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Sommer GM, Njom SD, Indermaur A, Nyom ARB, Jandová K, Kukla J, Petrtýl M, Horká P, Musilova Z. Trophic ecology of the African riverine elephant fishes (Mormyridae). Ecol Evol 2024; 14:e70173. [PMID: 39206461 PMCID: PMC11349487 DOI: 10.1002/ece3.70173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 07/22/2024] [Accepted: 07/30/2024] [Indexed: 09/04/2024] Open
Abstract
Multiple species of the elephant fishes (Mormyridae) commonly coexist in sympatry in most African tropical rivers and lakes. In this study, we investigated the trophic ecology and potential trophic niche partitioning of eleven mormyrid fish species from the Sanaga River system in Cameroon using the stable isotope composition of carbon and nitrogen in the muscle samples. Albeit most mormyrids mainly feed on invertebrates, we found differences in isotope ratios, and we report signs of the trophic niche partitioning among species. We further found significant differences in isotopic signatures within the Mormyrus genus, suggesting ecological niche diversification among three closely related species. We have also evaluated differences in the isotopic signals between seasons in four species, which could be possibly caused by species migration and/or anthropogenic agricultural activities. To evaluate body shape, we applied geometric morphometric analyses, and we show that most of the species are clearly morphologically separated. We focused on the mormyrid ecomorphology to identify a possible interaction between shape and ecology, and we found a relationship between the δ13C (but not δ15N) isotopic signal and morphology, suggesting their interplay during mormyrid evolution. Overall, we present robust evidence of the trophic niche partitioning within the mormyrid species community, and we integrate trophic ecology with morphometrics, shedding light on the enigmatic evolutionary history of these fascinating African fishes.
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Affiliation(s)
- Gina Maria Sommer
- Department of Zoology, Faculty of ScienceCharles UniversityPragueCzech Republic
| | - Samuel Didier Njom
- Department of Biological SciencesUniversity of NgaoundéréNgaoundéréCameroon
| | | | - Arnold Roger Bitja Nyom
- Department of Biological SciencesUniversity of NgaoundéréNgaoundéréCameroon
- Department of Management of Fisheries and Aquatic EcosystemsUniversity of DoualaDoualaCameroon
| | - Kateřina Jandová
- Institute for Environmental Studies, Faculty of ScienceCharles UniversityPragueCzech Republic
| | - Jaroslav Kukla
- Institute for Environmental Studies, Faculty of ScienceCharles UniversityPragueCzech Republic
| | - Miloslav Petrtýl
- Department of Zoology and Fisheries, Faculty of Agrobiology, Food and Natural ResourcesCzech University of Life Sciences PragueSuchdolCzech Republic
| | - Petra Horká
- Institute for Environmental Studies, Faculty of ScienceCharles UniversityPragueCzech Republic
| | - Zuzana Musilova
- Department of Zoology, Faculty of ScienceCharles UniversityPragueCzech Republic
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2
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Todorovic J, Swapna I, Suma A, Carnevale V, Zakon H. Dual mechanisms contribute to enhanced voltage dependence of an electric fish potassium channel. Biophys J 2024; 123:2097-2109. [PMID: 38429925 PMCID: PMC11309972 DOI: 10.1016/j.bpj.2024.02.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/31/2024] [Accepted: 02/27/2024] [Indexed: 03/03/2024] Open
Abstract
The voltage dependence of different voltage-gated potassium channels, described by the voltage at which half of the channels are open (V1/2), varies over a range of 80 mV and is influenced by factors such as the number of positive gating charges and the identity of the hydrophobic amino acids in the channel's voltage sensor (S4). Here we explore by experimental manipulations and molecular dynamics simulation the contributions of two derived features of an electric fish potassium channel (Kv1.7a) that is among the most voltage-sensitive Shaker family potassium channels known. These are a patch of four contiguous negatively charged glutamates in the S3-S4 extracellular loop and a glutamate in the S3b helix. We find that these negative charges affect V1/2 by separate, complementary mechanisms. In the closed state, the S3-S4 linker negative patch reduces the membrane surface charge biasing the channel to enter the open state while, upon opening, the negative amino acid in the S3b helix faces the second (R2) gating charge of the voltage sensor electrostatically biasing the channel to remain in the open state. This work highlights two evolutionary novelties that illustrate the potential influence of negatively charged amino acids in extracellular loops and adjacent helices to voltage dependence.
