Data from: Connectivity in the cold: the comparative population genetics of vent-endemic fauna in the Scotia Sea, Southern Ocean.

We report the first comparative population genetics study for vent fauna in the Southern Ocean using cytochrome C oxidase I and microsatellite markers. Three species are examined: the kiwaid squat lobster, Kiwa tyleri, the peltospirid gastropod Gigantopelta chessoia and a lepetodrilid limpet, Lepetodrilus sp. collected from vent fields 440 km apart on the East Scotia Ridge (ESR) and from the Kemp Caldera on the South Sandwich Island Arc, ~95 km eastwards. We report no differentiation for all species across the ESR, consistent with panmixia or recent range expansions. A lack of differentiation is notable for Kiwa tyleri, which exhibits extremely abbreviated lecithotrophic larval development, suggestive of a very limited dispersal range. Larval lifespans may, however, be extended by low temperature-induced metabolic rate reduction in the Southern Ocean, muting the impact of dispersal strategy on patterns of population structure. COI diversity patterns suggest all species experienced demographic bottlenecks or selective sweeps in the past million years and possibly at different times. ESR and Kemp limpets are divergent, although with evidence of very recent ESR-Kemp immigration. Their divergence, possibility indicative of incipient speciation, along with the absence of the other two species at Kemp, may be the consequence of differing dispersal capabilities across a ~1000 m depth range and/or different selective regimes between the two areas. Estimates of historic and recent limpet gene flow between the ESR and Kemp are consistent with predominantly easterly currents in the region and potentially therefore, cross-axis currents on the ESR, with biogeographic implications for the region.

本研究采用细胞色素C氧化酶亚基I（cytochrome C oxidase I）与微卫星标记（microsatellite markers），针对南大洋热液喷口动物群（vent fauna）开展了首个比较种群遗传学研究。本次共考察3个物种：基瓦科铠甲虾*Kiwa tyleri*、皮螺科腹足类*Gigantopelta chessoia*，以及Lepetodrilidae科帽贝*Lepetodrilus sp.*，样本采集自斯科舍海岭（East Scotia Ridge, ESR）上相距440公里的两处热液口区域，以及南桑威奇群岛弧带（South Sandwich Island Arc）的肯普破火山口（Kemp Caldera），两地直线距离约95公里（位于东侧）。针对斯科舍海岭的所有物种，本研究未检测到种群遗传分化，该结果与泛交（panmixia）或近期种群范围扩张的理论预期相符。其中*Kiwa tyleri*未出现种群分化的结果尤为值得关注：该物种具有极度简化的卵黄营养型幼虫发育（lecithotrophic larval development）模式，暗示其自然扩散范围极为有限。但南大洋的低温环境可通过降低代谢速率延长幼虫寿命，从而削弱扩散策略对种群遗传结构模式的影响。细胞色素C氧化酶亚基I的多样性模式显示，所有物种在过去百万年间均经历过种群瓶颈或选择性清除（selective sweep）事件，且事件发生的时间可能存在差异。斯科舍海岭与肯普破火山口的帽贝种群存在遗传分化，但存在极近期的跨区域迁移证据。这种分化可能代表初期物种形成（incipient speciation），再结合另外两个物种未在肯普破火山口被发现的现象，二者或许是1000米左右深度区间内物种扩散能力差异，以及两地间选择压力不同共同作用的结果。对斯科舍海岭与肯普破火山口帽贝的历史及近期基因流的估算结果，与该区域以东风为主的洋流模式相符，同时也暗示斯科舍海岭存在跨轴洋流，该发现对本区域的生物地理学研究具有重要参考价值。