Mitrella pseudofallax ( Kókay, 1966 ) 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 : 30-31

Mitrella pseudofallax ( Kókay, 1966) nov. comb.

Figs 10A 1 –A 2

Pyrene (Anachis) pseudofallax nov. sp. — Kókay 1966: 58, pl. 8, fig. 8.

Type material. Holotype: Museum of the Mining and Geological Survey of Hungary (Budapest), M.2539 (= M. 282, old inventory number), Márkó ( Hungary), Figs 10A 1 –A 2 .

Description. Shell small, moderately broad fusiform, with high conical spire and weakly incised suture. Protoconch low conical, paucispiral of about two whorls. Spire whorls almost flat-sided, smooth. Last whorl high, flat sided in adapical third, moderately convex below, slowly contracting at base, bearing sculpture of broad, convex, orthocline axial swellings restricted to first half of last whorl, weak spiral cords on siphonal fasciole. Aperture moderately narrow. Outer lip incomplete, but pinched inwards at level of D1, with inner labial callus pad, bearing about ten prominent denticles within; D1 strongest. Anal canal narrowly U-shaped. Siphonal canal short, wide. Columellar callus moderately thickened forming narrow callus rim, with five weak columellar denticles. Parietal callus weakly thickened. Colour pattern of small close set white dots covering entire shell.

Shell measurements and ratios. SL: 6.0 mm, MD: 2.4 mm, AA: 37°, SL/MD: 2.7, AL/AW: 3.7, LWH/AH: 1.4.

Discussion. We are not aware of any similar species in the European Neogene. The narrow aperture and the Ushaped anal canal, which is narrowed by a prominent D1 denticle, exclude a placement in Costoanachis as understood herein. Kókay (1966) discussed a similarity with Mitrella fallax Hoernes & Auinger, 1880 . Both species, however, have little in common and Mitrella fallax differs obviously in its higher spire, convex and strongly constricted last whorl and presence of a varix-like swelling close to the aperture.

Mitrella pseudofallax ( Kókay, 1966) is superficially reminiscent of Pardalinops deMaintenon, 2008 (type species Colombella pardalina Lamarck, 1822 [= Pardalinops testudinaria ( Link, 1807) ]). The Miocene species agrees with extant Pardalinops species , such as Pardalinops testudinaria ( Link, 1807) and Pardalinops jousseaumei ( Drivas & Jay, 1997) , in the absence of axial sculpture, the close set denticles, which cover the entire outer lip, the central swelling of the outer lip, the U-shaped anal canal and the colour pattern of white dots. Nevertheless, the Miocene species differs from extant Pardalinops species in its higher spire, more slender outline and its relatively small size of only 6 mm height, whereas extant Pardalinops species range between 9 and 17 mm ( deMaintenon 2008). Mitrella pseudofallax is documented from coastal mudflats ( Kókay 1966).

The Miocene species is reminiscent of the IWP genus Zafra A. Adams, 1860 (type species Zafra mitriformis A. Adams, 1860 ). DeMaintenon (2018: 361) stressed a narrow (but not slit-like) aperture and a thickened outer lip with marked central swelling, resulting in narrowly U-shaped anal canal as typical for Zafra . Zafra brunneastriata K. Monsecour & D. Monsecour, 2018 , from French Polynesia, is a morphologically very similar extant species concerning the elongate outline and the peculiar axial sculpture of the last whorl. Nevertheless, a placement in Zafra is excluded based on the absence of axial sculpture on early teleoconch whorls.

Palaeoenvironment. Coastal mudflats; Kókay (1966) described this species from a potamidid-dominated assemblage.

Distribution in Central Paratethys. Badenian (middle Miocene): Pannonian Basin: Márkó ( Hungary) ( Kókay 1966).

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 10 A1–A2. Mitrella pseudofallax (Kókay, 1966), M.2539, holotype, Márkó (Hungary).