Kano Yasunori, Chiba Satoshi, Kase Tomoki
Department of Geology, National Science Museum, 3-23-1 Hyakunincho, Shinjuku-ku, Tokyo 169-0073, Japan.
Proc Biol Sci. 2002 Dec 7;269(1508):2457-65. doi: 10.1098/rspb.2002.2178.
A well-supported phylogeny of the Neritopsina, a gastropod superorder archaic in origin, radiated ecologically and diverse in morphology, is reconstructed based on partial 28S rRNA sequences. The result (Neritopsidae (Hydrocenidae (Helicinidae + Neritiliidae) (Neritidae + Phenacolepadidae))) is highly congruent with the fossil records and the character distribution of reproductive tracts in extant taxa. We suggest that the Neritopsina originated in subtidal shallow waters, invaded the land and became fully terrestrial at least three times in different clades, by the extinct Dawsonellidae in the Late Palaeozoic and by the Helicinidae and Hydrocenidae in the Mesozoic. Invasion of fresh- and brackish waters is prevalent among the Neritopsina as the Jurassic and freshwater ancestory is most probable for helicinids. The Phenacolepadidae, a group exclusively inhabiting dysoxic environments, colonized deep-sea hydrothermal vents and seeps in the Late Cretaceous or Early Cenozoic. Submarine caves have served as refuges for the archaic Neritopsidae since the Early to Middle Cenozoic, and the marine neritopsine slug Titiscania represents a highly specialized but relatively recent offshoot of this family. The Neritiliidae is another clade to be found utilizing submarine caves as shelter by the Oligocene; once adapted to the completely dark environment, but some neritiliids have immigrated to surface freshwater habitats.
基于部分28S rRNA序列，重建了 Neritopsina（一种起源古老、生态辐射且形态多样的腹足纲超目）的系统发育关系，该系统发育关系得到了充分支持。结果（Neritopsidae（Hydrocenidae（Helicinidae + Neritiliidae）（Neritidae + Phenacolepadidae）））与化石记录以及现存类群生殖道的特征分布高度一致。我们认为，Neritopsina起源于潮下带浅水区，至少在不同分支中三次侵入陆地并完全成为陆生，一次是在晚古生代由已灭绝的 Dawsonellidae，另外两次是在中生代由 Helicinidae 和 Hydrocenidae。在Neritopsina中，侵入淡水和微咸水的情况很普遍，因为Helicinidae最有可能起源于侏罗纪的淡水环境。Phenacolepadidae是一个专门栖息于缺氧环境的类群，在晚白垩世或早新生代定居于深海热液喷口和渗漏区。自早新生代至中新生代以来，海底洞穴一直是古老的 Neritopsidae的避难所，海洋Neritopsina蛞蝓Titiscania是该科高度特化但相对较新的分支。Neritiliidae是另一个在渐新世就利用海底洞穴作为庇护所的分支；它们一旦适应了完全黑暗的环境，但一些Neritiliidae已迁移到地表淡水栖息地。
