Gastrodontoidea, Tryon, 1866

Hyman, Isabel T. & Ponder, Winston F., 2010, A morphological phylogenetic analysis and generic revision of Australian Helicarionidae (Gastropoda: Pulmonata: Stylommatophora), and an assessment of the relationships of the family 2462, Zootaxa 2462 (1), pp. 1-148 : 103

Superfamily Gastrodontoidea

Remarks. Gastrodontoidea is defined by Hausdorf (1998) as containing taxa that have lost the stimulator section A 5, undergone reduction of the stimulator papilla and lost the minor venation on the roof of the mantle cavity. He includes Vitreidae , Chronidae , Euconulidae , Trochomorphidae, Gastrodontoidea and Daudebardiidae . Gastrodontoidea was shown to be paraphyletic in our analysis; however, using different subsets of taxa sometimes resulted in a monophyletic Gastrodontoidea (results not shown) so we tentatively retain this grouping following Hausdorf (1998).

None of the members of Gastrodontoidea included in the current study had a stimulator, so the first two of Hausdorf’s (1998) synapomorphies for this group could not be confirmed. The third character, the absence of minor venation on the roof of the mantle cavity, was observed in all Gastrodontoidea species. However, it was also observed in a number of other groups as well (e.g., Durgella , Kalidos , most Ereptinae , species of Periclocystis and Echonitor ). Hausdorf (1998) also unites Trochomorphidae and Euconulidae within Gastrodontoidea , and gives as a synapomorphy the presence of a thin-walled spermatophore. This character was observed in Dendrotrochus , Orpiella and a number of Microcystinae . Spermatophores were not present in Trochomorpha Albers, 1850 , Videna H. and A. Adams, 1855 or any Euconulinae in this study or any previous studies, raising the possibility that in these taxa a spermatophore is not formed.

The key characters defining Gastrodontoidea are as follows: Shell rarely reduced. Mantle usually with no visible minor blood vessels. Stimulator absent or present; if present, stimulator sections A 3, A 4 and A 5 absent and papilla of section A 2 reduced (except in Gastrodontidae ). Penial sheath closed at distal end. Epiphallic retractor caecum and epiphallic flagellum absent in most taxa. Spermatophore absent or if present, softwalled.

Description. Shell present, complete or (rarely) reduced. Shell shape and sculpture variable; mantle laps and lobes absent ( Trochomorphidae , Euconulinae) or if present, usually small ( Microcystinae ). Sole of foot tripartite ( Euconulidae , some Trochomorphidae ) or undivided (some Trochomorphidae ); caudal apparatus present, formed from curled up sole ( Muratov’s 1999 helicarionid type) ( Euconulidae , some Trochomorphidae ) or with sole longer than foot ( Muratov’s 1999 zonitid type) (some Trochomorphidae ). Kidney unilobed; mantle usually with no visible minor blood vessels; mantle gland absent or present. Genital system oviparous ( Trochomorphidae , most Euconulinae ), sometimes ovoviviparous ( Microcystinae , few Euconulinae ). Bursa copulatrix inserted on vagina ( Euconulinae ), at junction of free oviduct and penis ( Trochomorphidae ) or on penis ( Microcystinae ). Stimulator absent or present; if present, stimulator section A 5 is missing and papilla of section A 2 is reduced (except in Gastrodontidae ). Penial sheath absent or present; if present, usually closed at distal end. Epiphallic retractor caecum absent (most taxa) or present ( Liardetia doliolum ); epiphallic flagellum rarely present (only in some Chronidae and Microcystinae ; Hausdorf 1998). Spermatophore soft-walled ( Euconulinae , Microcystinae , Trochomorphidae ) or hard-walled (other taxa) ( Hausdorf 1998).