Geometric morphometric analysis of morphological variation in Bogor and Solok populations of bony lip barb (Osteochilus vittatus)

Abstract

Bony lip barb (Osteochilus vittatus) represents a freshwater species belonging to the Cyprinidae family, which is naturally widely distributed in Southeast Asia. In Indonesia, it is reported to occur widely in the inland waters of the main islands of Java, Sumatra, and Kalimantan. Geographic isolation may contribute to divergent evolution, resulting in phenotypic diversity. The present study used the geometric morphometric method to identify and describe morphological feature differences between geographically distant populations, namely Bogor (West Java) and Solok (West Sumatera). Seventy individual samples were collected from Bogor and Solok, respectively. Images of each sample were taken using a digital camera, then digitized on 17 landmark points using tpsdig software, followed by shape analysis using MorphoJ software. Results showed that Geometric Morphometric analysis could identify and distinguish the body shape of both populations. Morphologically, the Bogor population had a slender body shape, while the Solok population had a shorter and broader (stubby) body shape. A combination of landmark points forming the dorsal arch (LMs 2, 3, and 15), those forming the ventral curve (LMs 9-14), and those located in the peduncle area (LM15) contributed most to the body shape differences. Possible factors causing the observed phenomena are discussed.