Lucinoma velosoi, 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 : 603-604

Lucinoma velosoi sp. nov.

Fig. 15 .

Zoobank LSID: urn:lsid:zoobank.org:act:7801672C-99B2-48F7-98AB-EB42257D6E9E

Etymology: In honur of Eduardo Veloso, the landowner of the type locality at Antipolo Point, Leyte, Philippines.

Type material: Holotype NMP-2166, disarticulated right and left valves.

Type locality: Antipolo Point, Leyte, Philippines .

Type horizon: Lower Pleistocene part of the Bata Formation.

Material.— Two specimens from the Pleistocene of Antipolo Point ( Meganodontia bed): holotype and NMNS PM 28162 ; two specimens from the Pleistocene of Cambantug Point : NMNS PM 28161 , 28163 .

Dimensions (in mm).—NMP-2166, L = 70.9, H = 63.8, W = 45.9 (articulated).

Diagnosis.—Well-inflated Lucinoma , outline rounded-oval, umbones broad, pointed, surface sculpture of numerous densely spaced, sharp commarginal ribs, few indistinct growth increments in interspaces; posterior sulcus indistinct; lunule broad, short; ligament nymph long.

Description.—Strongly and evenly inflated shell (W/H ratio of single valve = 0.37), greatest width at middle of shell; anterodorsal margin slightly concave, with angulation at transition to broadly 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; escutcheon lanceolate, greatest width in posterior half; lunule short, broad, deep; hinge plate broad and thick, two thick and short cardinal teeth in each valve, cardinals 1 and 2 pointing downward, cardinals 3 and 4 pointing toward posteroventral margin; ligament nymph lanceolate, about 2/3 of length of posterodorsal shell margin; anterior adductor muscle scar moderately narrow and of moderate length for genus, reaching down to 2/3 of shell height, detached slightly from pallial for ~70% of its length; posterior adductor muscle scar elongate-oval, its lower end situated at about mid-height of shell; shell interior covered by fine striation, most strongly developed at and beyond pallial line.

Remarks.— Lucinoma velosoi differs from the similarly inflated L. tinagoensis described below by reaching a larger size ( Table 1), its more elongated shell (that of L. tinagoensis is taller) and its narrower escutcheon. The Pliocene to Recent Lucinoma galathea Marwick, 1953 from New Zealand has a more pointed umbo than L. velosoi , broader and longer ligament nymph, reaches only about 50 mm in length, whereas L. velosoi reaches 70 mm, and is less inflated than L. velosi ( Marwick 1953; Campbell et al. 2010).

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

Figures

Fig. 15. The lucinid bivalve Lucinoma velosoi sp. nov. from the Pleistocene Antipolo Point seep deposits, Leyte, Philippines, holotype NMP-2166, outer surfaces of right (A1) and left (A2) valves; dorsal side (A3); inner surfaces of left (A4) and right (A5) valves; UV light image of right valve highlighting muscle scars, blood vessel scar, and pallial line (A6); close-up on hinges of left (A7) and right (A8) valves.