Ernel D. Bagbag Cesar G. Demayo Mark Anthony J. Torres Natural Science Department, College of Arts and Sciences, University of Southeastern Philippines, Barrio Obrero, Davao City, Philippines Center of Integrative Health, Primier Research Institute of Science and Mathematics, Mindanao State University-Iligan Institute of Technology, Tibanga, Iligan City, Philippines School of Intedisciplinary Studies, Mindanao State University-Iligan Institute of Technology, Tibanga, Iligan City, Philippines Arthropods ISSN 2224-4255 http://www.iaees.org/publications/journals/arthropods/online-version.asp 2025 14 4 192 207 International Academy of Ecology and Environmental Sciences Hong Kong 1 April 2025 5 May 2025 1 December 2025 Cladistics Coleopterans evolution systematic relationships Coleopterans present challenges in their classification due to their highly variable morphological traits. In the Philippines, beetle classification was limited to describing species based on a few character traits, which might result in taxonomic incongruencies. Hence, this research utilized Cladistic analysis to determine the morphological diversity of synanthropic beetles. This work included 48 synanthropic beetle taxa using 82 qualitative morphological characters. Tree searches found eight parsimonious trees with a length of 683 steps, a consistency index of 20, and a retention index of 46. These trees produced a strict consensus tree revealing three major clades with recurring traits, suggesting high homoplasy among Coleopterans. Furthermore, three polytomies were observed in the preferred tree, particularly species in Cerambycidae and Melolonthinae groups, indicating that these groups underwent various evolutionary mechanisms, such as parallel evolution, homoplasy, or convergent evolution. Analysis of the individual character traits revealed five uninformative morphological features and nine character traits that can be examined for character evolution. The results of Cladistic analysis are generally congruent with the molecular studies and enhance our understanding of the systematic relationships among synanthropic beetle species. http://www.iaees.org/publications/journals/arthropods/articles/2025-14(4)/phenotypic-variations.pdf