Adaptations of Xenograpsus testudinatus to shallow hydrothermal vent environments in the western Pacific: A comprehensive review

Abstract

The grapsoid crab Xenograpsus testudinatus, Ng et al. (2000) inhabits unique ecosystems of active shallow-water hydrothermal vents of the western Pacific volcanic rises as the dominant vent metazoan. This species provides a valuable model to explore population expansion, evolutionary ecology, metabolic regulation, genetic adaptation, and meta-population dynamics. A comprehensive literature review revealed that X. testudinatus, a dominant vent metazoan, has evolved robust metabolic strategies driven by mechanisms of acid-base regulation, allowing it to preserve its eco-physiological balance under extreme conditions. The species' physiology and metabolism are intricately linked to symbiotic relationships with beneficial microbiomes, which play a crucial role in its adaptive strategies. The genetic masterpiece of the genomic constitution of vent crabs showed extreme sulfur toxic tolerance through a specified genetic mechanism to H2S detoxification through epithelial and pillar cells of the gill filaments. Furthermore, the isotopic analyses of delta 13C and delta 15N values suggest extensive ingestion of dead zooplankton with microbes forming marine snow in the shallow vents, facilitating a highly efficient recycling trophic system. The overall review highlights critical advancements in our understanding of the eco-physiology, symbiotic relationships, and evolutionary adaptations of marine organisms thriving in one of the earth's most extreme environments.