Bellardithala undetermined

Bellardithala sp.

Figs 8G

Vexillum (Uromitra) sp.— Tomašových 1998: 378, pl. 10, figs 3–4.

Material. Inv. Z23408-P2003/27, Natural History Museum in Bratislava, SL: 9.4 mm, MD: 3.3 mm.

Description. Shell medium-sized, moderately slender with slightly gradate spire. Protoconch and first teleoconch whorls unknown. Early teleoconch whorls with broad, strongly opisthocline axial ribs, with interspaces of similar width. Axial ribs becoming sigmoidal and densely beaded on later whorls, with two more spiral rows of slightly more prominent beads along adapical suture. About eight spiral rows of beads on penultimate whorl. Beads replaced by prominent, convex spiral cords on strongly constricted base. Aperture is largely destroyed with three prominent columellar folds and much weaker abapical fourth fold. Siphonal canal long.

Discussion. Tomašových (1998) described a single fragmentary specimen of a Bellardithala from basinal clays at Devínska Nová Ves. Due to its peculiar sculpture of strongly opisthocline to sigmoidal, beaded axial ribs, this specimen differs from all other Paratethyan Bellardithala species and might represent a yet undescribed species. Due to its fragmentary preservation, we refrain from naming it formally.

Palaeoenvironment. The mollusc assemblage of Devínska Nová Ves indicates deeper neritic environments (Tomašových 1998).

Distribution in Central Paratethys. Badenian (middle Miocene): Vienna Basin: Devínska Nová Ves (Slovakia).

Genus Ebenomitra Monterosato, 1917

Type species. Mitra ebenus Lamarck, 1811, subsequent designation by Coan (1966: 130); Present-day, Mediterranean Sea.

Description. “ Shell small, turriform or fusiform to widely fusiform. Protoconch bulbous, paucispiral, with about two glossy whorls. Teleoconch of up to 7.5 moderately or strongly convex whorls. Early spire whorls with strong ribs or very strong and wide folds; later whorls with strong wide folds vanishing below periphery of last adult whorl, or smooth; spiral sculpture not pronounced. Siphonal canal short to moderately long, sculptured with between two and four strong oblique cords. Aperture ovate to elongate, sometimes constricted towards siphonal canal; outer aperture lip lirate within. Inner apertural lip with three strong oblique columellar folds, adapicalmost fold strongest ” (Fedosov et al., 2017: 601).

Discussion. Fedosov et al. 2017 considered Ebenomitra as a subgenus of Pusia. The pros and cons of the usage of subgenera was controversially discussed in a plethora of papers (e.g. Laurin 2010; Puillandre et al. 2014; Teta 2018 and references therein). As stated in our previous contributions (Harzhauser & Landau 2016, 2019) we consider supraspecific classification levels as arbitrary and try to avoid the usage of subgenera. Therefore, we prefer to raise Ebenomitra to full genus rank.

Key to Paratethyan Ebenomitra species:

1. Shell very broadly fusiform.................................................................... E. leucozona

- Shell narrow fusiform.................................................................................. 2

2. Axial sculpture restricted to early teleoconch whorls........................................ E. pseudopyramidella

- Axial sculpture almost absent, suggestion of ribs on last whorl.................................... E. januszkiewiczi