DNA barcoding and morphological identification of spiny lobsters in South Korean waters: a new record of Panulirus longipes and Panulirus homarus homarus

To date, 19 species of spiny lobsters from the genus Panulirus have been discovered, of which only P. japonicus, P. penicilatus, P. stimpsoni, and P. versicolor have been documented in South Korean waters. In this study, we aimed to identify and update the current list of spiny lobster species that inhabit South Korean waters based on the morphological features and the phylogenetic profile of cytochrome oxidase I (COI) of mitochondrial DNA (mtDNA). Spiny lobsters were collected from the southern and eastern coasts of Jeju Island, South Korea. Phylogenetic analyses were performed using neighbor-joining (NJ), maximum likelihood (ML), and Bayesian inference (BI) methods. The ML tree was used to determine the spiny lobster lineages, thereby clustering the 17 specimens collected in this study into clades A, B, C, and D, which were reciprocally monophyletic with P. japonicus, P. homarus homarus, P. longipes, and P. stimpsoni, respectively. These clades were also supported by morphological examinations. Interestingly, morphological variations, including the connected pleural and transverse groove at the third abdominal somite, were observed in four specimens that were genetically confirmed as P. japonicus. This finding is novel within the P. japonicus taxonomical reports. Additionally, this study updates the documentation of spiny lobsters inhabiting South Korean waters as P. longipes and P. homarus homarus were recorded for the first time in this region.

New records of Pseudotachidiidae from South Korea, including a key to species of the Pseudomesochrinae (Copepoda: Harpacticoida)

Two species of the marine harpacticoid family Pseudotachidiidae (Copepoda) are reported from subtidal sediments in the Southern Sea of Korea. Psammis wellsi sp. nov. (Danielsseniinae) is most closely related to P. longisetosa Sars, 1910 but differs from its European congener in the ventral ornamentation of the female genital double-somite, the dorsal ornamentation of the second abdominal somite in the male, the armature of the proximal endite of the maxillary syncoxa, the relative setal lengths and general shape of the female P5, and the relative length of the inner seta of the male P5 endopodal lobe and P6. The female of Pseudomesochra tatianae Drzycimski, 1968 is redescribed in detail, constituting the only other record of the species since its discovery at the type locality in western Norway. East Asian records of members of the four subfamilies currently recognized in the Pseudotachidiidae are summarized. Published and other records of the 23 described species in the Pseudomesochrinae are collated and their armature patterns of P1–P5 are tabulated and corrected where necessary. Pseudomesochra affinis (Sars, 1920) is removed from its synonymy with P. longifurcata T. Scott, 1902 and formally reinstated as a valid species. An updated female-based key to the 19 valid species of Pseudomesochra T. Scott, 1902 and four species of Keraia Willen & Dittmar, 2009 is presented.

The mantis shrimp superfamily Eurysquilloidea confirmed from Taiwan: Liusquilla taiwanica gen. et sp. nov.

Prior to the present study, the mantis shrimp superfamily Eurysquilloidea Manning, 1977, with the single family Eurysquillidae Manning, 1977, contained six genera and 32 species, most of which occur in the Indo-West Pacific. A new genus and species of eurysquilloid, Liusquilla taiwanica, recently discovered off southeastern Taiwan, is described herein, constituting the first record of the superfamily from the island. Sixty-eight species in six of the seven stomatopod superfamilies are now known from Taiwan. Liusquilla differs from other eurysquillids in the combination of four teeth on the dactylus of the raptorial claw and form of the eye and ocular scale. Liusquilla is possibly most closely related to Sinosquillla Liu & Wang, 1978, based on eye form and in the similarly ornamented, densely spinose telson and abdominal somite 6. A key to the eurysquillid genera is provided.

