Genus Gibborissoia Sacco, 1895

TYPE SPECIES. — Bulimus costellatus Grateloup, 1828 (younger subjective synonym of Gibborissoia prevostina (Basterot, 1825)), by original designation. Early Miocene, France.

Gibborissoia varicosa (Basterot, 1825) (Fig. 4 C1-C3)

Rissoa varicosa de Basterot, 1825: 37, pl. 1, fig. 2.

Gibborissoia varicosa – Landau et al. 2013: 49, pl. 4, fig. 9 (cum syn.).

Gibborissoia varicosa – Harzhauser et al. 2018: 155, fig. 10/N.

MATERIAL EXAMINED. — Sample F11: AMPG (IV) 2239-2250 (12 specimens); sample F12: AMPG (IV) 2251-2268 (18 specimens) .

DIMENSIONS. — Maximum height: 1.40 mm.

DISTRIBUTION. — Early Miocene. NE Atlantic: France (Cossmann & Peyrot 1917; Cossmann 1921; Lozouet et al. 2001); Proto-Mediterranean Sea: Italy (Sacco 1895b) (Burdigalian).

Middle Miocene. Proto-Mediterranean Sea: Turkey (Landau et al. 2013); Paratethys: Austria (Hörnes 1856), Bulgaria (Zilch 1934), Hungary (Strausz 1966), Poland (Bałuk 1975).

REMARKS

Gibborissoia varicosa displays a large morphological variability, which has led to the description of several varieties. It can range from smooth to varicated and from moderately to strongly elongate with a large last whorl. In the Greek material, the shells are all smooth and elongated, often with a larger last whorl. They are more similar in shape to Serravallian representatives of the species from Turkey (Landau et al. 2013) than with the specimens from the Aquitanian stratotype as illustrated in Lozouet et al. (2001). The Paratethyan subspecies Alaba costellata anomala (Eichwald, 1850), as illustrated in Bałuk (1975), is based on minor morphological features that do not suffice for such a separation, therefore was placed in synonymy with G. varicosa by Landau et al. (2013).