ABSTRACT
S 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.
ABSTRACT
The genera Bresedium Serène and Soh, 1970 and Sesarmops Serène and Soh, 1970 are two closely related taxa inhabiting terrestrial or freshwater environments from the Indo-West Pacific. Based on morphological and molecular evidence, two new species from Taiwan, the Philippines and Indonesia are described in this study, viz. B. eurypleon n. sp. and S. mora n. sp. The new species can be distinguished from congeners by a suite of carapace, chelipedal, gonopodal and vulvar characters. Bresedium philippinense (Rathbun, 1914) is here shown to be a junior synonym of B. brevipes (De Man, 1889). A poorly known Philippine species, Sesarmops mindanaoensis (Rathbun, 1914), is redescribed from the type and fresh material, and is recorded for the first time from Taiwan.
ABSTRACT
The identity of the widely distributed mangrove and riverine sesarmid crab Sesarmops impressus (H. Milne Edwards, 1837) is clarified. The species has been reported from Madagascar to the South Pacific, but its taxonomy was previously confused. On the basis of morphological characters and available molecular evidence (using 16S rDNA and cytochrome oxidase subunit I), Sesarmops impressus is restricted to the western Indian Ocean and S. frontale A. Milne-Edwards, 1869 is confirmed to be its junior synonym. Sesarmops similis (Hess, 1865), long synonymised under S. impressus, is here recognised as a separate species and a neotype from Samoa is designated. The identity of the poorly known S. atrorubens (Hess, 1865), which has often been confused with S. impressus, is also clarified, and a neotype is selected from Fiji. Specimens from the eastern Indian Ocean and western Pacific are here identified as two new species, S. indicus sp. nov. and S. imperator sp. nov.
ABSTRACT
Species of the varunid genus Parahelice Sakai, Türkay Yang, 2006, inhabit high intertidal areas of oceanic islands of the tropical Indo-West Pacific region. As several species of Parahelice and Pseudohelice subquadrata (Dana, 1851) were found to be sympatric in some places, and their morphological differences are minor, especially in females, the misidentification of species is not uncommon in the literature. In this study, the DNA barcoding marker, mitochondrial cytochrome c oxidase subunit I (COI), was applied to confirm species identities and this was correlated with the specific characters of males and females. Distributions of three species of Parahelice were also updated, with Par. daviei (Sakai, Türkay Yang, 2006), Par. pilimana (A. Milne-Edwards, 1873), and Par. pilosa (Sakai, Türkay Yang, 2006) being new records to Taiwan, and Par. pilosa new to Bali, Indonesia.
Subject(s)
Brachyura , Animals , Female , Male , MitochondriaABSTRACT
Parasesarma liho Koller, Liu & Schubart, 2010 and P. cognatum Rahayu & Li, 2013 from East and Southeast Asia are similar species that have been confused in several studies. Here, we re-examined the type specimens of both species and found identical main characters, which is supported by the molecular identity of the mitochondrial cytochrome oxidase subunit I gene. As a result, we treat P. cognatum as a junior subjective synonym of P. liho. We also show that the male paratype of P. paucitorum Rahayu & Ng, 2009 is conspecific with P. liho, although P. paucitorum s. str. remains a distinct but allied species. The distribution of P. liho is updated to include Japan (Ryukyus), Taiwan, Philippines (Cebu) and Indonesia (Sulawesi).
ABSTRACT
This study presents a rare sesarmid cavernicolous crab, Karstama boholano (Ng, 2002), from Taiwan. This genus and species are both new to Taiwan. We describe the diagnostic characteristics of the Taiwanese specimen and provide illustrations of the adult and first zoea, as well as photographs of an adult in its natural habitat. The identity was confirmed by the COI gene sequence and morphological data. In addition, the zoeal morphology and breeding ecology of the genus Karstama Davie and Ng, 2007 are reported for the first time.
ABSTRACT
Three new coastal crabs, Parasesarma aurifrons n. sp., P. sanguimanus n. sp. and P. gemmatum n. sp. (Sesarmidae), are described from Taiwan and the Philippines. Parasesarma aurifrons is morphologically similar to P. ungulatum (H. Milne Edwards, 1853), P. liho Koller, Liu & Schubart, 2010, and P. obliquefrons (Rathbun, 1924); P. sanguimanus most closely resembles P. cricotus (Rahayu & Davie, 2002); and P. gemmatum is related to P. lenzii (De Man, 1895), but they can be distinguished by a suite of characters, including the structures of the chelipeds, gonopods and vulvae. The three new species are also supported by genetic data from the mitochondrial cytochrome oxidase subunit I (COI). Two species, P. lenzii and P. dumacense (Rathbun, 1914), are also recorded from Taiwan for the first time. The poorly known P. obliquefrons (Rathbun, 1924) from Samoa is figured for the first time as part of the comparisons and its taxonomically important gonopod structures are illustrated.
ABSTRACT
The identity of the tree-spider crab, Parasesarma leptosoma (Hilgendorf, 1869) (family Sesarmidae), which is believed to be widely distributed in the Indo-West Pacific, is reassessed and shown to be a species-complex with nine species, seven of which are here described as new. Parasesarma leptosoma sensu stricto is now restricted to South and East Africa; and P. limbense (Rathbun, 1914) from Sulawesi, which had been regarded as a junior synonym, is here recognized as a valid species. The following species are described as new: P. gecko n. sp. from Vanuatu, Fiji, Guam and Japan; P. macaco n. sp. from Taiwan and the Philippines; P. kui n. sp. from Taiwan; P. parvulum n. sp. from the Philippines; P. gracilipes n. sp. from Indonesian Papua; P. purpureum n. sp. from Malaysia; and P. tarantula n. sp. from Sulawesi, Indonesia. The nine species of the Parasesarma leptosoma species-complex can be separated by the different shapes of their carapaces, the form of the dactylar tubercles on the male chelipeds, proportions of their ambulatory legs and the structure of the male first gonopod.
