Episcomitra pilsbryi ( Boettger, 1906 )

Harzhauser, Mathias & Landau, Bernard, 2021, The Mitridae (Gastropoda: Neogastropoda) of the Miocene Paratethys Sea, Zootaxa 4983 (3), pp. 1-72 : 13-15

Episcomitra pilsbryi ( Boettger, 1906)

Figs 3I 1 –I 2

* Mitra (Mitra) pilsbryi n. sp. — Boettger 1906: 6, nr. 31.

Mitra (Mitra) pilsbryi Boettger — Zilch 1934: 260, pl. 17, fig. 21.

Mitra (Mitra) pilsbryi Boettger, 1906 — Cernohorsky 1976: 379.

Type material. Holotype: SFM 360347 (= SFM XII 12.2207a), SL: 13.3 mm, MD: 4.1 mm, Senckenberg Museum, Frankfurt/Main, Germany, Coşteiu de Sus ( Romania), illustrated in Zilch (1934, pl. 17, fig. 21), figs 3I 1 –I 2.

Revised description. Shell small, moderately slender fusiform with high spire. Protoconch unknown. Teleoconch of seven whorls. Spire whorls only weakly convex, with narrow, weakly incised suture. Last whorl elongate, slowly contracting. Shell surface glossy, smooth, without axial sculpture except for faint growth lines. Spiral sculpture limited to delicate spiral threads on base and fasciole. Aperture short, moderately wide, posteriorly narrowly angulated with indistinct posterior sinus. Columellar callus narrow, sharply delimited, with three weak columellar folds adjoined by subobsolete fourth abapical fold. Outer lip thin. Siphonal canal moderately short, straight with very shallow anterior notch.

Shell measurements and ratios. SL = 13.3 mm, MD: 4.1 mm; AA = 32°, SL/ MD: 3.2, AL/AW: 4.6, AH/S: 2.5.

Discussion. Boettger (1906) discussed Episcomitra terebriformis (Bellardi, 1887) (SL: 16 mm), from the Burdigalian of Italy, as a closely related species. Episcomitra terebriformis , however, differs in its convex whorls and strongly constricted base (see Bellardi 1887a: 63, pl. 3, fig. 58 and Ferrero-Mortara et al. 1981: 157, pl. 47, figs 10a–b). Episcomitra macilenta (Bellardi, 1887) (SL: 18 mm) and Episcomitra subuliformis (Bellardi, 1887) (SL: 20 mm), both from the Burdigalian of the Colli Torinesi ( Italy), are very similar to E. pilsbryi , distinguished only by their larger size, the slightly higher aperture of E. macilenta and the less convex spire whorls and weaker basal concavity of E. subuliformis (see Bellardi 1887a: 52, pl. 3, fig. 38 and Ferrero-Mortara et al. 1981: 155, pl. 46, figs 6a–b for E. macilenta and Bellardi 1887a: 55, pl. 3, fig. 42 and Ferrero-Mortara et al. 1981: 156, pl. 46, figs 14a–b for E. subuliformis ). Unfortunately, represented by a single specimen, intraspecific variability cannot be assessed, but in respect to the difference in size and considering the large stratigraphic gap, we prefer to keep the Paratethyan species separate from the early Miocene Proto-Mediterranean congeners. Another similar species is Episcomitra ulivii ( Chirli, 2002) from the Pliocene of Italy, which is only distinguished from the Paratethyan species by its larger shell (SL: up to 30 mm) (see Chirli 2002: 41, pl. 20, figs 5–12).

Palaeoenvironment. Unknown. Probably middle to outer neritic environments.

Distribution in Central Paratethys. Badenian (middle Miocene): Făget Basin: Coşteiu de Sus ( Romania) ( Boettger 1906).

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).