Complete mitochondrial genome of Guigarra cailaoensis Wang, Chen & Zheng, 2022 (Cypriniformes, Cyprinidae) and its phylogenetic implications

Abstract

Guigarra cailaoensis is a member of family Cyprinidae, subfamily Labeoninae (Cypriniformes) which was recently discovered in southwestern China. Following its initial description, additional information on this species has remained notably scarce. In the current study, we assemble the complete mitochondrial genome (mitogenome) of G. cailaoensis using the Illumina sequencing platform. The mitogenome is identified as a circular, double-stranded DNA sequence of 16,593 base pairs, encompassing 13 protein-coding genes (PCGs), 22 transfer RNA genes, two ribosomal RNA genes, and a putative control region. Maximum-likelihood and Bayesian-inference approaches were used to construct phylogenetic trees for three datasets: (i) PCG sequences of the complete mitogenome (dataset 1); (ii) PCG sequences of the complete mitogenome combined with nuclear DNA (ncDNA) (Rag1) sequence (dataset 2); and (iii) ncDNA (Rag1) sequences (dataset 3). Phylogenetic analyses position G. cailaoensis as a sister taxon to the lineage consisting of Paraqianlabeo lineatus Zhao, Sullivan, Zhang & Peng, 2014 and Pseudogyrinocheilus prochilus Fang, 1933 in dataset 1, and to Pseudogyrinocheilus prochilus in dataset 2, species lacking an oral disc on the lower lip. However, G. cailaoensis showed a close relationship to the lineage consisting of Discogobio and Discocheilus in dataset 3, species possessing an oral disc on the lower lip. Nonetheless, a variety of species with an oral disc on the lower lip are clustered into different lineages across the three datasets that may indicate that the development of the oral disc is homoplastic within the subfamily Labeoninae. The outcomes of this study have the potential to support conservation efforts for this species and to enrich our understanding of genetic resources in the area.