Vologesia toucasi ( Lambert, 1911 )

Schlüter, Nils & Wiese, Frank, 2017, Late Cretaceous species of Vologesia (Echinoidea, Cassiduloida) from northern Spain, Zootaxa 4306 (2), pp. 261-270 : 267

publication ID

https://doi.org/10.11646/zootaxa.4306.2.6

publication LSID

lsid:zoobank.org:pub:D45C3578-0245-4CD0-98BE-79DCB35423AD

DOI

https://doi.org/10.5281/zenodo.6029224

persistent identifier

https://treatment.plazi.org/id/03F28781-FF8D-E170-87E5-6987C0ABFEE1

treatment provided by

Plazi

scientific name

Vologesia toucasi ( Lambert, 1911 )
status

 

Vologesia toucasi ( Lambert, 1911)

( Figs. 5 View FIGURE 5 C, E, G, 7)

1911 Clypeolampas toucasi Lambert , p. 155, pl. 3, Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 .

2014 Hungaresia toucasi (Lambert) , Saura & García p. 306, pl. 104, Figs. 1 View FIGURE 1 a–c.

Type. Holotype, by monotypy, is the specimen illustrated by Lambert (1911, pl. 3, Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 ), in the Lambert Collection at the Muséum national d’Histoire naturelle, Paris (MNHN.F.J01723) (not seen). It is from Sougraigne in the Corbières (Aude, France), having been collected from the “couches Hippurites ... avec Actinocamax Grossouvrei. Lambert (1911) considered those strata to be of Campanian age. According to the revised stratigraphy by Christensen et al. (1993), these levels are of late Santonian age ( Placenticeras polyopsis / Texanites gallicus Zone ).

Material. A single near-complete and four fragmentarily preserved specimens (MB.E.11463-11467) from the top of Bed 200, upper Santonian ( Placenticeras polyopsis Zone ), deposited in the Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung (Berlin, Germany).

Diagnosis. Small species with a domed to conical test and a flattened oral surface. The tetrabasal apical disc, with a prominent madreporite, is in a central position. The pentagonal, laterally elongated peristome is positioned close to the anterior margin. The phyllodes are short and slightly sunken, with an inner and an outer series of pore pairs; bourrelets are weakly developed.

Description. Vologesia toucasi is a small species with a maximum test length of c. 35 mm. The oval tests are domed to conical in profile, with its longest axis along the anterior-posterior direction in cross section. The ambitus is positioned close to the oral surface, in the lower quarter of test height. The apical disc is positioned at 47% of test length to the anterior margin. The apical disc is not completely preserved; it was presumably tetrabasal, with the madreporite formed by the large genital plate 2, occupying the centre of the apical disc, while other genital plates are much reduced in size ( Fig. 5 View FIGURE 5 G).

Petaloid ambulacra are present adapically; pore counts are not available due to poor preservation. The straight petals are relatively short, not reaching below the upper third of test height. Conjugate anisopores can be recognised within the petals.

The small peristome is laterally elongated and has a pentagonal outline. It is positioned anteriorly, with a distance to the anterior margin of 29% of test length (at a length of 29.8 mm). A weakly pronounced floscelle structure can be seen; the bourrelets are only weakly swollen, in combination with only slightly sunken phyllodes. The phyllodes are short, with an outer series of 10–11 pores, including small buccal pores, and an inner series of 3–4 pores (see Fig. 4 View FIGURE 4 C). The oval periproct is inframarginal.

The tubercules generally are small, largest on the oral surface and decreasing in size in aboral direction. A narrow, granular band without tubercles extends from the peristome to the periproct.

Discussion. Our record of V. toucasi from the upper Santonian of Langre is in accordance with the stratigraphic position of the type series from the Corbières, southern France and extends the known geographic range of the species to Spain. Vologesia toucasi differs from V. rollingstones sp. nov. by its subconical to conical profile and in phyllode structure that generally reveals a floscelle on account of more pronounced bourrelets. This species has a more inflated and circular shape in comparison to V. rawdahensis and V. tataosi . In addition, the apical disc is more central. Lambert (1919) mentioned Vologesia acuta (Des Moulins, 1837) from the Santander region. This is better referred to Clypeolampas (see Smith, 1995) and differs to Vologesia by a more centrally positioned peristome and better-developed bourrelets.