Timbellus calciacus, Merle & Pacaud & Ledon & Goret, 2024

Merle, Didier, Pacaud, Jean-Michel, Ledon, Daniel & Goret, Bernard, 2024, New Cenozoic Muricidae (Mollusca: Gastropoda) from Europe, Geodiversitas 46 (15), pp. 495-551 : 513-514

Timbellus calciacus n. sp.

( Figs 10 A-D; 26C, D)

urn:lsid:zoobank.org:act:E83D9D22-2B5E-4B2A-9693-8568559FA8D4

Pterynotus tripteroides – Merle 1990: 185, pl. 4, fig. 3 only [non Lamarck, 1822].

TYPE MATERIAL. — Holotype. France • Paris Basin, Val d’Oise , Chaussy (Les Garennes); Falun de Chaussy (biozone NP15); middle Eocene (middle Lutetian); MNHN.F.A90536 ( Merle coll.), H: 8 mm ( Figs 10A, B ; 26C ).

Paratypes. France • 3 spm; same as for the holotype; MNHN.F.A90537 ( Figs 10C, D ; 26D, H : 12 mm), MNHN.F.A90538, MNHN.F.A90539 ( Merle coll.) • 1 spm; idem; MNHN.F.R61443 ( Merle coll.), figured specimen of Merle (1990: pl. 4, fig. 3) • 1 spm; Paris Basin, Yvelines, Beynes (Ferme de l’Orme); middle Lutetian; MNHN.F.A90535 ( Merle coll.).

ETYMOLOGY. — Calciacus (Latin adjective): from the ancient name of the village of Chaussy given in 690. Name given in apposition.

TYPE HORIZON. — Falun de Chaussy (biozone NP15), see Gély & Lorenz (1991: pl. 1), middle Eocene (middle Lutetian).

TYPE LOCALITY. — France, Paris Basin, Val d’Oise, Chaussy (Les Garennes), see Fritel (1910: 88).

DISTRIBUTION. — Faluns de Chaussy and Calcaire à Orbitolites at La Ferme de l’Orme (biozone NP15), Paris Basin ( France), middle Eocene (middle Lutetian only).

DESCRIPTION

Bulbous protoconch of 1.2 whorls.Teleoconch up to 12 mm in height, up to 5.5 mm in width, biconic in profile, composed of four whorls. Moderately high spire. Last whorl up to 76% of total length. Apical angle 71° including winged varices, up to 55° excluding them. Spiral sculpture with poorly marked primary cords. First whorl: appearance of very weak P1, P2 and P3. Second whorl: weak P1 to P3. Third whorl: appearance of weak s1, s2 and threads covering base of whorl. Fourth whorl: P1 to P6 weak, ADP on siphonal canal, secondary cords undistinguishable from threads; threads covering entire surface of shell. On first whorl, axial sculpture with 8-9 lamellose protovarices. On second whorl: appearance of varices (three varices and one low intervarix between two varices). From third to last whorl, numerous growing microlamellae covering surface of shell and forming delicate, reticulate sculpture covering surface of shell. Intervarical relief very low, but slightly higher on P1-P2. Varices well winged on last two whorls. Appearance of short P1 spine on second whorl. On last whorls, axial ornamentation forming winged varices, rounded in outline, without evidence of spines, even on P1. Subtriangular aperture up to 33% of diameter and up to 74% of length of last whorl (including siphonal canal). Columellar lip smooth, narrow, slightly erect anteriorly and forming a curved inductura at base. Parietal lip slightly adherent. Outer lip with very weak denticles including D1 to D5. Siphonal canal open, up to 45% of apertural length. Pseudo-umbilicus narrow.

