Genetic and Morphometric Variation of the Genus Nyctixalus in Indonesia Based on mtDNA 16S rRNA Gene

The genus Nyctixalus was first described by Boulenger in 1882. Previous systematic studies of this group primarily focused on its relationships with other rhacophorid frogs and did not explore inter- and intraspecific variation in detail. This study aimed to determine the position of Indonesian species within their genus. We used DNA barcoding of the mitochondrial 16S rRNA gene and conducted a morphological analysis. Mitochondrial genealogies were constructed based on NJ, ML, and BI analyses, while uncorrected p-distance was also calculated. The Mann-Whitney U-test and PCA were used to analyse variations among species for each character component. Dissimilarity may contribute to measurable group structure. DNA barcoding revealed that Nyctixalus forms a monophyletic group. The PCA analysis revealed that N. margaritifer population from Java formed a group, while N. pictus could not be separated on the scatter plot. DNA barcoding revealed that Nyctixalus forms a monophyletic group. The genetic distance within the population of N. margaritifer (0–1.52 %) and N. spinosus (0–0.2 %) showed a variation of intraspecific genetic distance. However, in the two allopatric populations of N. pictus Kalimantan and Sumatra (p-distance = 4.3–4.6 %), there are high variations (6.9–9 %) between populations from Sumatra and Malaysia. These findings suggest that N. anodon van Kampen, 1907, from Kayu Tanam, Sumatra Barat, Indonesia, represents a distinct species from N. pictus Peters, 1871, originally described from Sarawak, Malaysia.