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Affiliation(s)
- Jelena Todorovic
- Department of Neuroscience, The University of Texas, Austin, Texas
| | - Immani Swapna
- Department of Neuroscience, The University of Texas, Austin, Texas
| | - Antonio Suma
- Institute for Computational Molecular Science, College of Science and Technology & Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, Pennsylvania
| | - Vincenzo Carnevale
- Institute for Computational Molecular Science, College of Science and Technology & Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, Pennsylvania
| | - Harold Zakon
- Department of Neuroscience, The University of Texas, Austin, Texas; Department of Integrative Biology, The University of Texas, Austin, Texas.
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3
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Dymek J, Dymek AM, Kuciel M, Żuwała K. Macro- and micro morphology of the olfactory organ of African bonytongue, Heterotis niloticus (Cuvier 1829), compared with other species of the family Osteoglossidae (Teleostei). ZOOLOGY 2024; 163:126156. [PMID: 38422714 DOI: 10.1016/j.zool.2024.126156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 02/05/2024] [Accepted: 02/17/2024] [Indexed: 03/02/2024]
Abstract
Osteoglossiformes (bonytongue fishes) possess many morphological specializations associated with functions such as airbreathing, feeding, and electroreception. The olfactory organ also varies among species, notably in the family Osteoglossidae. Herein, we describe the olfactory organ of an osteoglossid, Heterotis niloticus, to compare it with the olfactory organs of other osteoglossiforms. We demonstrate the presence of an olfactory rosette within the olfactory chamber. This structure consists of a short median raphe surrounded by olfactory lamellae, which possess dorsal lamellar processes. On the surface of the olfactory lamellae, there are secondary lamellae formed by the olfactory epithelium. Within the olfactory epithelium, two zones can be distinguished: parallel brands of sensory cells located in the cavities between the secondary lamellae and a nonsensory area covering the remaining part of the olfactory lamellae. The olfactory epithelium is formed by ciliated and microvillus olfactory sensory neurons, supporting cells, goblet cells, basal cells and ciliated nonsensory cells. Additionally, rodlet cells were observed. The results confirm large variability in terms of the olfactory organ of Osteoglossiformes, particularly of Osteoglossidae, and support the secondary lamellae evolution hypothesis within this family.
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Affiliation(s)
- Jakub Dymek
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Cracow, Poland.
| | - Anna M Dymek
- Department of Small Livestock Breeding, National Research Institute of Animal Production, 32-083 Balice n., Cracow, Poland
| | - Michał Kuciel
- Poison Information Centre, Department of Toxicology and Environmental Disease, Faculty of Medicine, Jagiellonian University, Cracow, Poland
| | - Krystyna Żuwała
- Department of Comparative Anatomy, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Cracow, Poland
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4
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Abstract
The electric organ discharges (EODs) produced by weakly electric fish have long been a source of scientific intrigue and inspiration. The study of these species has contributed to our understanding of the organization of fixed action patterns, as well as enriching general imaging theory by unveiling the dual impact of an agent's actions on the environment and its own sensory system during the imaging process. This Centenary Review firstly compares how weakly electric fish generate species- and sex-specific stereotyped electric fields by considering: (1) peripheral mechanisms, including the geometry, channel repertoire and innervation of the electrogenic units; (2) the organization of the electric organs (EOs); and (3) neural coordination mechanisms. Secondly, the Review discusses the threefold function of the fish-centered electric fields: (1) to generate electric signals that encode the material, geometry and distance of nearby objects, serving as a short-range sensory modality or 'electric touch'; (2) to mark emitter identity and location; and (3) to convey social messages encoded in stereotypical modulations of the electric field that might be considered as species-specific communication symbols. Finally, this Review considers a range of potential research directions that are likely to be productive in the future.
