Martesia fragilis Verrill & Bush, 1898

Mahapatro, Debasish, Sharma, Satyabrata Das & Kadam, Surendra S., 2020, On the record of two species of the family Pholadidae (Martesia fragilis and Martesia striata) off Dhamara Estuary (Odisha), Bay of Bengal, Records of the Zoological Survey of India 120 (4), pp. 351-356 : 352-354

1. Martesia fragilis Verrill & Bush, 1898 ( Figure 2 & 3 )

1898. Martesia (Martesiella) fragilis Verrill & Bush, Proc. U.S. Nat. Mus. , 20: 777.

2017. Martesia fragilis : Subba Rao, Rec. zool. Surv. India, Occasional Paper No., 375: 440

Material examined: Dhamara offshore region (30 m depth), three live specimens were examined from a deteriorated wooden structure ( Figure 1 , Point 2, 20°26’55”N 87°55’27”E).

Diagnosis: Shell obliquely divided in the middle with angularly and longitudinally ribbed anterior half; posterior part with concentrically striated towards margin; one ventral shield and two dorsal shields upon the umbo present; one elongated and narrow shield on posterior part body is straighter and posterior part is brittle. Metaplax proportionately larger and lanceolate; mesoplax depressed and with concentric lines dorsally, and hypoplax is lanceolate ( Mitra et al., 2010; Subba Rao, 2017).

Habitat: Found to be attached in the wooden pole and mangrove plants as borer.

Distribution: India: Odisha (Subarnarekha estuary; Offshore region of Dhamara estuary), Karnataka, Kerala, Maharashtra; Tamil Nadu, Gujarat and West Bengal, Andaman and Nicobar Islands ( Mitra et al., 2010; Subba Rao, 2017). Elsewhere: Eastern Pacific; Indo-Pacific; West Atlantic.

Figures

Figure 1. Map showing the occurrence location of M. striata (Point 1) and M. fragilis (Point 2) in the off Dhamara estuarine zone and offshore area respectively, Bay of Bengal.

Figure 2. Image showingMartesia fragilis collected from the offshore region off Dhamara estuary (30 m depth).

Figure 3. A. Image showing anterior an posterior portion of two halves of the bivalves joined with hypoplax,, B. exterior of Mesoplax, C. interior of Mesoplax of Martesia fragilis collected off Dhamara estuary, Bay of Bengal D. Metaplax of M. fragilis.