Anadara blanfordi (Newton, 1905)

Fig. 5

Arca blanfordi Newton, 1905: 298, pl. 16 fig. 5.

Anadara sp. – Hadi et al. 2024: 12, pl. 5 fig. 5a–c.

Material examined

IRAN – Sistan and Baluchestan • 23 shells; Dar Pahn Unit; GDZU-0314 to GDZU-0337.

Remarks

The specimens reported from “the beach off the Ormara Headland, facing the Mekran or Baluchistan coast, 130 miles west of Karachi” (Newton 1905: 293) are smaller than those reported here (45 mm vs 71 mm in length), but his description of shell outline, inflation, and the number and shape of the ribs leaves no doubt that these specimens belong to the same species.

Similar, but less inflated and smaller is Anadara garoensis Mukerjee, 1939, from the Miocene Garo Hills in the eastern Indian province of Meghalaya (Mukerjee 1939: 26, pl. 22 figs 2–3); it reaches only about a third of the size of A. blanfordi (25.8 mm vs up to 71 mm in length). Also similar is Arca yawensis Noetling, 1901, from the Miocene of Myanmar (Noetling 1901: 144, pl. 6 figs 4–6), which is nearly identical in outline and also very inflated. Noetling reported 29 radial ribs for this species, which falls within the range of the 28–31 present on A. blanfordi. However, the species can be distinguished by the difference in the size of the adductor muscle scars, described as “the posterior one much larger than the anterior one” for A. yawensis, whereas in A. blanfordi they are of subequal size (Fig. 5A–D). The Miocene Anadara gourae Dey, 1961, from Kerala, India, is similar to A. blanfordi especially regarding its outline, but it has more numerous and narrower radial ribs (Dey 1961: pl. 1 figs 4–8). The most similar extant species is Anadara rufescens (Reeve, 1844), an uncommon species that is, however, widely distributed in the Indo-West Pacific Ocean (Mukerjee 1939; Dey 1961).