Episcomitra missile, Harzhauser & Landau, 2021

Harzhauser, Mathias & Landau, Bernard, 2021, The Mitridae (Gastropoda: Neogastropoda) of the Miocene Paratethys Sea, Zootaxa 4983 (3), pp. 1-72 : 21-22

Episcomitra missile nov. sp.

Figs 5C 1 –C 2 , D 1 –D 2 , 12I 1 –I 2

Mitra fusiformis Brocc. — Hoernes & Auinger 1880: 75, pl. 8, figs 25a–b [non Brocchi, 1814].

Mitra cf. dufresnei Bast. — Sieber 1949: 110 [non de Basterot, 1825].

M [itraria]. (M [itraria].) cf. dufresnei (Bast.) — Sieber 1958a: 153 [non de Basterot, 1825].

? Mitra brusinae Hoernes & Auinger 1880 — Strausz 1966: 363, pl. 41, fig. 19 [non Hoernes & Auinger, 1990].

Type material. Holotype: NHMW 202 /0127/0001, SL: 63.7 mm, MD: 19.8 mm, Guntersdorf ( Austria), figs 5C 1 –C 2 . Paratypes: NHMW 202 /0128/0001, SL: 51.3 mm , MD: 16.4 mm, Grund ( Austria), figs 5D 1 –D 2 ; NHMW 1869 /0001/0275, SL: 74.3 mm , MD: 18.2 mm, Grund ( Austria), illustrated in Hoernes & Auinger (1880: 75, pl. 8, figs 25a–b), Figs 12I 1 –I 2 .

Type locality. Grund , Austria, North Alpine-Carpahian-Foredeep Basin-

Type stratum. Silty sand of the Grund Formation.

Age. Middle Miocene, early Badenian (Langhian).

Etymology. After missile (Latin for projectile), referring to the bullet-shaped outline (noun in apposition).

Diagnosis. Episcomitra species of large size, slender fusiform to bullet-shaped shell, with narrowly canaliculate suture, high spire composed of subcylindrical whorls, tall subcylindrical last whorl, and short aperture.

Description. Shell moderately large, very solid, moderately slender, weakly cyrtoconoid, slightly depressed spire with deep, narrowly canaliculate suture. Protoconch unknown. Teleoconch of seven whorls. Spire whorls convex with periphery slightly below mid-whorl. Last whorl high, weakly convex to subcylindrical, slowly contracting with indistinct basal concavity. Wide spaced spiral grooves on last whorl, poorly preserved due to slightly corroded shell surface. Aperture narrow to moderately narrow. Columellar callus indistinct, more prominent between adapical columellar fold and tip of siphonal canal. Columella with four oblique columellar folds; adapical two folds most prominent. Fasciole bearing prominent growth lines. Siphonal canal short, straight with wide siphonal notch. Broad flattish spiral cords on base and fasciole.

Shell measurements and ratios. SL = 51.3–88.1 mm, MD: 16.4–24.2 mm, AA = 38–45°, SL/MD: 3.1–4.0, AL/AW: 5.7–6.2, AH/S: 2.6–3.0.

Discussion. In the collection of the NHMW the specimens had been identified in the early 19 th century as Mitra fusiformis Brocchi, 1814 . Episcomitra fusiformis , as understood herein, differs from the Paratethyan species distinctly in its higher spire and higher spire whorls. Later, Sieber (1949, 1958a) referred to these specimens as Mitra dufresnei de Basterot, 1825 . Episcomitra dufresnei was described by de Basterot (1825) from the early Miocene of France. That large species (SL = 92 mm) is reminiscent of Episcomitra missile , but differs in its wider apical angle, broader last whorl, and even more prominent fasciole. Moreover, it bears deep spiral grooves on the last whorl, which are absent in the Paratethyan species (see Peyrot 1928: pl. 9, figs 34–36).

