Morphometrics and Meristics of Tubuca rhizophorae in Ca Mau and Bac Lieu Provinces, Vietnam

Abstract

This study investigates the morphological variations in the claw and walking leg characteristics of Tubuca rhizophorae, a fiddler crab species from the Ocypodidae family, collected from two coastal sites in the Mekong Delta, Vietnam. Monthly samples of T. rhizophorae were taken between December 2023 and September 2024 from Dong Hai, Bac Lieu, and Dam Doi, Ca Mau, with environmental parameters such as temperature, pH, and salinity recorded for each site. Morphological indices, including propodus length, manus length, pollex length, and dactyl length, were measured and analyzed. Results show that while the morphological index did not significantly vary between the two sites or across seasons, significant sex-based differences were observed, with male individuals displaying larger indices than females. Principal Component Analysis (PCA) indicated that temperature and salinity were substantial environmental factors influencing the morphological traits of T. rhizophorae. This research contributes to a deeper understanding of the species' ecological adaptations and morphological plasticity in response to environmental factors in mangrove ecosystems, providing valuable insights into the species’ ecological role in the Mekong Delta.