COMPARISONS

This small species was never distinguished from its congeners in the Paris Basin, probably mistaken for juveniles of T. tripteroides ( Lamarck, 1822) , with which it co-occurs at two localities: Chaussy and La Ferme de l’Orme. With a maximum height of 12 mm, T. calciacus n. sp. is a very small Timbellus . Timbellus calciacus n. sp. differs from juveniles of T. tripteroides in having the aperture completely formed and by having a peculiar reticulate microsculpture (see Fig. 6C, D ). This last character lacks in specimens of T. tripteroides at any growth stage. Specimens of T. occidentalis n. sp. from the upper Lutetian of Normandy and the early Bartonian of Loire-Atlantique share with T. calciacus n. sp. a small size, but T. occidentalis n. sp. is double the size (H: 26.6 mm vs 12 mm). As with T. tripteroides , T. occidentalis n. sp. lacks the peculiar microsculpture found in T. calciacus n. sp.

Figures

FIG. 10. — Spiral cords and internal denticles of the outer lip in Timbellus calciacusn. sp.:A, B, holotype,MNHN.F.A90536 (Merle coll.),Chaussy (Les Garennes),Val d’Oise,Paris Basin,France,middle Eocene (Lutetian);C, D, paratype,MNHN.F.A90537 (Merle coll.), Chaussy (Les Garennes).Scale bars:3 mm.Credits:L.Cazes.

FIG. 26. — New species of Timbellus De Gregorio, 1885: A, B, Timbellus occidentalis n. sp.: A, holotype, MNHN.F.A90533 (Le Marchand coll.), Fresville, France, upper Lutetian;B, paratype,MNHN.F.A24031 (Vasseur coll.),Saffré (Bois-Gouët),France,Bartonian;C, D, T.calciacus n. sp.: C, holotype,MNHN.F.A90536 (Merle coll.), Chaussy (Les Garennes), France, Lutetian; D, paratype, MNHN.F.A90537 (Merle coll.), Chaussy (Les Garennes); E, F, T. longicanalis n. sp.: E, holotype, MNHN.F.A24101 (Le Marchand coll.), Fresville, France, upper Lutetian; F, paratype, MNHN.F.A24100, Fresville; G-I, T. magnei n. name: G, MNHN.F.A32508 (Merle coll.), juvenile specimen, Gan (Tuilerie), France; H, MNHN.F.A90545 (Merle coll.), juvenile specimen with protoconch, Gan (Tuilerie); I, MNHN.F.A72443 (Varone coll.), Gan (Tuilerie); J-L, T. curvispina n. sp.: J, holotype, MNHN.F.A90541 (MNHN coll.), Parnes, France, Lutetian; K, paratype, MNHN.F.A90543 (Pons coll.), Fontenay-en-Vexin, France, Lutetian; L, paratype, MNHN.F.A73848 (Pons coll.), Fontenay-en-Vexin; M, T. sixi n. sp., holotype, MNHN.F.A90544 (Six coll.), Trosly-Breuil (Fond Couturier), France, Ypresian; N-P, T. radulfiensis n. sp.: N, holotype, MNHN.F.A77754 (MNHN coll.), Rauville-la-Place, France, Priabonian; O, paratype, MNHN.F.A77755 (MNHN coll.), Rauville-la-Place; P, paratype, MNHN.F.A90559 (Vasseur coll.), Rauville-la-Place. Scale bars: A,B, N-P, 5 mm; C, D, 3 mm; E-G, I-L, 10 mm; H, 2 mm.

FIG. 6. — Neotype, historical figures, spiral cords and denticles of the outer lip in T. tripteroides (Lamarck, 1822): A-D, morphotype with rounded varices and poorly distinguishable P1 spine; E-H, morphotype with easily distinguishable P1 spine: A, original figure of Lamarck (1805: pl. 3, fig. 4); B, C, neotype designated herein, MNHN.F.A90546 (Club géologique d'Île-de-France leg.), Thiverval-Grignon (Falunière), Yvelines, Paris Basin, France, middle Eocene (Lutetian); D, MNHN.F.A90552 (Pacaud coll.), Chaussy (Les Garennes),Paris Basin, France,middle Eocene (Lutetian); E, F, figured specimen of Deshayes (1835: pl. 82, fig. 1-2); G, H, figured specimen of Cossmann & Pissarro (1911: pl. 35, fig. 169-1; MNHN.F.J10350 (Cossmann coll.), Chaussy (Les Garennes). Scale bars: 20 mm. Credits: B-D, P. Loubry MNHN/CNRS; G, H, J. Mouchart.