Hsi-Te Shih

An updated annotated checklist of brachyuran crabs from Taiwan (Crustacea: Decapoda)

本報告彙整臺灣水域 (包括所屬小島) 已知短尾蟹類的註解名錄與引用文獻。臺灣之短尾蟹類相已達到800個原生種與3個外來種，分屬35總科、74科。本研究亦增加9個新記錄種，Alainodaeus rimataraDavie, 1993里島阿朗權蟹、Bathypluma spinifer Saint Laurent, 1989棘刺深羽蟹、Brusinia elongata (Sakai, 1969)長形布氏蟹、Haemocinus elatus(A. Milne-Edwards, 1873)高身血紅蟹、Hemigrapsus takanoi Asakuraand Watanabe, 2005 高野近方蟹、Leucosia longimaculata Chen and Fang,1991 長斑玉蟹、Metopograpsus frontalis Miers, 1880 寬額大額蟹、Paradynomene tuberculata Sakai, 1963顆粒擬貝綿蟹、Tauropus egeriae(Gordon, 1947)伊吉利亞牛頭蟹。最多樣性的科為扇蟹科，研究最透徹的則是沙蟹科。約250種新增的記錄是近十年內所增加的，其中多屬於深海性的種類。金門和馬祖地區共有75種，其中12種是臺灣本島所沒有的；東沙島和太平島共有76種，其中有11種未記錄於臺灣本島；本文亦簡要討論臺灣和所屬小島的特有種類。經由持續的採集，預期臺灣短尾蟹類的種類仍會大量的增加。

Population genetics of the fiddler crab Uca sindensis (Alcock, 1900) (Crustacea: Brachyura: Ocypodidae) from the Arabian Sea

BackgroundThe fiddler crab Uca sindensis (Alcock, 1900) (Crustacea: Brachyura: Ocypodidae) is distributed in the northern coasts of the Arabian Sea (Pakistan, Iran, Iraq, and Kuwait). Its typical habitat is on high intertidal areas with higher salinity, which might restrict its distribution, especially within the Persian Gulf. The purpose of the present phylogeographic study is to understand whether the Strait of Hormuz acts as a barrier to the gene flow of this species.ResultsThe genetic analyses of the mitochondrial 16S rRNA, cytochrome oxidase subunit I (COI), and control region (CR) of specimens from various localities showed that there was no genetic differentiation between the populations inside and outside of the Persian Gulf.ConclusionsWe conclude that the narrow Strait of Hormuz does not form a barrier for the larval dispersal in this species. Its restricted distribution in the northern Arabian Sea may instead be associated with its preference for higher salinity sediments present in the coasts of this region.

Phylogeny of the freshwater crab genus Somanniathelphusa Bott (Decapoda : Parathelphusidae) from Taiwan and the coastal regions of China, with notes on their biogeography

It is generally accepted that the southern part of mainland China was connected to, and then separated from, the island of Taiwan many times as a result of successive glaciation events, the most recent being 15 000 years ago. On the basis of this, many biogeographical hypotheses have been proposed to explain the origins and relationships of the flora and fauna of Taiwan and mainland China. However, no clear genetic evidence from the flora and fauna of Taiwan has been forthcoming to support the geological history or biogeographical hypotheses. Land-locked freshwater crabs of the genus Somanniathelphusa Bott, 1968 (Crustacea : Brachyura : Parathelphusidae) inhabit the lowland coastal plains of East Asia and also Taiwan Island, which is their only known locality outside of the main continent. Of the eight species of Somanniathelphusa known from Taiwan and the coastal regions of China (Fujian, Guangdong and Hong Kong), five are studied here: S. amoyensis Naiyanetr & Dai, 1997; S. taiwanensis Bott, 1968; S. zanklon Ng & Dudgeon, 1992; S. zhangpuensis Naiyanetr & Dai, 1997; and S. zhapoensis Naiyanetr & Dai, 1997. Somanniathelphusa taiwanensis has a restricted range in west-central Taiwan, which has been explained by the invasion of species from the mainland via the landbridge of Taiwan Strait during glaciation. This is confirmed by a molecular phylogenetic analysis of the species and its congeners on the mainland. Based on the comparisons of DNA sequences encoding part of the mitochondrial large subunit (16S) rRNA gene and cytochrome oxidase I (COI), two major groups are discernible. Somanniathelphusa zhapoensis from western Guangdong belongs to its own distinct group. The remaining species belong to the second group, but two constituent clades can be recognised, here referred to as the ‘S. taiwanensis’ and ‘S. zanklon’ clades, respectively. These two clades are currently isolated by a major mountain range between Fujian and Guangdong. The molecular evidence also strongly supports the recent invasion of Taiwan by the genus Somanniathelphusa from Fujian during the last glacial event.

