New Cenozoic Muricidae (Mollusca: Gastropoda) from Europe
Author
Merle, Didier
Author
Pacaud, Jean-Michel
Author
Ledon, Daniel
Muséum national d’histoire naturelle, Département Origines et Évolution (CR 2 P - MNHN, CNRS, UPMC, Sorbonne Université), 57 rue Cuvier, 75231 Paris cedex 05 (France) didier. merle @ mnhn. fr (corresponding author) jean-michel. pacaud @ mnhn. fr dnledon @ yahoo. fr
didier.merle@mnhn.fr
Author
Goret, Bernard
Raoul Ponchon, F- 31500 Toulouse (France) bernardgoret @ hotmail. com
bernardgoret@hotmail.com
text
Geodiversitas
2024
2024-10-24
46
15
495
551
https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/g2024v46a15.pdf
journal article
304811
10.5252/geodiversitas2024v46a15
fe16163e-5e9d-4c80-89c8-fce3fb2e064f
1638-9395
13985760
urn:lsid:zoobank.org:pub:C32EAAFD-85D8-45CD-8DF7-B894E1537713
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).
FIG
. 10. — Spiral cords and internal denticles of the outer lip in
Timbellus calciacus
n. 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.
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.