Park DC, et al. Ann Lab Med. 2019 Nov;39(6):537-544. https://doi.org/10.3343/alm.2019.39.6.537

Organisms occupy diverse ecological niches worldwide, each with characteristics finely evolved for their environments. Crustaceans residing in deep-sea hydrothermal vents, recognized as one of Earth’s extreme environments, may have adapted to withstand severe conditions, including elevated temperatures and pressure. This study compares the exoskeletons of two vent crustaceans (bythograeid crab Austinograea sp. and squat lobster Munidopsis lauensis) with four coastal species (Asian paddle crabs, blue crab, hermit crab, and mantis shrimp) to identify traits influenced by vent environments. The goal was to identify distinctive exoskeletal characteristics commonly observed in vent crustaceans, resulting from their exposure to severe abiotic factors, including elevated temperatures and pressures, found in vent environments. Results show that the exoskeletons of vent crustaceans demonstrated significantly enhanced thermal stability compared to coastal species. These vent crustaceans consistently featured exoskeletons characterized by a reduced proportion of volatile components, such as water, and an increased proportion of CaCO₃, compared with coastal crustaceans. Furthermore, vent crustaceans lacked carotenoid pigments that had low heat resistance. However, no apparent differences were observed in the mechanical properties. Our findings suggest that the similar composition of exoskeletons in vent crustaceans evolved convergently to withstand high temperatures.

This article contains supplementary data from the research paper entitled "A newly discovered Gigantidas bivalve mussel from the Onnuri Vent Field on the northern Central Indian Ridge" [1], describes a new mussel species within the subfamily Bathymodiolinae named Gigantidas vrijenhoeki. Data are comprised of two parts: 1) shell image and molecular analyses of G. vrijenhoeki and 2) metagenomic community analyses of gill-associated symbiotic bacteria on G. vrijenhoeki. G. vrijenhoeki data were obtained from type specimens described in Jang et al. 2020 [1]. The molecular analysis was conducted by calculating genetic distance at intra- and inter-specific level within genus Gigantidas based on the sequence data of two mitochondrial genes (COI and ND4). The metagenomic dataset of gill-associated symbionts were generated by Illumina Miseq sequencing of the V3-V4 region of 16S rRNA from 12 specimens of G. vrijenhoeki collected from the same vent site, Onnuri Vent Field.

Ghost crabs, as a species of the Ocypode within the subfamily Ocypodinae, are distributed in the upper intertidal zone worldwide and are ecologically remarkable. They play an important role in the energy circulation in the intertidal zone and are used as an ecological indicator to predict the impacts of environmental change or anthropogenic activities on the marine ecosystem. In this study, we provide the first evidence for the distribution of O. sinensis in Jeju Island and the southern coastal area on the Korean Peninsula. We generated a high-fidelity mitochondrial genome (mitogenome) for the species. The mitogenome was assembled into a circular chromosome of 15,589 bp, including 13 protein-coding genes, two ribosomal RNA genes, and twenty-two transfer RNA genes. High genetic variation compared with closely related species enabled the precise reconstruction of phylogenetic relationships and an estimation of the divergence times among the Ocypode species. The phylogenetic inference indicated that O. sinensis forms a monophyletic clade with O. cordimanus and diverged from ancestral species approximately 20.41 million years ago.

Ho Jong Lee, M.D., Ung Jun Kim, M.D., Woo Shin Kim, M.D., Young Jin Ko, M.D., Geon Park, M.D., Sook Jin Jang, M.D., Seong-Ho Kang, M.D.. Lab Med Online 2021;11:135-8. https://doi.org/10.47429/lmo.2021.11.2.135