Phylogeny and Phylogeography of the Genus Geothelphusa (Crustacea: Decapoda, Brachyura, Potamidae) in Southwestern Taiwan Based on Two Mitochondrial Genes

Abstract Eleven species of Geothelphusa have been reported from southwestern Taiwan (Tainan, Kaohsiung and the northern part of Pingtung counties): G. albogilva Shy, Ng, and Yu, 1994; G. ancylophallus Shy, Ng, and Yu, 1994; G. caesia Shy, Ng, and Yu, 1994; G. lili Chen, Cheng, and Shy, 2005; G. nanhsi Shy, Ng, and Yu, 1994; G. neipu Chen, Cheng, and Shy, 1998; G. olea Shy, Ng, and Yu, 1994; G. pingtung Tan and Liu, 1998; G. shernshan Chen, Cheng, and Shy, 2005; G. tsayae Shy, Ng, and Yu, 1994 and G. wutai Shy, Ng, and Yu, 1994. Comparisons of DNA sequences encoding parts of the mitochondrial large subunit (16S) rRNA and cytochrome oxidase subunit I (COI) genes revealed three major clades, of which one is the species G. ancylophallus, and the other two are species groups here referred to as the G. olea and G. pingtung clades. Geothelphusa ancylophallus is geographically restricted and adapted to an ecologically challenging habitat with an unstable water supply and uneven topology. The G. olea clade (G. olea, G. caesia, G. nanhsi, G. tsayae, and G. wutai) is widely distributed throughout central-western and southwestern Taiwan. The G. pingtung clade (G. pingtung, G. neipu and G. shernshan) is confined to southwestern Taiwan between the previously defined southernmost clades of G. tawu, G. albogilva, and G. ferruginea, and the G. olea clade to the north. It includes an isolated population on distant Chaishan Mountain near Taiwan Strait, which probably dispersed from the peripheral hills of the Central Range during the early Pleistocene. The available genetic evidence indicates that the differential coloration observed in members of the G. olea and G. pingtung clades is not reflected in mtDNA, appears to be dependent on environmental conditions, food, etc., and has little value as a taxonomic character. Possible geological events and climatic factors responsible for the historic isolation of the different freshwater crab clades in southwestern Taiwan are discussed in detail.

Diversity and biogeography of freshwater crabs (Crustacea: Brachyura: Potamidae, Gecarcinucidae) from East Asia

