Conus (Plagioconus) aquensis d'Orbigny 1852
Creators: name: Psarras, Christos
name: Merle, Didier
name: Koskeridou, Efterpi
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Neogastropoda
Conidae
Conus
Conus aquensis

description: Conus (Plagioconus) aquensis d’Orbigny, 1852
Figs 32–36; Table 15
Conus aquensis d’Orbigny, 1852: 11.
Conus antidiluvianus – Grateloup 1847: pl. 44 fig. 6 (non Conilithes antidiluvianus Bruguière, 1792).
Conus (Chelyconus?) aquensis – Peyrot 1930: 103–104.
Conus (Chelyconus) aquensis – Peyrot 1931: pl. 4 figs 4, 7, 16, 19.
Conus (Chelyconus) puschi – Symeonidis & Kostantinidis 1968: pl. 7 fig. 13 (non Conus (Plagioconus) elatus Michelotti, 1847) (non fig. 3).
Conus (Chelyconus) sp. – Caze et al. 2010: fig. 5m 1–m2.
Plagioconus puschi – Landau et al. 2013: pl. 81 fig. 9 (non Conus (Plagioconus) elatus Michelotti, 1847).
Plagioconus bellissimus – Harzhauser & Landau 2016: fig. 31f1–f2 only.
non Conus aquensis – Hall 1966: pl. 22 figs 2, 8, 13, 18–19, 23, 27. – Davoli 2003: pl. 1 figs 15a–b.
Type locality
Saint-Paul-lès-Dax.
Type material
Syntypes FRANCE – Dax • 2 specs; Saint-Paul-lès-Dax; Aquitaine Basin; Aquitanian-Burdigalian; MNHN.F. A13061.
Other material
GREECE – Crete • 8 specs; Achladhia; 1964; Nikolaos Symeonidis leg.; AMPG(IV) 3907 to AMPG(IV) 3914 • 4 specs; Filippi; 35.035° N, 25.250° E; 2017; Christos Psarras leg.; AMPG(IV) 3915.
Shell description
Moderately large (SL max.: 67.4 mm), elongated shell. Early spire whorls beaded, elongated, with angulated shoulder. Beads absent after the 7 th spire whorl, angulated shoulder smoother after the 5 th spire whorl (Fig. 34). Delicate spiral cords on sutural ramp (Fig. 32). In some specimens, up to three spiral grooves can be seen, just under shoulder (Fig. 34). Maximum diameter just below shoulder. Suture incised, subsutural flexure shallow, moderately curved, strongly asymmetrical (Fig. 40). Last whorl straight to slightly inflated. Surface of subadult shells decorated with spiral grooves on all of shell’s length, deeper grooves at anterior half of shell (Fig. 34). Spiral nodules present along last whorl in between spiral grooves (Fig. 32B 1), fading out on adult specimens (Fig. 32A 1). Also, on adult specimens, spiral grooves present only along half to two thirds of anterior part of last whorl. Aperture narrow, straight, widened slightly on fasciole. Siphonal canal medium. Fasciole indistinct, slightly twisted.
Description of colour pattern
The colour pattern consists of flammulae and blotches on the spire whorls, sometimes aligned with the subsutural flexures. Flammulae continue until just below the shoulder. The colour pattern on the last whorl consists of fluorescent, densely spaced dots and dashes, organized axially and spirally. Fluorescent axial blotches also exist, uniting several dashes axially (Fig. 35). These fluorescent blotches are mainly present on the upper, middle and bottom parts of the last whorl, organised as faint spiral bands.
