Cassidula nucleus (Gmelin, 1791)

Figs 8 S–T

Helix nucleus Gmelin, 1791: 3651 .

Cassidula nucleus: Okutani 2000: 818 –820, pl. 407, fig. 8; Thach 2005: 233, pl. 72, fig. 8; Raven & Vermuelen 2007: 43, 50, pl. 4, figs 35–36, Lozouet & Plaziat 2008: 148 –149, pl. 38, figs 15–16; Poppe 2010: 448, pl. 915, figs 9–11; Zvonareva et al. 2015: 9, fig 3(8).

Material examined. Nha Phu Bay, about 40 specimens.

Abundance. Common.

Measurements. Up to 22 mm (Raven & Vermuelen 2007).

Ecological notes. On tree trunks and seedlings attached above tide level in mangrove swamp. Also can live in salt marsh or on muddy tidal flats (Lozouet & Plaziat 2008).

In studied sites it was found on tree trunks and seedlings of mangrove trees as well as on sediment surface between mangrove roots.

Relation to mangroves. Predominantly mangrove-associated.

Distribution in Vietnam. Northern-east coast, central coast, southern delta (Thach 2005).

General distribution. From Ryukyu (Japan) to tropical IWP (Lozouet & Plaziat 2008).