Molecular phylogeny and historical biogeography of the cave fish genus Sinocyclocheilus (Cypriniformes: Cyprinidae) in southwest China

Abstract

Modern accumulations of genetic data offer unprecedented opportunities for understanding the systematic classification and origins of specific groups of organisms. The genus Sinocyclocheilus is among the most cave abundant genera in Cyprinidae, with 76 recognized species, belonging to 4 species groups. Recent phylogenetic studies have shown that the classification of species groups within the genus Sinocyclocheilus remains controversial. In this study, we constructed a sequence supermatrix of 26 species from 4 species groups of the genus Sinocyclocheilus using the mitochondrial genome to reveal phylogenetic relationships, historical biogeography and patterns of species diversification in the genus Sinocyclocheilus. Phylogenetic analysis strongly supports the monophyletic groups of the 3 species groups (S. jii, S. cyphotergous, and S. tingi groups) except the S. angularis group. Phylogenetic analysis showed that S. anshuiensis and S. microphthalmus, which were recognized as numbers of S. angularis group, formed a strongly supported independent clade. Therefore, we propose a new species group, the S. microphthalmus group, which contains S. anshuiensis and S. microphthalmus. Biogeographic reconstruction suggests that the living Sinocyclocheilus may have originated in north‐central Guangxi at the late Eocene and dispersed outward after a vicariance at 32.31 Million years ago (Ma). Early diversification is focused on the late Oligocene (ca. 25 Ma), which is related to the second uplift of the Qinghai−Tibetan Plateau and the lateral extrusion of the Indochina at the Oligocene/Miocene boundary. Our results suggest that 2 uplifts of the Qinghai−Tibetan Plateau and climate change in the Miocene may have influenced the diversification of the Sinocyclocheilus lineage.

Sinocyclocheilus longicornus (Cypriniformes, Cyprinidae), a new species of microphthalmic hypogean fish from Guizhou, Southwest China

“…Initially, Sinocyclocheilus was divided into four species groups, S. jii, S. angularis, S. cyphotergous, and S. tingi, based on mitochondrial Cyt b and morphological differences . Phylogenetic trees reconstructed using mitochondrial ND4 and Cyt b, mitochondrial genome, and restriction site-associated DNA sequencing supported monophyly of the S. jii and S. tingi species groups and rejected monophyly of the S. angularis and S. cyphotergous species groups (Xiang 2014;Liu 2018;Mao et al 2021Mao et al , 2022Wen et al 2022;this study). These studies proposed new classification schemes, such as two new clades (Clades E and F) from Mao et al (2022) and a new species group (S. microphthalmus group) from Wen et al (2022).…”

“…Phylogenetic trees reconstructed using mitochondrial ND4 and Cyt b, mitochondrial genome, and restriction site-associated DNA sequencing supported monophyly of the S. jii and S. tingi species groups and rejected monophyly of the S. angularis and S. cyphotergous species groups (Xiang 2014;Liu 2018;Mao et al 2021Mao et al , 2022Wen et al 2022;this study). These studies proposed new classification schemes, such as two new clades (Clades E and F) from Mao et al (2022) and a new species group (S. microphthalmus group) from Wen et al (2022). Inconsistent topological differences may be related to molecular marker types, number of species and evolutionary models.…”

Expansion and contraction of lake basin shape the genetic structure of Sinocyclocheilus (Osteichthyes: Cypriniformes: Cyprinidae) populations in Central Yunnan, China

“…Such speciation was likely favored by the uplifting of the Qinghai-Tibetan Plateau and the aridification of the regional climate, which led to the isolation of Sinocyclocheilus populations in cave systems (Mao, Liu, Vasconcellos, et al, 2021). Similar geological processes have been proposed to shape the divergence and evolution of other faunal species of the central Yunnan Plateau (Che et al, 2010;Deng et al, 2020;Guo et al, 2019;Xiang et al, 2021;Zhao & Li, 2017), including fish species in plateau lakes (Wen et al, 2022;Yang et al, 2016). Nonetheless, the relative importance of key geological events in shaping the distributions and genetic structures of faunal communities of the central Yunnan lake basin remains poorly understood.…”

“…However, the content of intraspecies systematic geography has not yet been mentioned, especially in the central Yunnan region where geological events are more complex. Moreover, according to previous studies, the divergence time of the genus Sinocyclocheilus in central Yunnan was between 14.82 and 4.05 Ma (Wen et al, 2022). To understand the impact of the Qingzang and Kunhuang periods movements on the genus Sinocyclocheilus in the central Yunnan, research can only focus on the interspecific populations with later divergence times.…”

“…The genus Sinocyclocheilus (Cyprinidormes: Cyprinidae) is endemic to the massive southwestern karst area in China, the most species‐rich cyprinid genus, according to Eschmeyer's Catalog of Fishes, there are 78 valid species in this genus (Fricke et al., 2023) that are distributed in underground rivers in the karst area of southwest China, including Guangxi, Guizhou, Hunan and Yunnan, as well as Hubei province (Jiang et al., 2019; Wen et al., 2022; Zhao & Zhang, 2009). Fishes in the genus Sinocyclocheilus are morphologically distinct.…”