Plagioconus

Harzhauser, Mathias & Landau, Bernard, 2016, A revision of the Neogene Conidae and Conorbidae (Gastropoda) of the Paratethys Sea, Zootaxa 4210 (1), pp. 1-178 : 132

Plagioconus breitenbergeri nov. sp.

Figs 30 G, 31G1–G5, 31H1–H2

Holotype: Figs 31 G1–G5: SL: 43.6 mm, MD: 17.6 mm, NHMW 2016/0041/0001.

Paratype: Figs 31 H1–H2: SL: 43.9 mm, MD: 16.1 mm, NHMW 2016/0041/0002.

Paratype: SL: 34.7 mm, MD: 14.3 mm, NHMW 2016/0041/0003.

Additional material: 2 spec. NHMW 2016 /0041/0004, Fig. 30 G: SL: 31.0 mm, MD: 12.3 mm, 1 spec. private collection Anton Breitenberger ; all specimens from Letkés, Hungary.

Type stratum: fossil-rich marly sand with coral blocks and andesite boulders of the Sámsonháza Formation ( Császár 1997).

Type locality: Letkés at the western part of the Börzsöny Mts. ( Hungary); see Kovács & Vicián (2013) for a map and description.

Age: Middle Miocene, early Badenian (= Langhian).

Etymology: Referring to Anton Breitenberger, who collected and donated the holotype.

Description. Medium-sized, slender elongate shells; spire mammillate, dome-shaped, high. Early spire whorls angulate just above suture, tuberculate. Tubercles become obsolete within 3rd–4th teleoconch whorl; angulation migrates to suture during ontogeny. Spire whorls weakly convex, faintly striate; suture narrowly impressed. Subsutural flexure very deep, moderately curved, strongly asymmetrical. Last whorl angulated; very slender, elongate, not constricted. Aperture narrow and only weakly widening anteriorly; siphonal canal long, straight to faintly recurved. Siphonal fasciole indistinct, narrow. Weak spiral cords on lower third of last whorl. Colour pattern in UV light consisting of broad axial stripes and flammulae on spire and shoulder. A light band below shoulder angulation follows in upper quarter of last whorl. Below appear broad, stretched zig-zag shaped axial streaks crossed mid-whorl by a spiral band; base and siphonal canal dark.

Shell measurements and ratios. n = 4: largest specimen: SL: 43.9 mm, MD: 17.6 mm, mean SL: 38.3 mm (σ = 6.5), mean MD: 15.1 mm (σ = 2.3), spire angle: µ = 84° (σ = 2.7°), last whorl angle: µ = 26° (σ = 1.4°), LW: µ = 2.54 (σ = 0.14), RD: µ = 0.50 (σ = 0.02), PMD: µ = 0.89 (σ = 0.02), RSH: µ = 0.21 (σ = 0.01).

Discussion. This species is not rare at Letkés but was probably mistaken as subadult Plagioconus marii (Sacco, 1893) by Kovács & Vicián (2013). It differs from Plagioconus marii in its dome-shaped spire, the lower height of the spire whorls, the less impressed suture and the smaller size. Conus s.l. mucronatolaevis Sacco (1893) and especially its globospira -morphotype develop a comparable spire but are broader and the last whorl is less elongate. The much deeper subsutural flexure allows a clear separation from Plagioconus puschi ( Michelotti, 1847) .

Paleoenvironment. The locality Letkés comprises a mixed assemblage of partly reworked taxa ( Kovács & Vicián 2013); the frequent occurrence of corals suggests a shallow marine depositional environment.

Distribution in Paratethys. Badenian (middle Miocene): Pannonian Basin: Letkés ( Hungary).

Figures

FIGURE 31 A 1 – A 3. Plagioconus austriaconoe (Sacco, 1893), Baden-Sooß (Austria), NHMW 2013 / 0300 / 0526. 31 B 1 – B 3. Plagioconus austriaconoe (Sacco, 1893), Lăpugiu de Sus (Romania), NHMW 1868 / 0001 / 0382. 31 C 1 – C 3. Plagioconus bellissimus nov. sp., Lăpugiu de Sus (Romania), NHMW 1874 / 0025 / 0002 a, holotype. 31 D 1 – D 2. Plagioconus bellissimus nov. sp., Lăpugiu de Sus (Romania), NHMW 1874 / 0025 / 0002 b, paratype. 31 E 1 – E 2. Plagioconus bellissimus nov. sp., Lăpugiu de Sus (Romania), NHMW 1890 / 0001 / 0012 a, paratype. 31 F 1 – F 3. Plagioconus bellissimus nov. sp., Letkés (Hungary), private collection Anton Breitenberger. 31 G 1 – G 5. Plagioconus breitenbergeri nov. sp., Letkés (Hungary), NHMW 2016 / 0041 / 0001, holotype. 31 H 1 – H 2. Plagioconus breitenbergeri nov. sp., Letkés (Hungary), NHMW 2016 / 0041 / 0002, paratype.