A blind trilobite with Baltic affinities from Cambrian Series 3 of the Iberian Chains, Spain, and its stratigraphical and palaeobiogeographical significance

Abstract

Three cranidia of a conocoryphid trilobite are described from the lower Caesaraugustan Regional Stage (upper part of provisional Cambrian Stage 5 within Cambrian Series 3) in the Iberian Chains, Spain. The material is from the upper part of the Mansilla Formation and the base of the overlying Murero Formation. It closely resembles Bailiella tenuicincta (Linnarsson, 1879), which has previously been described from the Ptychagnostus gibbus (Cambrian Stage 5) and lower P. atavus zones (lower Drumian Stage) of Baltica (Sweden and Bornholm), and from the P. atavus Zone of West Avalonia (Newfoundland). The record of B. cf. tenuicincta from the Mediterranean margin of West Gondwana provides additional evidence for considering the Acado-Baltic region a discrete biogeographical province, at least during the Cambrian 5 and Drumian ages.

Keywords::

• Trilobites
• Conocoryphidae
• systematics
• correlation
• palaeobiogeography
• middle Cambrian
• Iberian Chains
• Spain

Acknowledgments

We are grateful to Isabel Pérez Urresti (Universidad de Zaragoza) for technical support. This paper is a contribution to the project Consolider CGL2011-24516 from Ministerio de Educación y Ciencia de España and to the E17 Research Group of the Autonomous Government of Aragón. Comments and corrections by the journal reviewers, Anna Żylińska and an anonymous reviewer, significantly improved our manuscript and are greatly appreciated.

Disclosure statement

No potential conflict of interest was reported by the authors.