Cancilla nanostriatula Harzhauser & Landau 2021, nov. sp.

Cancilla nanostriatula nov. sp.

Figs 15C 1 –C 2, D 1 –D 2, E 1 –E 2, F 1 –F 2

Mitra striatula Brocc. — Hörnes 1852b: 102, pl. 10, figs 19–21 [non Lamarck, 1811].

[Mitra] striatula Brocc. — Auinger 1871: 8 [non Lamarck, 1811].

Mitra (Tiara) substriatula d’Orbigny, 1852 —Kojumdgieva in Kojumdgieva & Strachimirov 1960: 157, pl. 42, fig. 2 [non d’Orbigny, 1852].

Mitra (Nebularia) scrobiculata var. bellardii Hoernes & Auinger, 1880 — Strausz 1966: 365, pl. 26, figs 9–10 [non Hoernes & Auinger, 1880].

Type material. Holotype: NHMW 1846 /0037/0100, SL: 29.9 mm, MD: 8.9 mm, Baden (Austria), illustrated in Hörnes (1852b, pl. 10, fig. 20), figs 15D 1 –D 2. Paratypes: NHMW 2020 /0136/0002, SL: 28.5 mm, MD: 8.8 mm, Bad Vöslau (Austria), figs 15C 1 –C 2; NHMW 1863 /0015/0622, SL: 23.7 mm, MD: 6.3 mm, Niederleis (Austria), figs 15E 1 –E 2; NHMW 2020 /0136/0001, SL: 29.6 mm, MD: 9.2 mm, Baden (Austria), figs 15F 1 –F 2.

Additional material. NHMW 2013 /0078/0365, 7 specimens, Baden (Austria), NHMW 1855 /045/0869, 17 specimens, Bad Vöslau (Austria), NHMW 1862 /0001/0252, 6 specimens, Möllersdorf (Austria), NHMW 1867 /0019/0034, 3 specimens, Coşteiu de Sus (Romania).

The specimens from Baden (Austria) illustrated in Hörnes (1852b, pl. 10, figs 19, 21) are lost.

Type locality. Baden (Austria), Vienna Basin.

Type stratum. Clay of the Baden Formation.

Age. Middle Miocene, middle Badenian (Langhian).

Etymology. Referring to similarity with Cancilla substriatula and the relatively smaller size.

Diagnosis. Cancilla species of medium size, but small size for genus, moderately slender fusiform shell, with high slightly gradate spire, subcylindrical last whorl, spiral sculpture of three to four prominent spiral grooves in adapical third of whorls.

Revised description. Shell medium-sized, moderately slender fusiform with high, slightly gradate spire and faintly canaliculate suture. Protoconch conical of 3.5 moderately convex whorls. Teleoconch of ten whorls. Spire whorls subcylindrical with subobsolete/weak shoulder. Sculpture of first two teleoconch whorls of weak axial ribs, crossed in adapical third by two to four spiral grooves, resulting in cancellate sculpture. Subsequent whorls typically with three to four occasionally punctate spiral grooves on shoulder and adapical third of whorls, persisting on to last whorl. Number of spiral grooves variable due to secondary intercalations. Abapical part of whorls typically smooth, or less frequent with punctate spiral grooves of variable strength. Last whorl subcylindrical above periphery, moderately constricted with long base. Spiral cords on last whorl variable, usually reduced along periphery, prominent on base and fasciole. Growth lines may form cancellate pattern in spiral grooves. Aperture moderately narrow. Columellar callus broad, thin, sharply delimited. Columella with four oblique columellar folds, abapically decreasing in strength. Outer lip thin. Siphonal fasciole slightly twisted. Siphonal canal long, straight with deeply incised siphonal notch.

Shell measurements and ratios. SL = 16.0– 29.9 mm, MD: 5.1–9.2 mm, AA = 30–33°. SL/MD: 3.3–3.5, AL/ AW: 5.3–5.7, AH/S: 2.1–2.3.

Discussion. Glibert (1960) was the first to list Paratethyan occurrences of the species from Baden and Bad Vöslau (Austria) as Mitraria substriatula (d’Orbigny, 1852). Kojumdgieva in Kojumdgieva & Strachimirov (1960) followed this position and included the specimen from Baden (Austria) illustrated by Hörnes (1852b, pl. 10, fig 21) in her chresonymy of M. substriatula. Mitra substriatula was originally introduced by d’Orbigny (1852: 10) as new name for a specimens from the Burdigalian of Saint-Paul-lès-Dax (France), described by Grateloup (1846) as Mitra striatula Brocchi. The syntype of Mitra substriatula (MNHN.F. A12983, https://science.mnhn.fr/taxon/species/mitra/substriatula) differs from the Paratethyan specimens in its larger size, broader shell and convex last whorl. Its base is less constricted and the siphonal canal (although not fully preserved) seems to be shorter. The specimens from Saint-Jean-de-Marsacq (Burdigalian) and Saubrigues (Langhian) described by Peyrot (1928, pl. 9, figs 4, 10, 11, 53, 58), differ also from the syntype of Mitra substriatula in their higher subcylindrical spire whorls and elongate last whorl. Cancilla substriatula is also recorded from the Miocene of the North Sea Basin (Glibert 1852a; Janssen 1984). Janssen (1984, pl. 67, figs 2–4) considered Cancilla substriatula a polymorphic species with highly variable sculpture. This North Sea variety differs from the Paratethyan species in its much larger size (SL:> 45 mm) and its protoconch of 4.5 whorls. Moreover, its spiral grooves are more uniform, whereas the spiral grooves of Cancilla nanostriatula are distinctly more prominent along the shoulder than on the rest of the whorl.

Cancilla subtilestriata (Peyrot, 1928) from the Langhian of Saubrigues (France) is morphologically close to C. nanostriatula nov. sp. and attains a comparable size. It differs in its fewer, but more prominent spiral grooves, the less elongate last whorl, and less tapering siphonal canal (see Peyrot 1928: pl. 9, fig. 1).

Palaeoenvironment. The clay of the Baden Formation formed in middle to outer neritic settings with up to 250 m water depth (Hohenegger et al. 2008).

Distribution in Central Paratethys. Badenian (middle Miocene): Vienna Basin: Baden, Möllersdorf, Niederleis, Steinebrunn, Vienna /Pötzleinsdorf (Hörnes 1852b); Eisenstadt-Sopron Basin: Mattersburg, Forchtenau (Austria) (Hörnes 1852b), Pannonian Basin: Letkés (Hungary) (Strausz 1966); Dacian Basin: Urovene, Dobrusha (Bulgaria) (Kojumdgieva in Kojumdgieva & Strachimirov 1960).