eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2025-12-30 22 4 1628 1635 10.13005/bbra/3465 57018 article Elavarasi Siddhaiyan 1 Priyadharshini Saravanan 1 Horne Iona Averal 1 Revathi Ganesan 2 Saravanan Kaliyaperumal 2 Department of Zoology, Holy Cross College (Autonomous), Tiruchirappalli, Tamil Nadu. India. Department of Zoology, Nehru Memorial College (Autonomous), Tiruchirappalli District, Tamil Nadu, India. Dung beetles (Coleoptera: Scarabaeidae) play a crucial role in ecosystem functioning, yet their molecular taxonomy and phylogenetic relationships remain underexplored in tropical regions. India has almost 400 species of dung beetle representing 30 genera, even though genetic data on much of the taxa are still scarce in the global repositories. This paper used the methodology of mitochondrial cytochrome c oxidase subunit I (COI) DNA barcoding to determine the identification of Catharsius molossus specimens that were taken in Tiruchirappalli in Tamil Nadu. Amplification of genomic DNA was done using universal COI primers and sequencing produced 19 good quality barcode sequences. The sequences were uploaded to the BOLD Systems v3 and NCBI GenBank (Accession No. PP396739). Phylogenetic analysis using the Neighbor-Joining (NJ) method in MEGA11 was done to verify morphological identifications, which supported clustering at a species level. These findings validate that COI is a good molecular identification marker of dung beetles and they can be useful in future biodiversity survey and phylogenetic studies in India. https://www.biotech-asia.org/vol22no4/coi-based-dna-barcoding-and-phylogenetic-analysis-of-catharsius-molossus-coleoptera-scarabaeidae-from-tiruchirappalli-southern-india/ Biodiversity; Dung beetles; Catharsius molossus; DNA barcoding; Phylogenetic analysis.