Quantitative and qualitative frond analysis of the fern Cladophlebis: Distinguishing morphotypes from the Barremian locality of Las Hoyas (southwestern Iberia Basin, Cuenca, Spain)

Abstract

Cladophlebis is a very variable form genus of Mesozoic fern foliage. At the Spanish Konservat Lagerstätte of Las Hoyas (upper Barremian), several pinnae that could be assigned to this genus have been unearthed. The identification of different species is complicated due to the high morphological disparity of the sample. Therefore, a quantitative and qualitative analysis was performed using 16 different characters that were explored by means of a Principal Component Analysis, resulting in the identification of three different morphotypes that closely agree with the descriptions of three previously proposed Cladophlebis species: Cladophlebis albertsii, Cladophlebis browniana, and Cladophlebis dunkeri. Characters related to vein angles and their combination are shown to be important in the differentiation of Cladophlebis species and add to the previous diagnosis of Cladophlebis albertsii. The preservation and distribution of the morphotypes in the locality were also studied, and are coherent with variations in humidity, reflected by the water column level. This suggests that ecological differences as a cause for the disparity observed in Cladophlebis from Las Hoyas cannot be ruled out.