Episcomitra antibellardii, Harzhauser & Landau, 2021

Harzhauser, Mathias & Landau, Bernard, 2021, The Mitridae (Gastropoda: Neogastropoda) of the Miocene Paratethys Sea, Zootaxa 4983 (3), pp. 1-72 : 9-10

Episcomitra antibellardii nov. sp.

Figs 3A 1 –A 2 , B 1 –B 2 .

Mitra Bellardii nov. form.— Hoernes & Auinger 1880: 78 (pars), pl. 9, figs 15–16 [non Calcimitra bellardii ( Hoernes & Auinger, 1880) ].

Type material. Holotype: NHMW 1854 /0035/0100b, SL: 46.5 mm, MD: 16.0 mm, Lăpugiu de Sus ( Romania), illustrated in Hoernes & Auinger (1880, pl. 9, fig. 15), figs 3A 1 –A 2 . Paratype: NHMW 1854 /0035/0100c, SL: 35.5 mm , MD: 11.0 mm, Lăpugiu de Sus ( Romania), illustrated in Hoernes & Auinger (1880, pl. 9, figs 16a–b), figs 3B 1 –B 2 .

Type locality. Lăpugiu de Sus ( Romania), Făget Basin .

Type stratum. Silt and clay of the Dej Formation.

Age. Middle Miocene, early/middle Badenian (Langhian).

Etymology. Referring to Mitra bellardii with which this species was confused by Hoernes & Auinger (1880).

Diagnosis. Episcomitra species of moderately large size, moderately slender to moderately broad fusiform shell with high conical spire, slightly convex, moderately constricted last whorl, wide, moderately long siphonal canal, relatively low last whorl and aperture, delicate spiral sculpture in subsutural area, weak columellar folds, narrow columellar callus.

Description. Shell moderately large, moderately slender to moderately broad fusiform, biconical with high conical spire and weakly impressed suture. Protoconch unknown. Teleoconch of nine whorls. Early spire whorls nearly straight sided with cancellate sculpture, later spire whorls weakly convex, periphery at mid-whorl; suture narrow. Five convex spiral cords on third teleoconch whorl increasing to six broad cords on subsequent whorls, separated by narrower interspaces. Delicate axial ribs only developed in spiral interspaces. Axial sculpture fading out on fifth to sixth whorls. At same position, spiral cords increasing in number by intercalations of secondary cords but distinctly weakening, being slightly more prominent only in adapical third of whorls. Late spire whorls weakly convex with periphery in abapical third of whorls. Last whorl weakly convex above periphery, slowly contracting below with shallow concavity along base. Subsutural spiral sculpture on last whorl very weak to subobsolete. Numerous weak spiral cords on base and fasciole, typically bifid by intercalations of secondary grooves. Aperture moderately narrow, posteriorly narrowly angulated. Columellar callus narrow, thin, well demarcated from base. Columella with three weakly developed oblique columellar folds; fourth abapical fold subobsolete. Outer lip thin. Siphonal canal moderately long, wide, straight to weakly bent to left, with wide, shallow siphonal notch.

Shell measurements and ratios. SL = 35.5–46.5 mm, MD: 11.0–16.0 mm, AA = 28–32°, SL/MD: 3.0–3.4, AL/AW: 4.5–5.4, AH/S: 2.3–2.4.

Discussion. This species was treated by Hoernes & Auinger (1880) as large variety of Mitra bellardii [= Calcimitra bellardii ( Hoernes & Auinger, 1880) ]. A relationship with Calcimitra bellardii , however, can clearly be excluded based on the much larger size, the narrow columellar callus, the shorter siphonal canal and the much weaker spiral sculpture.

