Nerita undata Linnaeus, 1758

Figs 3 G–H

Nerita undata Linnaeus, 1758: 779 .

Nerita (Nerita) undata: Okutani 2000: 102 –103, pl. 51, fig. 5; Thach 2005: 36, pl. 6, figs 33–34.

Nerita undata: Poppe 2008a: 274 –275, pl. 82, fig. 10; Tan & Clements 2008: 487, figs 3-21, 3-22; Zvonareva et al. 2015: 8.

Material examined. Dam Bay, natural mangrove, about 10 specimens.

Abundance. Uncommon.

Measurements. Up to 33 mm (Tan & Clements 2008).

Ecological notes. Development with free swimming veliger (Fukumori & Kano 2014).

Found in crevices and under rocks of breakwaters and rocky shores of middle to upper intertidal zones. Nocturnal, emerging from their hiding places at dusk (Tan & Clements 2008).

In studied sites it was found on rocks in the lower intertidal zone.

Relation to mangroves. Eurybiotic.

Distribution in Vietnam. From northern-east coast to southern delta (Thach 2005).

General distribution. IWP: northeastern South Africa to Kenya, ranging through central region, including Indonesia and the Philippines, to Melanesia and Micronesia, southern Japan to northern Australia (Frey 2010).