Systematic analysis of the caridean shrimp superfamily Pandaloidea (Crustacea: Decapoda) based on molecular and morphological evidence.

One of the systematically controversial superfamilies in Caridea is the predominately deep-sea or cold water Pandaloidea, largely because this species-rich group of nearly 200 species in 25 genera exhibits a very high diversity of body forms and ecology. Although the relationships amongst the taxa within Pandaloidea have been repeatedly discussed based on morphology, no comprehensive molecular phylogeny exists. In this study, we present the first molecular phylogeny of the group, based on a combined dataset of two mitochondrial (12S and 16S rRNA) and six nuclear (ATP synthase ß-subunit, enolase, glyceraldehyde-3-phosphate dehydrogenase, histone 3, phosphoenolpyruvate carboxykinase and sodium-potassium ATPase α-subunit) markers, based on 62 species (about 1/3 of known biodiversity) in 22 genera (88% of genera) of two pandaloid families (Pandalidae, Thalassocarididae) and outgroups from seven other caridean families. With generally high support, the relationships within the clade are fully resolved. Pandalidae is shown to be paraphyletic with Thalassocarididae deeply nested within as a monophyletic group, and the latter is herein considered to be a synonym of Pandalidae. Five major clades are recovered, with the shallow water genera Anachlorocurtis, Chlorocurtis, Chlorotocella and Miropandalus forming a sister clade to the remaining genera. At the genus level, the phylogeny indicates Plesionika, Heterocarpus and Pandalus to be not monophyletic. The validity of Pandalopsis, Stylopandalus and Calipandalus is challenged and these genera are considered herein to be junior synonyms of Pandalus (Pandalopsis) and Plesionika (Stylopandalus and Calipandalus). Although not fully resolved, some evidence potentially considers Nothocaris to be a valid genus. Ancestral State Reconstruction successfully recovered 15 synapomorphies for the major clades, with 11 of them reported to be of systematic significance for the first time.

A new species of the palaemonid shrimp genus Palaemonella Dana, 1852 (Crustacea: Decapoda: Caridea) from Okinawa Island, Ryukyu Islands, Japan.

The palaemonid shrimp genus Palaemonella Dana, 1852 is currently represented by 21 formally described species worldwide, of which 17 species are known from the Indo-West Pacific. In this study, a new species, P. okunoi, is described and illustrated on the basis of two ovigerous female specimens collected from coastal waters in Okinawa Island, Ryukyu Islands, Japan, at depths of 5-30 m. The new species closely resembles P. hachijo Okuno, 1999, but the shorter rostrum, more anteriorly located postrostral teeth on the carapace, the presence of a pair of submedian teeth on the fourth thoracic sternite and the less slender pereopods distinguish P. okunoi n. sp. from P. hachijo. The discovery of the present new species raises the number of Japanese species of Palaemonella to eight. An updated key to the Indo-West Pacific species of the genus is presented.

Additional records of the laomediid mud-shrimp genus Naushonia Kingsley, 1897 (Crustacea: Decapoda: Gebiidea), with a revised identification key.

Six species of the peculiar mud-shrimp genus Naushonia Kingsley, 1897 (Laomediidae) from various localities in the world are treated in this study: N. carinata Dworschak, Marin & Anker, 2006 (newly recorded from Japan); N. japonica Komai, 2004 (second record since the original description); N. lactoalbida Berggren, 1992 (newly recorded from Papua New Guinea); N. portoricensis (Rathbun, 1901) (newly recorded from the French Antilles); N. serratipalma Komai & Anker, 2010 (newly recorded from Saudi Arabia); and N. draconis Anker, 2014 (newly recorded from Cuba). A detailed description and new illustrations are provided for N. portoricensis, a species for which a modern description was hitherto unavailable. Gill formula was re-examined in all six species. Colour photographs of living or fresh specimens are provided for most species. A revised key to all known species of Naushonia is presented, a eliminating misinterpretation of an important character in previous keys.

Deep-Sea decapod crustaceans (Caridea, Polychelida, Anomura and Brachyura) collected from the Nikko Seamounts, Mariana Arc, using a remotely operated vehicle "Hyper-Dolphin".

