Taxonomic and phylogeographic study of bulbuls in genus Iole (aves, passeriformes, pycnonotidae)

• Main Author: Sontaya Manawatthana
• Other Authors: Nuttaphon Onparn
• Language: English
• Published: Mahidol University. Mahidol University Library and Knowledge Center 2023
• Subjects: Bioacoustics; Criniger; Phylogeny; Phylogeography > Thailand; Sound production by animals
• Online Access: https://repository.li.mahidol.ac.th/handle/123456789/89794
• Institution: Mahidol University

Iole bulbuls (Aves: Pycnonotidae) are common resident birds found mainly in the middle to upper story of forest in South and Southeast Asia. There are presently 13 distinct taxa distributed among four recognized species within the genus. Relationships among Iole taxa are poorly known, partly due to the extremely similar plumages and vocalizations of all taxa in the genus. The objectives of this study were (i) to analyze evolutionary relationships among Iole taxa using morphology, morphometrics, vocalizations and molecular data and to describe their patterns of diversification. A phylogeographic reconstruction based on two mitochondrial and one nuclear markers (total 2,337 bp) revealed three strongly supported primary lineages: a Palawan lineage, a Sundaic group distributed in the Malay Peninsula, Sumatra and Borneo and an Indochinese group distributed throughout continental Southeast Asia. Divergence time estimation suggested that the Palawan lineage diverged during the Miocene (around 9.7 Mya) and a later split between the Sundaic and Indochinese lineages occurring around 7.2 Mya, during early Pliocene. The diversification pattern found in Iole bulbuls was similar to the patterns found in many Indochinese and Sundaic fauna, and coincided with climatic fluctuations during Cenozoic epochs. An integrative approach using morphometrics, vocalizations and molecular data indicated that the present classification among Iole taxa did not accurately reflect their relationships. In addition to the four species under the existing classification, five more species were recognized, while some presently recognized subspecies also require reassignment. These findings demonstrated the need for unraveling the confusion in traditional taxonomy, which mainly relies on external morphological characters, by integrating relatively modern approaches incorporating phylogenetic and bioacoustic data to reveal complex biodiversity patterns and provided new insights into the biogeographic history of the avifauna in the Southeast Asia