Munidopsis species (Crustacea: Decapoda: Munidopsidae) from carcass falls in Weijia Guyot, West Pacific, with recognition of a new species based on integrative taxonomy

New records of the squat lobster genus Munidopsis Whiteaves, 1874 (Crustacea, Decapoda, Munidopsidae) from the deep sea off Taiwan

Two species of the squat lobster family Munidopsidae, Munidopsisalbatrossae Pequegnat & Pequegnat, 1973 and M.pycnopoda Baba, 2005, are reported from Taiwan for the first time based on specimens collected from lower bathyal depths. The Taiwanese material of M.pycnopoda also represents the first record of the species from the Pacific Ocean and greatly extends this species' geographical range from the western Indian Ocean to western Pacific. The giant Munidopsis specimen from Taiwan is identified as M.albatrossae mainly by DNA barcoding even though M.albatrossae and M.aries (A. Milne-Edwards, 1880) are both morphologically and genetically extremely similar.

New records and species of deep-sea squat lobsters (Galatheoidea, Munidopsidae) from the Hawaiian Archipelago: an integrative approach using micro-CT and barcodes

The Hawaiian Archipelago remains extensively under-sampled for many marine invertebrate taxa, including squat lobsters. During the last few years, several deep-sea expeditions carried out in the Pacific Ocean have conducted opportunistic collections of specimens and image data from the vicinity of Hawai'i. Here we describe a new species: Munidopsis hawaii sp. nov. and provide new records for Munidopsidae in the Archipelago and its associations. We illustrate and describe the new species using an integrative approach including micro-CT 3D imaging. Phylogenetic analyses of the species collected from seamounts from Hawai'i indicate that the new species represents a divergent lineage compared to morphologically similar species such as M. dispar and M. papanui. We also study the genetic distances for the species recorded in Hawai'i and other populations of the same species in the adjacent West Pacific. Three species are now known in the Hawaiian region. We also compiled identifications from images captured with ROVs in the area. These observations suggest that munidopsid species are common in the deep sea of Hawaiian waters below 1,000 m.

Functional eye rudiments in the anchialine crab Munidopsis polymorpha (Crustacea: Galatheidae)

The white crab Munidopsis polymorpha (Crustacea: Galatheidae) is the only one of a species-rich genus not occurring in the deep sea. It is endemic to marine caves, anchialine pools and groundwaters of the volcanic island of Lanzarote (Canary Islands). The eye derives from the superposition type possessing a clear zone formed by the proximal extensions of the rudimentary crystalline cones. The number of ommatidia ranges among the lowest found in decapods and the optic ganglia are strongly diminished in size. The crystalline cones are rudimentary or lost and facets with individual corneas are not discernible. The rhabdoms are tiny and irregularly arranged in the rhabdom layer. Some rhabdoms display an open arrangement of rhabdomers with microvilli that are not aligned to form orthogonal layers. The eye is one of the rare exceptions of traits that despite being rudimentary is still partially functional. The absence of stabilizing selection is probably the reason for variability or reduction of the traits necessary for image formation. In contrast, negative phototactic behaviour is present, because light is still perceived by the eyes of M. polymorpha.

Microbial epibiotic community of the deep-sea galatheid squat lobster Munidopsis alvisca

Life at hydrothermal vent sites is based on chemosynthetic primary producers that supply heterotrophic microorganisms with substrates and generate biomass for higher trophic levels. Often, chemoautotrophs associate with the hydrothermal vent megafauna. To investigate attached bacterial and archaeal communities on deep-sea squat lobsters, we collected ten specimens from a hydrothermal vent in the Guaymas Basin (Gulf of California). All animals were identified as Munidopsis alvisca via morphological and molecular classification, and intraspecific divergence was determined. Amplicon sequencing of microbial DNA and cDNA revealed significant differences between microbial communities on the carapaces of M. alvisca and those in ambient sea water. Major epibiotic bacterial taxa were chemoautotrophic Gammaproteobacteria, such as Thiotrichaceae and Methylococcaceae, while archaea were almost exclusively represented by sequences affiliated with Ca. Nitrosopumilus. In sea water samples, Marine Group II and III archaea and organoheterotrophic Alphaproteobacteria, Flavobacteriia and Planctomycetacia were more dominant. Based on the identified taxa, we assume that main metabolic processes, carried out by M. alvisca epibiota, include ammonia, methane and sulphide oxidation. Considering that M. alvisca could benefit from sulphide detoxification by its epibiota, and that attached microbes are supplied with a stable habitat in proximity to substrate-rich hydrothermal fluids, a mutualistic host-microbe relationship appears likely.

Descriptions of eleven new species of squat lobsters (Crustacea: Anomura) from seamounts around the Yap and Mariana Trenches with notes on DNA barcodes and phylogeny

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.