Tricula

Abstract: A new species of pomatiopsid gastropod, Tricula hortensis, is described from Sichuan Province, PR China This new species is characterized by a large columellar peg or tooth situated mid body‐whorl The reproductive anatomy of the female shows a number of character states that are plesiomorphic for the Triculinae Tricula hortensis may be distinguished from the two other species of Tricula which bear a columellar tooth by differences in the shell and in pallial and/or reproductive structures Tricula hortensis is found in spring‐fed irrigation canals serving market gardens in Mianzhu County, Chengdu, Sichuan This species acts as intermediate host for the parasitic blood fluke Schistosoma sinensium Bao 1958

Abstract: The Schistosoma japonicum group and S. sinensium utilize intermediate snail hosts belonging to the genera Oncomelania and Tricula (Gastropoda: Pomatiopsidae). In the present study, partial sequences of the mitochon- drial 12S rRNA gene from 7 subspecies of O. hupensis, two species of Tricula (T. bollingi and T. humida )a ndO. minima were examined to infer a phylogeny for these. Nucleotide differences among subspecies of O. hupensis were less than 6.5% and among species from different genera, 10-12%. The phylogenetic tree obtained in this study indicates that O. hupensis subspecies fell into four distinct clades ; that is, O. h. quadrasi from the Philip- pines, O. h. lindoensis from Indonesia, O. h. hupensis from Yunnan, China and the remaining 5 subspecies (O. h. hupensis from other parts of China, O. h. robertsoni from China, O. h. formosana from Taiwan, O. h. chiui from Taiwan and O. h. nosophora from Japan). The phylogenetic tree also showed that O. minima was placed as sister to all of the subspecies of O. hupensis. Possible evolutionary relationships among the snail hosts were discussed.

Abstract: A detailed comparative anatomy of the monotypic genus Wuconchona Kang from Hubei Province, China is presented. The data are used for a phylogenetic analysis involving the ten known genera of Triculinae: Triculini sensu Davis 1979. A new tribe, Pachy- drobiini is named in which Wuconchona is classified, thus dividing the Triculini sensu Davis 1979 into the Triculini (Tricula, Delavaya, Fenouilia, Lacunopsis) and the Pachydrobiini (Halewisia, Neotricula, Pachydrobia, Robertsiella, Jinghongia, Wuconchona). Jinghongia Davis gen. nov. is described for a species previously classified as Neotricula. An important aspect of the evolution in this clade is the parallel loss in several lineages of the normal seminal receptacle and the replacement of the seminal receptacle with derived structures. The solution in the Triculini is different from those in the Pachydrobiini. The known capability of each clade to transmit a species of Schistosoma is presented. (Anatomy, China, cladistics, Pomatiopsidae, Schistosoma, Triculinae, systematics)