Similar to the Tasmanian P. atkinsoni but flatter, smaller (maximum diameter ~ 4 mm) and the whorls are less acutely angled, and the aperture wider but not so high. In both species the keel is positioned slightly towards the "base" (if viewed with the aperture on the right).
Original name: Planorbis isingi Cotton & Godfrey, 1932. Cotton, B. C. (1943). More Australian freshwater shells. Transactions of the Royal Society of South Australia 67: 143-148.
Type locality: Point McLeay, Lake Alexandrina, South Australia.
Synonyms: Glyptanisus caroli Iredale, 1943; Pygmanisus parvus Cotton, 1943.
Brown, (1981 & 2001), described the anatomy of this species.
South-eastern South Australia and southern Victoria.
According to Brown (2001) this species may be conspecific with G. gilberti, the latter occurring further north. He noted that (Brown 2001: 72) "Since G. isingi does not appear to differ in any clear respect of shell or anatomy from the range of variation among the specimens from New South Wales and Queensland described here under G. gilberti and G. macquariensis, it is maintained as a distinct species with considerable doubt."
Brown, D. S. (1981). Observations on the Planorbidae from Australia and New Guinea. Journal of the Malacological Society of Australia 5: 67-80.
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.
Smith, B. J. and Kershaw, R. C. (1979). Field guide to the non-marine molluscs of south eastern Australia. Australian National University Press, Canberra, Australia.