Conilithes asterousiaensis (Psarras & Koskeridou & Merle,2021)

Description:

Medium-sized, stout shell. Spire straight to coeloconoid, highly conical to flat. Protoconch multispiral. Early spire whorls elevated, coeloconoid, smooth, with straight to convex outline. Later spire whorls straight to concave, with smooth, conical outline. Last spire whorl convex, slightly striate. Shoulder rounded to angulated. Maximum diameter just below shoulder. Subsutural flexure shallow, moderately to weakly curved, strongly asymmetrical. Last whorl conical, straight. Aperture narrow, straight, widening near siphonal canal.Siphonal canal wide, short. Fasciole short, twisted. There are two extremes of a form.

The first extreme form (form 1, Fig. 24A) consists of conical spire whorls of medium height and rounded shoulder. The second extreme form (form 2, Fig. 24B) consists of relatively flat spire whorls and angulated shoulder. Intermediate forms also exist ⁽¹⁾.

DESCRIPTION OF COLOUR PATTERN

Colour pattern on spire whorls consists of two rows of regularly arranged, quadrangular to rectangular dots, near carina and near suture, respectively. Flammulae are visible on some specimens ( Fig. 24 B4 ). The colour pattern on last whorl consists of three layers. The first layer consists of two fluorescent bands, one on the middle of the last whorl and another near the anterior part of the shell. The second layer consists of multiple, continuous spiral lines, equally distant on individual shells. The lines are not always constant in width. Usually, the thin lines are surrounded by wider lines. The colour of the lines is dim-fluorescent or non-fluorescent. Inside those, there are bright, quadrangular, sharply edged, fluorescent dots alternated with nonfluorescent areas. The dots are usually as wide as the corresponding line, but sometimes the dots are engulfed by the dim-fluorescent material of the line. The lines overlap the pattern of the bands. One specimen shows a third layer of pattern that consists of axially arranged, fluorescent blotches, placed on top of the bands and lines, with dots preserved on top of all other patterns ⁽¹⁾.

REMARKS

The Greek specimens present two extreme forms, that are connected with intermediate shell forms, therefore we regard them as one species. Morphological characters like the subsutural flexure, the smooth spire whorls and the conical straight last whorl characterize this species. Despite the morphological variability, the colour pattern remains constant to all shells. Accordingly, we consider that this species displays a wide variability in spire height and angulation of shoulder, but bears a stable colour pattern variation. The Greek specimens are attributed to the subgenus Kalloconus , because of the lack of the spiral sculpture, a concave conical spire outline, a wide last whorl and broad shoulder.

The name is from Asterousia Mountains.

A syntype of Conus raristriatus Bellardi & Michelotti, 1841 , from the Tortonian of Sant’Agata Fossili (BS.038.05.133), was illustrated by Bellardi & Michelotti (1841: pl. 5, figs 8-9) and later figured by Ferrero Mortara et al. (1984). The illustration shows a colour pattern of evenly distanced spiral lines, but no spiral rows of dots as on Conus (Kalloconus) asterousiaensis n. sp. As such, the syntype suggests that Conus raristriatus and Conus (Kalloconus) asterousiaensis n. sp. belong to two different species. However, a Tortonian specimen figured by Davoli (1972: pl. 8, fig. 1a, b, specimen no. 5545 housed in the Museo Paleontologico dell ‘Universita di Modena’) and named Conus raristriatus displays a shell shape very similar to the morphotypes of Conus (Kalloconus) asterousiaensis n. sp. In addition, under natural light the Italian specimen figured by Davoli seems to be displaying similarities of colour pattern (discontinuous spiral lines) with the Greek specimens. For this reason, we consider it conspecific with the Greek material.

Conus (Kalloconus) asterousiaensis n. sp. could also be compared to Conus (Lautoconus) subraristriatus Pereira da Costa, 1866 . They differ morphologically, mainly in the cyrtoconoid, more elongate and higher spire. In terms of colour pattern variations, both species possess the spirally arranged rows of dots and dashes, with fluorescent bands. The difference is that Conus (Lautoconus) subraristriatus does not exhibit any pigmentation between the fluorescent bands ( Landau et al. 2013; Harzhauser & Landau 2016), whereas Conus (Kalloconus) asterousiaensis n. sp. possesses colour patterns along the whole length of the last whorl.

The colour pattern of Conus (Kalloconus) asterousiaensis n. sp. is similar to that of the extant species Conus genuanus Linnaeus, 1758 . This West African species could be related to C. (K.) asterousiaensis n. sp. and suggests a Proto-Mediterranean origin of some West African conids⁽¹⁾.

FIG. 24. — Conus (Kalloconus) asterousiaensis n. sp. from the Tortonian of Crete (Greece)

A, on apertural, abapertural and apical views, under natural and UV light: paratype AMPG(IV) 2689, Tefeli: the largest specimen with faint colour pattern of dots and dashes;

B, holotype AMPG(IV) 2683, Filippi: specimen in abapertural and apical view;

C, MNHN.F.A72642, Crete;

D, Paratype MNHN.F.A72644, Crete;

E, MNHN.F.A72647, Crete.

Scale bar: 1 cm.