Taxonomic discrimination of species of the genus Metapenaeus Wood-Mason, 1891 from Indian waters through morphometric and molecular studies

The present study identified useful characters in the discrimination of species of the genus Metapenaeus, viz., Metapenaeus affinis, M. alcocki, M. brevicornis, M. dobsoni, M. kutchensis, M. monoceros and M. moyebi, in Indian waters, on the basis of morphometric and molecular studies. Out of 40 morphometric measurements, a correlation matrix of 14 morphometric measurements: carapace width, carapace depth, length of rostrum, of antennular peduncle, of telson, and of 6th abdominal somite; 6th abdominal somite depth, antennal scale length, merus length of 1st pereopod, movable finger length of 1st pereopod, movable finger length of 2nd pereopod, movable finger length of 3rd pereopod, merus length of 5th pereopod, and carpus length of 5th pereopod, were all found to be important in discriminating those seven species. The generated classification matrix showed 100% accurate classification of six species, except M. kutchensis (87.09%). DNA barcodes (588 bp) were generated for Metapenaeus brevicornis, M. dobsoni, M. ensis, M. kutchensis and M. monoceros. A simple identification key is thus proposed for nine species of Metapenaeus from Indian waters.

The first occurrence of fossil shrimps (Crustacea, Decapoda) in the Ipubi Formation (Lower Cretaceous, Araripe Basin)

The Ipubi Formation of the Araripe Basin is an important gypsum reserve whose environment had resulted in the deposition of evaporites with narrow black shale lenses. The objective of the present work was to present the first occurrence of caridean for the dark shale levels of the Ipubi Formation. The specimen collected in the field and analyzed in the laboratory, although not achieving a detailed taxonomic determination, is a very important one because it is the first decapod crustacean found in this formation. We believe the specimen LPU-0918/A and B, is a caridean because of its second abdominal somite having a strongly rounded pleura in the base and it overlaps the first and the third. The knowledge about fossil shrimps is still sparse, and the information presented here can be valuable to the understanding of the evolutive history of the carideans.

A new species in the genus Heteromysoides (Crustacea, Mysida, Mysidae) from Songkhla Lagoon, southern Thailand

A new mysid, Heteromysoides songkhlaensis, is reported from shallow water in the Songkhla Lagoon, southern Thailand. The new species is closely similar to H. nana in having a triangular rostrum and the eyestalk without a process at the anteromesial corner. However, the new species can be readily distinguished from H. nana by three setae on the inner margin and five setae on distal margin of the second segment of the mandibular palp; the carpopropodus of the fifth and sixth thoracic endopod of the new species is composed of four articles, and the telson of the new species is distally rounded, shorter than the sixth abdominal somite, and 1.3 times longer than its basal width; the spines on the telson form elongated spines from the distal to posterior margin. The new species also resembles H. dennisi, H. simplex, and H. stenoura; however, it differs by (1) the presence of a rounded distal margin of telson, and (2) absence of a sharp process on the distolateral corner of the eyestalk.

Rhabdomoplea, a new superorder for the thaumatopsylloid copepods: the consequence of an alternative hypothesis of copepod phylogeny

The superorder Rhabdomoplea is established for copepods belonging to the order Thaumatopsylloida. Apomorphies for Rhabdomoplea are an adult prosome, including thoracic somites 1-4, complete at copepodid I, development of the posterior articulation of thoracic somite 7 of males delayed to copepodid IV and of abdominal somite 1 delayed to copepodid V, and absence of a posterior articulation of abdominal somites 2-3 forming with the anal somite a rod-like somite complex as part of the urosome. Rhabdomoplea appears to be the earliest branch of copepods because only thoracic somites 1-4 are broad throughout copepodid development, and thoracic somites 5 and 6 remain narrow. On podopleans and gymnopleans thoracic somite 5 is transformed from the anterior narrow somite to the posterior broad somite during the moult to copepodid II. On gymnopleans thoracic somite 6 also is transformed from the anterior narrow somite to the posterior broad somite but during the moult to copepodid III. Thus rhabdomopleans differ from podopleans in their body architecture as much as podopleans differ from gymnopleans. An alternative and traditional phylogeny that posits gymnopleans as the earliest branch of copepods requires reversal of these two transformations during copepod evolution; this hypothesis is not favoured here because the parsimonious hypothesis of direct, progressive transformations seems reasonable and plausible.

