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Glyptophysa (Glyptophysa) georgiana (Quoy and Gaimard, 1832)

Diagnostic features

The taxonomy of Glyptophysa is very poorly understood. This is one of several species of relatively smooth shelled Glyptophysa that are variable in shape and in periostracal development (periostracal hairs and spirals can be present), even within a single population. A large number of species-group names are available and it is quite possible that more species occur in Australia. At present we are recognising only three, in addition to G. aliciae.

This species, as we recognise it, is restricted to SW Western Australia.

Classification

Glyptophysa (Glyptophysa) georgiana (Quoy and Gaimard, 1832)

Common name: South-western Pouched Snail 

Class Gastropoda

Subclass Heterobranchia

Order Hygrophila

Superfamily Planorboidea

Family Planorbidae

Genus Glyptophysa Crosse, 1872

Subgenus Glyptophysa

Original name: Physa georgiana Quoy and Gaimard, 1832. Quoy, J.R., & J.-P. Gaimard (1834). Vogage de Découvertes de l’Astrolabe exécuté par Ordre du Roi, Pendant les Années 1826– 1827, 1828, 1829, sous le commandement de M. J. Dumont d’Urville. Vol. 3, part 1. Pp. 366. Paris: J. Tastu Zoologie.

Type locality: George's Sound (=King Georges Sound), Western Australia.

State of taxonomy

The taxonomy of Glyptophysa is very poorly understood. A large number of species-group names are available and it is quite possible that more species occur in Australia.  

This species is one of three that we are somewhat tentatively recognising (see statement under Notes) that were previously referred to as Glyptophysa gibbosa (now treated as a synonym of G. novaehollandica). These taxa are in need of revision, as the species concepts we have used have not been rigorously tested.  

Biology and ecology

On water weeds, wood etc., in ponds, billabongs, swamps and sluggish streams and rivers. Feeds on algae and detritus. Egg mass typically a bean (kidney)-shaped jelly strip containing many small eggs. Development direct.

Additional information on the biology and ecology of members of this family can be found in Fauna of Australia, vol. 5B, p. 1072-1074.

Distribution

South-western Western Australia.

Notes

This species is similar to the common introduced Haitia acuta (Physidae) in that both have similar-shaped, sinistral shells. Glyptophysa can be distinguished by the shell not being completely smooth (as it is in Haitia), Glyptophysa often - but not always - having some periostracal ornament. Haitia has a mottled mantle which can usually be seen through the semi- transparent shell whereas Glyptophysa has a uniformly dark-coloured mantle. The animal of Haitia has digitations (finger-like processes) along the mantle edge against the columella whereas this is smooth in GlyptophysaHaitia lacks a false gill (pseudobranch) which is present in Glyptophysa and all planorbids. The animal of Glyptophysa, if damaged when alive, has red-coloured blood whereas Haitia does not produce coloured blood.

Glyptophysa differs from the otherwise similar genus Isidorella in the penial apparatus having a penial stylet and an accessory flagellum. Isidorella lacks a stylet and an accessory structure but the penis has two lobes.

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 aid in delimiting species. This situation is not ideal, and can only be resolved by additional molecular and morphological studies involving dense sampling.

Further reading

Hubendick, B. (1955). Phylogeny of the Planorbidae. Transactions of the Zoological Society of London 28: 453-542.

Smith, B. J. (1992). Non-marine Mollusca. Pp. i-xii, 1-408 in W. W. K. Houston. Zoological Catalogue of Australia, 8. Canberra, Australian Government Publishing Service.

Walker, J. C. (1988). Classification of Australian buliniform planorbids (Mollusca: Pulmonata). Records of the Australian Museum 40: 61-89.