Multiple lines of evidence confirm that the critically endangered Blue-crowned Laughingthrush (Garrulax courtoisi) is an independent species

Abstract

The taxonomy of the Blue-crowned Laughingthrush (Garrulax courtoisi) and its relationship with the Yellow-throated Laughingthrush (G. galbanus) and G. c. simaoensis, a range-restricted subspecies in China, has not been fully elucidated. So the taxonomic status and system evolution of the three taxa G.courtoisi, G. galbanus and G. c. simaoensis need to be reclarified. Two gene sequences myoglobin (MYO) and the mitochondrial cytochrome coxidase subunit I (COI) were combined to investigate the phylogenetic relationships among courtoisi, simaoensis and galbanus, genetic data, combining with morphological, ecological and acoustic data were used to comb out the classification status and divergence level of the three taxa. Significant genetic and morphological differentiations (body size and plumage coloration) were detected between courtoisi and galbanus. However, no notable and reliable differences between the courtoisi and simaoensis were detected. The courtoisi, simaoensis and galbanus are clearly isolated in geographical distribution as a result of differing altitudes, climate conditions and habitats. The courtoisi has characteristic preference for nest location compared with galbanus. In addition, the results of song analysis also indicated that there are differences in maximum frequency between courtoisi and galbanus. G. courtoisi was confirmed to be an independent species based on genetic, morphological, geographical, ecological and vocal characteristics, and the validity of simaoensis as a subspecies still need more evidence. This study further confirmed the high conservation value of Blue-crowned Laughingthrush. In addition, due to the genetic differences between Simao and Wuyuan populations, this should be fully considered in future protection strategies.