Samples and images of deep-water benthic decapod crustaceans were collected from the Nikko Seamounts, Mariana Arc, at depths of 520-680 m, by using the remotely operate vehicle "Hyper-Dolphin", equipped with a high definition camera, digital camera, manipulators and slurp gun (suction sampler). The following seven species were collected, of which three are new to science: Plesionika unicolor n. sp. (Caridea: Pandalidae), Homeryon armarium Galil, 2000 (Polychelida: Polychelidae), Eumunida nikko n. sp. (Anomura: Eumunididae), Michelopagurus limatulus (Henderson, 1888) (Anomura: Paguridae), Galilia petricola n. sp. (Brachyura: Leucosiidae), Cyrtomaia micronesica Richer de Forges & Ng, 2007 (Brachyura: Inachidae), and Progeryon mus Ng & Guinot, 1999 (Brachyura: Progeryonidae). Affinities of these three new species are discussed. All but H. armarium are recorded from the Japanese Exclusive Economic Zone for the first time. Brief notes on ecology and/or behavior are given for each species.

A new species of the pontoniine shrimp genus Eupontonia (Crustacea: Decapoda: Caridea: Palaemonidae) from the Ryukyu Islands, Japan.

A third species of the pontoniine shrimp genus Eupontonia Bruce, 1971, E. gracilipes n. sp., is described and illustrated on the basis of a single female specimen collected from shallow water of Ishigaki Island, southern Ryukyu Islands, Japan. The new species is readily distinguished from the two congeneric species, E. noctalbata Bruce, 1971 and E. oahu Bruce, 2010, by a number of morphological characters, including the presence of a distinct postrostral median ridge and of the postrostral median tooth on the carapace. It is considered to be a free-living species. The generic diagnosis of Eupontonia is slightly emended to accommodate the present new species. A key in aid of identification of species of Eupontonia is provided.

New records of the caridean shrimp genus Processa Leach, 1815 (Crustacea: Decapoda: Processidae) from Japan, with descriptions of two new species.

Three species of the processid shrimp genus Processa Leach, 1815, including two new species, are reported from shallow coastal waters in Okinawa Island, Ryukyu Islands, Japan: P. affinis Hayashi, 1975, P. filipes n. sp. and P. hayashii n. sp. The present specimens of P. affinis represent the rediscovery and range extension of this poorly known species, originally described from Indonesia. Male characteristics of P. affinis are documented for the first time. The two new species are referred to the P. aequimana Paulson, 1875 species group. Processa filipes n. sp. is characteristic in the greatly elongate fifth pereopod and the transverse ridge on thoracic sternite 8 consisting of soft cuticle. Processa hayashii n. sp. is characterized by the presence of a deep concavity on the anterolateral margin of the carapace just inferior to the antennal tooth. The number of species of Processa known from Japanese waters is raised from five to eight.

A new species of Pinnixa (Crustacea: Decapoda: Brachyura: Pinnotheridae) associated with a tube worm, Chaetopterus cautus (Annelida: Polychaeta), from Tokyo Bay, Japan.

A new species of the pea crab genus Pinnixa White, 1846 (Pinnotheridae), P. banzu n. sp., is described and illustrated on the basis of four specimens from Banzu, an estuary of the Obitsu River, Kisarazu, Chiba Prefecture, Japan. All the specimens examined were associated with the polychaete tube worm Chaetopterus cautus Marenzeller, 1879 (Chaetopteridae). The new species is very similar to P. chaetopterana Stimpson, 1860 from the western Atlantic, P. occidentalis Rathbun, 1894 from northwest North America, and P. rathbuni Sakai, 1934 from East Asia. It is distinguished from the latter three species by characters of the carapace, ambulatory legs, male abdomen, and male first gonopod. It is suggested that previous records reporting on the association of P. rathbuni with Chaetopterus tube worms might be actually referred to the new species.

Reappraisal of Eiconaxius farreae Ortmann, 1891 and Eiconaxius mortenseni Sakai, 1992 (Decapoda: Axiidea: Axiidae), with description of a new species from Japan.

