Lucinoma tinagoensis, Kiel & Aguilar & Kase, 2020

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 : 604-605

Lucinoma tinagoensis sp. nov.

Fig. 16 .

Zoobank LSID: urn:lsid:zoobank.org:act:77B57F52-B70F-423A-8914-E0C8C7B5EEB4

Etymology: In reference to the Barangay Tinago, in which the type locality is situated.

Type material: Holotype NMP-2164, an articulated specimen. Paratypes: NMNS PM 28150–28152 (articulated specimens) from the type locality .

Type locality: Cambantug Point , Leyte, Philippines .

Type horizon: Lower Pleistocene part of the Bata Formation .

Material.—The type material only.

Dimensions (in mm).—NMP-2164, L = 57.8, H = 57.0, W = 38.9 (articulated).

Diagnosis.—Medium-large, well-inflated Lucinoma , outline rounded-pentagonal, umbones pointed, markedly prosogyrate for genus; surface sculpture of numerous sharp to cord-like commarginal ribs, several fine commarginal cords in interspaces; posterodorsal area narrow, posterior sulcus not well developed; lunule broad, short; escutcheon long, broad.

Description.—Shell medium-large for genus, greatest width at middle of shell (W/H ratio of single valve = 0.37); anterodorsal margin straight to sinuous,with angulation at transition to somewhat acutely rounded anterior margin; posterodorsal margin evenly convex, with slight angulation at transition to broadly rounded posterior margin; ventral margin evenly convex, without distinct transitions to anterior and posterior margins; shell surface covered by densely spaced, sharp to cord-like commarginal ribs; escutcheon elongate, broad, greatest width in middle; lunule elongate, heart-shaped. Anterior adductor muscle scar moderately narrow, of moderate length for genus, reaching down to ~70% of shell height, detached from pallial by ~30° for c. 2/3 its length.

Remarks.—The early Miocene Lucinoma saetheri differs by its smaller and more pointed umbones, narrower escutcheon ( Amano et al. 2018). Lucinoma galathea resembles Lucinoma tinagoensis in outline to but is described as “weakly inflated” ( Beu and Maxwell 1990: 281) in contrast to the strong inflation of L. tinagoensis .

Stratigraphic and geographic range.—Early Pleistocene, Leyte, Philippines.

Figures

Fig. 16. The lucinid bivalve Lucinoma tinagoensis sp. nov. from the Pleistocene Cambantug Point seep deposit, Leyte, Philippines. A. Holotype NMP-2164, a large, articulated specimen showing external (A1) and internal (A2) features, and its inflation (A3). B. Paratype NMNS PM 28150, showing fine external sculpture on right valve.