Polymesoda erosa (Solander, 1786)
Common geloina
Common mangrove clam,  tuway
Polymesoda erosa
photo by Coltro, Marcus

Family:  Cyrenidae ()
Max. size:  10.5 cm SHL (male/unsexed)
Environment:  benthic; brackish; marine
Distribution:  Indo-West Pacific: from India to Vanuatu; north to southern islands of Japan, and south to Queensland and New Caledonia.
Diagnosis:   
Biology:  Widely collected as food in Asia (Ref. 348). Found in intertidal areas in mangrove mud (Ref. 75831, 85174). Also in fresh and brackish waters of mangrove swamps, estuaries, and larger rivers. Highly tolerant to surface desiccation of its habitat; can survive by aerial respiration at the posterior mantle margin for a period of a few days, and feed from subterranean water by means of water exchange through a narrow anterior gape of valves (Ref. 345).
IUCN Red List Status: Not Evaluated (N.E.) Ref. 123251)
Threat to humans:  harmless
Country info:  Sporadically found throughout the Philippines (Ref. 821). Reported from the Calamianes Islands as Polymesoda coaxans (Ref. 8295); and known in Misamis Occidental as Geloina erosa (Ref. 75659). C: Refs. 821, 8295, 75831; M: Ref. 348; O: Ref. 821.

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