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Affiliation(s)
- Angel Ariel Caputi
- Sistema Nacional de Investigadores - Uruguay, Av. Wilson Ferreira Aldunate 1219, Pando, PC 15600, Uruguay
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5
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Losilla M, Gallant JR. Molecular evolution of the ependymin-related gene epdl2 in African weakly electric fish. G3 (BETHESDA, MD.) 2023; 13:6931758. [PMID: 36529459 PMCID: PMC9997568 DOI: 10.1093/g3journal/jkac331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 11/01/2022] [Accepted: 11/16/2022] [Indexed: 12/23/2022]
Abstract
Gene duplication and subsequent molecular evolution can give rise to taxon-specific gene specializations. In previous work, we found evidence that African weakly electric fish (Mormyridae) may have as many as three copies of the epdl2 gene, and the expression of two epdl2 genes is correlated with electric signal divergence. Epdl2 belongs to the ependymin-related family (EPDR), a functionally diverse family of secretory glycoproteins. In this study, we first describe vertebrate EPDR evolution and then present a detailed evolutionary history of epdl2 in Mormyridae with emphasis on the speciose genus Paramormyrops. Using Sanger sequencing, we confirm three apparently functional epdl2 genes in Paramormyrops kingsleyae. Next, we developed a nanopore-based amplicon sequencing strategy and bioinformatics pipeline to obtain and classify full-length epdl2 gene sequences (N = 34) across Mormyridae. Our phylogenetic analysis proposes three or four epdl2 paralogs dating from early Paramormyrops evolution. Finally, we conducted selection tests which detected positive selection around the duplication events and identified ten sites likely targeted by selection in the resulting paralogs. These sites' locations in our modeled 3D protein structure involve four sites in ligand binding and six sites in homodimer formation. Together, these findings strongly imply an evolutionary mechanism whereby epdl2 genes underwent selection-driven functional specialization after tandem duplications in the rapidly speciating Paramormyrops. Considering previous evidence, we propose that epdl2 may contribute to electric signal diversification in mormyrids, an important aspect of species recognition during mating.
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Affiliation(s)
- Mauricio Losilla
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA.,Graduate Program in Ecology, Evolution and Behavior, Michigan State University, East Lansing, MI 48824, USA
| | - Jason R Gallant
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA.,Graduate Program in Ecology, Evolution and Behavior, Michigan State University, East Lansing, MI 48824, USA
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6
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Sullivan JP, Hopkins CD, Pirro S, Peterson R, Chakona A, Mutizwa TI, Mukweze Mulelenu C, Alqahtani FH, Vreven E, Dillman CB. Mitogenome recovered from a 19 th Century holotype by shotgun sequencing supplies a generic name for an orphaned clade of African weakly electric fishes (Osteoglossomorpha, Mormyridae). Zookeys 2022; 1129:163-196. [PMID: 36761845 PMCID: PMC9836601 DOI: 10.3897/zookeys.1129.90287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 09/19/2022] [Indexed: 11/17/2022] Open
Abstract
Heteromormyrus Steindachner, 1866, a genus of Mormyridae (Teleostei: Osteoglossomorpha), has been monotypic since the description of Heteromormyruspauciradiatus (Steindacher, 1866) from a single specimen. No type locality other than "Angola" was given and almost no specimens have been subsequently identified to this species. In order to investigate the relationship of this taxon to fresh specimens collected in Angola and elsewhere, whole genome paired-end sequencing of DNA extracted from the holotype specimen of Heteromormyruspauciradiatus was performed and a nearly complete mitogenome assembled from the sequences obtained. Comparison of cytochrome oxidase I and cytochrome b sequences from this mitogenome to sequences from recently collected material reveal that Heteromormyruspauciradiatus is closely related to specimens identified as Hippopotamyrusansorgii (Boulenger, 1905), Hippopotamyrusszaboi Kramer, van der Bank & Wink, 2004, Hippopotamyruslongilateralis Kramer & Swartz, 2010, as well as to several undescribed forms from subequatorial Africa collectively referred to in the literature as the "Hippopotamyrusansorgii species complex" and colloquially known as "slender stonebashers." Previous molecular phylogenetic work has shown that these species are not close relatives of Hippopotamyruscastor Pappenheim, 1906, the type species of genus Hippopotamyrus Pappenheim, 1906 from Cameroon, and are thus misclassified. Hippopotamyrusansorgii species complex taxa and another species shown to have been misclassified, Paramormyropstavernei (Poll, 1972), are placed in genus Heteromormyrus and one genetic lineage from the Kwanza and Lucala rivers of Angola are identified as conspecific Heteromormyruspauciradiatus. Three additional new combinations and a synonymy in Mormyridae are introduced. The morphological characteristics and geographical distribution of the genus Heteromormyrus are reviewed. The electric organ discharges (EODs) of Heteromormyrus species are to be treated in a separate study.
