Molecular Phylogeny and Conservation Priorities of the Subfamily Acheilognathinae (Teleostei: Cyprinidae)

Abstract

It is increasingly accepted that conservation work should consider the evolutionary history of target species. Fishes in the subfamily Acheilognathinae, family Cyprinidae, are, with the exception of three species exclusively distributed in Europe, restricted to Asia and show a distinct spawning behavior in laying their eggs in gill chambers of freshwater mussels. At present, many of the 70 species recognized in this group are facing with serious population decline in China and Japan, and their phylogenetic relationships are not well resolved. In the present study, based on mtDNA cyt b and 12S rRNA gene sequences, we reconstructed a more detailed species-level phylogenetic tree of this group, and assessed species conservation priorities based on their evolutionary distinctiveness. Molecular phylogenetic analyses showed that the Acheilognathinae contains two major clades: Acheilognathus clade and Tanakia-Rhodeus clade. Based on this phylogenetic result, conservation priority analyses were conducted using ED (evolutionary distinctiveness)/HED (heightened evolutionary distinctiveness), and EDGE (evolutionary distinctiveness and global endangeredness)/HEDGE (heightened evolutionary distinctiveness and global endangeredness) methods. The results suggested that T. himantegus, T. lanceolata, A. gracilis, A. imberbis, T. tanago, and A. longipinnis should be ranked as the top-priority species for conservation. According to our results, we also discussed the current conservation efforts of the bitterling fishes and gave suggestions for future work.

Phylogenetic relationships of Acheilognathidae (Cypriniformes: Cyprinoidea) as revealed from evidence of both nuclear and mitochondrial gene sequence variation: Evidence for necessary taxonomic revision in the family and the identification of cryptic species

“…This result led Arai and Kato (2003) to hypothesize that Tanakia was the ''ancestral'' group, and both Acheilognathus and Rhodeus evolved from Tanakia. However, this hypothesis is inconsistent with results from two recent molecular studies based on either mitochondrial cytochrome b sequence data (Kawamura et al, 2014) or the combined data set with 12S rRNA sequences (Cheng et al, 2014). In these studies two reciprocal clades are resolved in the Acheilognathidae (Acheilognathus and Tanakia-Rhodeus).…”

“…No previous studies (when multiple species from the three current genera were sampled) including the most recent ones have recovered Tanakia as monophyletic (Arai and Kato, 2003;Cheng et al, 2014;Kawamura et al, 2014;Okazaki et al, 2001). Thus, the monophyly of the genera Tanakia and Rhodeus remains questionable.…”

“…Prior to two recent studies (Cheng et al, 2014;Kawamura et al, 2014), the most comprehensive molecular-based study on species was that by Okazaki et al (2001); however, this study suffered in data analysis. Okazaki et al (2001) reconstructed relationships of bitterlings based only on partial sequences of 12S rRNA for 27 bitterling species/subspecies using Neighbor-Joining (NJ) analysis, a distance-based method of analysis that is known to be inadequate for the inference of species relationships.…”

“…The two most recent molecular studies on bitterlings by Cheng et al (2014) and Kawamura et al (2014) both increased taxonomic sampling (44 and 82 taxa included, respectively) relative to previous studies. However, both studies were limited in character sampling in using primarily cytochrome b sequences.…”

“…Despite these limitations, the studies by Cheng et al (2014) and Kawamura et al (2014) consistently resolved Acheilognathidae as monophyletic with two major clades, Acheilognathus and TanakiaRhodeus. No previous studies (when multiple species from the three current genera were sampled) including the most recent ones have recovered Tanakia as monophyletic (Arai and Kato, 2003;Cheng et al, 2014;Kawamura et al, 2014;Okazaki et al, 2001).…”