Muricopsis pontileviensis Merle, Pacaud, Ledon & Goret, 2024, n. sp.
Creators: name: Merle, Didier
name: Pacaud, Jean-Michel
name: Ledon, Daniel
name: Goret, Bernard
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Neogastropoda
Muricidae
Muricopsis
Muricopsis pontileviensis

description: Muricopsis pontileviensis n. sp.
(Figs 3 A-D; 25A, B)
urn:lsid:zoobank.org:act: 0D061422-80CC-47A5-897C-47EA1FBA313F
Muricopsis dujardini – Merle 1999: pl. 12, fig. D, pl. 13, fig. D, pl. IX, figs 5, 6 [non Murex dujardini Peyrot, 1938].
Muricopsis sp. 2 – Merle et al. 2022: 63, 70, fig. 29D; pl. 3, figs 4-6.
TYPE MATERIAL. — Holotype. France • Loire Basin, Loir-et-Cher, Pontlevoy; Faluns du Blésois (mammal biozone MN5b); Middle Miocene (base of the Langhian); MNHN.F.A71120 (Dollfus coll.), figured specimen in Merle et al. (2022: pl. 3, fig. 4), H: 14 mm (Figs 3A, B; 25A).
Paratypes. France • 1 spm; same data as for the holotype; MNHN.F.A71122, figured specimen inMerle et al. (2022: pl. 3, fig. 5) • 11 spm; idem; MNHN.F.A77742 (Dollfus coll.) • 1 spm; idem; MNHN.F.A77743 (Dollfus coll., Figs 3C, D; 25B) • spm; idem; MNHN.F.B26846 (MNHN coll.) • 5 spm; idem; MNHN.F.A77744 (Lhomme coll.); • 2 spm; Loire Basin, Indre-et-Loire, Paulmy (Pauvrelay); idem; MNHN.F.A77745 (Faullummel coll.).
ETYMOLOGY. — The name pontileviensis refers to the type locality: Pontlevoy.
TYPE HORIZON. — Faluns du Blésois (mammal biozone MN5b), see Ginsburg (2000), Middle Miocene (base of the Langhian).
TYPE LOCALITY. — France, Loire Basin, Loir-et-Cher, Pontlevoy (see Macaire et al. 2020).
DISTRIBUTION. — Loire Basin (France), Faluns du Blésois, Middle Miocene (Langhian).
DESCRIPTION
Paucispiral and rounded protoconch of 1.5 whorls.Teleoconch up to 14 mm in height, up to 6.5 mm in width, biconic in profile, composed of six whorls. Moderately high spire with subcarinate whorls. Last whorl up to 67.7% of total length. Apical angle 42°. Spiral sculpture with marked primary cords. First whorl: appearance of P1 and P2 (P2 more developed than P1) at beginning of whorl and appearance of IP on second half of whorl; second to fifth-sixth whorl: no change, but sometimes s3 placed slightly above suture. Sixth whorl: IP (sutural ramp), P1 to P5 (convex part of whorl, P6 atrophied (on siphonal canal), ADP and MP well developed, ABP poorly developed. Secondary cords s1, s4, s5 and s6 appear between end of fourth whorl and fifth whorl; s2 and s3 appear earlier. On first whorl: 14 varices; from second to fourth whorl: 10-12 varices; from fifth to sixth whorl: 10-11 varices. On spire axial ornamentation forming small nodules placed on IP, P1 and P2. P1 and P2 nodules more developed than IP. On convex part of last whorl, P1 to P4 nodules more or less equally developed; P5 slightly more developed; on siphonal canal, P6 not atrophied, ADP and MP more developed than ABP when present. Ovate aperture up to 42% of diameter and up to 70% of length of last whorl (including siphonal canal). Columellar lip narrow, entirely adherent, bearing two weak tubercles anteriorly. No anal sulcus, no parietal callus. Outer lip with strong internal denticles. Series of denticles including: ID, D2 to D5. D1 missing. D2 stronger than other denticles. Outer lip not crenulate. Siphonal canal open, up to 33% of apertural length and slightly dorsally recurved. Pseudoumbilicus narrow.
COMPARISONS
This species is comparable to Muricopsis crassicostata (Benoist, 1880) from the late Oligocene/Early Miocene of Aquitaine Basin (France) and M. dujardini Peyrot, 1938 from the Middle Miocene of Loire Basin (France). Muricopsis crassicostata clearly differs from M. pontileviensis n. sp. in being larger (19-23 mm for 6-7 whorls vs 12-14 for 5.5-6 whorls) and having a multispiral protoconch of three convex whorls (for more comparative details, see Merle 1999: 348, fig. 115). Muricopsis dujardini and M. pontileviensis n. sp. both occur at Pontlevoy. Specimens of M. dujardini are larger (19-24 mm for 6-6.5 whorls), but they are mainly distinguishing from M. pontileviensis n. sp. by having short spines on P1 to P 5 in which P3 is atrophied and by having stronger denticles within the outer lip. Muricopsis pontileviensis n. sp. never bears spines. Merle (1999) wrongly attributed studied specimens of M. pontileviensis n. sp. to M. dujardini, however, he demonstrated that they display a paedomorphic shape (particularly because of the post-displacement of the secondary cords s1, s4 and s6) compared to larger shells as M. crassicostata.
description: Published as part of Merle, Didier, Pacaud, Jean-Michel, Ledon, Daniel & Goret, Bernard, 2024, New Cenozoic Muricidae (Mollusca: Gastropoda) from Europe, pp. 495-551 in Geodiversitas 46 (15) on pages 503-504, DOI: 10.5252/geodiversitas2024v46a15, http://zenodo.org/record/13985760