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Wu L, Fan C, Lan C, Yu J, Wen H, Yang Q, Xiao N, Zhou J. A long-ignored unique ecosystem of cavefishes in the southern karst: achievements, challenges, and prospects. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:90489-90499. [PMID: 37479926 DOI: 10.1007/s11356-023-28806-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 07/11/2023] [Indexed: 07/23/2023]
Abstract
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.
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Affiliation(s)
- Li Wu
- School of Karst Science, Guizhou Normal University, Guiyang, 550001, China
| | - Cui Fan
- School of Karst Science, Guizhou Normal University, Guiyang, 550001, China
| | - Changting Lan
- School of Life Sciences, Guizhou Normal University, Guiyang, 550001, China
| | - Jing Yu
- School of Life Sciences, Guizhou Normal University, Guiyang, 550001, China
| | - Huamei Wen
- College of Science, Qiongtai Normal University, Haikou, 571127, China
| | - Qin Yang
- School of Karst Science, Guizhou Normal University, Guiyang, 550001, China
| | - Ning Xiao
- Guiyang Healthcare Vocational University, Guiyang, 550081, Guizhou, China
| | - Jiang Zhou
- School of Karst Science, Guizhou Normal University, Guiyang, 550001, China.
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Liu Y, Jiang Y, Xu J, Liao W. Evolution of Avian Eye Size Is Associated with Habitat Openness, Food Type and Brain Size. Animals (Basel) 2023; 13:ani13101675. [PMID: 37238105 DOI: 10.3390/ani13101675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/14/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023] Open
Abstract
The eye is the primary sensory organ that obtains information from the ecological environments and specifically bridges the brain with the extra environment. However, the coevolutionary relationships between eye size and ecological factors, behaviours and brain size in birds remain poorly understood. Here, we investigate whether eye size evolution is associated with ecological factors (e.g., habitat openness, food type and foraging habitat), behaviours (e.g., migration and activity pattern) and brain size among 1274 avian species using phylogenetically controlled comparative analyses. Our results indicate that avian eye size is significantly associated with habitat openness, food type and brain size. Species living in dense habitats and consuming animals exhibit larger eye sizes compared to species living in open habitats and consuming plants, respectively. Large-brained birds tend to possess larger eyes. However, migration, foraging habitat and activity pattern were not found to be significantly associated with eye size in birds, except for nocturnal birds having longer axial lengths than diurnal ones. Collectively, our results suggest that avian eye size is primarily influenced by light availability, food need and cognitive ability.
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Affiliation(s)
- Yating Liu
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, China
| | - Ying Jiang
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, China
| | - Jiliang Xu
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, China
| | - Wenbo Liao
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637009, China
- Key Laboratory of Artificial Propagation and Utilization in Anurans of Nanchong City, China West Normal University, Nanchong 637009, China
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Chen B, Mao T, Liu Y, Dai W, Li X, Rajput AP, Pie MR, Yang J, Gross JB, Meegaskumbura M. Sensory evolution in a cavefish radiation: patterns of neuromast distribution and associated behaviour in Sinocyclocheilus (Cypriniformes: Cyprinidae). Proc Biol Sci 2022; 289:20221641. [PMID: 36476002 PMCID: PMC9554722 DOI: 10.1098/rspb.2022.1641] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Accepted: 09/22/2022] [Indexed: 02/07/2023] Open
Abstract
The genus Sinocyclocheilus, comprising a large radiation of freshwater cavefishes, are well known for their presence of regressive features (e.g. variable eye reduction). Fewer constructive features are known, such as the expansion of the lateral line system (LLS), which is involved in detecting water movements. The precise relationship between LLS expansion and cave adaptation is not well understood. Here, we examine morphology and LLS-mediated behaviour in Sinocyclocheilus species characterized by broad variation in eye size, habitat and geographical distribution. Using live-staining techniques and automated behavioural analyses, we examined 26 Sinocyclocheilus species and quantified neuromast organ number, density and asymmetry within a phylogenetic context. We then examined how these morphological features may relate to wall-following, an established cave-associated behaviour mediated by the lateral line. We show that most species demonstrated laterality (i.e. asymmetry) in neuromast organs on the head, often biased to the right. We also found that wall-following behaviour was distinctive, particularly among eyeless species. Patterns of variation in LLS appear to correlate with the degree of eye loss, as well as geographical distribution. This work reveals that constructive LLS evolution is convergent across distant cavefish taxa and may mediate asymmetric behavioural features that enable survival in stark subterranean microenvironments.
