Crucibiscutum gracile Aguado in Aguado, Company, O'Dogherty, Sandoval & Martinez

Plant Fossil Names Registry Number: PFN001008

Act LSID: urn:lsid:plantfossilnames.org:act:1008

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: 16

Illustrations or figures: fig. 14 O-AB

Types

Original diagnosis/description

Diagnosis: Small (3.4–4.7 μm) sub-circular to broadly elliptical (axial ratio ~1.1) Crucibiscutum coccoliths with a wide central-area spanned by slim axial cross bars. Under cross-polarized litht microscopy (XPL), the rim is narrow, bicyclic, with the bright inner cycle being usually slightly narrower (~0.5 μm width) than the outer dark cycle.

Description: The central-area is wide (around twice as wide as the rim width) and partially covered by a slim bright cross with arms aligned with respect to the axes of the ellipse defined by the rim. The central cross is slightly brighter under XPL when oriented at 45º than when oriented to 0°.

Dimensions: length = 3.4–4.7 (average 4.1) μm; width = 3.2–4.4 (average 3.8) μm; specimens measured: 20.

Holotype dimensions: lenght = 4.4 μm, width = 4.2 μm.

Etymology

From the Latin word ‘gracilis’ meaning ‘slim’, ‘slender’, ‘delicate’, referring to the narrow rim and slim axial cross of this species.

Stratigraphy

Cretaceous, Lower Cretaceous, Barremian
Type level: Uppermost Barremian, sample X.HA-2 [DGF001] (NC5E nannofossil Zone; upper part of the Imerites giraudi ammonite Zone).

Occurrence: Found throughout the upper Barremian to lower Aptian (upper part of the NC5E Zone to NC6A Zone of calcareous nannofossils; upper part of the Gassendiceras alpinum ammonite Subzone to Hedbergella excelsa Zone of planktonic foraminifera) in sections X.Cp2, X.F, XF1, X.HA, X.Kv, X.Kv2, and Rambla Seca from the Subbetic domain in the Betic Cordillera (southern Spain). This species was also recorded, as Cruciplacolithus hayi, in DSDP Site 603 off Cape Hatteras by Covington and Wise (1987) and as Corollithion cf. C. achylosum across the upper Barremian-lowermost Aptian of the ODP Site 641 by Bralower et al (1994).

Locality

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