The diversity and biogeography of the two families of freshwater crabs in East Asia (China, Taiwan, Ryukyus and mainland Japan) were studied. The richness in different areas, as well as the distributions of all 40 genera and 311 species were analysed, the patterns examined and possible mechanisms discussed. The published data of freshwater crab species and their distributions in East Asia were analysed by using clustering, diversity index and graphical methods. Six biogeographical districts were recognized for the East Asian freshwater crabs based on similarity of distribution: (I) Hengduanshan Area, including Yunnan and Tibet; (II) Karst Area of Guizhou; (III) Yangtze River Basin, extending to Yellow River basin, with three subdivisions; (IV) Wuyishan Area and Pearl River Basin in Southeast and South China; (V) Hainan Island; and (VI) East Asian Islands, with subdivisions of Taiwan, Ryukyus and mainland Japan. The most diverse genera are the potamids Sinopotamon (84 species) and Geothelphusa (54 species), as well as the gecarcinucid Somanniathelphusa (27 species). Yunnan has the highest species richness (48 species) and diversity (Shannon index 2.21) in continental China, while Taiwan has the highest species richness (42 species) of the island systems. The distribution of the species of the potamid Sinopotamon and other genera along Chinas longest drainage, the Yangtze River, can be subdivided into several zones corresponding to the upper, middle and lower reaches of the river basin. The freshwater crab fauna of continental China, the East Asian islands and Hainan Island were all different from each other, and this finding agreed with the findings of molecular phylogenetic studies. The distribution of freshwater crabs in the Yangtze River showed a similar pattern with other freshwater organisms in this drainage. The present biogeographical interpretation contrasts sharply with the traditional zoogeographical patterns proposed that are based on Chinese terrestrial vertebrates. The present analyses of crab distributions suggest that Yunnan is a possible centre of origin for the Potamidae of China and perhaps the whole of East Asia. The freshwater crab species richness in Yunnan is probably the result of its generally warmer climate, more diverse habitats and a long history of cladogenesis.

Seven new species of Amynthas (Clitellata: Megascolecidae) and new earthworm records from Taiwan

Earthworm specimens collected in southern Taiwan consisted of seven new species of Amynthas and several previously known species, mostly widely distributed peregrines. The new species are A. nanrenensis of the octothecal A. corticis species group, A. monsoonus and A. huangi of the sexthecal A. aelianus species group, and four proandric octothecal species: A. chaishanensis, A. hengchunensis, A. kaopingensis and A. ailiaoensis. Amynthas chaishanensis has dorsal intrasegmental spermathecal pores, but the other three proandric species have dorsal, lateral or ventral intersegmental spermathecal pores, respectively. The proandric species are united by several features, including the enclosure of segment xi in a sac, as in A. formosae (also proandric), octothecal with spermathecae in vi–ix, spermathecal diverticula stalks generally kinked and often enclosed in membrane, and prostatic ducts divided polytomously into numerous small ductlets, which may be grouped into bundles of two to five. In A. ailiaoensis the prostatic duct trunk contains up to seven separate lumens in the ental half, surrounded by the circular muscle of the duct, while in A. chaishanensis the prostatic duct trunk contains about 40 small lumens. Of the previously known species in the collection, Pontodrilus litoralis and Metaphire houlleti are first reported from Taiwan. Additional locations for A. incongruus and A. robustus are given, and in the latter case the material appears to be the usual male‐sterile morph. Other species found are Pontoscolex corethrurus, Amynthas corticis, A. gracilis, Metaphire californica, and Polypheretima elongata.

Recent vicariant and dispersal events affecting the phylogeny and biogeography of East Asian freshwater crab genus Nanhaipotamon (Decapoda: Potamidae).

The molecular phylogeny and biogeography of the East Asian freshwater crabs of the genus Nanhaipotamon (Decapoda: Brachyura: Potamidae) were studied, using two mitochondrial (16S rRNA and cytochrome oxidase I) and one nuclear (28S rRNA) markers, and correlated with various vicariant and dispersal events which have occurred in this region. The results showed Nanhaipotamon to be a monophyletic taxon with four clades which correspond to the topography of the coastal region of southeastern China and Taiwan Island. Mountains appear to play an important role in the distribution. The genus occurs only from east of the Wuyishan Range (Zhejiang and Fujian) and south of the Nanling Range (Guangdong) in southern China, and is also present west of the Central Range in Taiwan. The molecular and geological data suggest that Nanhaipotamon originated in an area between the Wuyishan and Nanling Ranges. In this area, the main and earliest cladogenesis occurred at ∼4.8 million years ago (mya), with speciation probably taking place at around 4mya. The molecular evidence strongly supports the recent invasion of the genus into Taiwan Island from northeastern Fujian, via the paleo-Minjiang River on the landbridge of Taiwan Strait. The presence of the genus in Dongyin Island, however, is through invasion from southeastern Zhejiang, during the Pleistocene glaciation period. Nanhaipotamon reached Taiwan and Dongyin Island at ∼1.0 and 0.4 mya, respectively. A small population of Nanhaipotamon formosanum from Penghu Islands (Pescadores) in the central Taiwan Strait has a slightly different genetic constitution and suggests it is a relict of past Pleistocene glaciations.

