A Mysterious Asian Firefly Genus, Oculogryphus Jeng, Engel & Yang (Coleoptera, Lampyridae): The First Complete Mitochondrial Genome and Its Phylogenetic Implications.

Simple Summary: The family Lampyridae, commonly known as fireflies, is a cosmopolitan group comprising approximately 100 genera and 2200 species. Oculogryphus Jeng, Engel & Yang, 2007 is a small firefly genus endemic to Asia with only four known species and the phylogenetic position of it remains unresolved. It has been considered enigmatic because of its characteristic morphology intermingling different subfamilies, while its systematic status has never been rigorously tested due to a lack of molecular data. In this study, we obtained a large series of O. chenghoiyanae Yiu & Jeng, 2018 from southeastern China. We successfully sequenced and annotated its complete mitochondrial genome and clarified the systematic status of Oculogryphus. The firefly genus Oculogryphus Jeng, Engel & Yang, 2007 is a rare-species group endemic to Asia. Since its establishment, its position has been controversial but never rigorously tested. To address this perplexing issue, we are the first to present the complete mitochondrial sequence of Oculogryphus, using the material of O. chenghoiyanae Yiu & Jeng, 2018 determined through a comprehensive morphological identification. Our analyses demonstrate that its mitogenome exhibits similar characteristics to that of Stenocladius, including a rearranged gene order between trnC and trnW, and a long intergenic spacer (702 bp) between the two rearranged genes, within which six remnants (29 bp) of trnW were identified. Further, we incorporated this sequence into phylogenetic analyses of Lampyridae based on different molecular markers and datasets using ML and BI analyses. The results consistently place Oculogryphus within the same clade as Stenocladius in all topologies, and the gene rearrangement is a synapomorphy for this clade. It suggests that Oculogryphus should be classified together with Stenocladius in the subfamily Ototretinae at the moment. This study provides molecular evidence confirming the close relationship between Oculogryphus and Stenocladius and discovers a new phylogenetic marker helpful in clarifying the monophyly of Ototretinae, which also sheds a new light on firefly evolution. [ABSTRACT FROM AUTHOR]