Episcomitra praenigra ( Mayer-Eymar, 1890 )

Harzhauser, Mathias & Landau, Bernard, 2021, The Mitridae (Gastropoda: Neogastropoda) of the Miocene Paratethys Sea, Zootaxa 4983 (3), pp. 1-72 : 16-17

Episcomitra praenigra ( Mayer-Eymar, 1890)

Figs 4D 1 –D 2 , E 1 –E 2

* Mitra praenigra May-Eym. — Mayer-Eymar 1890: 300.

Mitra praenigra Mayer-Eymar — Mayer-Eymar 1891: 342, pl. 10, fig. 9.

Mitra (Mitra) praenigra Mayer-Eymar — Cernohorsky 1976: 377, pl. 323G, fig. 1.

Type material. Lectotype (designated herein): Inv. Nr. t3360, illustrated in Mayer-Eymar (1891, pl. 10, fig. 9), SL: 58 mm, MD: 19 mm, Lăpugiu de Sus ( Romania), stored in the collection of the Naturhistorisches Museum Basel ( Switzerland), figs 4D 1 –D 2 . Paralectotype: Inv. Nr. t3361, SL: 43 mm, MD: 16 mm, Lăpugiu de Sus ( Romania), stored in the collection of the Naturhistorisches Museum Basel ( Switzerland), figs 4E 1 –E 2 .

Revised description. Shell moderately large, solid, moderately slender fusiform with conical spire and impressed suture. Protoconch unknown. Teleoconch of nine moderately convex whorls. Sculpture of prominent, orthocline to weakly prosocline growth lines. No spiral sculpture except for few faint spiral grooves. Last whorl evenly convex, constricted at base with distinct basal concavity. Aperture short, moderately wide, ovoid. Columellar callus thickened, sharply delimited. Columella with four prominent columellar folds, decreasing in strength abapically. Outer lip solid. Siphonal canal moderately short, wide, straight with shallow siphonal notch.

Shell measurements and ratios (lectotype). SL = 58 mm, MD: 19 mm, AA = 35°, SL/ MD: 3.1, AL/AW: 4.4, AH/S: 2.8.

Discussion. The paralectotype is a subadult specimen. Its early teleoconch whorls are identical to those of the lectotype, but its last three whorls are more inflated, and the subsutural spiral sculpture is more prominent. It remains unclear if both specimens are conspecific. Based on the lectotype, Episcomitra praenigra ( Mayer-Eymar, 1890) is characterised by its relatively large size, absence of spiral sculpture (except for a few faint grooves), and low aperture due to a short siphonal canal. The outer lip is incomplete, which may exaggerate the small size of the aperture, however, the siphonal canal is complete, and short for the genus. This species is superficially reminiscent of Episcomitra brusinai ( Hoernes & Auinger, 1880) , but has a lower and wider aperture, a much shallower siphonal notch and a more convex last whorl with a more strongly constricted base.

Episcomitra praenigra belongs to the speciose Neogene European Episcomitra fusiformis ( Brocchi, 1814) group, but that species is even larger, with an elongated bullet-shaped last whorl and a much taller aperture. Numerous species were described from the Italian Neogene by Bellardi (1887), but none have such a short siphonal canal. The low and wide aperture seen in E. praenigra allows a separation from Mediterranean species such as E. inedita (Bellardi, 1887) , E. albignonensis (Bellardi, 1887) , and E. astensis (Bellardi, 1887) . Unfortunately, we lack further material to better characterise this species.

Palaeoenvironment. Unknown.

Distribution in Central Paratethys. Badenian (middle Miocene): Făget Basin: Lăpugiu de Sus ( Romania) ( Mayer-Eymar 1890).

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 4. A1–A2. Episcomitra leopoldiana nov. sp., holotype, Steinebrunn (Austria), NHMW 1846/0037/0097a. B1–B2. Episcomitra leopoldiana nov. sp., paratype, Steinebrunn (Austria), NHMW 1846/0037/0097b. C1–C2. Episcomitra leopoldiana nov. sp., paratype, Steinebrunn (Austria), NHMW 2020/0131/0001. D1–D2. Episcomitra praenigra (Mayer-Eymar, 1890), lectotype, Lăpugiu de Sus (Romania), NMB Inv. Nr. t3360. E1–E2. Episcomitra praenigra (Mayer-Eymar, 1890), paralectotype, Lăpugiu de Sus (Romania), NMB Inv. Nr. t3361. F. Episcomitra pseudoincognita nov. sp., paratype, Lăpugiu de Sus (Romania), Jerutek at Lysice (Czech Republic), NHMW 1854/0035/0100. G1–G2. Episcomitra pseudoincognita nov. sp., holotype, Lăpugiu de Sus (Romania), NHMW 1854/0035/0100e. H1–H2. Episcomitra pseudoincognita nov. sp., paratype, Lăpugiu de Sus (Roma- nia), NHMW 1854/0035/0100f. I1–I2. Episcomitra pseudoincognita nov. sp., paratype, Lăpugiu de Sus (Romania), NHMW 1854/0035/0100g,