Sulcomitrella januskiewiczi ( Friedberg, 1938 ) Harzhauser & Landau, 2021

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 : 19-20

Sulcomitrella januskiewiczi ( Friedberg, 1938) nov. comb.

Figs 7B 1 –B 2

* Columbella Januskiewiczi Friedb. — Friedberg 1938: 129, text-fig. 40.

Type material. Lectotype (designated herein): ZNG PAN 2528, Zborów ( Ukraine), stored in the Geological Museum of the Institute of Geological Sciences , Polish Academy of Sciences (Kraków), illustrated in Friedberg (1938, text-fig. 40), Figs 7B 1 –B 2 .

Description. Small shell with high, weakly cyrtoconoid spire and narrowly incised suture, Protoconch unknown. Teleoconch of six whorls. Spire whorls rapidly increasing in height, weakly convex, with periphery slightly below mid-whorl on penultimate whorl. Last whorl high, weakly convex, slowly contracting. Columellar callus forming narrow rim terminating at siphonal canal, with indistinct denticles. Outer lip weakly thickened with prominent denticles within. Anal canal narrowly incised, V-shaped. Siphonal canal very short, wide, shallow. Sculpture consisting of weak spiral grooves, being most prominent below adapical suture and on base and fasciole.

Shell measurements and ratios. SL: 7.0 mm, MD: 4.5 mm, AA: 48°, SL/MD: 2.5, AL/AW: 3.2, LWH/AH: 1.4.

Discussion. Two specimens are labelled as type specimens of Columbella januskiewiczi in the collection of the Geological Museum of the Institute of Geological Sciences, Polish Academy of Sciences (Kraków). These differ from the illustration in Friedberg (1938, text-fig. 40) in their much narrower aperture, less convex whorls and slightly smaller size but agree in the spiral sculpture. The pupoid text figure in Friedberg (1938) is reminiscent of Aesopus Gould, 1860 (type species Aesopus japonicus Gould, 1860 ; present-day, Japan) as defined by deMaintenon (2019: 161). The most characteristic feature of Aesopus is the descending suture of the last whorl, which was already emphasized by Gould (1860: 383). This feature is also developed in the Paratethyan species to some degree. The narrow aperture and the weakly incised siphonal canal, however, are atypical for Aesopus .

We tentatively place Columbella januszkiewiczi in Sulcomitrella mainly because of the prominent spiral sculpture but note that the narrow aperture and high last whorl are atypical for Sulcomitrella . Consequently, the otherwise comparable extant Sulcomitrella leylae Monsecour & Monsecour, 2018 and Sulcomitrella monodonta ( Habe, 1958) differ in their higher spires and wider apertures.

Sulcomitrella sceauxensis Landau, Ceulemans & Van Dingenen, 2019 from the Tortonian of France, differs in its much broader outline and prominent spiral cords on base and fasciole.

Palaeoenvironment. Unknown.

Distribution in Central Paratethys. Badenian (middle Miocene): Carpathian Foredeep: Zborów ( Ukraine) ( Friedberg 1938).

Genus Mitrella Risso, 1826

Type species. Mitrella flaminea Risso, 1826 [= Mitrella scripta ( Linnaeus, 1758) ]; subsequent designation by Moerch 1859: 258, Present-day, Mediterranean Sea.

Discussion. Radwin (1978: 337) characterised Mitrella as small to moderately large fusiform, with high, acute spire and flat-sided whorls, moderately broad aperture, denticulate and straight columella, denticulate outer lip, very short to moderately long siphonal canal. The genus Mitrella Risso, 1826 , as used here, is interpreted rather widely and is unlikely to be monophyletic. Preliminary molecular results reject the genus, as presently used, being monophyletic (deMaintenon and Strong, unpublished results; Bouchet personal communication, August 2020).

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.

FIGURE 7. Species described by Friedberg (1911, 1938). A1–A2. “Columbella” paucicostata (Friedberg, 1911), ZNG PAN 1257, holotype, Dryszczów (Ukraine).B1–B2. Sulcomitrella januskiewiczi (Friedberg, 1938), ZNG PAN 2528, lectotype, Zborów (Ukraine). C2–C2. Mitrella convexa Friedberg, 1911, re-illustrated from Friedberg (1911, pl. 2, fig. 2).