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Affiliation(s)
- John P. Sullivan
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, USA,Cornell University Museum of Vertebrates, Ithaca, New York, USA
| | - Carl D. Hopkins
- Cornell University Museum of Vertebrates, Ithaca, New York, USA,Department of Neurobiology and Behavior, Cornell University, Ithaca, New York, USA
| | | | - Rose Peterson
- The George Washington University, Washington, D.C., USA
| | - Albert Chakona
- NRF-South African Institute for Aquatic Biodiversity, Makhanda, South Africa,Department of Ichthyology and Fisheries Science, Rhodes University, Makhanda, South Africa
| | - Tadiwa I. Mutizwa
- NRF-South African Institute for Aquatic Biodiversity, Makhanda, South Africa,Department of Ichthyology and Fisheries Science, Rhodes University, Makhanda, South Africa
| | - Christian Mukweze Mulelenu
- Département de Zootechnie, Faculté des Sciences Agronomiques, Université de Kolwezi, Kolwezi, Democratic Republic of the Congo,Département de Gestion des Ressources Naturelles Renouvelables, Unité de recherche en Biodiversité et Exploitation durable des Zones Humides, Université de Lubumbashi, Lubumbashi, Democratic Republic of the Congo,Laboratory of Biodiversity and Evolutionary Genomics, Katholieke Universiteit, Leuven, Belgium,Zoology Department, Ichthyology, Royal Museum for Central Africa, Tervuren, Belgium
| | - Fahad H. Alqahtani
- National Centre for Bioinformatics, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
| | - Emmanuel Vreven
- Laboratory of Biodiversity and Evolutionary Genomics, Katholieke Universiteit, Leuven, Belgium,Zoology Department, Ichthyology, Royal Museum for Central Africa, Tervuren, Belgium
| | - Casey B. Dillman
- Cornell University Museum of Vertebrates, Ithaca, New York, USA,Department of Neurobiology and Behavior, Cornell University, Ithaca, New York, USA
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7
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Why Osteoglossomorpha is one of the most peculiar groups of fish - a review. ANNALS OF ANIMAL SCIENCE 2022. [DOI: 10.2478/aoas-2022-0043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Abstract
Osteoglossomorpha is a significant taxon for studies of evolution and various aspects of fish biology as an evolutionarily old group of fish. The taxon exhibits anatomical, morphological and physiological diversity and various adaptations such as air breathing or electroreception as well as modifications visible in sight and olfactory organs. A peculiarity of this group is the presence of four types of spermatozoa, namely complex introsperm and uni-, bi-, and aflagellate aquasperm. Given the unique morphology and large dimensions of some species, osteoglossomorphs are popular in aquaristics as ornamental fish, and in fisheries because they are an important source of food in many countries. The aim of this paper is to focus on some aspects of the biology and unique features as well as the importance for humans of this unusual group of fish.
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8
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Intergenus F1-hybrids of African weakly electric fish (Mormyridae: Gnathonemus petersii ♂ × Campylomormyrus compressirostris ♀) are fertile. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:355-371. [PMID: 35119505 PMCID: PMC9123046 DOI: 10.1007/s00359-022-01542-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 01/09/2022] [Accepted: 01/10/2022] [Indexed: 11/16/2022]
Abstract
Hybridisation is an important element of adaptive radiation in fish but data are limited in weakly electric mormyrid fish in this respect. Recently, it has been shown that intragenus hybrids (Campylomormyrus) are fertile and are able to produce F2-fish. In this paper, we demonstrate that even intergenus hybrids (Gnathonemus petersii ♂ × Campylomormyrus compressirostris ♀) are fertile. Three artificial reproduction (AR) trials, with an average fertilisation rate of ca. 23%, yielded different numbers of survivals (maximally about 50%) of the F1-hybrids. The complete ontogenetic development of these hybrids is described concerning their morphology and electric organ discharge (EOD). Two EOD types emerged at the juvenile stage, which did not change up to adulthood. Type I consisted of four phases and Type II was triphasic. The minimum body length at sexual maturity was between 10 and 11 cm. Malformations, growth and mortality rates are also described.