A new species of freshwater crab (Decapoda : Brachyura : Potamidae) from Dongyin Island, Matsu, Taiwan, defined by morphological and molecular characters, with notes on its biogeography

A new species of freshwater crab, Nanhaipotamon dongyinense sp. nov. (Decapoda: Brachyura: Potamidae), is described from Dongyin Island, Matsu, Taiwan. Based on morphological and molecular (mitochondrial 16S rRNA) evidence, it can be distinguished from its congeners. The biogeography of the species, found on an island 50 km from mainland China, is also discussed.

Genetic and Morphological Differentiation of the Indo-West Pacific Intertidal Barnacle Chthamalus malayensis

Chthamalus malayensis is a common intertidal acorn barnacle widely distributed in the Indo-West Pacific. Analysis of sequences of mitochondrial cytochrome c oxidase subunit I reveals four genetically differentiated clades with almost allopatric distribution in this region. The four clades exhibit morphological differences in arthropodal characters, including the number of conical spines and number of setules of the basal guard setae on the cirri. These characters are, however, highly variable within each clade; such that the absolute range of the number of conical spines and setules overlaps between clades, and therefore, these are not diagnostic characters for taxonomic identification. The geographic distribution of the four clades displays a strong relationship between surface temperatures of the sea and ocean-current realms. The Indo-Malay (IM) clade is widespread in the tropical, equatorial region, including the Indian Ocean, Malay Peninsula, and North Borneo. The South China (SC) and Taiwan (TW) clades are found in tropical to subtropical regions, with the former distributed along the coasts of southern China, Vietnam, Thailand, and the western Philippines under the influence of the South China Warm Current. The TW clade is endemic to Taiwan, while the Christmas Island (CI) clade is confined to CI. There was weak or no population subdivision observed within these clades, suggesting high gene flow within the range of the clades. The clades demonstrate clear signatures of recent demographic expansion that predated the Last Glacial Maximum (LGM), but they have maintained a relatively stable effective population in the past 100,000 years. The persistence of intertidal fauna through the LGM may, therefore, be a common biogeographic pattern. The lack of genetic subdivision in the IM clade across the Indian and Pacific Oceans may be attributed to recent expansion of ranges and the fact that a mutation-drift equilibrium has not been reached, or the relaxed habitat requirements of C. malayensis that facilitates high concurrent gene flow. Further studies are needed to determine between these alternative hypotheses.

A re-appraisal of the widely-distributed freshwater crab genus Sinopotamon Bott, 1967, from China, with establishment of a new genus (Crustacea: Decapoda: Potamidae)

Freshwater crabs of the genus Sinopotamon Bott, 1967 (family Potamidae) are widely distributed along the Yangtze River (= Chang Jiang) drainage and are endemic to China. Two distinct clades can be distinguished within Sinopotamon s. lato. on the basis of morphological and molecular data. One clade corresponds to Sinopotamon s. str., with the type species Potamon (Potamon) davidi Rathbun, 1904, and 11 other species, all which occur in the Sichuan Basin (including Sichuan Province and Chongqing City) and reach the border areas of adjacent Shaanxi, Hubei, and Guizhou provinces. A new genus, Longpotamon gen. nov., is proposed for the second clade, with Sinopotamon exiguum Dai, 1997, designated as the type species. Sinopotamon s. str. can be distinguished from Longpotamon gen. nov. by the shape of the male telson and by characters of the male first gonopod and the female vulvae. These differences are supported by the mitochondrial 16S rDNA and cytochrome oxidase subunit I (COI) genetic data. Longpotamon gen. nov. is the largest clade, with 73 known species and a wide distribution along the Yangtze River drainage extending north to the Yellow River drainage and south to the eastern side of Wuyishan Range. The two genera overlap in the Sichuan Basin and the adjacent provinces.