Work

Acrostemma kuehnelti

Year: 2026

Type: article

Abstract: Acrostemma kuehnelti (Berger, 1953) Figs 39A 1 –A 3 Retusa (Acrostemma) kühnelti n. sp. — Berger 1949: 82 [nomen nudum]. * Retusa (Acrostemma) kühnelti n. sp. — Berger 1953: 96, pl. 16, fig. 31. R [etusa]. (A [crostemma). kühnelti Berg.— Sieber 1958: 163. Type material. Holotype, NHMW-ZOO-MO-75000-E-42897, SL: 5.2 mm, MD: 1.6 mm, Vienna / Ottakring (Austria), illustrated in Berger (1953: pl. 16, fig. 31), Figs 39A 1 –A 3. Revised description. Medium sized, strongly elongate, very slender pyriform shell (SL/MD = 3.2), only last whorl visible. Protoconch unknown. Last whorl subcylindrical, weakly convex; periphery placed just above mid-whorl (SL/ PH = 1.9), almost straight in adapical third, forming angle of about 23°. Rounded at slowly contracting base. Apex sharply truncated, moderately broad (MD/ApD = 1.9), apical plane strongly oblique (AP = 19°), deeply and narrowly umbilicate, delimited by prominent, round-edged apical crest. Surface of apical crest with broad, low, short growth lines. Sculpture of numerous moderately deep, partly punctate spiral grooves over entire last whorl. Broad, flat spiral cords occasionally bifid. Aperture longer than shell, very narrow down to mid-whorl (MD/AW = 8.3), weakly widening anteriorly (MD/MAW = 2.7), resulting in moderate expansion rate (ER = 3.1). Outer lip thin, relatively high, very narrowly alate apical extension. Columella obscured by sediment. Columellar callus forming delicate, narrow rim delimiting umbilical chink. Discussion. This species differs from all congeners in its very slender outline and prominent spiral sculpture. Acrostemma anatolica sp. nov. is broader, the apical crest is more prominent, and the spiral grooves become increasingly wider spaced adapically on the last whorl. Paleoenvironment. Probably middle neritic based on co-occurring assemblage (own data, M.H.). Distribution in Central Paratethys. Badenian (Middle Miocene): Vienna Basin: Vienna /Ottakring (Austria) (Berger 1953).

DOI: 10.5281/zenodo.20492805

Authors: Harzhauser, Mathias, Landau, Bernard M., Malaquias, Manuel António E.

Institutions: Natural History Museum Vienna, Naturalis Biodiversity Center, University of Lisbon, Instituto Dom Luiz, University of Bergen

Topic: Mollusks and Parasites Studies

Subfield: Insect Science

Field: Agricultural and Biological Sciences

Domain: Life Sciences

Open Access status: gold

OpenAlex ID: W7162999622

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