Two new species of Ginkgoales from the Middle Jurassic of Mexico

Abstract

This paper reports two new species of Ginkgoales collected from the Cañada Alejandro and Río Ñ umi (Zorrillo and Zorrillo -Taberna Undifferentiated Formations, Middle Jurassic). Thirty-one fossils were selected and compared with 14 species from different localities. A numerical taxonomy analysis was performed through a data matrix formed by 15 characters. Results indicate an important speciation process of the Ginkgoales during the Jurassic in the southeast of Mexico. New evidence suggests the existence of eight species from the Ginkgoidium Yokoyama, 1889 and Sphenobaiera (Florin) Harris and Millington, 1974 genera and two new species Ginkgoidium nundichii Velasco-de León,

Paleobotany to understand evolution and biodiversity in Mexico

“…Mexican fossil wood and leaves have been identified based on anatomical comparisons with extant taxa (Magallón-Puebla & Cevallos-Ferriz 1994, Ramírez & Cevallos-Ferriz 2002, Calvillo-Canadell & Cevallos-Ferriz 2005, 2007, Estrada-Ruiz et al 2010, Velasco-de León et al 2015, Centeno-González et al 2019, O n l i n e f i r s t O n l i n e f i r s t 2021, Cevallos-Ferriz et al 2021, and although this method is standard in Mexican studies, also statistical and phylogenetic tools are used to identify fossils and to model paleoclimatic parameters (e.g., Hernández-Damián et al 2016, Rubalcava-Knoth & Cevallos-Ferriz 2021. These latter tools added certainty to the identifications and improved the morphological comparisons of multiple taxa, and thus allow the integration of fossils into classification schemes of modern plants (phylogenetic systematics), besides providing paleoclimatic and paleoecological data.…”