Seamounts are well known for the high biodiversity and endemism of their macrobenthic fauna. Hundreds of squat lobster species from seamount environments have been reported in recent years, but squat lobster fauna on the seamount groups around ocean trenches in the tropical West Pacific are still poorly known. In this paper, we describe 11 new species (two Munida, three Munidopsis, one Sternostylus, one Uroptychodes and four Uroptychus) based on specimens collected during expeditions to seamounts around the Yap Trench and Mariana Trench. Of these species, six belong to the superfamily Chirostyloidea and five belong to Galatheoidea. We also provide DNA barcode data for three genes to support the taxonomic status of these new species. The morphological variations, genetic differentiation and phylogenetic relationships of these species are discussed.

Several squat lobster specimens of the genus Munidopsis were collected from an artificially placed carcass fall (cow bones) on Weijia Guyot in the western Pacific Ocean. Based on morphological comparisons and molecular analysis, three specimens were confirmed as juveniles of M. albatrossae Pequegnat & Pequegnat, 1973, which represents the first record of this species in the western Pacific. The other specimens collected are newly described as Munidopsis spinifrons sp. nov., which is distinguished from the closely related species in having a spinose rostrum and basal lateral eyespine on the eyestalk. The M. albatrossae from Weijia Guyot exhibited very low genetic distances when compared with a conspecific sample from Monterey Bay, USA, and the closely related species M. aries (A. Milne Edwards, 1880) from the northeastern Atlantic. A phylogenetic tree based on the mtCOI gene shows M. spinifrons sp. nov. as sister to M. vrijenhoeki Jones & Macpherson, 2007 and M. nitida (A. Milne Edwards, 1880), although M. vrijenhoeki presents a complex relationship with other species in the clade. The systematic status of the new species and the closely related species are discussed.

Galatheid and chirostylid crustaceans (Decapoda: Anomura) from a cold seep environment in the northeastern South China Sea

Thoracican barnacles represent a unique group that has evolved in parallel identical somatotype s (sessile, stalked and asymmetric) in both normal and chemosynthetic environments. Hydrothermal vents and methane seeps are typical extreme deep-sea chemosynthetic habitats for marine macrobenthos. Characterizing the evolutionary history and adaptive strategy of barnacles is fundamentally important for understanding their origin, speciation, and diversification. Herein, we performed a series of phylogenetic analyses focusing on the mitochondrial genomes of the main extant barnacle lineages. Phylogenetic inferences and topology tests contradict the view of the sister relationship between verrucomorphs and balanomorphs, instead revealing that pollicipedids, calanticids and balanomorphs share common ancestor. Selective pressure analyses indicate that the two barnacle lineages of chemosynthetic ecosystems exhibit similar patterns in their evolution of adaptive characters, but have diverse and specific positive substitution sites of mitogenomes. Divergence times suggest that chemosynthetic barnacles originated in the Cenozoic, coinciding with the origins of other metazoan animals in chemosynthetic habitats as well as the Paleogene mass extinction and oceanic anoxic events. It is reasonable to suppose that ecological niche vacancy, sitotaxis, gene specificity in adaptive stress responses, and the subdivision of the ecological niche contributed to the origin and diversification of barnacles in chemosynthetic ecosystems.

Munidopsis species represent some of the dominant macrobenthos in cold seep habitats of the northern South China Sea. Earlier studies documented high abundances of M. verrilli Benedict, 1902 at Site F cold seep and M. lauensis Baba & de Saint Laurent, 1992 at Haima cold seep. However, comparative morphological and genetic analysis of additional materials from the deep waters of California, Manus Basin, and southern Okinawa Trough now indicate that those specimens in the South China Sea require taxonomic revision: the specimens at Site F should be M. longispinosa Cubelio, Tsuchida & Watanabe, 2007 and the specimens at Haima cold seep belong to M. ryukyuensis Cubelio, Tsuchida & Watanabe, 2007. Complementary descriptions of M. ryukyuensis , M. longispinosa and M. verrilli , as well as their geographic distributions, are provided to facilitate future identification.

"Petrolisthes polychaetus n. sp., a new species of Porcellanidae (Decapoda, Anomura) from Hainan Island, China" published on 01 Jan 2010 by Brill.