Rhagodiscus sicutclipeus Aguado in Aguado, Company, O'Dogherty, Sandoval & Martinez

Plant Fossil Names Registry Number: PFN001009

Act LSID: urn:lsid:plantfossilnames.org:act:1009

Author: R. Aguado Merlo

Rank: species

Reference: Aguado, R., Company, M., O'Dogherty, L., Sandoval, J. & Martinez, M. (2022): New insights into the Barremian–lower Aptian calcareous nannofossils of the Mediterranean Tethys: Chronostratigraphic and paleobiogeographic implications. – Marine Micropaleontology 173: 102114 (24 pp.).

Page of description: 18

Illustrations or figures: 14 AQ-BD

Types

Original diagnosis/description

Diagnosis: Medium-sized (4.6–5.9 μm) normally elliptical Rhagodiscus coccoliths with a relatively wide central area bearing a small spine base, which is bright in cross-polarized light micrscpy (XPL). The rim and central area images are distinctly dark in XPL.

Description: This species has an elliptic rim (axial ratio ~1.4) and central area that remain relatively dark under XPL. The central area bears a small spine base, which is seen as a bright circle traversed by four sharp extinction gyres. The spine base is relatively small (~1.3 μm in diameter), remains isolated in the middle of the central area and usually do not reaches the internal margin of the rim.

Dimensions: length = 4.6–5.9 (average 5.1) μm; width = 3.3–4.6 (average 3.7) μm; specimens measured: 20.

Holotype dimensions: length = 5.3 μm, width = 3.7 μm.

Etymology

From the Latin words ‘sicut’ meaning as, such as, and ‘clipeus’, the elliptical war shield used by the ancient Greeks and Romans which resembles the XPL image of this species.

Stratigraphy

Cretaceous, Lower Cretaceous, Barremian
Upper Barremian, sample X.HA-4 (NC6A nannofossil Zone; Martelites sarasini ammonite Zone).

Occurrence: Found, as a rare species, from the upper Barremian (upper part of the NC5E Zone of calcareous nannofossils, Gerhardtia sartousiana Subzone of ammonites) to uppermost lower Aptian (lower part of the NC7A Zone of calcareous nannofossils, Deshayesites deshayesi ammonite Zone). Recorded in sections X.Ag6, X.Cp2, X.F, X.F1, X.HA, X.Kv, X.Kv2, and Rambla Seca from the Subbetic domain in the Betic Cordillera (southern Spain).

Locality

Spain
X.HA section (37.852 N; 2.589 W), Province of Granada, southeastern Spain.