Opsariichthys, Bleeker, 1863

Huang, Shih-Pin, Wang, Feng-Yu & Wang, Tzi-Yuan, 2017, Zavreliella shidai Han & Liu & Luo & Tang 2021, sp. n., Zoological Studies 56 (40), pp. 1-13 : 9

Opsariichthys group is a monophyletic group

In order to verify taxonomic placements and assignments in the Opsariichthys group, related species from Xenocyprididae ( Stout et al. 2016; Tang et al. 2013) were included ( Table 1; Fig. 1 ). Among the two phylogenetic trees reconstructed, the BI tree topology revealed a relatively stable and reliable grouping based on higher posterior probability values and reliable tree topology ( Fig. 3 ). The mitogenomic phylogeny suggests that Opsariichthys is monophyletic and sister to Xenocyprididae . Acheilognathidae , Leuciscidae , Tincidae , and Gobionidae are closely related families as outgroups.

Our results show that Parazacco , Candidia , Nipponocypris , Zacco , and Opsariichthys comprise a stable monophyletic group distinct from Xenocyprididae in both BI and ML trees ( Figs. 3 , 4 ). Moreover, all these members were previously confirmed as a monophyletic group ( Tang et al. 2013; Stout et al. 2016). Therefore, we propose the Opsariichthys group contains Parazacco , Candidia , Nipponocypris , Zacco , and Opsariichthys .

In addition, Liao et al. (2011b) assigned Aphyocypris and Yaoshanicus to subfamily Opsariichthyinae based on a single mitochondrial cytochrome b gene. Nelson et al. (2016) proposed that several additional genera, including Candidia , Macrochirichthys , Nicholsicypris , Nipponocypris , Oxygaster , Parachela, Pararosbora , and Parazacco , would be assigned to Opsariichthyinae if monophyly of the entire clade is confirmed. Tree topology clearly shows that only Parazacco , Candidia , Nipponocypris , Zacco , and Opsariichthys should be assigned to a monophyletic group, the Opsariichthys group ( Figs. 3 and 4 ). Tang et al. (2013) also showed similar results with different topology ( Fig. 1 ).

Five genera reassigned into Xenocyprididae

Liao et al. (2011c) classified five genera into Opsariichthyinae , which was placed into Xenocyprididae in two later studies ( Tang et al. 2013; Stout et al. 2016). Our present results also revealed that Aphyocypris , Yaoshanicus , Nicholsicypris , and Pararasbora are monophyletic with high support at the nodes (1.00 in BI, and 100 in ML), which was confirmed in Tang et al. (2010, 2013). Yaoshanicus , Nicholsicypris , and Pararasbora should be considered to be junior synonyms of Aphyocypris ( Liao et al. 2011b) . In addition, our study revealed Hemigrammocypris is nested with four species of Metzia and congruent with previous studies ( Tang et al. 2013; Stout et al. 2016).

Figures

Fig. 1. Systematic positions of the Opsariichthys group and related genera from this and other studies. © 2017 Academia Sinica, Taiwan

Fig. 3. Molecular phylogenetic tree of the Opsariichthys group and related families based on 13 concatenated protein-coding genes and two rRNA gene sequences reconstructed with Bayesian inference (values above the branch are posterior probabilities). Subfamily and family names follow those in Liao et al. (2011c), Nelson et al. (2016), Tang et al. (2013) and Stout et al. (2016).

Fig. 4. Molecular phylogenetic tree of the Opsariichthys group and related families based on 13 concatenated protein-coding genes and two rRNA gene sequences reconstructed with the maximum likelihood method (values below the branch are bootstrap numbers, bootstrap values less than 50 not shown). Subfamily and family names follow those in Liao et al. (2011c), Nelson et al. (2016), Tang et al. (2013) and Stout et al. (2016).