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9
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Peterson RD, Sullivan JP, Hopkins CD, Santaquiteria A, Dillman CB, Pirro S, Betancur-R R, Arcila D, Hughes LC, Ortí G. Phylogenomics of bonytongue fishes (Osteoglossomorpha) shed light on the craniofacial evolution and biogeography of the weakly electric clade Mormyridae. Syst Biol 2022; 71:1032-1044. [PMID: 35041001 DOI: 10.1093/sysbio/syac001] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 01/03/2022] [Accepted: 01/10/2022] [Indexed: 11/14/2022] Open
Abstract
Bonytongues (Osteoglossomorpha) constitute an ancient clade of teleost fishes distributed in freshwater habitats throughout the world. The group includes well-known species such as arowanas, featherbacks, pirarucus, and the weakly electric fishes in the family Mormyridae. Their disjunct distribution, extreme morphologies, and electrolocating capabilities (Gymnarchidae and Mormyridae) have attracted much scientific interest, but a comprehensive phylogenetic framework for comparative analysis is missing, especially for the species-rich family Mormyridae. Of particular interest are disparate craniofacial morphologies among mormyrids which might constitute an exceptional model system to study convergent evolution. We present a phylogenomic analysis based on 546 exons of 179 species (out of 260), 28 out of 29 genera, and all six families of extant bonytongues. Based on a recent reassessment of the fossil record of osteoglossomorphs, we inferred dates of divergence among trans-continental clades and the major groups. The estimated ages of divergence among extant taxa (e.g., Osteoglossomorpha, Osteoglossiformes, Mormyroidea) are older than previous reports, but most of the divergence dates obtained for clades on separate continents are too young to be explained by simple vicariance hypotheses. Biogeographic analysis of mormyrids indicates that their high species diversity in the Congo Basin is a consequence of range reductions of previously widespread ancestors and that the highest diversity of craniofacial morphologies among mormyrids originated in this basin. Special emphasis on a taxon-rich representation for mormyrids revealed pervasive misalignment between our phylogenomic results and mormyrid taxonomy due to repeated instances of convergence for extreme craniofacial morphologies. Estimation of ancestral phenotypes revealed contingent evolution of snout elongation and unique projections from the lower jaw to form the distinctive Schnauzenorgan. Synthesis of comparative analyses suggests that the remarkable craniofacial morphologies of mormyrids evolved convergently due to niche partitioning, likely enabled by interactions between their exclusive morphological and electrosensory adaptations.
