Mitogenomic phylogeny resolves Cuneopsis (Bivalvia: Unionidae) as polyphyletic: The description of two new genera and a new species

Abstract

Freshwater mussels are known to have two types of mitochondrial DNA (mtDNA) transmitted separately through oocytes and sperms, namely, maternal (F‐type) and paternal (M‐type) mtDNA. The additional suite of mitochondrial genes provides a great opportunity to resolve phylogenetically problematic relationships. East Asian freshwater mussels of the genus Cuneopsis were considered a compact group of taxa having wedge‐shaped shells. However, preliminary results from previous studies challenged the monophyly of Cuneopsis, and the exact phylogenetic relationships among Cuneopsis and its allied genera are yet to be determined with comprehensive species sampling. Here, we evaluated species boundaries in Cuneopsis based on COI barcoding and obtained 11 new F‐ and M‐type mitogenomes via genome skimming to elucidate the evolutionary history of Cuneopsis. COI barcode data supported the validity of all sampled six Cuneopsis species (missing C. kiangsiensis). Our mitochondrial phylogenomic analyses confirmed that the currently recognized genus Cuneopsis sensu lato was polyphyletic, recovering three well‐supported clades. Molecular dating analysis suggested Cuneopsis s.l. diversified at ~58.06 million years ago in the Paleogene. Hereby, we propose two new genera, that is, Arcuneopsis gen. nov. and Pseudocuneopsis gen. nov. Additionally, we report a new species, Pseudocuneopsis sichuanensis sp. nov., from Chengdu, Sichuan, China, and a newly recorded species from China, Cuneopsis demangei.

Revisiting the genus Pseudocuneopsis (Bivalvia, Unionidae): Morphology, mitochondrial phylogenomics, and the description of a new species

“…newly established genus Pseudocuneopsis was found to be distantly related to Cuneopsis, and Pseudocuneopsis was sister to the group (Cuneopsis + Tchangsinaia + Schistode smus + Nodularia) (Wu et al, 2022). This is in agreement with our present phylogenetic results.…”

“…These regions have the potential to harbour undiscovered, mysterious species. Recent studies conducted in China have revealed new species, thus corroborating this point (Chen et al, 2023;Dai et al, 2023;Wu, Liu, et al, 2021;Wu et al, 2022Wu et al, , 2023.…”

“…The sequencing of the complete mitochondrial genome of P. wuana in future studies is imperative for accurate determination of its position in Pseudocuneopsis. In previous studies, the (Liu et al, 2023;Wu et al, 2022Wu et al, , 2023.…”

“…Five species of Pseudocuneopsis have varying distributions. Except for P. capitata, which is found in provinces in the middle and lower reaches of the Yangtze River, all species have narrow distribution (Liu et al, 1979(Liu et al, , 2022Wu et al, 2022Wu et al, , 2023. Although P. yemaoi sp.…”

“…Mitochondrial DNA (mtDNA) has long been popular in population genetics and phylogenetic studies and has greatly facilitated the discovery of new species because of their often high mutation rates and fast lineage sorting (Pentinsaari et al, 2017). In recent years, complete mitochondrial genomes have increasingly been used to resolve disputes about the phylogenetic relationships of freshwater mussels (Huang et al, 2018(Huang et al, , 2019Wu et al, 2022;Zieritz et al, 2021), and they are fully congruent with recent phylogenomic analyses using genome-scale data (Pfeiffer et al, 2019).…”