Posticobia ponderi is generally smaller than the other two species of the genus; it only has 1–2 weakly developed pegs on the inner side of the operculum and the prostate gland is half in the mantle cavity. However, probably the most distinctive character is the total lack of a keel or shoulder on the body whorl of P. ponderi compared to the other species.
Posticobia ponderi Clark, 2009
Class Gastropoda
Infraclass Caenogastropoda
Order Littorinida
Suborder Rissoidina
Superfamily Truncatelloidea
Family Tateidae
Genus Posticobia Iredale, 1943
Original name: Posticobia ponderi Clark, 2009. In Clark, S. A. (2009). The genus Posticobia (Mollusca:Caenogastropoda: Rissoidea: Hydrobiidae s.l.) from Australia and Norfolk Island. Malacologia 51: 319-341.
Type locality: Mulligan Springs, Lake Callabonna, 40.1kms east of the Wooltana-Moolawatanna road, South Australia.
Amongst small sedges in springs. Eggs similar to Posticobia brazieri.
Known from a number of small springs that make up the Mulligan Springs complex on the western edge of Lake Callabonna. South Australia.
Clark, S. A. (2009). The genus Posticobia (Mollusca: Caenogastropoda: Rissooidea: Hydrobiidae SL) from Australia and Norfolk Island. Malacologia 51: 319-341.
Rossini, R. A., Fensham, R. J., Stewart‐Koster, B., Gotch, T. & Kennard, M. J. (2018). Biogeographical patterns of endemic diversity and its conservation in Australia's artesian desert springs. Diversity and Distributions 24: 1199-1216.
