Systematic study of Limnonectes kuhlii (Tschudi, 1838) Complex in Kalimantan, Indonesia (Anura: Dicroglossidae)

Abstract

Limnonectes kuhlii was described from Java, Indonesia and had been considered as a single species that was widely distributed in Southeast Asia. Along with the development of DNA Barcoding, molecular studies revealed that the populations outside of Java represent distinct species, including the population from Borneo. In the Kalimantan region, there are two unnamed lineages, namely Lineages 3 and 4. These two lineages are genetically distinct; however, no further morphological analyses have been performed. This study aims to evaluate the taxonomic status of Lineages 3 and 4 based on morphology and molecular analysis using additional samples collected from Meratus Mountain Range, Kalimantan, Indonesia. In molecular analysis, we used 62 sequences to construct the phylogenetic tree using Maximum Likelihood and Bayesian Inference analyses. Twenty-nine morphological characters were measured from 35 specimens collected from the Meratus Mountain Range. Principal Component Analysis, Tukey-Kramer, and Student’s t-test were used to differentiate the morphological differences between Lineages 3 and 4. We also developed four modifications of odontoid measurement and three patterns of tibial tuberculation to differentiate Bordnean L. kuhlii complex. The phylogenetic tree shows our new samples from Central Kalimantan and South Kalimantan are clustered together with previously published samples, Lineage 3 from Samboja and Lineage 4 from Paramasan, respectively. Lineage 3 and Lineage 4, respectively, form a monophyletic group with highly supported nodes, and have a high genetic distance to their congeners. Morphologically, Lineages 3 and 4 can be distinguished from each other by the multivariate and univariate analyses and from other described species by the combination of morphological characters. This study, while a valuabe contribution, remains incomplete and necessitates further study to address existing gaps to deepen our understanding of these two undescribed species. These descriptions are also an initiation step in taxonomic work to encourage studies of the L. kuhlii complex in Kalimantan, Indonesia