A variable species with a long, slender shell and small aperture, smooth or sculptured with some spiral threads and distinct axial growth lines. Usually with angled shoulder just below the suture, in some individuals this shoulder is strong. In some populations most shells are decollate, while in others they are not. They can also be variable in size.
"Stenomelania" denisoniensis (Brot, 1877)
Common name: Denison marsh snail
Class Gastropoda
Infraclass Caenogastropoda
Megaorder Cerithiimorpha
Order Cerithiida
Superfamily Cerithioidea
Family Thiaridae
Genus Stenomelania Fischer,1885
Original name: Melania denisoniensis Brot, 1877. In Brot, A. (1877). Die Melaniaceen (Melanidae) in Abbildungen nach der Natur. Systematisches Conchylien-Cabinet 1(24): 193-272, plates 25-30.
Type locality: Port Denison, Queensland.
Synonyms: Stenomelania denisonensis ultra Iredale, 1943; Stenomelania denisonensis tacita Iredale, 1943.
On and in sediment, rocks and on water weeds in freshwater rivers, streams, lakes and dams. A detritus and algal feeder. Stenomelania denisoniensis broods larvae in a brood pouch in the head which may contain a dozen shelled juveniles and many unshelled juveniles in different embryonic stages.
Tropical and subtropical Australia (the northern half of the continent).
Glaubrecht et al. (2009) indicated that a new generic name might be necessary for this taxon based on unpublished molecular data - those authors referred to this species in the same way we do here.
Glaubrecht, M., Brinkmann, N. & Pöppe, J. (2009). Diversity and disparity ‘down under’: systematics, biogeography and reproductive modes of the ‘marsupial’ freshwater Thiaridae (Caenogastropoda, Cerithioidea) in Australia. Zoosystematics and Evolution 85: 199-275.
Iredale, T. (1943). A basic list of the fresh water Mollusca of Australia. Australian Zoologist 10: 188-230.
Iredale, T. (1944). Guide to the freshwater shells of New South Wales. Part 2. Australian Naturalist (Sydney) 11: 113–127.
Maaß, N. & Glaubrecht, M. (2012). Comparing the reproductive biology of three “marsupial”, eu-viviparous gastropods (Cerithioidea, Thiaridae) from drainages of Australia’s monsoonal north. Zoosystematics and Evolution 88: 293–315.
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.
Willan, E. C. & Kessner, V. (2021). A conspectus of the freshwater molluscs of the Daly River catchment, Northern Territory. Northern Territory Naturalist 30: 108-137.
