Timbellus curvispina 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
Timbellus
Timbellus curvispina

description: Timbellus curvispina n. sp.
(Figs 14 D-H; 26J-L)
urn:lsid:zoobank.org:act: 00EFA23B-DFE2-4272-AC88-BF1C6253EBA7
Murex tricarinatus – Deshayes 1835: 597, pl. 82, figs 9, 10 [non Lamarck, 1803].
Timbellus crenulatus tricarinatus – Merle et al. 2011: 440, pl. 98, figs 6, 7 only [non Lamarck, 1803].
TYPE MATERIAL. — Holotype. France • Paris Basin, Oise, Parnes (Les Bôves); Falun de Parnes (biozone NP15); middle Eocene (middle Lutetian); MNHN.F.A90541 (ex B63594), H: 51.8 mm (Figs 14E, F; 26J).
Paratypes. France • 3 spm Paris Basin; Eure; Fontenay-en-Vexin (Bois du but); Falun de Parnes (biozone NP15); middle Eocene (Lutetian); MNHN.F.A73848 (Figs 14D; 26L), MNHN.F.A90542, MNHN.F.A90543 (Pons coll.) (Figs 14G, H, 26K) • 1 spm; idem; MNHN.F.A32514 (Pacaud coll.), figured in Merle et al. (2011: 440, pl. 98, fig. 7) • 1 spm; Paris Basin, Yvelines, Villiers-Saint-Frédéric (Butte Saint-Léonard); Falun de Parnes (biozone NP15); Lutetian; MNHN.F.A32516 (Schtrock coll.), figured in Merle et al. (2011: 440 pl. 98, fig. 6) • 1 spm; Paris Basin, Yvelines, Parnes; Falun de Parnes (biozone NP15); Lutetian; MNHN.F.A90544 (ex Galerie de Zoologie coll.).
ETYMOLOGY. — Name derived from Latin curv - (meaning curved) and spina (meaning spine) and refers to the P1 spine dorsally curved; gender female.
TYPE HORIZON. — Falun de Parnes (biozone NP15), see Gély & Lorenz (1991: pl. 1), middle Eocene (middle Lutetian).
TYPE LOCALITY. — France, Paris Basin, Oise, Parnes (Les Bôves), see Fritel (1910: 221).
DISTRIBUTION. — Calcaire grossier moyen, biozone NP15, Paris Basin (France), middle Eocene (middle Lutetian).
DESCRIPTION
Protoconch not preserved. Teleoconch up to 51.8 mm in height, up to 30 mm in width, subfusiform in profile, composed of six whorls. Moderately high spire. Last whorl up to 85% of total length. Apical angle 63°. Spiral sculpture with marked primary cords on varices, but weaker on intervarices. First and second whorls eroded. From third: appearance of weak P1 and P2. Third word: no change. Fourth whorl: appearance of s1. Fifth whorl: occasional appearance of s2. Sixth whorl: P1 to P6, s1, s2, P6 not atrophied, s1 well developed; ADP developed, MP, ABP weak or missing on siphonal canal. Axial sculpture eroded on two early whorls. On second whorl, eight protovarices. Third whorl: appearance of varices; three varices and one intervarix between. From fourth to last whorl, no change. Higher relief of intervarices on P2. Varices sublamellose. Appearance of short straight P1 spine on fourth whorl. On last whorl, axial ornamentation forming very short spinelets, dorsally recurved on P1 to P6. P1 spine more strongly developed than other cord spines. Rounded aperture up to 34% of diameter and up to 74% of length of last whorl (including siphonal canal). Columellar lip smooth, narrow, slightly erect anteriorly, forming curved inductura at base. Parietal lip slightly adherent. Outer lip with very weak denticles including D1 to D6. Small crenulations at edge of outer lip. Siphonal canal narrow, open, bent, slightly dorsally recurved, up to 81% of apertural length. Pseudoumbilicus narrow
COMPARISONS
This species can be included in the group of T. crenulatus defined by Harasewych & Jensen (1979), Vokes (1992), and updated by Merle et al. (2011: 15). In this group the last whorl is generally wider than in species of the T. tripteroides group, the shoulder spine (P1) is more delineated and the internal denticles within the outer lip are weaker. The spiral sculpture corresponds to fine primary cords, as in the T.tripteroides group. Timbellus curvispina n. sp. was mistaken for the Lutetian species T. crenulatus tricarinatus (Lamarck, 1803) but it differs by the construction of the P1 spine. This spine is straight, long and oriented abaperturally in T. crenulatus tricarinatus, whereas it is shorter, curved and dorsally oriented in T. curvispina n. sp. (see Fig. 14). Timbellus curvispina n. sp. also bears cord spines that are always more developed than in T. crenulatus tricarinatus. Moreover, the spiral cords of T. curvispina n. sp. are weak in the intervarical spaces, whereas those of T. crenulatus tricarinatus are well marked. Pacaud et al. (2017) recently designated the lectotype of Murex tricarinoides Deshayes, 1835 demonstrating that authors confused this species with another: T. capitaneus Pacaud, Ledon & Goret, 2017. In addition, they synonymised T. tricarinoides with T. crenulatus tricarinatus. However, T. tricarinoides differs from T. crenulatus tricarinatus in lacking true P1 spines and in displaying a rounded outer lip. T. crenulatus crenulatus (Röding, 1798) from the Bartonian is easily distinguishable from T. curvispina n. sp. by its acute and long P1 spine pointing abaperturally.
SPECIES GROUP OF T. PHYLLOPTERUS (LAMARCK, 1822) Members of this group are usually large sized and share a strong development of the internal denticles within the outer lip and strong primary cords; secondary cords are poorly developed. All species lack columellar denticles, except in the holotype of T. xenos (Harasewych, 1982), which is presumably a pathological specimen (Vokes 1992: 18). In the middle Eocene from Europe, Timbellus submicropterus n. sp. (upper Lutetian) and the Bartonian T. micropterus (Deshayes, 1835) represent the oldest members of this species group. It becomes more diversified in the late Eocene/early Oligocene with T. lamarckii (Grateloup, 1845), T. detritus (von Koenen, 1890), T. arenarius (Steuer, 1912), T. danapris Pacaud, 2018 and T. radulfiensis n. sp. It contains three Miocene species: T. perlongus (Bellardi, 1872), T. rosavendae (Bellardi, 1872) and T. pseudolamarcki (Magne, 1941), and becomes extinct before the Pliocene.
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 519-520, DOI: 10.5252/geodiversitas2024v46a15, http://zenodo.org/record/13985760