Orthosurcula? ketzchovelii ( Kharatishvili, 1952 ), 1904

Harzhauser, Mathias, Landau, Bernard & Janssen, Ronald, 2022, The Clavatulidae (Gastropoda, Conoidea) of the Miocene Paratethys Sea with considerations on fossil and extant Clavatulidae genera, Zootaxa 5123 (1), pp. 1-172 : 148

Orthosurcula? ketzchovelii ( Kharatishvili, 1952)

* Pleurotoma ketzchovelii sp. nov. — Kharatishvili 1952: 242, pl. 32, figs 1–4, 6, 7, 13.

? Turricula regularis ( Koninck, 1837) — Amitrov 1973: 119 (partim, Miocene records only) [non Orthosurcula regularis (de Koninck, 1837) ].

Type material. Holotype: Nr. 930/10668, Georgian National Museum , Tiblisi ( Georgia), SL. 27 mm, MD: 11 mm, illustrated in Kharatishvili (1952, pl. 32, fig. 1); Tqwartscheli in Georgia; early Miocene, Sakaraulian.

Description. The material of Kharatishvili (1952) cannot be found and we refer only to his illustrations and description: Shell medium sized, moderately broad biconic; apical angle ~45°. Protoconch not preserved. Teleoconch of eight whorls. No information on sculpture of early teleoconch whorls available. Early teleoconch whorls with weak, broad subsutural cord and rounded suprasutural cord. Last whorl with weak concavity below broad flattened subsutural collar and rounded shoulder. Strongly convex base slowly contracting into long, narrow siphonal canal (incomplete in all specimens). Insertion of outer lip placed distinctly below shoulder. Siphonal fasciole indistinct. Aperture narrowly pyriform; columella straight. Shell surface smooth except for weak spiral cords on base and siphonal canal. Anal sinus deep.

Discussion. Orthosurcula Casey, 1904 is a Paleogene genus, which was represented by few species in the Oligocene of the North Sea Basin (R. Janssen 1979; Schnetler & Beyer 1990), the northeastern Atlantic ( Lozouet 2017) and the Central and Eastern Paratethys ( Seneš 1958; Báldi 1973; Amitrov 1973; Kovács & Vicián 2016). After the Egerian, the genus disappeared from the Central Paratethys and is unknown from Eggenburgian strata. Thus, Orthosurcula ? ketzchovelii would be the youngest record of this genus. It is indeed reminiscent of Oligocene Orthosurcula species, such as Orthosurcula ex. gr. regularis sensu Kovács & Vicián (2016) from the Egerian of Hungary and Orthosurcula striatula degrangei ( Peyrot, 1931) from the Chattian of France ( Lozouet 2017), but differs in their much shorter spire. Amitrov (1973) mentioned specimens of Orthosurcula regularis (de Koninck, 1837) from the Sakaraulian (Burdigalian) of Abkhazia. The specimens have not been illustrated and we were not able to trace them. Amitrov (1973: 120) himself emphasized the poor preservation and listed Pleurotoma ketzchovelii Kharatishvili, 1952 with question mark under his T. regularis . New material from Eastern Paratethyan assemblages will be needed to decide if the Neogene Eastern Paratethys formed a refuge for the Paleogene Orthosurcula .

Paleoenvironment. Shallow marine based on co-occurring fauna described by Kharatishvili (1952).

Distribution in eastern Paratethys. early Miocene:Sakaraulian (Aquitanian/early Burdigalian):Transcaucasia: Tqwartscheli ( Georgia) ( Kharatishvili 1952).