Zhang Le-Jia, Shi Zi-Ang, Chen Zhe-Yu, von Rintelen Thomas, Zhang Wei, Lou Zheng-Jie
Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, 10115, Germany.
State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, People's Republic of China.
Proc Biol Sci. 2024 Jan 10;291(2014):20231557. doi: 10.1098/rspb.2023.1557.
E. Lamy, 1926 is a unique freshwater gastropod species with a sessile habit. This enigmatic species was first found cemented on river limestones from China about 120 years ago and described together with the genus. It was never collected again and has been considered monotypic. Here, we report the rediscovery of from several rivers in China, and describe a second species of this genus based on a comprehensive study. In addition to the unique sessile habit of both species, the new species presents one of the most remarkable cases of sexual dimorphism within molluscs. Only the adult female is sessile and the original aperture of the female is sealed by shell matter or rock, while an opening on the body whorl takes the function of the original aperture. The male is vagile, with a normal aperture. Our results confirm the recently suggested placement of within the family Bithyniidae. The sessility of species is considered as an adaption to the limestone habitat in large rivers. The extreme sexual dimorphism and secondary aperture of females are considered as adaptations to overcome the obstacles for mating and feeding that come with a sessile life style.
拉米埃螺（E. Lamy, 1926）是一种独特的具有固着习性的淡水腹足纲物种。大约120年前，这种神秘的物种首次在中国的河流石灰岩上被发现并与该属一同被描述。此后它再也没有被采集到，一直被认为是单型种。在此，我们报告在中国几条河流中重新发现了该物种，并基于全面研究描述了该属的第二个物种。除了这两个物种都具有独特的固着习性外，新物种呈现出软体动物中最显著的两性异形案例之一。只有成年雌性是固着的，雌性的原始开口被壳物质或岩石封闭，而体螺层上的一个开口承担了原始开口的功能。雄性是可移动的，具有正常的开口。我们的结果证实了最近关于将拉米埃螺置于短沟蜷科内的提议。拉米埃螺物种的固着习性被认为是对大型河流中石灰岩栖息地的一种适应。雌性的极端两性异形和次生开口被认为是为克服固着生活方式带来的交配和觅食障碍而做出的适应。
