Molecular Phylogenetic Relationships among Seven Species of Pteris L. from Southwestern Nigeria

Abstract

Fern systematics in tropical Africa remains insufficiently characterised because molecular phylogenetic evidence for indigenous taxa is limited. This study investigated the phylogenetic relationships among seven Pteris species collected from six states in southwestern Nigeria using the chloroplast regions trnL-F and rbcL. Total genomic DNA was extracted from silica gel-dried leaf material, amplified by polymerase chain reaction, and assessed by agarose gel electrophoresis. Successful amplification was obtained for all sampled taxa, and purified amplicons were subjected to Sanger sequencing. Edited sequences were aligned, and phylogenetic relationships were inferred using the analytical procedures described in the manuscript, with bootstrap resampling used to evaluate branch support. The inferred topology indicated varying degrees of genetic relatedness among the seven taxa. Pteris atrovirens and P. mildbraedii were closely positioned, while P. similis and P. acanthoneura occurred within the same broader grouping. Pteris togoensis and P. ensiformis also formed a close association, whereas P. vittata occupied a comparatively distinct position. These findings provide preliminary molecular evidence that complements existing morphological and anatomical observations for regional Pteris taxonomy. The combined use of trnL-F and rbcL was informative for estimating relationships among the sampled taxa. This study represents one of the first molecular phylogenetic investigations of Pteris species in southwestern Nigeria using the chloroplast DNA markers trnL-F and rbcL, thereby providing baseline molecular data that complement morphological taxonomy and improve understanding of the evolutionary relationships among tropical African ferns.