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Affiliation(s)
- Rose D Peterson
- Department of Biological Sciences, The George Washington University, Washington, DC USA
| | - John P Sullivan
- Cornell University Museum of Vertebrates, Department of Ecology and Evolutionary Biology Ithaca, NY USA
| | - Carl D Hopkins
- Cornell University Museum of Vertebrates, Department of Ecology and Evolutionary Biology Ithaca, NY USA
| | | | - Casey B Dillman
- Cornell University Museum of Vertebrates, Department of Ecology and Evolutionary Biology Ithaca, NY USA
| | | | | | - Dahiana Arcila
- Department of Biology, University of Oklahoma, Norman, OK USA.,Department of Ichthyology, Sam Noble Oklahoma Museum of Natural History, Norman, OK, USA
| | - Lily C Hughes
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL USA
| | - Guillermo Ortí
- Department of Biological Sciences, The George Washington University, Washington, DC USA.,National Museum of Natural History, Smithsonian Institution, Washington, DC USA
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10
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Prié V, Adam B, Melki F. From fin rays to DNA: supplementary morphological and molecular data to identify Mormyrus subundulatus Roberts, 1989 (Pisces: Mormyridae) from the Bandama River in Côte d'Ivoire. ZOOSYSTEMA 2021. [DOI: 10.5252/zoosystema2021v43a27] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Vincent Prié
- Biotope, Service international, Diversification, Innovation, 22 boulevard du Maréchal Foch, F-34140 Mèze (France)
| | - Benjamin Adam
- Biotope, Service international, Diversification, Innovation, 22 boulevard du Maréchal Foch, F-34140 Mèze (France)
| | - Frédéric Melki
- Biotope, Service international, Diversification, Innovation, 22 boulevard du Maréchal Foch, F-34140 Mèze (France)
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11
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Simanovsky S, Medvedev D, Tefera F, Golubtsov A. Derived karyotypes in two elephantfish genera ( Hyperopisus and Pollimyrus): lowest chromosome number in the family Mormyridae (Osteoglossiformes). COMPARATIVE CYTOGENETICS 2021; 15:345-354. [PMID: 34721818 PMCID: PMC8520028 DOI: 10.3897/compcytogen.v15.i4.67681] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 08/25/2021] [Indexed: 06/13/2023]
Abstract
The African weakly electric elephantfish family Mormyridae comprises 22 genera and almost 230 species. Up-to-date cytogenetic information was available for 17 species representing 14 genera. Here we report chromosome number and morphology in Hyperopisusbebe (Lacepède, 1803) and Pollimyrusisidori (Valenciennes, 1847) collected from the White Nile system in southwestern Ethiopia. Both taxa displayed the diploid chromosome number 2n = 40, but they differed in fundamental numbers: FN = 66 in H.bebe and FN = 72 in P.isidori; previously the same diploid chromosome number 2n = 40 was reported in an undescribed species of Pollimyrus Taverne, 1971 (FN = 42) from the same region. Our results demonstrate that not only pericentric inversions, but fusions also played a substantial role in the evolution of the mormyrid karyotype structure. If the hypothesis that the karyotype structure with 2n = 50-52 and prevalence of the uni-armed chromosomes close to the ancestral condition for the family Mormyridae is correct, the most derived karyotype structures are found in the Mormyrus Linnaeus, 1758 species with 2n = 50 and the highest number of bi-armed elements in their compliments compared to all other mormyrids and in Pollimyrusisidori with the highest number of bi-armed elements among the mormyrids with 2n = 40.
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Affiliation(s)
- Sergey Simanovsky
- Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, 33 Leninskij prosp., Moscow, 119071 RussiaSevertsov Institute of Ecology and Evolution, Russian Academy of SciencesMoscowRussia
| | - Dmitry Medvedev
- Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, 33 Leninskij prosp., Moscow, 119071 RussiaSevertsov Institute of Ecology and Evolution, Russian Academy of SciencesMoscowRussia
| | - Fekadu Tefera
- National Fishery and Aquatic Life Research Center, Ethiopian Institute of Agricultural Research, Sebeta, P.O. Box 64, EthiopiaEthiopian Institute of Agricultural ResearchSebetaEthiopia
| | - Alexander Golubtsov
- Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, 33 Leninskij prosp., Moscow, 119071 RussiaSevertsov Institute of Ecology and Evolution, Russian Academy of SciencesMoscowRussia
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12
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Mutizwa TI, Kadye WT, Chakona A. Deep genetic and morphological divergence in the Hippopotamyrus ansorgii species complex (Teleostei: Mormyridae) in southern Africa. JOURNAL OF FISH BIOLOGY 2021; 99:543-556. [PMID: 33811353 DOI: 10.1111/jfb.14743] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 03/18/2021] [Accepted: 03/30/2021] [Indexed: 06/12/2023]
Abstract
The present study used molecular and morphological approaches to investigate hidden diversity within the Hippopotamyrus ansorgii species complex in southern Africa. Phylogenetic reconstructions and three species delimitation methods based on two mitochondrial markers (cytochrome b and cytochrome oxidase I) and one nuclear marker (S7) revealed 12 Molecular Operational Taxonomic Units (MOTUs), with two of them representing two recently described species, Hippopotamyrus longilateralis and Hippopotamyrus szaboi. The highest diversity occurred in the Kwanza River system, which contained five MOTUs, and the Upper Zambezi River system that had two MOTUs. Five other river systems contained a single MOTU each. A major impediment to the review of this complex has been the uncertainty surrounding the type locality of the specimens that were used for the description of H. ansorgii. The present study has, through a careful examination of published literature and synthesis of information on the travel activities of Dr. William Ansorge who collected the specimens, identified the Kwanza River system as the most plausible source of the syntypes. The resolution of the type locality of H. ansorgii facilitates future work on the review of this complex which is critical for providing reliable biodiversity estimates, identifying effective conservation management strategies and understanding the evolutionary history and biogeographic patterns of the fishes of this region.
