Shell small, pupiform to subtrochiform, non-umbilicate, smooth, with thin periostracum; spire convex in outline; aperture with continuous periostome partially free from parietal area, outer lip slightly to moderately opisthocline. The operculum typically has a white smear on its inner side (present in the type species of Fluviopupa and some others) but it lacks the opercular pegs that are seen in many tateids In the radula there is a a flexible connection between the ‘head’ and lateral extension of the lateral teeth. Members of the ‘Fluviopupa group’ can be recognized by their penial characters, primarily the possession of a non-glandular swelling associated with the distal section of the penis, although this is lost in some species (Haase et al. 2006), and a well-developed gastric caecum. The female genitalia are typical of the family with a globular posterior bursa copulatrix, a well-developed ventral channel with an anterior opening and a seminal receptacle. However the Little Mulgrave River Fluviopupa lacks a seminal receptacle.
Species of Fluviopupa are similar to those included in Potamopyrgus, but differ in having a bilobed penis. This character, together with the simple operculum, also separates the species of Fluviopupa from those in other genera on Lord Howe Island.
Genus Fluviopupa Pilsbry, 1911
Type species: Fluviopupa pupoidea Pilsbry, 1911.
Original reference: Pilsbry, H. A. (1911). Non-marine Mollusca of Patagonia. Princeton University Expeditions to Patagonia, Report. (Ed. William B. Scott.) Vol. 3, pt 2, pp. 513-633.
Type locality: Fiji.
Synonyms: Fluviorissoina (Preston MS) Iredale, 1944; Pupidrobia Iredale, 1944
We follow Ponder (1982) and Ponder and Shea (2014).
The species on Lord Howe Island live only at low altitudes in permanent streams, with many populations confined to disconnected pools during times of low precipitation. They do not seem to favour any particular microhabitat. It is assumed they feed on bacteria, microscopic algae, diatoms and, possibly, decaying vegetation where snails are abundant. Furthermore, leaves are sometimes reduced to the veins, apparently as a result of feeding by the snails. The Mulgrave River and Little Mulgrave River Fluviopupa lives in root mats and amongst leaves along edges of side ponds and the main river channels and tributary streams.
Mulgrave River and Little Mulgrave River in the Wet Tropics of northeast Queensland, as well as some tropical Pacific islands - Fiji, New Hebrides, Rapa Island, New Caledonia, Lord Howe Island and possibly New Guinea.
Etheridge, R. (1889). The general zoology of Lord Howe Island. (Mollusca by J. Brazier.) Australian Museum Memoirs No. 2.
Haase, M., Gargominy, O. & Fontaine, B. (2005). Rissooidean freshwater gastropods from the middle of the Pacific: the genus Fluviopupa on the Austral Islands (Caenogastropoda). Molluscan Research 25: 145-163.
Haase, M., Ponder, W. F. & Bouchet, P. (2006). The genus Fluviopupa Pilsbry, 1911 from Fiji (Caenogastropoda, Rissooidea). Journal of Molluscan Studies 72: 119-136.
Iredale, T. (1944). The land Mollusca of Lord Howe Island. Australian Zoologist 10: 299-334, pls XVII-XX.
Ponder, W. F. & Shea, M. E. (2014). A new species of the Fluviopupa group (Caenogastropoda: Tateidae) from north-east Queensland, Australia. Molluscan Research 34: 71-78.
Zielske, S. & Haase, M. (2014). New insights into tateid gastropods and their radiation on Fiji based on anatomical and molecular methods (Caenogastropoda: Truncatelloidea). Zoological Journal of the Linnean Society 172: 71-102.