Wareniconcha aff. winckworthi ( Prashad, 1932 )

Kiel, Steffen, Aguilar, Yolanda M. & Kase, Tomoki, 2020, Mollusks from Pliocene and Pleistocene seep deposits in Leyte, Philippines, Acta Palaeontologica Polonica 65 (3), pp. 589-627 : 613

Wareniconcha aff. winckworthi ( Prashad, 1932)

Fig. 26 .

Material.— Two specimens from the Pliocene of Liog-Liog Point : NMNS PM 28187 , a right valve with partly exposed hinge and NMNS PM 28188 , an articulated specimen .

Dimensions (in mm).—NMNS PM 28187, L = 64.0, H = 56.6; NMNS PM 28188, L = 58.0, H = 44.1.

Remarks.— Wareniconcha aff. winckworthi is slightly more inflated and has broader umbones than the extant Wareniconcha winckworthi from Indonesia ( Prashad 1932). Furthermore, it has a truncate posterior margin (see Fig. 26B 2 ) whereas it is more obliquely truncated in Wareniconcha winckworthi ; however, this difference might not be a distinguishing character but instead a case of intraspecific dimorphism, as reported for example for the vesicomyid genus Calyptogena (see Krylova and Sahling 2006). The recently described Wareniconcha mercenarioides Kase, Isaji, Aguilar, and Kiel, 2019 from the same seep deposit is much larger (up to 120 mm) and has a roundish-triangular outline, whereas W. aff. winckworthi has an oval outline.

Figures

Fig. 26. The vesicomyid bivalve Wareniconcha aff. winckworthi (Prashad, 1932) from the Pliocene Liog-Liog Point seep deposit in Leyte, Philippines. A. NMNS PM 28188, articulated specimen, with views on right (A1) and left (A2) valves, dorsal (A3) and anterior (A4) sides. B. NMNS PM 28187, right valve with hinge partly exposed, close-up on hinge (B1), view on outer shell surface (B2).

Fig. 2. Bathymodiolin bivalves from Pliocene (B, C, Liog-Liog Point) and Pleistocene (A, Antipolo Point) seep deposits in Leyte, Philippines. A, B. Bathymodiolus securiformis Okutani, Fujikura, and Sasaki, 2004. A. NMNS PM 28169, a right valve. B. NMNS PM 28202, an articulated specimen in dorsal view (B1), exterior of left valve (B2). C. The unidentified bathymodiolin, NMNS PM 28170, outside of right valve (C1), specimen in dorsal (C2), ventral (C3), and anterior (C4) views.