Fimbria multilamellosa (d’Orbigny, 1850)

Fig. 20K

Corbis multilamellosa d’Orbigny, 1850: 131, n° 34.

Lucina contorta – C. d’Orbigny 1836: 284 (non Defrance, 1823).

? Corbis (Fimbria) multilamellosa – Combes 1908: 14.

Corbis multilamellosa – Chavan 1948: 566–567, 569. — Pacaud & Merle 2002: 595, fig. 1.1a–b.

Fimbria multilamellosa – Pacaud 2018a: 252, fig. 198d–f; 2018b: 51. — Merle & Pacaud 2018a: 176, fig. 159f. — Merle 2023: 25.

For a detailed synonymic list, see Pacaud (2018b: 51).

Type locality

Meudon, Hauts-de-Seine, France.

Type horizon

Pisolitic limestone of Meudon, Danian.

Type material

Lectotype FRANCE – Hauts-de-Seine • RV, EF; Meudon; Danian; A. d’Orbigny coll.; designated by Pacaud (2018a: 253, 256, fig. 198f); MNHN.F.R63237.

Paralectotypes (2 specs) FRANCE – Hauts-de-Seine • 1 spec., LV, EF; same data as for lectotype; A. d’Orbigny coll.; figured in Pacaud (2018a: 156, fig. 198d; MNHN.F.R63246. – Yvelines • 1 spec., LV, EF; Le Port-Marly; Danian; A. d’Orbigny coll.; MNHN.F.R63253.

Other material examined

FRANCE – Marne • 1 spec., RV, EF; Vertus; probably sandy limestone of Vertus; Ch. d’Orbigny coll., ex n°GG.gg2005/5961; figured in Merle & Pacaud (2018a: 176, fig. 159e) and herein Fig. 20K; MNHN.F.C03002.

Measurements

MNHN.F.C03002, DVL: 13 mm; APL: 18.5 mm.

Description

Original description (A. d’Orbigny 1850: 131): “Grande espèce ovale, voisine du C. pectunculus, mais beaucoup moins bombée, à côtes concentriques très rapprochées, à côtes rayonnantes à peine visibles”. [English translation: “Large oval species, similar to C. pectunculus, but much less rounded, with very closely spaced concentric ribs and barely visible radial ribs”.]

Description of the Maastrichtian material: small shell (juvenile), transversely elliptical, subequilateral. Posterior margin shorter than anterior margin. Around 40 low, lamellose commarginal ribs. Radial ribs slightly pronounced. Intersections between marginal and radial ribs forming small scales, more distinct on anterior margin than posterior margin.

Remarks

d’Orbigny (1850) described this species based on two syntypes from the Danian of the Paris Basin (Meudon and Le Port Marly) and one syntype from Vertus (MNHN.F.R63253). Pacaud (2018a: 253, 256, fig. 198f) designated the syntype from Meudon (MNHN.F.R63237) as the lectotype. According to Merle & Pacaud (2018a), the Vertus paralectotype has more widely spaced commarginal ribs. It does not correspond to Fimbria multilamellosa, but to Fimbria sp. 1, a species discussed below. However, another specimen from Vertus (MNHN.F.C03002), found in the geology collection of the Muséum, bears close similarities to the Danian specimens. In particular, the tightly packed commarginal lamellae at the beginning of growth are completely identical. Because of these strong similarities, this specimen is thus identified herein as Fimbria multilamellosa. Combes (1908: 14) cited two species of Fimbria from the Bois d’Esmans, Fimbria multilamellosa and F. sublamellosa (d’Orbigny, 1850), but in the absence of material, these identifications cannot be confirmed. Squires & Godaert (1994) described Linearia (Linearia) louellasaulae Squires & Godaert, 1994, a Tellinidae from the Lower Eocene of the Crescent Black Hills Formation, Southwestern Washington (USA), whose sculpture is somewhat reminiscent of that of Fimbria multilamellosa. However, the radial ribs are much more pronounced and the American species is taller in shape.

Stratigraphic range

Maastrichtian to Danian, Paris Basin, France.