The sponge associated axiid shrimp Eiconaxius farreae Ortmann, 1891 was originally described based on specimens from Sagami Bay, central Japan. Morphological examination of many specimens of Eiconaxius collected from Sagami Bay and nearby areas, and genetic data from the mitochondrial COI and 16S rRNA genes have revealed that three species are represented. This finding led to a reappraisal of the identity of E. farreae and E. mortenseni Sakai, 1992, also originally described from Sagami Bay. It has been clarified that two species (E. farreae and an undescribed species) were mixed in the syntype material of E. farreae, and consequently, a lectotype of E. farreae is designated in the interest of nomenclatural stability. Here, E. farreae and E. mortenseni are redescribed, and the third species is described as new, E. reconditus. The new species is morphologically very similar to E. mortenseni. Differentiating characters among closely allied species are reassessed. Previous records of E. farreae are reviewed in light of the present findings.

Revision of the alvinocaridid shrimp genus Rimicaris Williams & Rona, 1986 (Decapoda: Caridea) with description of a new species from the Mariana Arc hydrothermal vents.

A new species of alvinocaridid shrimp is reported, from the Northwest Eifuku hydrothermal vent field at 16191667 m depth on the Mariana Arc. A comprehensive phylogenetic reconstruction of Alvinocarididae based on the mitochondrial cytochrome c oxidase subunit I (COI) gene including this new species reveals the paraphyly of the genus Rimicaris Williams & Rona, 1986 with four other generaAlvinocaridinides, Manuscaris, Opaepele, and Shinkaicarisnested within it. We re-examine material of these four problematic genera, and synonymise them under Rimicaris whose diagnosis has been amended, in order to maintain a monophyletic Rimicaris. Our new species, Rimicaris cambonae sp. nov. is genetically close to Rimicaris loihi (Williams & Dobbs, 1995) comb. nov. (previously Opaepele loihi) with which it co-occurs, but can be morphologically distinguished by the less elevated dorsal surface of the rostrum, this being devoid of a median carina, a stronger pterygostomial tooth on the carapace, and a blunt rather than acuminate proximolateral process on the antennular stylocerite. Species previously assigned to the above listed, synonymized genera are also discussed, with new material examined for three key species: R. loihi, R. acuminata, and R. leurokolos. Further, Alvinocaridinides formosa Komai & Chan, 2010 and Manuscaris liui Wang & Sha, 2016 are synonymized under Rimicaris leurokolos (Kikuchi & Hashimoto, 2000) comb. nov. and R. acuminata (Komai & Tsuchida, 2015) comb. nov., respectively. Revised diagnoses are presented for R. loihi, R. acuminata, and R. leurokolos. After the present revision revision, Rimicaris now consists of 15 species.

Additional records of the pagurid hermit crab genus Trichopagurus de Saint Laurent, 1968 (Crustacea: Decapoda: Anomura), with description of a new species from the Philippines.

The pagurid hermit crab genus Trichopagurus de Saint Laurent, 1968 is currently represented by three shallow water spe- cies from the tropical Indo-West Pacific region. In this paper, three species of the genus, including one new species, are reported. Trichopagurus tenuidactylus n. sp. is described on the basis of a single ovigerous female from the Bohol Sea, the Philippines, and compared with two close relatives, T. asper Komai & Poupin, 2012 and T. macrochela Komai & Os- awa, 2005. New locality records are provided for T. macrochela (the Philippines) and T. trichophthalinus (Forest, 1954) (Taiwan and Marianas). An identification key to the four species of the genus is presented.

A new species of the hippolytid genus Paralebbeus Bruce & Chace, 1986 (Crustacea: Decapoda: Caridea) from the Coral Seamount, southwestern Indian Ocean.

The hippolytid genus Paralebbeus Bruce & Chace, 1986, is only known from two species, P. zotheculatus Bruce & Chace, 1986 (type species) and P. zygius Chace, 1997. Both are known from the western Pacific, though P zotheculatus was originally described from the Australian Northwest Shelf in the Indian Ocean. In this paper, a new species, P. mollis, is described and illustrated on the basis of a single ovigerous female from the Coral Seamount, southwestern Indian Ocean, at a depth of 952 m as the third representative of the genus. The new species is readily distinguished from its congeners by the rostrum being armed with one tooth on both the dorsal and ventral margin and the conspicuous pterygostomial tooth on the carapace. Because of these characteristics of the new species, the diagnosis of Paralebbeus is slightly emended. The holotype of P mollis n. sp. was associated with an unidentified hexactinellid sponge, like the other two known species.

