New Record of Two Melanopsid Species (Melanopsis costata and Melanopsis buccinoidea) in the Eastern Mediterranean Basin: Morphological Variation in the Söğütlü Stream (Hatay, Türkiye)

Abstract: Melanopsis costata and Melanopsis buccinoidea are freshwater gastropods within the Melanopsidae family characterized by their wide geographical distribution. The geographical distribution of the two species was evaluated within the Eastern Mediterranean Basin as part of this study. Aquatic sites were surveyed across diverse habitats in Söğütlü Stream (Hatay, Türkiye). The shell characteristics [shell height (SH), shell width (SW), spire height (SpH), aperture length (AL), and aperture width (AW)] of the two species were also examined within the ecosystem. The maximum values recorded for M. costata were a shell length (SL) of 17.40 mm and a weight (W) of 0.62 g. The highest values for M. buccinoidea were 13.75 mm for SL and 0.30 g for W. The PCA analysis demonstrated a significant relationship between shell length and shell width, aperture length, aperture width, and weight. The initial evidence of the presence of M. costata and M. buccinoidea was identified in the water body, and the distribution of both species exhibited habitat-dependent variations in their morphological traits.