Mitrella complanata (Sacco, 1890)

Harzhauser, Mathias & Landau, Bernard M., 2021, The Columbellidae (Gastropoda, Buccinoidea) in the Miocene Paratethys Sea — striking diversity of a negelected group, Zootaxa 5025 (1), pp. 1-75 : 32-33

Mitrella complanata (Sacco, 1890)

Figs 11A 1 –A 2 , B 1 –B 2 , C 1 –C 2

Columbella semicaudata Bon. —Hörnes 1852: 117, pl. 11, fig. 10 [non Bellardi, 1848].

Columbella (Mitrella) semicaudata Bon. — Hoernes & Auinger 1880: 95 [non Bellardi, 1848].

* Columbella (Mitrella) complanata Bell. — Sacco 1890b: 36, pl. 2, fig. 29 [non Bellardi, 1848].

Columbella (Mitrella) semicaudata Bon. — Boettger 1902: 16 [non Bellardi, 1848].

[ Columbella ] Mitrella complanata Bell. var. angustolonga Sacc. —Sacco 1904: 93, pl. 19, fig. 49.

[ Columbella ] Mitrella complanata Bell. var. acutelongiuscula Sacc. —Sacco 1904: 93, pl. 19, fig. 50.

Columbella (Mitrella) semicaudata Bon. — Friedberg 1911: 36, pl. 2, fig. 2 [non Bellardi, 1848].

Columbella semicaudata Bon. — Friedberg 1938: 128 [non Bellardi, 1848].

Mitrella semicaudata Bon. — Sieber 1953: 187 [non Bellardi, 1848].

Pyrene (Mitrella) semicaudata Bon. — Csepreghy-Meznerics 1956: 403, pl. 7, figs 16–17 [non Bellardi, 1848].

M.[itrella]. (M [itrella].) semicaudata (Bon.) — Sieber 1958a: 147 [non Bellardi, 1848].

Mitrella (M [itrella].) semicaudata (Bon.) — Sieber 1958b: 148 [non Bellardi, 1848].

Columbella (Mitrella) semicaudata Bonelli — Strausz 1962: 104, pl. 42, figs 23–24 [non Bellardi, 1848].

Mitrella semicaudata Bonelli 1825 — Zelinskaya 1968: 207, pl. 48, figs 17–18 [non Bellardi, 1848].

Columbella (Mitrella) semicaudata Bonelli (in Bellardi), 1849— Strausz 1966: 290, pl. 42, figs 23–24 [non Bellardi, 1848]. Columbella (Alia) semicaudata Bonn — Atanacković 1969: 207, pl. 11, figs 5–5a [non Bellardi, 1848].

Columbella (Mitrella) complanata Bellardi, 1890 — Ferrero Mortara et al. 1981: 179, pl. 56, fig. 5.

[ Columbella (Mitrella) complanata Bell. ] var. angustolonga Sacco, 1890 — Ferrero Mortara et al. 1981: 179.

[ Columbella (Mitrella) complanata Bell. ] var. acutelongiuscula Sacc. — Ferrero Mortara et al. 1981: 179.

Mitrella (Mitrella) semicaudata (Bonelli, 1849) — Atanacković 1985; 142, pl. 32, figs 3–4 [non Bellardi, 1848].

? Mitrella (Mitrella) semicaudata Bonelli, 1825 — Iljina 1993: 98, pl. 13, fig. 7 [non Bellardi, 1848].

Type material. Lectotype (designated herein): BS.022.01.014, Museo Regionale di Scienze Naturali , Torino , Tortonian, Stazzano ( Italy), illustrated in Ferrero Mortara et al. 1981: 180, pl. 56, fig. 11.

Illustrated material. NHMW 1846/0037/0156, SL: 22.9 mm, MD: 8.7 mm, Gainfarn ( Austria), illustrated in Hörnes (1852, pl. 11, fig. 10), Figs 11A 1 –A 2 . NHMW 1846/0037/0156a, SL: 16.3 mm, MD: 6.3 mm, Gainfarn ( Austria), Figs 11B 1 –B 2 . NHMW 2020/0164/0001, SL: 16.1 mm, MD: 7.0 mm, Gainfarn ( Austria), Figs 11C 1 –C 2 .

