Morphological reassessments and DNA barcoding of Pheidole rugaticeps Emery and Pheidole decarinata Santschi collected in Nigeria

Studies have revealed that the genus Pheidole (Formicidae: Myrmicinae) is the most diverse group of ants and highly distributed around the globe. Species delimitation through DNA-based approaches has lately received increased attention to overcome the taxonomic hurdle. This study reassessed the morphology and barcode Pheidole rugaticeps Emery and Pheidole decarinata Santschi collected in Nigeria. P. rugaticeps and P. decarinata are the most abundant ant species in the area sampled. Taxonomy of both Pheidole spp were reassessed using morphometrics. The morphological diagnosis of the worker castes was consistent with P. rugaticeps Emery, 1877 specimen (CASENT0281618), and P. decarinata Santschi specimen (CASENT0913301) from AntWeb.org. For the DNA-based identification, LCO1490/HCO2198 and LepF1/LepR1 primer pairs that consistently amplified a 710-bp fragment of Cytochrome oxidase subunit 1 (CO1) of invertebrates were used. The Basic Local Alignment Search Tool (BLAST) program of the NCBI database was used to confirm the genus as Pheidole. However, the species identity produced less than 90% match with the available CO1 sequences in the database. DNA sequences of P. rugaticeps and P. decarinata were not previously submitted at NCBI or other online databases. Hence, DNA sequences of P. rugaticeps (accession no; MT309805) and P. decarinata (accession no; MT308581) were added to the NCBI database for the first time and will be additional diagnostic tools for future studies. The phylogenetic result suggested that both Pheidole species were distinct. The study encourages the combination of morphological and molecular practices to identify this diverse ant group.