Remarks
The Cretan specimens are very similar to the syntypes of Conus (Plagioconus) aquensis d’Orbigny, 1852 originally described from the early Miocene of Aquitaine Basin, as they share similarly beaded early spire whorls, spiral grooves along the two thirds of the anterior part of the last whorl. The subsutural flexures are shallow and the colour pattern is identical. The species is easily recognised by the prominent beaded early to middle spire whorls (see Fig. 32B 7), the grooved last whorl and the moderately elevated spires (Table 15). The colour pattern of spiral dashes is also easily recognisable under UV light. Conus (Plagioconus) aquensis d’Orbigny, 1852 has been mistakenly named as Conus antidiluvianus by Grateloup (1847) from which it mainly differs in the convex spire whorls and the colour pattern (Janssen et al. 2014). d’Orbigny (1852) noticed the error and named this species Conus aquensis. Peyrot (1930) was the first who gave a detailed description of this species and figured some examples. The type specimen of Conus burdigalensis Mayer, 1858 (from Saucats near Bordeaux, Burdigalian, Mayer-Eymar coll. N 2741, whereabouts are unknown), figured in Hall (1966: pl. 27 fig. 11) is similar in morphology to Conus (Plagioconus) aquensis, but we have not studied the specimen’s colour patterns. Landau et al. (2013: pl. 81 fig. 9) identified one of their fossils as Plagioconus puschi (Michelotti, 1847) (RGM 777 891 (ex JvdV collection), Pınarlar Yaylası, Akpınar, Karaman Basin, Turkey). The colour pattern resembles the pattern described herein. The morphological characteristic of multiple spiral grooves on the anterior part of the shell are evident in their figure, they match those of Conus (Plagioconus) aquensis. For these reasons, we consider the Turkish specimens as Conus (Plagioconus) aquensis. Furthermore, Landau et al. (2013) compared a specimen from the Langhian of Romania attributed by Caze (2010) to Conus (Chelyconus) sp. (Caze 2010: fig. 5m 1–2), which has a similar colour pattern. We studied this specimen (MNHN.F.A31836) and confirmed that the pattern is similar to Conus (Plagioconus) aquensis. The morphology of the spire is very similar to that of the type specimen, with beads on early spire whorls and a shallow subsutural flexure. The pattern is also similar to Conus (Plagioconus) aquensis, but the faint spiral and axial bands, underlying the spiral dashes, cover a larger portion of the shell. This pattern is considered here as a variation; therefore, the specimen (MNHN.F.A31836) is considered here as Conus (Plagioconus) aquensis. Harzhauser & Landau (2016) named a new species Conus (Plagioconus) bellissimus, but they showed the pattern of only one specimen out of four figured therein (fig. 31c–f). The shells figured (Harzhauser & Landau 2016) have a similar morphology to each other, except for a specimen from the Langhian of Letkés in Hungary (private collection Anton Breitenberger), which is provided with its colour pattern, that has a more inflated sutural ramp and a shorter spire than the rest of the specimens shown by the authors (Harzhauser & Landau 2016). This specimen illustrated under UV light bears an outline and a colour pattern similar to that of specimen AMPG(IV) 3909, Achladhia, Crete. Additionally, the colour pattern of this Hungarian specimen is identical to that of the Turkish and Romanian ones illustrated by Landau et al. (2013).
Stratigraphic range
Aquitanian–Burdigalian of France (Aquitaine Basin) (d’Orbigny 1852; Mayer 1858); Burdigalian of Italy (Hall 1966); Langhian of Hungary (Pannonian Basin) (Harzhauser & Landau 2016) and Romania (Caze et al. 2010); Serravallian of Turkey (Karaman Basin) (Landau et al. 2013) and Tortonian of Greece (Sitia Basin and Messara Basin, Crete).
Concluding remarks about Conus (Plagioconus) (Tucker & Tenorio, 2009)
From the PCA graph (Fig. 36), it is evident that Conus (Plagioconus) sp. (Fig. 36, yellow colour) forms a distinct cluster, thus verifying our hypothesis of its existence. Conus (Plagioconus) elatus Michelotti, 1847 (Fig. 36, black colour) and Conus (Plagioconus) aquensis d’Orbigny, 1852 (Fig. 36, red colour) show a slight convergence in their morphology. The result does not consider the presence of beads and spiral grooves on Conus (Plagioconus), but overall, the species are clearly defined.
description: Published as part of Psarras, Christos, Merle, Didier & Koskeridou, Efterpi, 2022, Late Miocene Conidae (Mollusca: Gastropoda) of Crete (Greece). Part 2, pp. 1-70 in European Journal of Taxonomy 816 on pages 52-57, DOI: 10.5852/ejt.2022.816.1747, http://zenodo.org/record/6484261