Additional material. NHMW1855 /0055/0043, 18 spec., Steinebrunn ( Austria) ; NHMW2020 /0169/0002 (ex B. Landau coll.), 3 spec., Szob ( Hungary) .

Revised description (based on Paratethyan material). Shell large, solid, moderately broad biconic, with narrow, weakly-incised suture. Protoconch unknown. Teleoconch of at least eight whorls. Spire nearly flat-sided. Last whorl high, moderately convex to subcylindrical, weakly contracting at base. Shell surface smooth except for prominent spiral cords on abapical portion of base and siphonal fasciole. Aperture narrow. Outer lip moderately thickened with about seven prominent, elongated denticles within. Anal canal incised, V-shaped. Siphonal canal short, narrow with deeply notched tip. Columellar callus forming broad rim, detached from base, with four denticles. Parietal callus weak, thin, adherent. Apex decollate in all available specimens.

Shell measurements and ratios. SL: 16.1–22.9 mm, MD: 6.1–8.7 mm, AA: 32–36°, SL/MD: 2.8–2.9, AL/AW: 3.5–3.9, LWH/AH: 1.3–1.4.

Discussion. Since Hörnes (1852) the Paratethyan specimens have been identified by all authors as Mitrella semicaudata ( Bellardi, 1848) , a species originally described from the Italian Pliocene. Mitrella semicaudata , however, differs in its higher spire, convex spire whorls, narrower columellar callus and well-preserved apex (see Ferrero Mortara et al. 1981, pl. 56, figs 11a–b; Chirli, 2002, pl. 5, figs 7–11). The Paratethyan specimens agree fully with the syntype of Mitrella complanata (Sacco, 1890) (see Ferrero Mortara, pl. 56, fig. 5), originally described from the upper Miocene Tortonian of Italy, which is characterised by its bullet-shaped outline, subcylindrical last whorl, narrowly incised suture and flat-sided whorls, broad columellar callus and decollate apex. Mitrella erythrostoma (Sacco, 1890) , from the Pliocene of Italy, differs in its more convex whorls and more constricted base (see Sacco 1890b; Ferrero Mortara et al. 1981, pl. 56, figs 9a–b). Mitrella acuminata (Sacco, 1890, fom the Tortonian of Italy, is more slender and has a higher spire (see Sacco 1890b; Ferrero Mortara et al. 1981, pl. 57, figs 1a–b).

Palaeoenvironment. The occurrence at Gainfarn suggests inner neritic environments with seagrass cover ( Zuschin et al. 2007).

Distribution in Central Paratethys. Badenian (middle Miocene): Carpathian Foredeep: Hołdy, Stary Poczajów, Żukowice, Żabiak, Ternopil ( Ukraine) ( Friedberg 1911); Vienna Basin: Vienna /Pötzleinsdorf, Steinebrunn ( Austria) ( Sieber 1953; Sieber 1959b); Pannonian Basin: Szob ( Hungary ( Strausz 1966); southern Pannonian Basin: Hrvaćani-Drenik ( Bosnia and Hercegovina) ( Atanacković 1985).

? Eastern Paratethys. Konkian (middle Miocene): St. Agara ( Georgia) ( Iljina 1993).

(Proto-)Mediterranean Sea. Tortonian (late Miocene): Po Basin: Stazzano ( Italy).

Figures

FIGURE 1. A. Map of central and south–eastern Europe, representing the area that was partly covered by the Central Paratethys Sea. The white insert corresponds to the area that is restored in the palaeogeographic map below. B. Paleogeography of the Middle Miocene Paratethys Sea showing the most important sedimentary basins (NAFB: North Alpine Foreland Basin, E–Sopr B: Eisenstadt–Sopron Basin).

FIGURE 2. Measurements for shell morphology and whorl profiles. SL: shell length, MD: maximum diameter, AA: apical angle, LWH: last whorl height, AH: aperture height. AL: aperture length. AW: aperture width.