Pleurophopsis talarensis, Kiel & Hybertsen & Hyžný & Klompmaker, 2020

Kiel, Steffen, Hybertsen, Frida, Hyžný, Matúš & Klompmaker, Adiël A., 2020, Mollusks and a crustacean from early Oligocene methane-seep deposits in the Talara Basin, northern Peru, Acta Palaeontologica Polonica 65 (1), pp. 109-138 : 116-117

publication ID	https://doi.org/ 10.4202/app.00631.2019
persistent identifier	https://treatment.plazi.org/id/F104879E-3B25-AD24-F66B-739DFB3EFB8D
treatment provided by	Felipe
scientific name	Pleurophopsis talarensis
status	sp. nov.

Treatment

Pleurophopsis talarensis View in CoL sp. nov.

Fig. 7 View Fig .

Zoobank LCID: urn:lsid:zoobank.org:act:E668EC27-89CE-4B98-A2D0-B7A6FE856EA8

Etymology: For the Talara Basin.

Type material.— Holotype, NRM Mo187019 from block 6 . Paratypes NRM Mo187022 , NRM Mo187024–26 from block 6, NRM Mo187023 from block 7, and NRM Mo187020 and NRM Mo187021 from block 9.

Type locality: The Cerro La Salina seep deposits, Talara Basin, Peru .

Type horizon: Presumably the early Oligocene part of the Heath shale.

Material.—The type material and further, unnumbered fragmentary specimens from type locality and horizon, blocks 1, 2, 6–9.

Dimensions (in mm).—NRM Mo187019, L = 37, H = 9.5, W (single valve) = 3; NRM Mo187020, L = 33 (incomplete),

H = 10.5, W = 6.5; NRM Mo187021, L = 36 (incomplete) and H = 10.

Diagnosis.—Small and very elongate Pleurophopsis (H/L ratio c. 0.26) with slightly curved shell with subparallel dorsal and ventral margins.

Description.—Shell small, very elongate (H/L ratio c. 0.26), and little inflated (W/H ratio c. 0.61–0.63), umbo anterior at c. 16% shell length, slightly elevated; dorsal and ventral margin subparallel, dorsal margin slightly convex, ventral margin slightly concave; no lunule or lunular incision; ligament external, about 1/3 of shell length; sculpture of irregular growth increments. Anterior adductor muscle scar subcircular, deeply impressed, pallial line starting at posteroventral corner; hinge plate narrow, hinge teeth radiating, RV with two strong cardinals, cardinal 1 short, pointing downward and somewhat anterior, cardinal 3b blunt, pointing posteroventrally; LV with three teeth, cardinal 2a very elongate, subparallel to anterodorsal margin, 2b blunt, broad, pointing downward, cardinal 4b short and thin; subumbonal pit large, elongate and deep in both valves.

Remarks.—The differences from Pleurophopsis unioides and P. lithophagoides have been outlined above. The early Miocene Japanese vesicomyid “ Adulomya ” uchimuraensis Kuroda, 1931 , has a H/L ratio of c. 0.22 and is thus even more elongate than P. talarensis , and is also much larger ( Kuroda 1931; Kanno et al. 1998; Amano and Kiel 2011). Differences to other species of Pleurophopsis are summarized in Table 1.

Stratigraphic and geographic range.—Early Oligocene of the Talara Basin, northern Peru.