Class Bivalvia Linnaeus, 1758
Order Venerida Gray, 1854
Superfamily Tellinoidea Blainville, 1814
Family Tellinidae Blainville, 1814
Genus Serratina Pallary, 1920
Serratina ostracea (Lamarck, 1818) (Fig.1)
1986. Tellina (Moerella) ostracea: Tikader, Daniel and Subba Rao, p.177.
2000. Tellina (Moerella) ostracea: Subba Rao and Dey, Rec. zool. Surv. India, Occ. paper, 187: 256.
2006. Tellina (Moerella) ostracea: Dey, Rec. zool. Surv. India, Occ. paper, 249: 30, PL.VI, fig.2, PL. VIII, fig.6.
2010. Tellina (Moerella) ostracea: Ramakrishna and Dey, Rec. zool. Surv. India, Occ. paper, 320: 187
2017. Tellina ostracea: Subba Rao, Rec. zool. Surv. India, Occ. paper, 375: 368, fig.383.
Shell medium, 44.8mm length, 32.5mm height, and 14mm body depth, sub trigonal, and compressed. The right valve was bigger than left, having unequal ridges. Umbo raised and posterior. Anterior margin rounded while the posterior margin short, straight, and formed an oblique truncation. Dorsal margin straight and slopes gradually on the anterior side and abruptly on the posterior end. Sculpture of raised concentric ridges more prominent at the posterior end, radial striae absent. Ligament short, brown colour and lunule absent. Pallial sinus equal in both valve and large with an arcuated anterior end that does not touch anterior adductor. In the left valve, the cardinal complex consists of an unequal bilobed anterior tooth and a thin laminated posterior tooth, laterals less prominent and forms by the thickening on the hinge line. In the right valve the cardinal complex with a thin, laminated anterior tooth and a bifid posterior tooth, laterals strong, socketed above and anterior one closer to cardinal complex. Muscle scars moderately impressed. Anterior adductor scar elongate, posterior adductor scar more or less rectangular. Cruciform scars two, oval shaped. Shell externally dull white and internally shiny.
Distribution: Andaman (Chiriatapu) and Nicobar Islands (Camorta and Nancowry) (Subba Rao 2017).