Bellardithala boehmi Harzhauser & Landau 2021, nov. comb.
Creators: name: Harzhauser, Mathias
name: Landau, Bernard
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Neogastropoda
Costellariidae
Bellardithala
Bellardithala boehmi

description: Bellardithala boehmi (Boettger, 1906) nov. comb.
Figs 6A 1 –A 2, B 1 –B 2, C 1 –C 2
* Mitra (Micromitra) boehmi n. sp. — Boettger 1906: 11.
Pusia (Thala) boehmi (Boettger) — Zilch 1934: 258, pl. 17, fig. 14.
Type material. Lectotype: SMF 360342 (= SMF XII.2217 a), SL: 6.4 mm, MD: 2.3 mm, illustrated by Zilch (1934, pl. 22, fig. 14), Senckenberg Museum, Frankfurt/Main, Germany, Coşteiu de Sus (Romania), figs 6A 1 –A 2.
Additional material. NHMW 2020 /0059/0001, SL: 7.9 mm, MD: 2.8 mm, Lăpugiu de Sus (Romania), figs 6B 1 –B 2; NHMW 1854 /0035/0107, SL: 7.9 mm, MD: 2.7 mm, Lăpugiu de Sus (Romania), figs 6C 1 –C 2; 7 specimens, NHMW 2020 /0059/0002, Lăpugiu de Sus (Romania); BL collection, 4 specimens, Lăpugiu de Sus (Romania).
Revised description. Shell medium-sized, moderately slender fusiform with conical spire. Protoconch high mammillate of three smooth, weakly convex whorls; height: 600 μm, diameter: 550 μm. Teleoconch of 5.5 weakly convex whorls with periphery slightly above abapical suture. Suture narrowly incised. First three teleoconch whorls with, convex axial ribs, separated by narrower interspaces. Axial sculpture intersected by about 8 spiral grooves. Sculpture weakening abruptly after third whorl. Penultimate whorl nearly smooth; last whorl with faint spiral cords. Prominent spiral cords on base and fasciole with delicate axial growth lines in interspaces. Aperture moderately narrow, elongate with narrow anal sinus; inner lip narrow. Columella with four prominent folds (adapical two being stronger). Outer lip thickened with 10–12 small denticles, becoming nearly obsolete in abapical third of aperture. Last whorl convex, moderately constricted at base. Siphonal canal moderately short, straight with shallow anterior notch.
Shell measurements and ratios. SL: 6.4–7.9 mm, MD: 2.3–2.8 mm, AA= 37–42°, SL/MD: 2.7–3.0, AL/AW: 4.4–5.0, AH/S: 2.5–2.7.
Discussion. This rare species is reminiscent of Thala kovaci nov. sp. (= Thala obsoleta sensu Hörnes, 1852, non Brocchi, 1814) due to its reduced sculpture on the last whorl, but differs in its more slender fusiform outline, the much more prominent axial and spiral sculpture on the early teleoconch whorls, and the lower aperture/spire ratio (0.9 versus 1.1).
Bellardithala seminuda (Bellardi, 1888), from the Burdigalian of the Colli Torinesi (Italy), is reminiscent of B. boehmi, but differs in its larger size and in the absence of spiral sculpture on the last whorl (see Bellardi 1888: 7, pl. 6, figs 46a–b).
Palaeoenvironment. Unknown; the collections from Lăpugiu de Sus indicate a mixing of coastal-inner neritic and middle neritic elements.
Distribution in Central Paratethys. Badenian (middle Miocene): Făget Basin: Lăpugiu de Sus (own data), Coşteiu de Sus (Boettger 1906).
description: Published as part of Harzhauser, Mathias & Landau, Bernard, 2021, An overlooked diversity-the Costellariidae (Gastropoda: Neogastropoda) of the Miocene Paratethys Sea, pp. 1-70 in Zootaxa 4982 (1) on pages 16-18, DOI: 10.11646/zootaxa.4982.1.1, http://zenodo.org/record/4921842