Leptaxinus subovatus Jeffreys 1881

• Main Authors: Negri, Mauro Pietro, Corselli, Cesare
• Format: Other/Unknown Material
• Language: unknown
• Published: 2016
• Subjects: Biodiversity; Taxonomy; Animalia; Mollusca; Bivalvia; Lucinoida; Thyasiridae; Leptaxinus; Leptaxinus subovatus; Arctic; Argentina; Lamarck; Levin; Payne; Faroes; Iceland
• Online Access: https://zenodo.org/record/6082185; https://doi.org/10.5281/zenodo.6082185

Leptaxinus subovatus (Jeffreys, 1881) Fig. 7 j–l Axinus subovatus Jeffreys, 1881 (p. 704, pl. 61, fig. 8). Axinulus subovatus (Jeffreys, 1881) — Nordsieck 1969 (p. 80, pl. 13, fig. 48.13). Leptaxinus (L.) subovatus (Jeffreys) — Di Geronimo 1974 (p. 156, pl. 3, fig. 2). Thyasira (Parathyasira) subovata subovata (Jeffreys, 1881) — Payne & Allen 1991 (p. 513, figs. 48–50, 53 a–b). Thyasira (Parathyasira) subovata minuta Payne & Allen 1991 (p. 515, figs. 51–52, 53 c–d). Thyasira (Parathyasira) subovata (Jeffreys, 1881) — Giribet & Peñas 1997 (fig. 100). Thyasira subovata Jeffreys, 1881 — Oliver et al. 2002 (p. 60, pl. 25, figs. A–B). Leptaxinus subovatus (Jeffreys, 1881) — Repetto et al. 2005 (p. 310, bottom right fig.). Diagnostic characters. Oval, oblique shell; long anterior side; roundly angular posterior side; outer surface with uneven and rather coarse growth markings; right valve hinge with 1 cardinal tubercle and 2 lamellar lateral teeth; left valve hinge with 1 cardinal tubercle. Prodissoconch: shell type ST-2D; length about 120 µm; roundish Dshaped outline; low convex profile; surface smooth; P-2 absent; transition to the nepioconch poorly marked. Remarks. The specimens at hand appear to be more similar to the subspecies minuta Payne & Allen, 1991, than to the nominal species of Jeffreys, in having an oval (not subtriangular) shell with rounded (not wedgeshaped) posterior angulation. We follow Oliver & Levin (2006) in preferring the genus Leptaxinus Verrill & Bush, 1898 for the present taxon, rather than Thyasira Lamarck, 1818, for the presence of both cardinal tubercles and lateral teeth. Occurrence. Box-corer samples BC10 (2 specimens), BC66 (2), BC67 (3), BC72 (5); cores BC21 (1), BC72 (5). Maximum length: 2.5 mm. Distribution and habitat. Leptaxinus subovatus is distributed troughout the Atlantic, from Iceland and Faroes to Cape Verde, Angola and Argentina, and in the Mediterranean; it is found in the 200–4000 m bathymetric interval, reaching shallower depths at arctic latitudes ...