This genus is in need of revision, as the species concepts we have used have not been rigorously tested. Unpublished molecular data indicate that the species units we are here using appear to be justified, however they are not accompanied by clear-cut morphological characters that allow separation based on shell characters alone. As the species units appear to be overall concordant with state boundaries, we have used these boundaries to delimit species. This situation is not ideal and can only be resolved by additional molecular and morphological studies involving dense sampling.
Snails with a medium sized subglobose to globose, sinistrally coiled shell. Low to moderately raised spire with unshouldered to weakly shouldered whorls; with or without narrow umbilicus, whorls rounded with indented sutures. Aperture large, ovate. Outer lip and columella are entire without columella twist or plait. Smooth or with spiral threads and periostracal setae. Isidorella lacks a stylet and an accessory structure but the penis has two lobes.
Isidorella Tate, 1896
Class Gastropoda
Infraclass Heterobranchia
Megaorder Hygrophila
Order Lymnaeida
Superfamily Planorboidea
Family Planorbidae
Subfamily: Miratestinae
Genus Isidorella Tate, 1896
Type species: Physa newcombi A. Adams & Angas, 1864 (= Isidorella newcombi (A. Adams & Angas, 1864))
Original reference: Tate, R. (1896) Mollusca in Baldwin, S. (ed.) Report on the Work of the Horn Scientific Expedition to Central Australia Part II – Zoology. Dulau & Co., London and Melville, Muller & Slade, Melbourne; pp.181-226.
Type locality: Ponds, Mt. Margaret, South Australia
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On aquatic vegetation in ponds, billabongs, swamps, and sluggish streams and rivers. Locally common. Capable of aestivation, biology generally unstudied. Development direct.
Mainland Australia.
Some forms of Glyptophysa - particularly the species G.(G.) vandiemenensis from Tasmania - are very similar to Isidorella species. However, Isidorella lacks a stylet and an accessory structure, and the penis has two lobes. The taxonomy of species of Isidorella is poorly understood.
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