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Affiliation(s)
- Bing Chen
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, People's Republic of China
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, Center of Evolutionary Biology, School of Life Sciences, Fudan University, Shanghai 200438, People's Republic of China
| | - Tingru Mao
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, People's Republic of China
| | - Yewei Liu
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, People's Republic of China
| | - Wenzhang Dai
- School of Life Science and Institute of Wetland Ecology, Nanjing University, Nanjing 210000, People's Republic of China
| | - Xianglin Li
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, People's Republic of China
| | - Amrapali P. Rajput
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, People's Republic of China
| | - Marcio R. Pie
- Biology Department, Edge Hill University, Ormskirk, Lancashire L39 4QP, UK
| | - Jian Yang
- Key Laboratory of Environment Change and Resource Use, Beibu Gulf, Nanning Normal University, Nanning, Guangxi, People's Republic of China
| | - Joshua B. Gross
- Department of Biological Sciences, University of Cincinnati, Cincinnati OH 45221, USA
| | - Madhava Meegaskumbura
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, People's Republic of China
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Zhou S, Rajput AP, Mao T, Liu Y, Ellepola G, Herath J, Yang J, Meegaskumbura M. Adapting to Novel Environments Together: Evolutionary and Ecological Correlates of the Bacterial Microbiome of the World's Largest Cavefish Diversification (Cyprinidae, Sinocyclocheilus). Front Microbiol 2022; 13:823254. [PMID: 35359710 PMCID: PMC8964274 DOI: 10.3389/fmicb.2022.823254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Accepted: 02/09/2022] [Indexed: 11/27/2022] Open
Abstract
The symbiosis between a host and its microbiome is essential for host fitness, and this association is a consequence of the host’s physiology and habitat. Sinocyclocheilus, the largest cavefish diversification of the world, an emerging multi-species model system for evolutionary novelty, provides an excellent opportunity for examining correlates of host evolutionary history, habitat, and gut-microbial community diversity. From the diversification-scale patterns of habitat occupation, major phylogenetic clades (A–D), geographic distribution, and knowledge from captive-maintained Sinocyclocheilus populations, we hypothesize habitat to be the major determinant of microbiome diversity, with phylogeny playing a lesser role. For this, we subject environmental water samples and fecal samples (representative of gut-microbiome) from 24 Sinocyclocheilus species, both from the wild and after being in captivity for 6 months, to bacterial 16S rRNA gene profiling using Illumina sequencing. We see significant differences in the gut microbiota structure of Sinocyclocheilus, reflective of the three habitat types; gut microbiomes too, were influenced by host-related factors. There is no significant association between the gut microbiomes and host phylogeny. However, there is some microbiome related structure at the clade level, with the most geographically distant clades (A and D) being the most distinct, and the two overlapping clades (B and C) showing similarities. Microbes inhabiting water were not a cause for significant differences in fish-gut microbiota, but water quality parameters were. Transferring from wild to captivity, the fish microbiomes changed significantly and became homogenized, signifying plastic changes and highlighting the importance of environmental factors (habitat) in microbiome community assembly. The core microbiome of this group, at higher taxonomic scale, resembled that of other teleost fishes. Our results suggest that divergent natural environments giving rise to evolutionary novelties underlying host adaptations, also includes the microbiome of these fishes.
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Affiliation(s)
- Shipeng Zhou
- Eco-Evo-Devo Laboratory, Guangxi Key Laboratory in Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
| | - Amrapali P Rajput
- Eco-Evo-Devo Laboratory, Guangxi Key Laboratory in Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
| | - Tingru Mao
- Eco-Evo-Devo Laboratory, Guangxi Key Laboratory in Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
| | - Yewei Liu
- Eco-Evo-Devo Laboratory, Guangxi Key Laboratory in Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
| | - Gajaba Ellepola
- Eco-Evo-Devo Laboratory, Guangxi Key Laboratory in Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
| | - Jayampathi Herath
- Eco-Evo-Devo Laboratory, Guangxi Key Laboratory in Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
| | - Jian Yang
- Key Laboratory of Environment Change and Resources Use in Beibu Gulf, Nanning Normal University, Nanning, China
| | - Madhava Meegaskumbura
- Eco-Evo-Devo Laboratory, Guangxi Key Laboratory in Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
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Lam SM, Li J, Sun H, Mao W, Liu Z, Zhao Q, Han C, Gong X, Jiang B, Chua GH, Zhao Z, Meng F, Shui G. Quantitative lipidomics and spatial MS-Imaging uncovered neurological and systemic lipid metabolic pathways underlying troglomorphic adaptations in cave-dwelling fish. Mol Biol Evol 2022; 39:6547622. [PMID: 35277964 PMCID: PMC9011034 DOI: 10.1093/molbev/msac050] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The Sinocyclocheilus represents a rare, freshwater teleost genus endemic to China that comprises the river-dwelling surface fish and the cave-dwelling cavefish. Using a combinatorial approach of quantitative lipidomics and mass-spectrometry imaging (MSI), we demonstrated that neural compartmentalization of lipid distribution and lipid metabolism are associated with the evolution of troglomorphic traits in Sinocyclocheilus. Attenuated DHA biosynthesis via the Δ4 desaturase pathway led to reductions in docosahexaenoic acid (DHA)-phospholipids in cavefish cerebellum. Instead, cavefish accumulates arachidonic acid (ARA)-phospholipids that may disfavor retinotectal arbor growth. Importantly, MSI of sulfatides, coupled with immunostaining of myelin basic protein and transmission electron microscopy images of hindbrain axons revealed demyelination in cavefish raphe serotonergic neurons. Demyelination in cavefish parallels the loss of neuroplasticity governing social behavior such as aggressive dominance. Outside the brain, quantitative lipidomics and qRT-PCR revealed systemic reductions in membrane esterified DHAs in the liver, attributed to suppression of genes along the Sprecher pathway (elovl2, elovl5, acox1). Development of fatty livers was observed in cavefish, likely mediated by an impeded mobilization of storage lipids, as evident in the diminished expressions of pnpla2, lipea, lipeb, dagla and mgll; and suppressed β-oxidation of fatty acyls via both mitochondria and peroxisomes, reflected in the reduced expressions of cpt1ab, hadhaa, cpt2, decr1 and acox1. These neurological and systemic metabolic adaptations serve to reduce energy expenditure, forming the basis of recessive evolution that eliminates non-essential morphological and behavioral traits, giving cavefish a selective advantage to thrive in caves where proper resource allocation becomes a major determinant of survival.