The specimen illustrated by Hoernes & Auinger (1880, pl. 8, fig. 25) ( Figure 12I 1 –I 2 ) is a teratogenic specimen with spire whorls that are rapidly increasing in height. An additional specimen from Létkes ( Hungary) in the private collection of Anton Breitenberger (Bad Vöslau, Austria) represents an intermediate morphotype and therefore, we do not separate this specimen as a separate species. Already Bellardi (1887a: 25) doubted that this Paratethyan specimen was conspecific with Episcomitra fusiformis and proposed a relationship with Mitra affinis Cocconi, 1873 (non Lesson, 1842) [= Mitra cocconii Mayer-Eymar, 1898 ]. Indeed, the Austrian specimen differs from Episcomitra fusiformis in its higher, subcylindrical last whorl, shorter aperture, narrowly canaliculate suture and long anal canal. The proposed similarity with Mitra cocconii , from the Pliocene of Prato-Ottesola ( Italy), is also unlikely in respect to the conical spire, smaller size, strongly callused inner lip and the higher number of spiral cords of the Italian species. A morphologically closely related species is Episcomitra dignota (Bellardi, 1887) from the Mediterranean Pliocene, which differs especially in its much smaller size (SL = 26 mm) at the same growth stage and the conical early spire (see Bellardi 1887a, pl. 4, fig. 20; Ferrero-Mortara et al. 1981, pl. 49, figs 2a–b).

Palaeoenvironment. At the locality Grund fossiliferous channel fills, which formed in middle to outer neritic environments bear allochthonous assemblages uniting coastal-mudflat faunas with inner neritic ones ( Zuschin et al. 2005; Roetzel 2009).

Distribution in Central Paratethys. Badenian (middle Miocene): North-Alpine-Carpathian Foredeep: Grund, Guntersdorf ( Austria) ( Hoernes & Auinger 1880);? Pannonian Basin: Letkés, Hidas ( Hungary).

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 5. A1–A2. Episcomitra brusinai (Hoernes & Auinger, 1880), lectotype, Lăpugiu de Sus (Romania), NHMW 1854/0035/0100. B1–B2. Episcomitra cf. brusinai (Hoernes & Auinger, 1880), Steinebrunn (Austria), NHNW 2020/0123/0001. C1–C2. Episcomitra missile nov. sp., holotype, Guntersdorf (Austria), NHMW 202/0127/0001. D1–D2. Episcomitra missile nov. sp., paratype, Grund (Austria), NHMW 202/0128/0001. E1–E2. Episcomitra friedbergi (Cossmann, 1912), lectotype, Lăpugiu de Sus (Romania), NHMW 20200124/0001. F1–F2. Episcomitra friedbergi (Cossmann, 1912), Lăpugiu de Sus (Romania), NHMW 1868/0001/0398. G1–G2. Episcomitra neubaueri nov. sp., holotype, Lăpugiu de Sus (Romania), NHMW 1854/0035/0084. H1– H2. Episcomitra neubaueri nov. sp., paratype, Lăpugiu de Sus (Romania), NHMW 1854/0035/0086. I1–I2. Episcomitra neubaueri nov. sp., paratype, Lăpugiu de Sus (Romania), NHMW 1855/0043/0006.

FIGURE 12. A1–A2. Isara hoernesi (Mayer, 1864), lectotype, Steinebrunn (Austria), NHMW 1846/0037/0097c. B1–B2. Isara hoernesi (Mayer, 1864), paralectotype, Mikulov (Czech Republic), NHMW 1860/0001/0116. C1–C2. Isara hoernesi (Mayer, 1864), Lăpugiu de Sus (Romania), NMB Inv. Nr. t3350, holotype of Mitra multistriata Mayer-Eymar, 1890 [non Bellardi, 1887]. D1–D2. Isara hoernesi (Mayer, 1864), Lăpugiu de Sus (Romania), NHMW 1865/0001/0170a. E1–E2. Isara hoernesi (Mayer, 1864), Lăpugiu de Sus (Romania), NHMW 1868/0001/0397. F1–F2. Isara hoernesi (Mayer, 1864), Mikulov (Czech Republic), NHMW 1855/0045/0383. G1–G2. Isara hoernesi (Mayer, 1864), Grund (Austria), NHMW 1851/0002/0014. H1–H2. Isara hoernesi (Mayer, 1864), Lăpugiu de Sus (Romania), NHMW 1865/0001/0170b. I1–I2. Episcomitra missile nov. sp., paratype, Grund (Austria), NHMW 1869/0001/0275.