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Affiliation(s)
- Tadiwa I Mutizwa
- Department of Ichthyology and Fisheries Science, Rhodes University, Makhanda (Grahamstown), South Africa
- NRF-South African Institute for Aquatic Biodiversity, Makhanda (Grahamstown), South Africa
| | - Wilbert T Kadye
- Department of Ichthyology and Fisheries Science, Rhodes University, Makhanda (Grahamstown), South Africa
| | - Albert Chakona
- Department of Ichthyology and Fisheries Science, Rhodes University, Makhanda (Grahamstown), South Africa
- NRF-South African Institute for Aquatic Biodiversity, Makhanda (Grahamstown), South Africa
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13
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Mambo Baba T, Kisekelwa T, Danadu Mizani C, Decru E, Vreven E. Hidden species diversity in Marcusenius moorii (Teleostei: Mormyridae) from the Congo Basin. JOURNAL OF FISH BIOLOGY 2020; 96:1100-1122. [PMID: 31820447 DOI: 10.1111/jfb.14226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 12/01/2019] [Indexed: 06/10/2023]
Abstract
New collections from the Yangambi Biosphere Reserve (YBR) and Okapi Wildlife Reserve (OWR) revealed the presence of two groups of specimens similar to, but different from Marcusenius moorii. To study both these groups, an integrated morphological and genetic (mtDNA, cytb) approach was used. This study revealed that one of the two groups is conspecific with Marcusenius lambouri, a junior synonym of M. moorii, which is herein revalidated, with M. moorii longulus as its junior synonym. Marcusenius lambouri differs from M. moorii by a higher number of lateral line scales (44-46 vs. 40-43), a shorter pectoral-fin length (14.6-19.9 vs. 20.3-25.2% standard length; LS ) and a more elongated body due to a usually shallower middle body depth (19.8-26.5 vs. 26.3-35.9% LS ). The other group revealed to be a new species for science, Marcusenius verheyenorum, which can be distinguished from its congeners with eight circumpeduncular scales by the following unique combination of characters: a rounded head with a terminal mouth; a short and deep caudal peduncle (middle caudal-peduncle depth, 44.9-54.6% caudal-peduncle length; LCP ), a deep body (middle body depth, 27.7-34.2% LS ), 38-43 scales on the lateral line, 40-41 vertebrae, 20-21 dorsal-fin rays and 26 anal-fin rays. Some specimens previously attributed to M. moorii were examined and reassigned to M. lambouri or M. verheyenorum. As a result, M. moorii and M. lambouri occur in sympatry in the middle Congo Basin, with the distribution area of M. moorii still further extending into the lower Congo Basin. Instead, the distribution of M. verheyenorum is limited to some right bank tributaries of the upstream part of the middle Congo Basin. Two museum records from the Lilanda River (YBR), collected in the 1950s and previously identified as M. moorii, were re-identified as belonging to the new species, M. verheyenorum. However, the species now seems locally extinct in that region, which reflects the significant anthropogenic effects even within this reserve.