Episcomitra antibellardii nov. sp. is characterised by a relatively high spire and low last whorl for the genus. The Pliocene Episcomitra atilis (Bellardi, 1887) (SL: 53 mm) is reminiscent of E. antibellardii in profile, but has a distinctly more inflated last whorl and lacks the subsutural spiral sculpture (see Bellardi 1887a, pl. 1, fig. 33; Ferrero-Mortara et al. 1981, pl. 43, fig. 7). The Italian Pliocene Episcomitra albignonensis (Bellardi, 1887) (SL: 60 mm) is also similar and like E. antibellardii , has spiral sculpture in the subsutural area, but is larger and its last whorl is less convex and less constricted (see Bellardi 1887a, pl. 1, fig. 32; Ferrero-Mortara et al. pl. 43, fig. 10; Chirli 2002, pl. 15, figs 11–12). Episcomitra subestriata (Bellardi, 1887) (SL: 56 mm) has a wider apical angle, a lower spire and lacks the subsutural spiral sculpture (see Bellardi 1887a, pl. 1, fig. 34; Ferrero-Mortara et al. 1981, pl. 43, fig. 8; Chirli 2002, pl. 19, figs 7–12).

Janssen (1972) referred to this species when discussing his new subspecies Mitra bellardii woltrupensis , from the Miocene of the North Sea. It seems to represent a distinct species, which differs from Episcomitra antibellardii in its canaliculate suture, relatively shorter and more convex last whorl and the more constricted base (see Janssen 1972: 42, pl. 7, figs 5–6). The specimen from the Miocene of Belgium, identified as Mitra bellardii by Glibert (1952a) is clearly not conspecific with the Paratethyan species, and differs in its slightly shouldered whorls, deeply incised suture and prominent subsutural spiral cords.

Palaeoenvironment. Unknown.

Distribution in Central Paratethys. Badenian (middle Miocene): Făget Basin: Lăpugiu de Sus ( Romania) ( Hoernes & Auinger 1880).

Figures

FIGURE 1. A. Map of central and south–eastern Europe, representing the area that was partly covered by the Central Paratethys Sea (for detailed maps with the localities mentioned in the text see Kroh (2005) and Nosowska (2020). The white insert corresponds to the area that is restored in the palaeogeographic map below. B. Palaeogeography of the Middle Miocene Paratethys Sea (modified from Harzhauser & Landau 2017) showing the most important sedimentary basins (NAFB: North Alpine Foreland Basin, E–Sopr B: Eisenstadt–Sopron Basin).

FIGURE 2. Measurements for shell morphology and whorl profiles. SL: shell length, MD: maximum diameter, AA: apical angle, LWH: last whorl height, AH: aperture height. AL: aperture length. AW: aperture width. S: length of siphonal canal.

FIGURE 3. A1–A2. Episcomitra antibellardii nov. sp., holotype, Lăpugiu de Sus (Romania), NHMW 1854/0035/0100b. B1–B2. Episcomitra antibellardii nov. sp., paratype, NHMW 1854/0035/0100c. C1–C2. Episcomitra bouei (Hoernes & Auinger 1880), lectotype, Lăpugiu de Sus (Romania), NHMW 1854/0035/0100d. D1–D2. Episcomitra cochlearella (Mayer-Eymar, 1890), lectotype, Lăpugiu de Sus (Romania), NMB Inv. Nr. t3238). E1–E2. Episcomitra cochlearella (Mayer-Eymar, 1890), paralectotype, Lăpugiu de Sus (Romania), NMB Inv. Nr. t3238. F1–F2. Episcomitra facilis (Mayer-Eymar, 1890), holotype, Lăpugiu de Sus (Romania), Inv. Nr. t3308. G1–G2. Episcomitra hilberi (Hoernes & Auinger 1880), paralectotype, Lăpugiu de Sus (Romania), NHMW 1854/0035/0100. H1–H2. Episcomitra hilberi (Hoernes & Auinger 1880), lectotype, Jerutek at Lysice (Czech Republic), NHMW 1865/0015/0014. I1–I2. Episcomitra pilsbryi (Boettger, 1906), holotype, Coşteiu de Sus (Romania), SFM 360347 (= SFM XII 12.2207a).