Records of the hermit crab genus Pagurixus Melin, 1939 (Crustacea: Decapoda: Anomura: Paguridae) from Europa Island, Western Indian Ocean, with descriptions of two new species.

Three species of the pagurid hermit crab genus Pagurixus Melin, 1939, are reported from Europa Island in the Mozambique Strait, western Indian Ocean: P. haigae Komai & Osawa, 2007, P. annulus n. sp., and P. europa n. sp. Pagurixus haigae is recorded from the western Indian Ocean for the first time. Pagurixus annulus n. sp. and P. europa n. sp. are referred to the P. boninensis (Melin, 1939) species group and P. anceps (Forest, 1954) group, respectively. Diagnostic characters of these two new species are discussed.

A new species of sesarmid crab of the genus Chiromantes (Crustacea: Decapoda: Brachyura) from the Ogasawara Islands, Japan.

A new species of sesarmid crab, Chiromantes magnus, is described from the Ogasawara (Bonin) Is., Japan. The new species was previously confused with C. dehaani (H. Milne Edwards, 1853). The different carapace shape, proportionally longer ambulatory legs, large adult size and the distinct live coloration distinguish the new species from its two closest congeners, C. dehaani and C. neglectus (De Man, 1887). Available information indicates that C. magnus n. sp. is endemic to the Ogasawara Is.; there is no evidence of the occurrence of the true C. dehaani in the Ogasawara Is.

A new species of the pagurid hermit crab genus Lophopagurus McLaughlin, 1981 (Crustacea: Decapoda: Anomura) from French Polynesia, and additional record of L. indonesiensis McLaughlin, 1997 from the Philippines.

Two species of the pagurid hermit crab genus Lophopagurus McLaughlin, 1981 are reported herein. Lophopagurus (Lophopagurus) minimus n. sp., described on the basis of two females from Tuamotu Archipelago, French Polynesia, appears closest to L. (L.) nanus (Henderson, 1888), but is easily distinguished from the latter by the different shape of the ocular peduncles and the less developed armature of the right cheliped. A single female from the Bohol Sea, the Philippines, is identified with L. (Australeremus) indonesiensis McLaughlin, 1997, a species for which possible synonymy with L. (A.) triserratus has been suggested. The newly collected specimen confirms the validity of the species and represents its second record since the original description.

A new species of fiddler crab from the Ogasawara (Bonin) Islands, Japan, separated from the widely-distributed sister species Uca (Paraleptuca) crassipes (White, 1847) (Crustacea: Decapoda: Brachyura: Ocypodidae).

A new species of fiddler crab (Brachyura: Ocypodidae), Uca boninensis sp. nov., is described from the Ogasawara (Bonin) Islands, Japan. The new species has previously been identified with the widely distributed U. crassipes (White, 1847), from which it differs by having a slightly differently shaped carapace, and relatively stouter male first gonopods (G1). The recognition of the new species is also supported by differences in the mitochondrial cytochrome oxidase I (COI) and control region (CR) genes. U. boninensis sp. nov., appears to be endemic to the Ogasawara Islands, and as the only known population is small, urgent conservation measures are needed for its protection. Our study brings the total number of the Japanese fiddler crab species to 12.

A redescription of a rare axiid shrimp, Amakusaxius amakusanus (Miyake & Sakai, 1967) (Crustacea: Decapoda: Axiidea) from new material collected off Taiwan.

Miyake & Sakai (1967) described a new species of axiid shrimp, Calocaris (Calastacus) amakusana, from a single female specimen lacking a major cheliped. Later, Sakai & de Saint Laurent, 1989 transferred this species to their new genus Acanthaxius. However, Sakai (2011) recently established a new monotypic genus Amakusaxius to accommodate Acanthaxius amakusana. Since the original description no additional specimen of this rare species has been reported and consequently an appraisal of A. amakusanus (Miyake & Sakai, 1967) has not been possible. Now six specimens including three males and three ovigerous females have been collected from Taiwan. This has enabled the diagnostic characters of the species to be fully evaluated. The presence of a postcervical median carina on the carapace, weak armature on the major cheliped, and the morphology of the uropod are characters that distinguish Amakusaxius from Acanthaxius. Consequently the monotypic genus Amakusaxius Sakai, 2011 is retained.

