潮间带蟹类是近岸底栖生物区系中最具代表性的生态类群之一。我国南海北部潮间带底栖蟹类丰富, 但不同区域的研究进展差异显著。相较于粤东、北部湾和海南岛, 目前对粤西岸段潮间带蟹类区系的了解相对欠缺。东海岛与硇洲岛地处雷州半岛东侧, 其潮间带蟹类区系是揭示粤西及南海北部近岸底栖生物地理格局不可或缺的一环。本文基于对东海岛与硇洲岛22个采样点的潮间带采样调查, 结合对硇洲岛历史记录种的整理和订正, 编目更新了两岛的潮间带蟹类物种名录, 并梳理了各物种在中国海区沿岸的地理分布。本次调查共采集蟹类标本325号, 分属26科62属91种, 其中52种为两岛潮间带的新记录。至本研究止, 东海岛与硇洲岛共记录潮间带蟹类33科91属150种。其中72.0%的种类为南海-台湾海峡或南海-东海分布的热带/亚热带种, 28.0%为南海-黄渤海广布种。研究区域在近岸底栖生物区系上与南海周边地区关系密切, 90.7%的潮间带蟹类物种在海南岛有分布, 82.7%在北部湾有分布, 82.0%在台湾岛有分布, 72.7%在东南亚有分布。结果表明, 雷州半岛东侧在生物地理区划上与海南岛北部同属于中国亚热带近海底栖动物区系, 雷州半岛及琼州海峡对潮间带底栖生物扩散的地理屏障效应不甚明显。本研究可为中国近岸底栖生物区系区划研究、海洋生物资源利用与保护提供数据和参考。

Aim: Intertidal crabs represent significant ecological groups within the nearshore zoobenthic biota. The northern South China Sea is rich in intertidal crabs, but the research progress varies considerably across different regions. Compared with eastern Guangdong, Beibu Gulf, and Hainan Island, our understanding of the intertidal crab fauna in western Guangdong remains relatively limited. To bridge this knowledge gap, it is crucial to explore the intertidal crab fauna on Donghai Island and Naozhou Island, located on eastern side of the Leizhou Peninsula. These islands play a vital role in unveiling the nearshore zoobenthic biogeography of western Guangdong and the northern South China Sea. In this study, we present the findings of a comprehensive field survey and incorporate previous studies to report on the species diversity and distribution patterns of intertidal crabs from these two islands.

Method: During the period of 2021-2022, intertidal crabs were collected from 22 sampling sites located Donghai Island and Naozhou Island. And the taxon recorded in previous studies were revised by literature review. A comprehensive and current checklist of intertidal crabs in the two islands was conducted, and an analysis was conducted to determine the distribution patterns of each species along the coasts of the China seas.

Results: A total of 91 species of brachyuran crabs were collected, representing 26 families and 62 genera during the field survey. Within this collection, 52 species were previously undocumented in the study area. The updated checklist now encompasses 150 intertidal crab species, originating from 33 families and 91 genera. Out of them, 108 species (72.0%) are characterized as the tropical and/or subtropical, with their distribution spanning from the northern South China Sea to the Taiwan Strait or the East China Sea. The remaining 42 species (28.0%) are considered widespread, with each of them being found across from the northern South China Sea to the Yellow and Bohai seas. The intertidal brachyuran fauna of the study area is tightly related to other areas of the South China Sea. Among these 150 species, 136 species (90.7%) have also been documented on Hainan Island, 124 species (82.7%) in the Beibu Gulf, 123 species (82.0%) on Taiwan Island, and 109 species (72.7%) in Southeast Asia.

Conclusions The results indicate a strong connection between the intertidal crab population on the eastern coast of Leizhou Peninsula and the northern coast of Hainan Island. Both regions fall within the Subtropical Provinces in terms of nearshore zoobenthic biota. Interestingly, it appears that neither the Leizhou Peninsula nor the Qiongzhou Strait significantly hinder the dispersal of intertidal crabs. The results offer fresh perspectives on the biogeographical classification of nearshore zoobenthic biota in China, as well as the sustainable utilization and preservation of marine biological resources.