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Affiliation(s)
- Sin Man Lam
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.,LipidALL Technologies Company Limited, Changzhou 213022, Jiangsu Province, China
| | - Jie Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Huan Sun
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Weining Mao
- Qujing Aquaculture Station, Qujing 655000, Yunan Province, China
| | - Zongmin Liu
- Qujing Aquaculture Station, Qujing 655000, Yunan Province, China
| | - Qingshuo Zhao
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China.,State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Chao Han
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry Chinese Academy of Sciences, Beijing Mass Spectrum Center, Beijing, China
| | - Xia Gong
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Binhua Jiang
- LipidALL Technologies Company Limited, Changzhou 213022, Jiangsu Province, China
| | - Gek Huey Chua
- LipidALL Technologies Company Limited, Changzhou 213022, Jiangsu Province, China
| | - Zhenwen Zhao
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry Chinese Academy of Sciences, Beijing Mass Spectrum Center, Beijing, China
| | - Fanwei Meng
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China.,State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Guanghou Shui
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
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Evolution in Sinocyclocheilus cavefish is marked by rate shifts, reversals, and origin of novel traits. BMC Ecol Evol 2021; 21:45. [PMID: 33731021 PMCID: PMC7968296 DOI: 10.1186/s12862-021-01776-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 03/08/2021] [Indexed: 12/11/2022] Open
Abstract
Background Natural model systems are indispensable for exploring adaptations in response to environmental pressures. Sinocyclocheilus of China, the most diverse cavefish clade in the world (75 species), provide unique opportunities to understand recurrent evolution of stereotypic traits (such as eye loss and sensory expansion) in the context of a deep and diverse phylogenetic group. However, they remain poorly understood in terms of their morphological evolution. Therefore, we explore key patterns of morphological evolution, habitat utilization and geographic distribution in these fishes. Results We constructed phylogenies and categorized 49 species based on eye-related condition (Blind, Micro-eyed, and Normal-eyed), habitat types (Troglobitic—cave-restricted; Troglophilic—cave-associated; Surface—outside caves) and existence of horns. Geometric-morphometric analyses show Normal-eyed morphs with fusiform shapes segregating from Blind/Micro-eyed deeper bodied morphs along the first principal-component axis; second axis accounts for shape complexity related to horns. The body shapes showed a significant association with eye-related condition and horn, but not habitat types. Ancestral reconstructions suggest at least three independent origins of Blind morphs, each with different levels of modification in relation to their ancestral Normal-eyed morphs; Sinocyclocheilus are also pre-adapted for cave dwelling. Our geophylogeny shows an east-to-west diversification spanning Pliocene and Pleistocene, with early-diversifying Troglobitic species dominating subterranean habitats of karstic plains whereas predominantly Surface forms inhabit hills to the west. Evolutionary rates analyses suggest that lineages leading to Blind morphs were characterized by significant rate shifts, such as a slowdown in body size evolution and a 5–20 fold increase in rate of eye regression, possibly explained by limited resource availability. Body size and eye size have undergone reversals, but not horns, a trait entailing considerable time to form. Conclusions Sinocyclocheilus occupied cave habitats in response to drying associated with aridification of China during late Miocene and the Pliocene. The prominent cave-adaptations (eye-regression, horn-evolution) occur in clades associated with the extensive subterranean cave system in Guangxi and Guizhou provinces. Integration of morphology, phylogeny, rate analyses, molecular-dating and distribution show not only several remarkable patterns of evolution, but also interesting exceptions to these patterns signifying the diversification of Sinocyclocheilus as an invaluable model system to explore evolutionary novelty. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-021-01776-y.
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