This genus is in need of revision, and the species concepts we have used have not been rigorously tested. This situation can only be resolved by additional molecular and morphological studies involving comprehensive sampling.
Members of this genus have a sinistral, cylindrical carinate shell with a flat to low spire. The last whorl is strongly keeled, or with rounded shoulders. The aperture is almost as long as the shell, angular posteriorly, narrowly curved anteriorly, and there is a slight to distinct columellar fold.
The shell surface is usually smooth; some specimens, especially juveniles, possess spiral rows of periostracal hairs. The copulatory organ is an unbranched (uniramous), pendant penis with a terminal or lateral pore; the bursa copulatrix is elongate. There are three ridges on the roof of pulmonary cavity and a rectal ridge (Walker 1988).
Amerianna Strand, 1928
Class Gastropoda
Infraclass Heterobranchia
Megaorder Hygrophila
Order Lymnaeida
Superfamily Planorboidea
Family Planorbidae
Subfamily: Miratestinae
Genus Amerianna Strand, 1928
Type species: Physa (America) carinata H. Adams, 1861 (=Amerianna carinata (H. Adams, 1861))
Original reference: Adams, H. (1861). Descriptions of a new genus and some new species of the shells from the collection of Hugh Cuming, Esq. Proceedings of the Zoological Society of London 1861: 143-145.
Type locality: Boyne River, Queensland.
Synonyms: Ameria H. Adams, 1861 (not Ameria Walker, 1854); Ameriella Cotton, 1943.
The species of Amerianna require taxonomic revision - the classification presented here is modified from that presented in earlier versions of this key, but is still based on shells alone.
On water weeds, wood, and similar substrates, in ponds and billabongs. Feeds on algae and detritus. Egg mass a jelly strip containing many small eggs. Development direct.
Northern regions of Australian mainland, New Guinea, Moluccas, Philippines.
Introduced into Java, Thailand, and Nigeria. The number of species and their distribution is uncertain.
Relatively small to medium-sized shells with a raised (stepped), flat or depressed spire. The top of the whorls are angled to keeled.
This genus is in need of revision, and the species concepts we have used have not been rigorously tested. This situation can only be resolved by additional molecular and morphological studies involving comprehensive sampling.
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Beesley, P. L., Ross, G. J. B. & Wells, A., Eds. (1998). Mollusca: The Southern Synthesis. Parts A & B. Melbourne, CSIRO Publishing.
Gauffre-Autelin, P., Stelbrink, B., von Rintelen, T., & Albrecht, C. (2021). Miocene geologic dynamics of the Australian Sahul Shelf determined the biogeographic patterns of freshwater planorbid snails (Miratestinae) in the Indo-Australian Archipelago. Molecular Phylogenetics and Evolution 155: 107004.
Hubendick, B. (1955). Phylogeny of the Planorbidae. Transactions of the Zoological Society of London 28: 453-542.
Iredale, T. (1943). A basic list of the fresh water Mollusca of Australia. Australian Zoologist 10: 188-230.
Iredale, T. (1944a). Guide to the freshwater shells of New South Wales. Part 2. Australian Naturalist (Sydney) 11: 113–127.
Ng, T. H., Tan, S. K., Wong, W. H., Meier, R., Chan, S.-Y., Tan, H. H. & Yeo, D. C. J. (2016). Molluscs for sale: assessment of freshwater gastropods and bivalves in the ornamental pet trade. PLOS One. 11: e0161130.
Walker, J. C. (1988). Classification of Australian buliniform planorbids (Mollusca: Pulmonata). Records of the Australian Museum 40: 61-89.
