deep-water inhabitants. There are more species in the deep-water eastern coast but many of them are rare. In the shallow water western coast there are much less species but most species there are common or very abundant. It is very likely that the shallow water hard bottoms are not yet well sampled in Taiwan and it is estimated that there are probably 2 times more diversity of thalassinids await to be discovered in Taiwan. The present thalassinid diversity in Taiwan is 6.2 % of the world or 15.5% of the Indo-West Pacific. There is very low similarity in the thalassinid fauna amongst the different localities in the Indo-West Pacific. This is mainly due to the high endemism in thalassinids, with both Australia and Indonesia more than 50%, Japan and Thailand of about 45% and even at 66.7% endemism in Taiwan. The high endemism of thalassinid shrimps may be due to their cryptic lifestyles and generally short larval durations. The highest endemism of the Taiwan thalassinid fauna suggests a special zoogeographical position of Taiwan and the importance of the biodiversity and conservation aspects of the thalassinid fauna of Taiwan.