Specimens previously identified as Bathyconchoecia paulula sensu Yin & Chen, 1991 and Bathyconchoecia galerita sensu Yin & Chen, 1991, together with two similar specimens, are reclassified as a new species, Bathyconchoecia incisa sp. nov., which we describe and illustrate in detail here. The present species is similar to Bathyconchoecia sagittarius and Bathyconchoecia kornickeri in having a shallow notch on the posterodorsal corner of the carapace, but can be easily distinguished from these species by the structure of the posterior margin of the carapace and the striated sculpturing on the surface of the valves. The specimens on which this new classification was based were collected at shallow depths (<125 m) off the east coast of Hainan Island, in the northern South China Sea and in the Zengmu (James) Shoal and adjacent areas in the southern South China Sea. B. incisa is likely to be a shallow-water species or has a wide bathymetric range.
Crustacean vitellogenesis is a process that involves Vitellin, produced via endoproteolysis of its precursor, which is designated as Vitellogenin (Vtg). The Vtg gene, mRNA and protein regulation involve several environmental factors and physiological processes, including gonadal maturation and moult stages, among others. Once the Vtg gene, mRNAs and protein are obtained, it is possible to establish the relationship between the elements that participate in their regulation, which could either be species-specific, or tissue-specific. This work is a systematic analysis that compares the similarities and differences of Vtg genes, mRNA and Vtg between the crustacean species reported in databases with respect to that obtained from the transcriptome of Callinectes arcuatus, C. toxotes, Penaeus stylirostris and P. vannamei obtained with MiSeq sequencing technology from Illumina. Those analyses confirm that the Vtg obtained from selected species will serve to understand the process of vitellogenesis in crustaceans that is important for fisheries and aquaculture.
Population structure and life history of the mysid Neomysis nigra Nakazawa, 1910 were studied on Jeju Island, South Korea. N. nigra was collected monthly from a shallow embayment of Jeju Island from May 2013 to May 2014. Temperature and salinity were measured during the sampling. The carapace length (CL) of N. nigra was measured. Life stages were divided into six categories and embryos in the marsupium were classified by developmental stages. During the study period, water temperatures ranged from −0.3 to 35.7°C. The CL of females was larger than that of males. The mean CL of adults was negatively correlated with water temperature. CL values in winter and spring were higher than those in summer and autumn. Brooding females and juveniles were found all year round. The abundance of juveniles was relatively higher in May, July, December, and February than in other months. The number of embryos in the marsupium increased with increasing female size. In conclusion, the present study suggests that the populations of N. nigra have four major spawning groups in a year and reproduce all year round.
Total length, and the length of carapace and telson, are generally used to measure the size of mysid crustaceans. However, this method may not be as accurate for measuring these animals, since mysids commonly bend their abdomen when they are collected and preserved. Besides, the fragile carapace of mysids may result in less accurate outputs in such size measurements. The aim of this study was to determine the relationship between carapace length and statolith diameter in Mysida. The carapace length and statolith diameter were measured in 1199 individuals of Neomysis nigra Nakazawa, 1910. The statolith diameter was significantly correlated with carapace length. It is suggested that the statolith diameter of mysids could be used as an alternative measurement for characterizing body size in these crustaceans.
The rare euryplacid crab, Trissoplax tuberosa Castro & Ng, 2010 is recorded from Taiwan for the first time and the known range of this species is extended to the southern part of the island. The female characters of the species are also described for the first time and are compared with those of its congener, T. dentata (Stimpson, 1858).