Bellardithala partschi Harzhauser & Landau 2021, nov. comb.

Bellardithala partschi (Hörnes, 1852) nov. comb.

Figs 4D, 9D 1 –D 2, E 1 –E 2, F 1 –F 2

[Mitra] pulchella [Partsch]— Hörnes 1848: 17 [nomen nudum] [non Reeve, 1844].

* Mitra partschi Hörnes — Hörnes 1852b: 111, pl. 10, figs 33a–c.

[Callithea] Partschi M. Hoern.—Hoernes 1880: 125.

Mitra Partschi M. Hoern.— Hoernes & Auinger 1880: 88, pl. 10, figs 15–18.

[Turricula] Partschi Hoern. — Cossmann 1899: 166.

Turricula Partschi M. Hoernes — Friedberg 1911: 29, pl. 1, fig. 21.

Turricula Partschi Hoern. —Friedberg 1928: 579, pl. 37, figs 26–27.

Thala partschi Hörn. — Meznerics 1933: 322.

Vexillum (Costellaria) partschi (M. Hörn.) — Sieber 1956: 244.

Thala partschi (H Ö.)— Sieber 1953: 188.

Th [ala]. partschi (Hörn.) — Sieber 1958a: 153.

Thala partschi Hörn. — Sieber 1958b: 149.

Thala partschi (Hörnes) — Kókay 1966: 61, pl. 9, fig. 5.

Thala partschi (Hörnes) — Bałuk 1970: 119. Fig. 6.

Type material. Lectotype (designated herein): NHMW 1846 /0037/0113, SL: 6.9 mm, MD: 2.5 mm, Steinebrunn (Austria), illustrated in Hörnes (1852b: pl. 10, figs 33a–c), figs 9D 1 –D 2. Paralectotypes: NHMW 1855 /0045/0390, SL: 7.5 mm, MD: 2.4 mm, Steinebrunn (Austria), illustrated in Hoernes & Auinger (1880, pl. 19, fig. 15); NHMW 2020 /0060/0004, SL: 6.5 mm, MD: 2.3 mm, Steinebrunn (Austria), illustrated in Hoernes & Auinger (1880, pl. 19, fig. 16), figs 9E 1 –E 2; NHMW 1860 /0001/0110, SL: 6.9 mm, MD: 2.4 mm, Steinebrunn (Austria), illustrated in Hoernes & Auinger (1880, pl. 19, fig. 18), figs 9F 1 –F 2; NHMW 2020 /0060/0003, SL: 6.5 mm, MD: 2.3 mm, Steinebrunn (Austria), fig. 4D; NHMW 1855 /0011/0407, Steinebrunn (Austria), illustrated in Hoernes & Auinger (1880, pl. 19, fig. 17).

Additional material. NHMW 2020 /0060/0001, 968 specimens, Steinebrunn (Austria), NHMW 2020 /0060/0002, 382 specimens, Steinebrunn (Austria), NHMW 2020 /0060/0003, 315 specimens Steinebrunn (Austria).

Revised description. Shell medium-sized, moderately slender fusiform, with high conical to faintly cyrtoconoid, weakly scalate spire. High conical protoconch (fig. 4D) comprising 2.7 weakly convex whorls (height: 500 μm, diameter: 550 μm). Teleoconch of five subcylindrical to weakly convex whorls, separated by incised suture. First teleoconch whorl with prominent axial ribs, crossed by three narrow spiral cords, forming indistinct nodules at intersections. Axial sculpture remains dominant on later whorls and especially on last whorl; spiral cords often strongly reduced forming four to five spiral rows of indistinct nodules on spire whorls, and up to ten cords on last whorl. Last whorl weakly convex to subcylindrical, slowly contracting below periphery. Aperture elongate, moderately narrow with indistinct anal sinus. Columellar callus indistinct. Columella with four columellar folds; adapical two columellar folds prominent, third one weak and fourth abapical fold strongly reduced. Outer lip only weakly thickened, with about five small denticles within, sometimes strongly reduced. Siphonal canal moderately long, straight with shallow siphonal notch.

Shell measurements and ratios. SL: 6.5–7.5 mm, MD: 2.3–2.5 mm, AA: 25–37°, SL/MD: 2.8, AL/AW: 4.8– 5.6, AH/S: 2.2–2.4.

Discussion. Bellardithala partschi (Hörnes, 1852) is characterised by its weakly scalate spire, strongly predominant axial sculpture, and flattened, relatively broad spirals separated by narrow grooves. It is most similar to B. lapugyensis (Hoernes & Auinger, 1880), but that species is smaller, with rounded spire whorls and more evenly cancellate sculpture. Bellardithala partschi is rather variable concerning slenderness and convexity of the whorls. Similarly, the spiral sculpture varies considerably and is reduced in many specimens. Intercalations of secondary spiral grooves may raise the number of spiral rows to six or seven on the penultimate whorl.

Palaeoenvironment. This species is very common in shallow water settings, partly indicating sea grass meadows (e.g. Steinebrunn, Gainfarn; Zuschin et al. 2007, own data).

Distribution in Central Paratethys. Badenian (middle Miocene): Nowy Sącz Basin: Niskowa (Poland) (Bałuk 1970); Voronyaky Hills: Podhorce (Pidhirtsi) (Ukraine) (Friedberg 1911); Ukrainian Fore-Carpathian Basin: Zborów (Zboriv) (Ukraine) (Friedberg 1928); Vienna Basin: Niederleis, Gainfarn, Pötzleinsdorf/ Vienna, Steinebrunn (Austria) (Sieber 1953, 1958b), Mikulov (Czech Republic); Pannonian Basin: Herend (Hungary) (Kókay 1966); Eisenstadt-Sopron Basin: Forchtenau (Austria) (Sieber 1956).