This species is distinguished by 1) turreted, rather straightsided, light shell up to 50 mm in height, 2) apex usually truncate, 3) teleoconch whorls convex, the diameter nearly twice the height, 4) aperture wide, subcircular, with flaring, thick outer lip and rudimentary abapical canal, 5) sculpture of slightly opisthocline collabral ribs and overriding spiral cords. The Australian Cerithidea anticipata Iredale, 1929, appears to be closely related, differing in that has more convex whorls and thicker ribs.

DISTRIBUTION AND HABITAT. Cerithidea obtusa is distributed in the Indian Ocean and the tropical Pacific, from Madagascar to Australia, Indonesia and Philippines. The species occurs commonly in mangrove swamps (COOMANS, 1969; SASEKUMAR, 1974; PLAZIAT, 1984; WILSON & GILLETT, 1985). According to VAN BENTHEM JUTTING (1956), it lives in the tidal zone, on mud banks that are partly dry at low tide, concentrating in the wettest spots. Cerithidea obtusa is collected in large quantities from among the buttress roots on the seaward margin of the mangroves in Malayan and Singapore waters (PURCHON & PURCHON, 1981). In Thailand, the species is common in mangrove forest and Nipa palm swamps on almost all coasts (BRANDT, 1974; TANTANASIRIWONG, 1978).