Planorbidae, Rafinesque, 1815

Jindal, Rajinder & Wats, Meenu, 2021, Systematic descriptions and seasonal variations of mollusc in Chandigarh (U. T., India) and its surrounding freshwater bodies, International Journal of Fisheries and Aquatic Studies 9 (3), pp. 165-173 : 168

Family: Planorbidae

The Planorbids are hermaphroditic and non-operculate. The shells of this family may be discoidal or planispiral, dextral or sinistral. They inhabit clear freshwater (stagnant or slow running), live on aquatic vegetation and feed on minute algae and fine organic deposits. Few species are also reported as the intermediate hosts for several trematode parasites.

Gyraulus convexiusculus (Hutton, 1849)

Taxonomic description- Shell dextral, non-operculate, discoidal, very small, greatly depressed, smooth, glossy, pale horny brown coloured, periphery subangulate; number of whorls 4, rounded, widely coiled, last whorl covers the shell; body whorl not ribbed; spire sunken; sutures well defined; aperture oblique, oval shaped; lips simple; umbilicus wide and deep.

Gyraulus euphraticus (Mousson, 1874)

Taxonomic description - Shell dextral, non-operculate, discoidal, very small, thin, greatly depressed, narrow, peripheral angle slightly keeled, more compressed and strongly carinate, more opaque and coarser than G. convexiusculus ; number of whorls 3; sutures deep; irregularly sculptured with longitudinal and spiral stripes, striations very fine but visible; umbilicus narrow.

Indoplanorbis exustus (Deshayes, 1834)

Taxonomic description - Shell sinistral, non-operculate, discoidal, thin, dorso-ventrally flat, creamish-brown coloured, surface transpirally ridged; body whorl large and greatly expanded; penultimate whorl very narrow; number of whorls 4; spire depressed; sutures deeply impressed; aperture ear shaped; umbilicus wide; callus developed; inner peristome fused with body whorl, outer peristome reflected outwards, rounded at periphery.