Antithala claviformis Harzhauser & Landau 2021, nov. sp.
Creators: name: Harzhauser, Mathias
name: Landau, Bernard
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Neogastropoda
Costellariidae
Antithala
Antithala claviformis

description: Antithala claviformis nov. sp.
Figs 3A 1 –A 2, 3B 1 –B 2, 3C 1 –C 2
Mitra Sturi nov. form.— Hoernes & Auinger 1880: 90 (pars; syntypes not illustrated) [non Antithala sturi (Hoernes & Auinger, 1880)].
Type material. Holotype: NHMW 1869 /0001/0670, SL: 4.4 mm, Coşteiu de Sus (Romania), MD: 1.8 mm, figs 3A 1 –A 2. Paratypes: NHMW 2020 /0056/0001, SL: 4.5 mm, MD: 1.9 mm, Coşteiu de Sus (Romania), figs 3B 1 –B 2; NHMW 2020 /0056/0002, SL: 4.1 mm, MD: 1.9 mm. Coşteiu de Sus (Romania), figs 3C 1 –C 2; 11 specimens, NHMW 2020 /0056/0004, Coşteiu de Sus (Romania).
Type locality. Coşteiu de Sus (Romania), Făget Basin.
Type stratum. Silt and clay of the Dej Formation.
Age. Middle Miocene, Badenian.
Etymology. “ Clava ” (Latin: club), referring to the club-like shape.
Diagnosis. Antithala species of small size, with prominently beaded sculpture, three beaded cords on spire whorls, four columellar folds.
Description. Shell small, stout fusiform. Protoconch unknown. Teleoconch of 4.5 straight-sided whorls with periphery at abapical suture; suture distinctly incised. Spire weakly gradate, conical to slightly cyrtoconoid. First teleoconch whorl with prominent axial ribs intersected by two weaker spiral grooves forming three spiral rows of nodes; spiral rows strengthen abapically, forming prominent subquadrate nodes on later whorls. Fourth spiral cord at abapical suture largely covered by succeeding whorl. Last whorl regularly convex at periphery, passing via distinct concavity into strongly constricted base. Seven to eight spiral rows of nodes on last whorl forming orthocline to weakly sigmoidal axial ribs. Fasciole weak, bearing about five spiral cords with reduced nodes. Aperture elongate, narrow with distinct anal sinus narrowed by broad, low parietal denticle. Columella narrow, sharply delimited, bearing four folds, abapically rapidly decreasing in strength. Outer lip thickened, with six small denticles within. Siphonal canal moderately long, recurved, bent slightly to left, with shallow siphonal notch.
Shell measurements and ratios. SL: 3.5–4.5 mm, MD: 1.8–1.9 mm; AA: 45–51°, SL/MD: 2.2–2.6, AL/AW: 4.8–5.6, AH/S: 2.2–2.5.
Discussion. The specimens here described as Antithala claviformis nov. sp. were probably identified by Hoernes & Auinger (1880) as Mitra sturi (Hoernes & Auinger, 1880) due to them having almost identical sculpture. Antithala claviformis, however, is constantly smaller, broader and has a strongly constricted base, resulting in a club-like last whorl. Most importantly, A. claviformis has four columellar folds whereas A. sturi has only three. Antithala filipescui nov. sp. and A. neugeboreni both differ in having four rows of nodules on the spire whorls.
Palaeoenvironment. The assemblages from Coşteiu de Sus suggests middle neritic palaeoenvironments with soft bottom (own data).
Distribution in Central Paratethys. Badenian (middle Miocene): Făget Basin: Coşteiu de Sus.
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 8-9, DOI: 10.11646/zootaxa.4982.1.1, http://zenodo.org/record/4921842