Monoplex subcorrugatus (d’Orbigny, 1852)

Kovács, Zoltán & Vicián, Zoltán, 2017, Middle Miocene Tonnoidea and Ficoidea (Caenogastropoda) assemblages from Letkés (Hungary), Fragmenta Palaeontologica Hungarica 34, pp. 75-104 : 87-88

Monoplex subcorrugatus (d’Orbigny, 1852)

( Figs 31–32 )

1852 Triton subcorrugatum – D’ORBIGNY, p. 77.

1969 a Cymatium (Ranularia) multicostatum Cossmann et Peyrot – CSEPREGHY-MEZNERICS, p. 80, pl. 3, figs 9–12.

2001 Cymatium subcorrugatum (d’Orbigny) – LOZOUET et al., p. 46, pl. 19, fig. 1 (cum syn.).

2009 Monoplex subcorrugatus (d’Orbigny) – LANDAU et al., p. 71 (pars).

Material – Three specimens (SL 20–26); HNHM: INV 2017.676 . (2) , one specimen in private collection.

Description – Broad shell, elevated spire, four subangulate teleoconch whorls, slightly concave, sloping sutural ramp, convex last whorl. Ovate aperture, denticulate outer lip thickened by labral varix, weakly plicate columella. Spiral sculpture of fine cords on the ramp, two well-developed primary cords on the spire whorls and 6 on the last whorl (adapical five divided by median grooves), one secondary cord in interspaces, axial sculpture of broad, rounded ribs (7–9 on the last whorl) and growth lines.

Remarks – M. subcorrugatus differs in morphology from M. corrugatus in smaller size, broader shell and lack of varices on the early teleoconch whorls, it is probably the ancestor of the latter. It also differs from M. heptagonus in broader shell, conical spire and less developed, broader primary cords.

Distribution – Aquitanian-Langhian: NEA ( France), late Burdigalian-Langhian: NSB ( the Netherlands), Badenian: CP ( Hungary).

Figures

Figs 31–32. Monoplex subcorrugatus (d’Orbigny), Coll. TN, SL 26, MD 18 (2×), apertural and abapertural views. – Figs 33–34. Monoplex heptagonus (Brocchi), HNHM INV 2017.677., SL 25, MD 17 (2×), apertural and abapertural views. – Figs 35–36. Monoplex sp., Coll. TH, SL 30.5, MD 18 (2×), apertural and abapertural views. – Figs 37–38. Turritriton grundensis (Hoernes et Auin- ger), HNHM INV 2017.679., SL 22, MD 12 (2×), abapertural and apertural views