Dulcina magoi, 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 : 596-598

Dulcina magoi sp. nov.

Fig. 8 .

Zoobank LSID: urn:lsid:zoobank.org:act:10726DC8-540E-4521-A334-B1A80540EED4

Etymology: In honour of Wenceslao Mago (Mines and Geoscience Bureau, Quezon City, Philippines) for his invaluable help with collecting Philippine fossils.

Type material: Holotype NMP-2162, an articulated specimen; paratypes: NMNS PM 28132 (left valve), NMNS PM 28134 (articulated), NMNS PM 28148 (articulated specimen with little shell), and NMNS PM 28409 (internal mold); from type locality. Note that NMNS PM 28132 , 28133 , and 28148 are from a small (<1 m long) float concretion from the beach; NMNS PM 28134 and 28409 are from the very large block.

Type locality: Liog-Liog Point , Leyte, Philippines .

Type horizon: Upper Pliocene part of the Bata Formation .

Material.—The type material only.

Dimensions (in mm). — NMP-2162 L = 79.3, H = 77.7; NMNS PM 28132, H = 79.0; NMNS PM 28134, L = 70.2, H = 64.6, W = 31.4 (articulated); NMNS PM 28148, L = 80.1, H = 80.0.

Diagnosis.—Large, little inflated, subcircular shell; posterior ridge low; anterodorsal area with shallow, distinct groove; anterior adductor muscle scar elongate, reaching well below midline of shell, detached from pallial line for little more than half its length; hinge plate broad, edentulous.

Description.—Large, subcircular, little inflated shell; umbones small, prosogyrate, elevated, pointed, situated just anterior to vertical midline of shell; lunule narrow, elongate, escutcheon lanceolate; anterodorsal area bordered by low but distinct ridge, shallow but distinct groove in middle; anterior shell margin with distinct angulation at horizontal midline of shell; ventral and posterior margins well rounded; posterodorsal ridge and groove low, close to shell margin; external sculpture of indistinct growth lines. Interior of shell with numerous radial grooves; pallial line entire; anterior adductor muscle scar elongate, reaching almost 2/3 of entire shell height, detached from pallial line for just over half its length; posterior adductor muscle scar broad, pear-shaped; hinge plate moderately wide, edentulous, ligament nymph stretching the entire posterodorsal shell margin.

Remarks.— Dulcina magoi sp. nov. differs from the five species described by Cosel and Bouchet (2008) ( D. guidoi , karubari, madagascarensis, minor , and musorstomi ) by being larger (up to 80 mm length compared to 25–47 mm), and more circular, particular on the anterior side. In addition, D. minor and D. musorstomi differ by having distinct, sharp commarginal sculpture. From D. liogliogensis n. sp. described above it differs by being rounder (=not having an acutely rounded posterior side) and having a longer anterior adductor scar.

Stratigraphic and geographic range.—Late Pliocene, Leyte, Philippines.

Figures

Fig. 8. The lucinid bivalve Dulcina magoi sp. nov. from Pliocene (A, C, D from a concretion found float at Liog-Liog Point) and Pleistocene (B, Buhoc Point) seep deposits in Leyte, Philippines. A. Holotype NMP-2162, articulated specimen; view on outer shell surface of left (A1) and right (A3) valves, dorsal view (A2). B. Paratype NMNS PM 28409, internal mold, view on right valve showing anterior adductor muscle scar.C. Paratype NMNS PM 28132, showing hinge area of left valve. D. Paratype NMNS PM, view of right valve showing anterior adductor muscle scar.