Monteiroconus supracompressus (Sacco, 1893)

Figs 17 V, 26F1–F3, 26G1–G3, 26H

Conus Mercati Brocc. —Hörnes 1851: 23 (partim), pl. 2, figs 2a–c [non Monteiroconus mercati (Brocchi, 1814)]. [ Conus (Lithoconus)] supracompressa Sacc.— Sacco 1893a: 20 [nov. nom. pro Conus mercati in Hörnes 1851, pl. 2, fig. 2]. Conus (Lithoconus) moravicus R. Hoernes et M. Auinger – Švagrovský 1982: 404, pl. 5, fig. 4 [non Kalloconus moravicus

(Hoernes & Auinger, 1879)].

Type material. Holotype NHMW 1851 /0010/0003, Mikulov-Kienberk (Czech Republic), illustrated in Hörnes (1851, pl. 2, fig.2); middle Miocene, Badenian (late Langhian).

Studied material. Holotype and 1 spec. NHMW 1851 /0010/0004, Mikulov-Kienberk (Czech Republic); 3 spec . NHMW 1847/0037/0025, 2 spec. NHMW 1850/0009/0018, 2 spec. NHMW 1851/0026/0074, 2 spec. NHMW 1878 /0041/0001, Pötzleinsdorf (Austria).

Illustrated material. Figs 26 F1–F3: holotype, Mikulov (Czech Republic): SL: 62.9 mm, 43.2 mm, NHMW 1851/0010/0004, illustrated in Hörnes (1851, pl. 2, fig. 2); Figs 26 G1–G3: Mikulov (Czech Republic): SL: 62.8 mm, 38.7 mm, NHMW 2016/0034/0001; Fig. 26 H, 17V: Mikulov (Czech Republic), SL: 53.9 mm, MD: 33.0 mm, NHMW 2016/0034/0001.

Revised description. Moderately large shells; spire strongly depressed to flat with slightly protruding early spire. Adapical part of spire whorls flat to weakly concave, abapical part convex, often bulgy; faintly striate. Irregular, deeply incised suture. Subsutural flexure deep, moderately curved, strongly asymmetrical. Last whorl moderately broad, straight-sided to weakly ventricose, not constricted at base. Position of maximum diameter slightly below rounded shoulder. Aperture moderately wide, broadening abapically; adapically slightly expanding, extending to or slightly above apex. Siphonal canal very short, straight, wide; siphonal fasciole broad but weak, rounded. Spiral grooves on base. Colour pattern under UV light consisting of narrow flammulae on shoulder and broad, somewhat blotchy dark bands separated by three narrow fluorescing stripes.

Shell measurements and ratios. n = 13 adult and subadult specimens: largest specimen: SL: 82.8 mm, MD: 49.5 mm, mean SL: 64.0 mm (σ = 8.4), mean MD: 40.9 mm (σ = 4.9), spire angle: µ = 153° (σ = 9.7°), last whorl angle: µ = 37.7° (σ = 1.7°), LW: µ = 1.57 (σ = 0.07), RD: µ = 0.65 (σ = 0.03), PMD: µ = 0.93 (σ = 0.03), RSH: µ = 0.02 (σ = 0.02).

Discussion. This species is most reminiscent of Monteiroconus daciae (Hoernes & Auinger, 1879) but is distinctly more slender (RD 0.65 vs. 0.73). The differences in shape allow also a clear separation of both species in a Principal Component Analysis based on shell ratios (Fig. 27). Moreover, the broad bands on the last whorl differ from the dashes and blotches of M. daciae as documented by Landau et al. (2013). This species is known so far only from the mid-Badenian locality Mikulov-Kienberk and the late Badenian locality Pötzleinsdorf, both in the Vienna Basin. It might represent a northern offshoot of Monteiroconus daciae, which is mainly found in southern basins of the Paratethys.

Paleoenvironment. The localities Pötzleinsdorf and Mikulov-Kienberk represent shallow sublittoral environments within the photic zone based on the co-occurring mollusc assemblages (Sieber 1953; own data, M.H.).

Distribution in Paratethys. Badenian (middle Miocene): Vienna Basin: Pötzleinsdorf (Austria), Mikulov- Kienberk (Czech Republic).