Research paper
Bailiaspis (Trilobita) with English affinities from the Mansilla Formation (Cambrian Series 3 of the Iberian Chains; NE Spain)
JUAN B. CHIRIVELLA MARTORELL
Departamento de Ciencias de la Educación, Universidad CEU Cardenal Herrera. Avda. Seminario s/n, E-46113 Moncada, Spain. juanchirivella@ieslesfoies.org
ELADIO LIÑÁN
Departamento de Ciencias de la Tierra-IUCA. Universidad de Zaragoza, E-50009 Zaragoza, Spain. linan@unizar.es
Mª EUGENIA DIES ÁLVAREZ
Departamento de Didáctica de las Ciencias Experimentales-IUCA, Universidad de Zaragoza, C/ Valentín Carderera 4, E-22003-Huesca, Spain. medies@unizar.es
RODOLFO GOZALO
Departamento de Botánica y Geología, Universitat de València, C/ Dr. Moliner 50, E-46100- Burjassot, Spain; rodolfo.gozalo@uv.es
Corresponding author
ABSTRACT
A new study of the trilobite record in the Mansilla Formation (Iberian Chains, NE Spain) has led to the discovery of the presence of Bailiaspis aff. tuberculata, B. cf. tuberculata and Bailiaspis sp., the first certain citation of this genus in the Mediterranean subprovince. The age of the findings extends from Eccaparadoxides asturianus Zone (upper Leonian) to the lowermost Badulesia tenera Zone (lower Caesaraugustan), which correspond to the upper part of Stage 5 of Cambrian Series 3 and, probably, the lowermost Drumian.
The specimens show the cranidial anterior border expanding backwards, forming a plectrum that is characteristic of Bailiaspis. The main characters of the three taxa include: a low convexity of the cranidium, with a very short or absent preglabellar field, and a cranidial sculpture with numerous densely-packed coarse tubercles. The only species that shows these diagnostic characters is Bailiaspis tuberculata from the middle Cambrian of England (Nuneaton, Warwickshire) in horizons inconclusively dated as the Ptychagnostus gibbus Zone (Cambrian Stage 5). This zone has been previously correlated with the upper Leonian and lower Caesaraugustan; thus, the British and Spanish materials are probably of similar age.
Key words: Systematic, trilobites, Cambrian Stage 5 and lowermost Drumian (Cambrian Series 3), biostratigraphy.
How to cite: Chirivella Martorell, J.B., Liñán, E., Dies Álvarez, Mª E., & Gozalo, R. 2017. Bailiaspis (Trilobita) with English affinities from the Mansilla Formation (Cambrian Series 3 of the Iberian Chains; NE Spain). Spanish Journal of Palaeontology, 32 (1), 17-26.
Received 27 May 2016, Accepted 24 January 2017, Published 30 June 2017
https://doi.org/10.7203/sjp.32.1.17027
