Favartia jansseni 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
Favartia
Favartia jansseni

description: Favartia jansseni n. sp.
(Figs 4 A-D; 25E, F)
urn:lsid:zoobank.org:act: D34B3691-CAE8-4FB4-9492-05EFDF71FCD3
Favartia collega – Janssen 1984: 214, pl. 59, fig.7 [non Boettger,1906].
Favartia sp. 2 – Merle et al. 2022: pl. 58, figs 3, 4.
TYPE MATERIAL. — Holotype. The Netherlands • North Sea Basin, Miste, Winterswijk; Miste bed; Middle Miocene (middle Langhian); RGM.225979 (figured specimen in Janssen [1984: pl. 59, fig. 7]), H: 12.5 mm (Figs 4A, B; 25E).
Paratype. The Netherlands • 1 spm; same as for the holotype; MNHN.F.A77748 (Ledon coll., Figs 4C, D; 25F).
ETYMOLOGY. — Dedicated to Arie W. Janssen for his paleontogical and malacological work.
TYPE HORIZON. — Miste bed, Middle Miocene (middle Langhian), see Janssen (1984) and Schneider & Heissig (2005).
TYPE LOCALITY. — The Netherlands, North Sea Basin, Miste, Winterswijk (see Janssen 1984).
DISTRIBUTION. — Only known from the type locality.
DESCRIPTION
Protoconch not preserved. Delicate teleoconch up to 12.5 mm in height, up to 7.5 mm in width, composed of five whorls. Moderately high spire with subangular whorls. Last whorl up to 72% of total length. Apical angle 72° (including spines) and 48° (excluding spines). Spiral sculpture with strong primary cords. From first to fourth whorl: P1 and P2; on fourth whorl, appearance of IP. Fifth whorl: IP and abis, P1 to P5, P6 atrophied (on siphonal canal), ADP and MP present, ABP missing. Surface of P1, P2 and P3 bearing deep spiral grooves. Second whorl: 8-9 varices; from third to fourth whorl: 8 varices; fifth whorl: 6-7 varices. Adapertural face of varices with some imbricated growth lamellae. Axial ornamentation forming short spines on P1 to P5, ADP and MP. Axial microsculpture with small erect lamellae. Suboval aperture up to 29% of diameter and up to 71% of length of last whorl (including siphonal canal). Columellar lip smooth, narrow, erect anteriorly. Outer lip lacking denticles. Siphonal canal open, up to 42% of apertural length and slightly dorsally recurved. Pseudo-umbilicus rather wide.
COMPARISONS
This rare species from the Langhian of Miste (North Sea) was identified as Favartia collega (Boettger, 1906) by Janssen (1984). The holotype of F. collega (SMF XII2258 a, figured in Merle et al. 2022: pl. 58, fig. 2) comes from the Langhian of Costeiu de Sus (Romania, Paratethys Sea). It differs from F. jansseni n. sp. by having a slenderer shell, a rounded shoulder sinus in the aperture, and weak internal denticles within the outer lip (D1 to D5). Secondary cords are poorly developed, but the holotype of F. collega is a juvenile specimen of only 7.5 mm height. Favartia collega and F. czjzeki (Hoërnes & Auinger, 1885) from the Langhian of Austria (Paratethys Sea) and Hungary (Kovács et al. 2018) share a slender shell, a rounded shoulder sinus, and a multispiral protoconch (Kovács et al. 2018). The shells of F. collega and F. czjzeki are very similar, and therefore, F. collega is considered to be a junior synonym of F. czjzeki herein. The syntype of F. czjzeki (NHMW 1855/0045/008 figured in Merle et al. 2022: pl. 58, fig. 1) and other adult specimens of this species display the secondary cords (s1, s2, s3 and s5) and weak internal denticles missing in F. jansseni n. sp.
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 505-506, DOI: 10.5252/geodiversitas2024v46a15, http://zenodo.org/record/13985760