Mitrella hilberi ( Cossmann, 1901 )

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 : 28-29

Mitrella hilberi ( Cossmann, 1901)

Figs 4A, 8D 1 –D 2 , E 1 –E 2 , F 1 –F 2

Columbella carinata Hilb. — Hilber 1879: 421, pl. 1, figs 3a–c [non Hinds, 1844].

Mitrella carinata nov. form.—Hoernes 1880: 127 [nomen nudum].

Columbella (Mitrella) carinata Hilber — Hoernes & Auinger 1880: 97 (pars), [non pl. 12, figs 9a–c: Mitrella dacica nov. sp.; non pl. 12 figs 10–11: Mitrella elongatissima nov. sp.].

* Atilia (Macrurella) Hilberi nobis — Cossmann 1901: 245.

Columbella (Mitrella) carinata Hilb. — Boettger 1902: 17 [non Hinds, 1844].

Columbella (Mitrella) carinata Hilb. — Boettger 1906: 15 [non Hinds, 1844].

Mitrella carinata Hilber — Meznerics 1933: 341 [non Hinds, 1844].

Columbella carinata Hilb. — Strausz 1946: 27 [non Hinds, 1844].

Pyrene (Mitrella) hilberiana n. sp. — Csepreghy-Meznerics 1950: 49.

Mitrella (Atilia) hilberi Cossmann 1901 —Kojumdgieva in Kojumdgieva & Strachimirov 1960: 184, pl. 45, fig. 8.

Mitrella (Atilia) hilberi ( Cossmann, 1901) — Atanacković 1985; 144, pl. 32, figs 11–12.

non Pyrene (Mitrella) hilberiana Mezn. — Csepreghy-Meznerics 1954: 39, pl. 6, fig. 6, pl. 6., fig. 12 [= Mitrella elongatissima nov. sp.].

non Mitrella (Atilia) hilberi (M. Cossmann, 1901) — Švagrovský 1981: 146, pl. 45, fig. 7 [= Mitrella dacica nov. sp.].

non Columbella (Atilia) hilberi Cossmann — Strausz 1966: 293, pl. 12, fig. 12 [= Mitrella dacica nov. sp.].

non Mitrella hilberi ( Cossmann, 1901) — Harzhauser et al. 2011: 215, fig. 4.2.

Type material. Lectotype (designated herein): NHMW 1861/0001/0243, SL: 9.2 mm, MD: 2.7 mm, Pöls ( Austria), illustrated in Hilber (1879, pl. 1, figs 3a–c), Figs 4A, 8D 1 –D 2 [note that Hilber (1879) and Hoernes & Auinger (1880) listed St. Florian ( Austria) as locality, but the original label, written by V. Hilber, states the close by Pöls as locality].

Illustrated material. NHMW 2020/0163/0001, SL: 10.2 mm, MD: 3.6 mm, Coşteiu de Sus ( Romania), Figs 8E 1 –E 2 . NHMW 2020/0163/0002, SL: 9.7 mm, MD: 3.5 mm, Coşteiu de Sus ( Romania), Figs 8F 1 –F 2 .

Additional material. NHMW 2020 /0172/0002 (ex B. Landau coll.), 9 spec., Lăpugiu de Sus ( Romania) .

Description. Shell moderately small, slender fusiform, with shallow suture. Protoconch large, multispiral, of three strongly convex whorls terminating in moderately deep sinusigera. Teleoconch of seven whorls. First teleoconch whorl distinctly narrower than protoconch; spire whorls almost flat-sided, forming regularly conical spire profile. Last whorl weakly convex with marked basal angulation; peripheral keel; rapidly contracting, concave base. Shell surface smooth except for low, broad spiral cords on siphonal fasciole separated by broad interspaces. Aperture moderately wide. Outer lip broken off in all specimens. Anal canal indistinct. Siphonal canal moderately long, deflected, notched at tip. Columella slightly twisted. Columellar callus not thickened, forming very narrow, indistinct rim; no columellar denticles. Parietal callus not developed.

Shell measurements and ratios. SL: 9.2–10.5 mm, MD: 2.7–3.6 mm, AA: 23°, SL/MD: 3.1, AL/AW: 3-0–3.3, LWH/AH: 1.4.

Discussion. Mitrella hilberi is distinguished from all other Paratethyan Columbellidae by its high, regularly conical spire and marked basal angulation. Unfortunately, the understanding of this species was strongly distorted by Hoernes & Auinger (1880), who illustrated three specimens as Columbella (Mitrella) carinata Hilber [= Mitrella hilberi ( Cossmann, 1901) ] from Coşteiu de Sus ( Romania), which are not all conspecific with the lectotype. Their figures 10 and 11 are placed herein in Mitrella elongatissima nov. sp., whereas their figure 9 is separated as Mitrella dacica nov. sp. Some specimens of the Pliocene Mitrella subulata ( Brocchi, 1814) tend to develop a weak basal angulation, which, however, is rounded, and the last whorl of Mitrella subulata is much higher (see Chirli 2002, pl. 6, figs 5–6).

Palaeoenvironment. The occurrence at Pöls suggests inner neritic, lagoonal environments (own data).

Distribution in Central Paratethys. Badenian (middle Miocene): Styrian Basin: Pöls, Wetzelsdorf ( Austria) ( Strausz 1946; own data); southern Pannonian Basin: Hrvaćani-Drenik, Čaklovica ( Bosnia and Hercegovina) ( Atanacković 1985); Făget Basin: Coşteiu de Sus, Lăpugiu de Sus ( Romania) (own data); Dacian Basin: Dobrusha ( Bulgaria) (Kojumdgieva in Kojumdgieva & Strachimirov 1960).

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.