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 submicropterus
n. sp.
(
Figs 16
A-H, K; 27A-D)
urn:lsid:zoobank.org:act:
77B79E49-DDB1-413B-983A-A19753441F55
Murex
(
Pterymurex
)
tricarinatus
–
Cossmann & Pissarro 1901: 128
, pl. 14, fig. 1 [
non
Lamarck, 1803
].
Timbellus micropterus
–
Merle
et al.
2011: 448
, pl. 102, fig. 4a, b only [
non
Deshayes, 1865
].
TYPE
MATERIAL
. —
Holotype
.
France
•
Normandy
, Manche, Fresville;
Calcaire
de Fresville
; middle Eocene (uppermost Lutetian);
MNHN
.F.A24111 (
MNHN
coll.), H:
23.6 mm
(
Figs 16A, B
;
27A
).
Paratypes
.
France
• 1 spm; same as for the holotype;
UCBL-EM 33438
(
Bourdot
coll., figured specimen of
Cossmann & Pissarro 1901
)(
Figs 16E, F
;
27C
)
• 1 spm; idem;
MNHN
.F.A90556 (
MNHN
coll.) (
Fig. 16K
)
•
1 spm; idem;
MNHN
.F.B63700 (
de Morgan
coll.)
•
1 spm;
Normandy
,
Manche
,
Gourbesville
;
Calcaire de Fresville
;
upper Lutetian
;
MNHN
.F.A24126 (
Munier-Chalmas
coll.), figured specimen of
Merle
et al.
(2011: 135
, pl. 102, fig. 4a, b) (
Figs 16C, D
;
27B
).
ADDITIONAL
MATERIAL
(material referring to
Timbellus
cf.
submicropterus
n. sp.
). —
France
• 3 spm; Loire-Atlantique,
Loire
Basin, Saffré (Bois Gouët); middle Eocene (lower Bartonian); MNHN.F.A29660 (Pacaud coll.)
•
2 spm; Saint-Aignan-GrandLieu (Pierre-Aiguë), Loire-Atlantique; idem; MNHN.F.A29662, (Brébion coll.),MNHN.F.A90557 (Brébion coll. (
Figs 16G, H
;
27D
).
ETYMOLOGY
. — Name formed by the prefix
sub-
and
micropterus
for this species older than Bartonian
Timbellus micropterus
(
Deshayes, 1835
)
.
TYPE
HORIZON
. — Calcaire de Fresville, middle Eocene (uppermost Lutetian), see
Bignot
et al.
(1968)
.
TYPE
LOCALITY
. —
France
,
Normandy
, Manche, Fresville, see
APGN (2024)
.
DISTRIBUTION
. —
Normandy
(Calcaire de Fresville) middle Eocene (uppermost Lutetian) and?
Loire
Basin (Sables du Bois-Gouët), lowermost Bartonian, see
Mathelin & Bignot (1989)
.
DESCRIPTION
Bulbous protoconch of one whorl (
Fig. 16K
). Teleoconch up to
23.6 mm
in height, up to
11.6 mm
in width, biconic in profile, composed of six whorls. Moderately high spire. Last whorl up to 70% of total length. Apical angle 59°. Spiral sculpture with coarse primary cords. First to third whorl: no cord. Fourth whorl: appearance of weak P1, s1 and P2. Fifth whorl: P1, s2 and P2 coarser. Sixth whorl: P1 to P6, s1; P6 not atrophied on convex part of whorl; ADP, MP and ABP on siphonal canal. From first whorl to second whorl: 6-7 protovarices. On third whorl: appearance of varices; three varices and one intervarix intercalated. From third to sixth whorl: no change. Higher relief of intervarices on P2. Varices rather thick. Appearance of short P1 spine on third whorl. Ovate aperture up to 27% of diameter and up to 71% of length of last whorl (including siphonal canal). Columellar lip smooth, narrow, poorly erect anteriorly, forming curved inductura at base. Parietal lip slightly adherent. Outer lip with developed denticles including ID, D1 to D6. D
6 in
some specimens. Outer lip not crenulate. Siphonal canal open, straight, up to 40% of apertural length. Pseudoumbilicus narrow.
COMPARISONS
A specimen of this species (
Figs 16E, F
;
27C
) was identified as
Murex
(
Pterymurex
)
tricarinatus
Lamarck, 1803
(synonym of
Timbellus crenulatus tricarinatus
) by
Cossmann & Pissarro (1901)
.
Timbellus crenulatus tricarinatus
differs greatly by apertural (with weak internal denticles within the outer lip), sculptural and shape characters, and belongs to another group species (see above
Fig. 14
). In fact, this specimen illustrated by
Cossmann & Pissarro (1901)
more closely resembles
T. micropterus
from the Bartonian Paris Basin.
Merle
et al.
(2011)
attributed another Norman specimen (pl. 102, fig. 4a, b) to
T. micropterus
(
Figs 16C, D
;
27B
). It is true that these
two specimens
are superficially similar to
T. micropterus
, but further comparison reveals some differences, such as only one intervarice (instead two in typical
T. micropterus
) and finer secondary cords on the last whorl. The bivariate plot of total length against width (
Fig. 17
) does not suggest strong differences
Normandy
and Paris Basin populations. Finally, it is tempting to conclude that the observed teleoconch differences in
T. submicropterus
n. sp.
fall within the intraspecific variation of
T. micropterus
. However,
T. submicropterus
n. sp.
has a paucispiral protoconch, whereas
T. micropterus
has a multispiral (
Fig. 16K, L
), suggesting two separate species with different modes of larval development. In the Bartonian from Loire-Atlantique, there are specimens showing coarse spiral cords like those of typical
T. submicropterus
n. sp.
, but they bear a more pronounced shoulder (
Fig. 16G, H
). Their protoconch is not preserved. We therefore attribute these specimens to
T. submicropterus
n. sp.
with hesitation.