Balitoraanlongensis, the first cavefish species of the genus Balitora (Teleostei, Balitoridae) from Guizhou Province, southwest China.

This work describes a new species, Balitoraanlongensissp. nov., collected from a cave at Xinglong Town, Anlong County, Guzihou, China. Phylogenetic trees reconstructed based on two mitochondrial and three nuclear genes show that the new species represents an independent evolutionary lineage with large genetic differences, 7.1%-12.0% in mitochondrial gene cytochrome b and 9.2%-12.1% in cytochrome oxidase subunit 1, from congeners. Morphologically, the new species can be distinguished from the 18 species currently assigned to the genus Balitora by a combination of characters, most clearly by having two pairs of maxillary barbels; 8½ branched dorsal-fin rays; 5½ branched anal-fin rays; pectoral fin not reaching pelvic fin origin; dorsal-fin origin in front of pelvic fin origin; eye small (eye diameter approximately equal to outer maxillary barbel length); and fins lacking pigment in live fish. The new species represents the first record of Balitora inhabiting caves in China and increases the number of species in the genus Balitora in its present concept from 18 to 19. The study suggests that more evidence is needed to further clarify the taxonomic composition of the genus Balitora.

Four new hypogean species of the genus Triplophysa (Osteichthyes, Cypriniformes, Nemacheilidae) from Guizhou Province, Southwest China, based on molecular and morphological data.

Recently described cave species of the genus Triplophysa have been discovered in southwestern China, suggesting that the diversity of the genus is severely underestimated and that there may be many undescribed species. In this work, four new species of the genus Triplophysa are described from southwestern Guizhou Province, China, namely Triplophysacehengensis Luo, Mao, Zhao, Xiao & Zhou, sp. nov. and Triplophysarongduensis Mao, Zhao, Yu, Xiao & Zhou, sp. nov. from Rongdu Town, Ceheng County, Guizhou, Triplophysapanzhouensis Yu, Luo, Lan, Xiao & Zhou, sp. nov. from Hongguo Town, Panzhou City, Guizhou, and Triplophysaanlongensis Song, Luo, Lan, Zhao, Xiao & Zhou, sp. nov. from Xinglong Town, Anlong County, Guizhou. These four new species can be distinguished from all recognized congeners by a combination of morphological characteristics and significant genetic divergences. The discovery of these species increases the number of known cave species within the genus Triplophysa to 39, making the genus the second most diverse group of cave fishes in China after the golden-line fish genus Sinocyclocheilus. Based on the non-monophyletic relationships of the different watershed systems in the phylogenetic tree, this study also discusses the use of cave species of the genus Triplophysa to determine the possible historical connectivity of river systems.

Integrated phylogenetic analyses reveal the evolutionary, biogeographic, and diversification history of Asian warty treefrog genus Theloderma (Anura, Rhacophoridae).

Asian warty treefrogs, genus Theloderma, are morphologically variable arboreal frogs endemic to Southeast Asia and Southern China. However, integrated systematic studies are lacking, and knowledge of the genus in terms of diversity, origin, and historical diversification remains limited. To address these knowledge gaps, we used three mitochondrial and five nuclear gene fragments to reconstruct the Theloderma phylogeny, estimate divergence times, and examine the biogeography of the genus. Phylogenetic and species delimitation analyses suggest that the genus Theloderma comprises three major clades corresponding to two subgenera and seven species groups, and mPTP identified at least 12 putative cryptic species, suggesting that species diversity has been underestimated. Biogeographic analyses indicated that most recent common ancestor of Theloderma originated in the Indochina Peninsula during the Middle Oligocene (ca. 27.77 Ma) and the splitting of Clade A to C occurred in the Late Oligocene (ca. 23.55-25.57 Ma). Current biogeographic patterns result from two distinct processes: in situ diversification in the Indochina Peninsula and dispersal in multiple areas, namely southward dispersal to the Malay Peninsula and Borneo, northeastward dispersal to Southern China, northward dispersal to the Himalayas, and dispersal from Southern China to the Indochina Peninsula. Ancestral character reconstruction suggests that the ancestor of Theloderma may have possessed a small body size, rough dorsal skin, and absence of vomerine teeth and hand webbing, and that these four characters have undergone multiple evolutions. Principal component analysis based on eight bioclimatic variables did not clearly distinguish the three major clades of Theloderma, suggesting that species in these clades may occupy similar climatic ecological niches. Our research highlights the importance of orogeny and paleoclimatic changes, in shaping amphibian biodiversity in mountain ecosystems.

Oreonectesdamingshanensis (Cypriniformes, Nemacheilidae), a new species of stream fish from Guangxi, Southwest China.

In this work, a new species of the genus Oreonectes is described, named Oreonectesdamingshanensis Yu, Luo, Lan, Xiao & Zhou, sp. nov., collected from the Damingshan Mountains of the Guangxi Zhuang Autonomous Region, China. Phylogenetic trees constructed based on the mitochondrial Cyt b showed that the new species represents an independent evolutionary lineage, with uncorrected genetic distances (p-distance) from congeners ranging from 6.1% to 8.9%. Morphologically, the new species can be distinguished from five other species of the genus by a combination of characters. The discovery of this new species raises the number of known species of Oreonectes from five to six. Our study suggests that O.platycephalus may be a complex containing multiple species and that previously recorded areas need to be further delimited and reevaluated.

A long-ignored unique ecosystem of cavefishes in the southern karst: achievements, challenges, and prospects.

Cavefishes represent a taxon that has experienced natural selection pressures. This paper summarizes the results with respect to the taxonomy, diversity, phylogeny, and adaptation aspects of cavefishes research. It showed that: 1) These studies suggest that cavefishes play important roles in the study of geologic history and adaptation to extreme environments, but the mechanisms involved 168 species of cavefishes belonging to 17 genera, four families, and two orders have been recorded in China. Meanwhile, more new species are being discovered recently, and the species diversity of cavefishes are still underestimated, indicating the need to strengthen the survey in field. 2) The biogeography of cavefishes have focused on Sinocyclocheilus and Triplophysa, that have helped understand the geomorphology of karst areas in southern China and the spatial pattern of species diversity. These studies revealed the influences of evolution and geological history in Sinocyclocheilus, but there are still many species that have not been studied accordingly. 3) Some adaptive mechanistic studies have been conducted on cavefishes, primarily focusing on eye and body color degradation and energy metabolism in the genus Sinocyclocheilus to reveal adaptive mechanisms in the dark environment. 4) The IUCN list of protected cavefishes species in China only includes 21 species. The List of Key Protected Wild Animals for 2021 includes all species of Sinocyclocheilus as National Class II.It is necessary to strengthen the research on the biodiversity and adaptation and need consider the conservation actions for cavefishes.

Mitochondrial genome of a typical cavefish of Sinocyclocheilus anatirostris.

Sinocyclocheilus anatirostris Lin and Luo, 1986 is a member of the endemic Chinese genus Sinocyclocheilus Fang, 1936, living in dark caves with absence of eyes and scales. Muscle tissue was collected from cavefish samples from Guangxi, China, and complete mitogenome was sequenced. This is the first report of the mitogenome of S. anatirostris. This mitogenome consists of 13 protein-coding genes (PCGs), two rRNA genes (12S rRNA and 16S rRNA), 22 tRNA genes, a control region (CR), and comprises 31.2% A, 24.4% T, 16.7% G, and 27.7% C bases. Phylogenetically, S. anatirostris is closely related to the Sinocyclocheilus furcodorsalis, and originated in the late Miocene, ∼6.07 Ma.