Coleglabra nordaustralis Ponder, Fukuda & Hallan, 2014

Diagnostic features

Shell minute (up to 1.9 mm in diameter). Whorls with few dorsally distinct spiral cords and indistinct spirals on base; strong spiral keels absent. Aperture near circular, peristome simple, prosocline, external varix absent. Operculum simple with no peg or white deposit on inner side. Head-foot colourless with no pigment. Penis long, slender, tapering, with no distinct swellings or glands; arising from right side of head behind right eye; tip pointed, with no distinct papilla. Bursa copulatrix large, about 1/2 behind posterior wall of mantle cavity; bursal duct extremely wide, forming large, round chamber at anterior part. One seminal receptacle.

The shell is similar to that of Colenuda kessneri in having a few spiral threads on the dorsal surface of the shell and weaker spirals on the base, lacking spiral keels and in having a relatively narrow umbilicus and a low to moderate spire. The shell of Coleglabra differs most obviously from that of Colenuda in having a simple peristome, that of Colenuda having a wide, shallow excavation and in lacking any external varix. The head-foot is unpigmented but it is not in the other genus. The penis, like that of Colenuda, lacks distinct lobes or glands and, like Colenuda, the operculum lacks a central projection. The edge of the aperture, viewed dorsally, is convex in Coleglabra.

Classification

Coleglabra nordaustralis Ponder, Fukuda & Hallan, 2014

Class Gastropoda

Infraclass Caenogastropoda

Order Littorinida

Suborder Rissoidina

Superfamily Truncatelloidea

Family Clenchiellidae

Genus Coleglabra Ponder, Fukuda and Hallan, 2014 (Type species: Coleglabra nordaustralis Ponder, Fukuda & Hallan, 2014).

Original name: Coleglabra nordaustralis Ponder, Fukuda & Hallan, 2014. In Ponder, W. F, Fukuda, H. & Hallan, A. 2014. A review of the family Clenchiellidae (Mollusca: Caenogastropoda: Truncatelloidea). Zootaxa 3872: 101-153.

Type locality: Douglas-Daly Research Farm, Top End, Douglas River, approximately 1 km east from the junction with Daly River, Northern Territory.

Biology and ecology

Permanent freshwater river above tidal influence.

Willan & Kessner (2021) note that it lives in the Douglas River where it flows over a limestone basement. It was collected alive by washing the roots of Melaleuca trees.

Distribution

This species is only known from its type locality.

Notes

Known only from the type locality, but may occur in similar conditions in the lower reaches of other coastal rivers in the Northern Territory. A congeneric species lives in a freshwater lake in Papua.

Further reading

Ponder, W. F., Fukuda, H. & Hallan, A. (2014). A review of the family Clenchiellidae (Mollusca: Caenogastropoda: Truncatelloidea). Zootaxa 3872: 101-153.

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.