A new species of freshwater crab of the genus Teretamon Yeo & Ng, 2007 (Decapoda: Brachyura: Potamidae) from Arunachal Pradesh, northeastern India

A new species of potamid crab of the genus Teretamon Yeo & Ng, 2007, is described from Namdapha Tiger Reserve in Changlang district of Arunachal Pradesh, India. The new species, T. kempi n. sp., can be distinguished from its congeners by a distinct combination of carapace and gonopod characters: a relatively high carapace with a bilobed frontal margin; subquadrate sixth abdominal somite with nearly parallel lateral margins; and a relatively small G1 terminal segment with a semicircular to bluntly triangular dorsal flap. All known Teretamon species are compared with the new species, and a key for this genus is provided.

Fecundity, embryo size and embryo loss in the estuarine shrimp Salmoneus carvachoi Anker, 2007 (Crustacea: Alpheidae) from a tidal mudflat in northeastern Brazil

Studies on fecundity and embryo size have been frequently used to infer about the reproductive potential, embryogenesis, and the energy investment in embryo production in crustaceans. These parameters are relevant to the knowledge of life-history and diversity of reproductive strategies developed by this group. This study addressed the embryo production by the estuarine shrimp Salmoneus carvachoi Anker, 2007, a poorly known caridean shrimp. We investigated whether there was (1) a correlation between fecundity and carapace length, (2) an increase in embryo volume along the embryonic development, and (3) loss of embryos along development. In addition, we investigated whether the esternite length and height and width of the pleura of the second abdominal somite were good predictors of fecundity. A total of 53 embryo-carrying individuals were collected in December 2016 and February 2017 in a tidal mudflat from the estuary of the Paripe River, Ilha de Itamaracá, Pernambuco, Brazil. The carapace length ranged from 3.23 to 4.64 mm (3.78 ± 0.26 mm). Among those, 25 individuals had embryos in initial stage, 5 in intermediate stage and 15 in final stage. Fecundity ranged from 14 to 67 (33.65 ± 12.51 embryos) and was weakly correlated with carapace length. However, fecundity was strongly correlated with the width of the second sternite and width of the pleura of the second abdominal somite. Embryo volume increased markedly (93%) from the initial to the final stage of development. This increase might be due to water uptake to facilitate the membrane rupture at the onset of larvae hatching. There was significant loss of embryos only between the initial and intermediate stage. Future studies on the embryo production by other species of Salmoneus Holthuis, 1955 are necessary to understand and compare these aspects of reproductive biology.

A new species of Chorisquilla Manning, 1969 (Stomatopoda: Protosquillidae) from Korea and Japan with redescription of C. mehtae Erdmann & Manning, 1998

A new species of protosquillid mantis shrimp is described from the coastal waters of Korea and Japan. Chorisquilla orientalis n. sp. is distinguished from congeners by the combination of deep grooves and pits on the dorsal surface of abdominal somite 5, 8–14 spines on lateral margin of the telson, numerous minute dorsal spines on the telson and abdominal somite 6, and large, pyriform submedian bosses on the telson preceded by a small rounded boss. Chorisquilla orientalis is morphologically closest to C. mehtae Erdmann & Manning, 1998, from Indonesia, but differs chiefly in the dorsal ornamentation of abdominal somite 6 and the telson and reaches a considerably larger size. Chorisquilla orientalis n. sp. shows developmental changes from juvenile to adult in the shape of the ocular scales and anterior margin of lateral plates of carapace, and in the number of lateral spines on telson. Also, C. mehtae Erdmann & Manning, 1998, which, to date has not been adequately illustrated, is redescribed and figured. A key to the Korean gonodactyloids is presented.