Conus ponderovagus

Conus (Kalloconus) ponderovagus (Sacco, 1893)

Descrizione e caratteristiche:

Conus ventricosus (Bronn, 1831) in Hörnes 1851: 32 (partim), pl. III, fig. 8 [non Lautoconus ventricosus ( Gmelin, 1791): questa forma è quella indicata da sacco come var. ponderovaga ⁽¹⁾.

Conus (Chelyconus) conoponderosus var. ponderovaga Sacc. — Sacco 1893b: 76 [nov. nom. pro Conus ventricosus in Hörnes 1851 , pl. 3, fig. 8].

Conus (Cleobula) steindachneri Hörnes & Auinger, 1879 — Harzhauser 2002: 114, pl. 10, figs 1–3 [non Lautoconus steindachneri (Hoernes, 1879) ].

Revised description ⁽²⁾.

Medium-sized, robust shells; moderately high, broad conical to weakly cyrtoconoid, spire. Convex, bulgy spire whorls with deeply incised, channelled suture; early whorls striate with undulating suture. Last spire whorl less convex; subsutural flexure deep, moderately curved, strongly asymmetrical. Distinct, subangulate shoulder coinciding with position of maximum diameter. Conical last whorl rapidly contracting, rarely with weak concavity below shoulder. Weakly constricted at base; siphonal fasciole weak; siphonal canal moderately long, slightly reflected. Aperture narrow with subparallel margins. Very weak spiral cords on base; irregularly spaced growth lines on last whorl may form prominent grooves. Colour pattern consisting of broad flammulae on spiral whorls, parallel to subsutural flexure; two broad dark bands below shoulder and on the posterior third with spirally arranged, somewhat irregularly spaced light dots on entire last whorl. Major growth lines coincide with thin, light axial threads in UV light.

Shell ratios and measurement. n = 7 adult specimens: largest specimen: SL: 53.9 mm, MD: 35.5 mm, mean SL: 48.6 mm (σ = 3.6), mean MD: 31.4 mm (σ = 3.2), spire angle: µ = 106.1° (σ = 8.6°), last whorl angle: µ = 38.2° (σ = 1.4°), LW: µ = 1.55 (σ = 0.09), RD: µ = 0.76 (σ = 0.05), PMD: µ = 0.89 (σ = 0.02), RSH: µ = 0.14 (σ = 0.03).

Discussion ⁽²⁾.

This species was mixed with Conus steindachneri (Hoernes, 1879) by Hoernes & Auinger (1879) and subsequent authors (e.g. Harzhauser 2002).

It differs in the narrower last spire whorl, the higher, broad conical to cyrtoconoid spire, the broader last whorl, the weaker siphonal fasciole and the shorter siphonal canal. A further difference is the colour pattern of broad flammulae on the spire whorls, which are absent in Lautoconus steindachneri.

Kalloconus ponderovagus is also reminiscent of Kalloconus tschermaki (Hoernes & Auinger, 1879) but differs in its smaller size and the colour pattern, which consist of wide-spaced spirals in K. tschermaki .

Sacco (1893b) introduced this name for the specimen illustrated by Hörnes (1851, pl. 3, fig. 8), which he recognised as “totally different from Conus steindachneri ”, thus rejecting the synonymization by Hoernes & Auinger (1879). Although we agree with Sacco (193b), his act was correct just by chance, as the specimen of Hörnes (1851) is a subadult specimen, lacking the characteristic broad shoulder. Therefore, we provide illustrations of adult specimens from the type locality.

Conus parvicaudatus Sacco, 1893 , from the early Miocene of the Turin Hills, differs in the pronounced constriction of the last whorl and the higher position of the adapical part of the aperture, which reaches above the shoulder.

Paleoenvironment ⁽²⁾.

The species occurs in sandy shallow water deposits.

Distribution in Paratethys. Karpatian (early Miocene): Alpine-Carpathian Foredeep: Niederkreuzstetten ( Austria); Korneuburg Basin: Karnabrunn (Austria).

Conus ponderovagus ⁽²⁾

Holotype NHMW 1849/0004/0016

mm. 34,5 x 21,3

Niederkreuzstetten ( Austria)

illustrated in Hörnes (1851, pl. 3, fig. 8)

Conus ponderovagus ⁽²⁾

Holotype NHMW A991

mm. 53,9 x 34,0

Niederkreuzstetten ( Austria)

Bibliografia Consultata