Freshwater Molluscs of India: An Insight of into Their Diversity, Distribution and Conservation - Aquatic Ecosystem: Biodiversity, Ecology and Conservation - page 181

Table 11.4 (continued)
Name Key character for identii cation Habitat Distribution

Parreysia ( Parreysia ) smaragdites
(Benson)

Shell with narrow anterior broad posterior;
lunule prominent

Brahmaputra river basin Assam

Parreysia ( Parreysia ) triembolus (Benson) Shell thick with large teeth; posterior end

tapering

Rivers, Narmada river basin Assam, Uttar Pradesh, West

Bengal

Parreysia ( Radiatula ) andersoniana
(Nevill)

Shell smaller, thin, umbon indistinct, not at all
raised; sculpture strong on umbonal region,
pallial line prominent

River bed Assam, West Bengal

Parreysia ( Radiatula ) bonneaudi
(Eydoux)

Sculpture only on umbonal region and with
vertical marking on the rest of the surface

River bed Andhra Pradesh, Assam,

Manipur

Parreysia ( Radiatula ) caerulea (Lea) Shell elongate, variable in shape, sculpture

restricted to the upper half of the valves in the
adult, posterior umbonal carina very distinct

River bed, Gangetic delta Andhra Pradesh, Assam,

Jharkhand, Meghalaya,
Mizoram, Orissa, Punjab,
Rajasthan, Uttar Pradesh,
West Bengal

Subsp. gaudichaudi (Eydoux)

Parreysia ( Radiatula ) cylindrica
(Annandale and Prashad)

Shell thick, dorsal margin straight and anterior
margin broadly rounded, umbonal region
sculptured with corrugated ridges

River bed Maharashtra

Endemic

Parreysia ( Radiatula ) involuta (Benson) Shell compressed in front, swollen in the

umbonal region with a few longitudinal
corrugations, beaks incurved

River bed Assam

Parreysia ( Radiatula ) khadakvaslaensis
(Ray)

Shell elongated more infl ated, posterior end
pointed; sculpture appears to be a little more
pronounced

River bed Maharashtra: Pune

Parreysia ( Radiatula ) lima (Simpson) Shell small with broad posterior end; umbo

much anterior, sculpture more prominent on
umbona region, zigzag and transverse lines
prominent on posterior side, fi ner on anterior

River bed Assam, Sikkim, and West

Bengal

Parreysia ( Radiatula ) nuttalliana (Lea) Shell small, smooth, devoid of any sculpture;

umbon prominent, olive green in colour

River bed Assam: Cachar

Parreysia ( Radiatula ) occata (Lea) Shell rhomboidal, narrow, sculptured with

granular ridges throughout the surface

Gangetic delta, and its tributaries, river bed Assam, Madhya Pradesh,

Manipur, Meghalaya,
Rajasthan, Uttar Pradesh,
West Bengal