Systematics of the landsnail genus Gyrocochlea and relatives (Mollusca: Charopidae)

This study reviews the charopid snails of Gyrocochlea s.l. This genus has been used as a convenient ‘catch-all’ for thosespecies characterised by chiefly biconcave brown shells that have a strong radially-ribbed teleoconch. The genuscurrently comprises 34 species but could include many more undescribed species that reside in museum collections usingthis broad conchological definition. The study aims to establish a framework for defining natural monophyletic groupswithin the genus and its relatives based on both morphological and molecular data. In doing so, a number of new generaand species that must be characterised to circumscribe this new definition are also described. The study utilisesqualitative and quantitative conchological data, scanning electron microscopy—primarily of the shell protoconch,anatomical studies of the male reproductive system and DNA sequences of cytochrome c oxidase subunit I and theinternal transcribed spacer 2 region of the ribosomal RNA cistrons.This study reaffirms Gyrocochlea s.s. (type species: Helix vinitincta Cox, 1868) as a geographically restricted genuscomprising only a handful of species occurring in the Border Ranges of NSW and Qld following Stanisic (1990) but withthe additional exclusion of Gyrocochlea curtisiana (Hedley, 1912) which will require re-assignment to a new genus. Gyrocochlea vinitincta (Cox) is re-examined and new anatomical details presented. Eight new genera comprising Cumberlandica n. gen., Planorbacochlea n. gen., Barringtonica n. gen., Comboynea n. gen., Cancellocochlea n. gen., Dictyoropa n. gen., Richmondaropa n. gen. and Macphersonea n. gen. are diagnosed to accommodate species rangingfrom mid-eastern to north-eastern NSW. Seventeen new species are described comprising Cumberlandica wilsoniana n. sp. , Cu. wombeyanensis n. sp. , P. dandahra n. sp. , P. manningensis n. sp. , P. nambucca n. sp. , P. watagan n. sp. , P. graemei n. sp. , P. reticulata n. sp. , P. yessabahensis n. sp. , P. parriwiensis n. sp. , Barringtonica polblue n. sp. , B. montana n. sp. , Comboynea boorganna n. sp. , Co. mountaineer n. sp. , Co. winghamensis n. sp. , Cancellocochlea coolongolook n. sp. and Ca. heatherae n. sp. Gyrocochlea impressa Hedley, 1924, G. planorbis Hedley, 1924, G. conferta Hedley, 1924, G. prava Hedley, 1924, G. eurythma Hedley, 1924, G. conjuncta (Iredale, 1941), G. ponderi Stanisic, 2010, G. hawkesburyana Stanisic, 2010 and G. canalis Stanisic, 2010 are variously reassigned to the newgenera. Neotypes are erected for Gyrocochlea impressa Hedley, 1924 (holotype crushed) and Roblinella conjuncta Iredale, 1941 (holotype presumed lost). Lectotypes are designated for Gyrocochlea conferta Hedley, 1924 and Gyrocochlea eurythma Hedley, 1924. The anatomy of the Sydney Basin Diphyoropa saturni (Cox, 1864) is figured forthe first time and comparisons made between the shell morphology of this species and the general Gyrocochlea shellform. A number of species from other genera are also investigated using molecular techniques to provide a broader viewof the east coast charopid radiation. The biogeographical implications of generic ranges and the conservation status of species are discussed.