A new genus and species of gecarcinucid crab are described here from the Namdapha Tiger Reserve of Arunachal Pradesh, India; Abortelphusa namdaphaensis gen. et sp. nov. is morphologically distinct from other related genera, like Phricotelphusa Alcock, 1909, Globitelphusa Alcock, 1909, Liotelphusa Alcock, 1909, and in having a discrete suite of characters, i.e., carapace squarish, surface randomly pitted, a wide frontal margin ca. 0.5 times the total carapace width; epigastric cristae rugose, post orbital cristae indiscernible; third maxilliped exopod lacking a flagellum; male pleon narrowly triangular, sixth pleonal somite trapezoidal; terminal segment of male first gonopod subcylindrical, outwardly bent, tip not truncated. The relationship of this new genus and species with other gecarcinucid genera from India is discussed.
The identity of the potamid freshwater crab, Indochinamon manipurense (Alcock, 1909) from the state of Manipur in northeast India, is clarified based on an examination of the type specimens. The species is redescribed and a lectotype designated. Specimens from the same region previously referred to this species were compared to the types of I. manipurense and shown to belong to a new species of Potamiscus Alcock, 1909, instead. The new species, Potamiscus takedai sp. nov., can easily be separated from I. manipurense by the characters in the carapace, third maxilliped, male pleon, male gonopods, and female vulvae. Potamiscus takedai sp. nov. can be differentiated from congeners mainly by the strongly bent terminal segment of the male first gonopod and a relatively shorter distal segment of the male second gonopod.
The ecdysone receptor (EcR) is a crucial nuclear transcription factor that participates in ecdysteroid signalling. In this study, cDNA of EcR in Panulirus homarus (Linnaeus, 1758) (PhEcR) was cloned and characterized. PhEcR cDNA was 3141 bp, in which a 12 bp insert/deletion splice variant region in the hinge domain was identified. PhEcR mRNA presented the most abundant expression in the ovary. PhEcR mRNA expression was rapidly upregulated in the premoult stage and downregulated in the ecdysis stage. PhEcR mRNA maintained a relatively high expression level from egg-nauplius stage to embryo stage with compound eye pigments formed. The transcript levels of PhEcR in muscle were up-regulated on the 5th and 10th day after antenna ablation. These data suggest that PhEcR may not only play a vital role in the ecdysteroid signalling, but also have relation to embryonic development and limb regeneration.
A new species of long-legged sesarmid crab of the Leptarma leptosoma (Hilgendorf, 1869) species-group is described from mangroves in south-western India. In the general carapace features as well as in the proportions of the long ambulatory legs, L. biju n. sp. is most similar to L. gracilipes (Li, Rahayu & Ng, 2018), from eastern Indonesia and Papua New Guinea, but can easily be distinguished by the structure of the gonopods as well as the leg proportions.
The preparation of specimens is a crucial aspect of zoological studies. Some specific study techniques or certain taxonomic groups require staining processes. However, an excessive exposure to the staining agents can turn a specimen improper for morphological studies. Here, we report that an excess of chlorazol black, one of the most used stains in biology, can be easily removed from crustacean specimens with a solution of methanol and Extran® detergent or, less effectively, with a solution of methanol and commercial dishwashing soap.
Two Southeast Asian species of Parasesarma De Man, 1895, P. indiarum (Tweedie, 1940) and P. foresti (Rahayu & Davie, 2002), have been reported to be morphologically and genetically very similar. Present comparisons of a range of material show the two species to be identical in male chelar dactylar tuberculation, pleon, and first gonopod characters, all typically used to separate close sibling species in this genus. CO1 genetic distances between the two putative species are also too low to be regarded as interspecific. Parasesarma foresti is thus here regarded as a junior subjective synonym of P. indiarum.
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.
A new species of the thermosbaenacean genus Tethysbaena Wagner,1994 is described as T. ledoyeri n. sp.
Together with an as yet undescribed amphipod (Niphargus sp.) it is an inhabitant of the brackish water of an aquifer that flows through the Basse-Provence Urgonian karstic system and reaches the Mediterranean Sea, 15 km east of Marseille, in the “Calanques” coast. The new taxon, being part of the T. argentarii-group, is compared with its closest allies in this group. Preliminary DNA data obtained from two specimens of the new species provide confirmation of its close ties to T. argentarii but also to T. scabra, the two geographically closest described species.
We report on 13 species collected during the 1973 expedition onboard the MY “Velero IV”: seven Euphausiidae (krill), two Benthesicymidae shrimp, two Sergestidae shrimp, one Acanthephyridae shrimp, and one Portunidae crab. Four species are new records for Costa Rica: Bentheogennema burkenroadi, Gennadas scutatus, Neosergestes consobrinus, and Phorcosergia filicta.