Rediscovery and range extension of Ciliopagurus liui Forest, 1995 and description of a new species of Pagurus Fabricius, 1775 (Crustacea: Decapoda: Anomura: Paguroidea) from the Kerala State, southwestern India.

Two species of paguroid hermit crabs, Ciliopagurus liui Forest, 1995 (Diogenidae) and Pagurus spinossior n. sp. (Paguridae), are reported from the Kerala State, southwestern India. Ciliopagurus liui, is first recorded from the Indian Ocean. This species was originally described on the basis of a single male specimen from the Tonkin Gulf in the South China Sea, though its geographical range also included Japan, based on literature. Supplemental description and illustrations are provided for better understanding of the diagnostic features of this little known species. Pagurus spinossior n. sp., described on the basis of a single male specimen, appears closest to P. spinulentus (Henderson, 1888), known only by the holotype from the Philippines, but the lack of spinules on the dorsal margins of the dactyli of the second pereopods, the different shape of the anterior lobe of the thoracic stemite 6, and the more numerous spines on the terminal to posterior margins of the telson distinguish the new species from P. spinulentus.

A new species of the hermit crab genus Diogenes (Crustacea: Decapoda: Anomura: Diogenidae) from southern India.

A new species of the hermit crab genus Diogenes Dana, 1851 (Diogenidae), D. canaliculatus, is described and illustrated on the basis of material from off the Kerala State, southern India. It is referred to the D. edwardsii (De Haan, 1849) species group, and compared with D. bicristimanus Alcock, 1905, D. fasciatus Rahayu & Forest, 1995, D. laevicarpus Rahayu, 1996 and D. moosai Rahayu & Forest, 1995. The characteristically sculptured left chela and the unarmed dorsal margins of the propodi of the second and third pereopods distinguish the new species from these congeners.

A new intertidal species of the thorid shrimp genus Heptacarpus Holmes, 1900 (Decapoda: Caridea) from Japan.

A new species of the thorid shrimp genus Heptacarpus Holmes, 1900, H. sadoi, is described and illustrated on the basis of six specimens from the southeastern coast of the Boso Peninsula, central Japan. All the specimens were collected from intertidal tide pools at low tide. Heptacarpus sadoi n. sp. belongs to the species group with epipods on the pereopods 13 and appears morphologically close to H. jordani (Rathbun, 1902) known from Japan and Korea. The new species is readily differentiated from H. jordani by the short rostrum with fewer dorsal teeth and the possession of only one spine on the distal margin of the basal article of the antennular peduncle. Genetic comparison using two mitochondrial markers (COI and 16S rRNA genes) also supports that the new taxon is distinct from H. jordani.

Clarification of the identity of deep-sea crab Tymolus uncifer (Ortmann, 1892) and validation of Tymolus melanommus (Doflein, 1904) (Decapoda: Brachyura: Cyclodorippidae).

Examination of material from Japanese waters has disclosed that two species have been confounded under Tymolus uncifer (Ortmann, 1892) (Decapoda: Brachyura: Cyclodorippidae) in previous literature. The identity of Tymolus uncifer sensu stricto is clarified in reference to the lectotype, and the second taxon is herein attributed to T. melanommus (Doflein, 1904), which was originally recognised as a forma of T. uncifer with one specimen from off Kenya and one specimen from Japan. A lectotype is herein selected for T. melanommus in the interest of nomenclatural stability. Differentiating characters between the two species are assessed in detail, and those two species are compared also with T. glaucommus (Alcock, 1894), T. similis (Grant, 1905), T. brucei Tavares, 1991, T. daviei Tavares, 1997, T. hirtipes Tan & Huang, 2000 and T. globosus Spiridonov & Trkay, 2007, all of them are considered as valid. Sexual dimorphism and ontogenetic variation are seen in the relative length and stoutness of the pereopods 2 and 3 in T. uncifer and T. melanommus, but the morphometric characters derived from the two pereopods are useful as diagnostic at comparison between same sex in adults. Comparison of partial fragments of the mitochondrial COI and 16S rRNA gene sequences strongly supports that the two taxa are distinct. Previous records of T. uncifer, including fossil records, are reviewed based on the present findings. Tymolus uncifer and T. melanommus are restricted to Japanese waters at present.