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 (2024-06-21 03:29:47, last updated 2024-06-21 03:45:59)

scientific name

Pleurophopsis talarensis
status

sp. nov.

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.

Amano, K. and Kiel, S. 2011. Fossil Adulomya (Vesicomyidae, Bivalvia) from Japan. The Veliger 51: 76 - 90.

Kanno, S., Tanaka, K., Koike, H., Narita, K., and Endo, T. 1998. Adulomya uchimuraensis Kuroda (Bivalvia) from the Miocene Bessho Formation in Shiga-mura, Nagano Prefecture, Japan. Research Reports of the Shinshushinmachi Fossil Museum 1: 17 - 28.

Kuroda, T. 1931. Fossil Mollusca. In: F. Homma (ed.), Geology of the Central Part of Shinano, Part 4, 1 - 90. Kokon Shoin, Tokyo.

Olsson, A. A. 1931. Contributions to the Tertiary paleontology of northern Peru: Part 4, The Peruvian Oligocene. Bulletins of American Paleontology 17: 97 - 264.

Gallery Image

Fig. 7. The vesicomyid Pleurophopsis talarensis sp. nov., from early Oligocene seep deposits at Cerro La Salina (block 6, A, D, F–H; block 7, E; block 9, B, C), Talara Basin, northern Peru. A. Holotype (NRM Mo187019), right valve showing shell outline. B. Paratype (NRM Mo187022), posteriorly damaged, articulated specimen; view on dorsal side (B1) and on right valve (B2). C. Paratype (NRM Mo187020), right valve with posterior tip missing. D. Paratype (NRM Mo187023), internal mold of left valve showing anterior adductor muscle scar and pallial line (D1), arrow indicates onset of pallial; close-up on hinge area (D2. E. Paratype (NRM Mo187021), semi-articulated specimen, view on incomplete right valve). F. Paratype (NRM Mo187024), anterior part of fight valve. G. Paratype (NRM Mo187026), anterior part of right valve (G1), view on hinge area (G2). H. Paratype (NRM Mo187025), hinge area of right valve.

NRM

Swedish Museum of Natural History - Zoological Collections

Kingdom

Animalia

Phylum

Mollusca

Class

Bivalvia

Order

Venerida

Family

Vesicomyidae

Genus

Pleurophopsis