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Affiliation(s)
- Taylor Mambo Baba
- Département d'Ecologie et Biodiversité des Ressources Aquatique, Centre de Surveillance de la Biodiversité (CSB), Université de Kisangani, Kisangani, R.D. Congo
| | - Tchalondawa Kisekelwa
- Unité d'Enseignement et de Recherche en Hydrobiologie Appliquée (UERHA), Institut Supérieure Pédagogique (ISP) de Bukavu, Biology-Chemistry Department, Bukavu, R.D. Congo
- Vertebrate Section, Ichthyology, Royal Museum for Central Africa (RMCA), Tervuren, Belgium
- Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Leuven, Belgium
| | - Célestin Danadu Mizani
- Département d'Ecologie et Biodiversité des Ressources Aquatique, Centre de Surveillance de la Biodiversité (CSB), Université de Kisangani, Kisangani, R.D. Congo
| | - Eva Decru
- Vertebrate Section, Ichthyology, Royal Museum for Central Africa (RMCA), Tervuren, Belgium
- Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Leuven, Belgium
| | - Emmanuel Vreven
- Vertebrate Section, Ichthyology, Royal Museum for Central Africa (RMCA), Tervuren, Belgium
- Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Leuven, Belgium
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14
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Tagliacollo VA, Camelier P, Zanata AM, Reis RE. A shocking discovery of threat risks on newly described species of weakly electric fishes. JOURNAL OF FISH BIOLOGY 2020; 96:1077-1086. [PMID: 31297822 DOI: 10.1111/jfb.14096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 07/11/2019] [Indexed: 06/10/2023]
Abstract
This study aims to investigate relationships between species traits and publication date in the weakly electric osteoglossiform Mormyroidea (African knifefish and elephantfishes) and the ostariophysan Gymnotiformes (Neotropical knifefishes). It is investigated whether body size and geographic distribution area are correlated with publication date and whether extinction risk differs between both phylogenetically distant and geographically isolated clades. Statistical modelling indicates that the number of new species described annually is stable in mormyroids and clearly increasing in gymnotiforms. Best-fitting generalised linear models (GLM) indicate that the newly discovered species are more often of small-bodied, predominantly narrowly distributed and more likely to be threatened with extinction. These characteristics are more pronounced in mormyroids when compared with gymnotiforms, suggesting that some African electric fishes may live an ephemeral existence after formal description. Despite taxonomic work has been more intense in the Neotropics than in Africa in the recent decades, there is evidence that the African continent represents the next frontier of species descriptions. Taxonomic studies are fundamental for the understanding of richness and distribution and hence extinction risk assessment and conservation, of these remarkable convergent fish clades.
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Affiliation(s)
| | - Priscila Camelier
- Instituto de Biologia, Universidade Federal da Bahia, Salvador, Bahia, Brazil
| | - Angela M Zanata
- Instituto de Biologia, Universidade Federal da Bahia, Salvador, Bahia, Brazil
| | - Roberto E Reis
- Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
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15
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Abstract
Neuroscience has a long, rich history in embracing unusual animals for research. Over the past several decades, there has been a technology-driven bottleneck in the species used for neuroscience research. However, an oncoming wave of technologies applicable to many animals hold promise for enabling researchers to address challenging scientific questions that cannot be solved using traditional laboratory animals. Here, we discuss how leveraging the convergent evolution of physiological or behavioral phenotypes can empower research mapping genotype to phenotype interactions. We present two case studies using electric fish and poison frogs and discuss how comparative work can teach us about evolutionary constraint and flexibility at various levels of biological organization. We also offer advice on the potential and pitfalls of establishing novel model systems in neuroscience research. Finally, we end with a discussion on the use of charismatic animals in neuroscience research and their utility in public outreach. Overall, we argue that convergent evolution frameworks can help identify generalizable principles of neuroscience.
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Affiliation(s)
- Jason R Gallant
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
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16
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Simanovsky S, Medvedev D, Tefera F, Golubtsov A. First cytogenetic information for five Nilotic elephantfishes and a problem of ancestral karyotype of the family Mormyridae (Osteoglossiformes). COMPARATIVE CYTOGENETICS 2020; 14:387-397. [PMID: 32904050 PMCID: PMC7449985 DOI: 10.3897/compcytogen.14i3.52727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 07/23/2020] [Indexed: 05/17/2023]
Abstract
The elephantfish family Mormyridae is the most diverse lineage of the primitive teleostean clade Osteoglossomorpha distributed in inland waters of all continents except Antarctica and Europe. The family Mormyridae is endemic to Africa and includes 22 genera and almost 230 species. The evolutionary radiation of mormyrids most probably should be attributed to their capability of both generating and receiving weak electric signals. Up-to-date cytogenetic studies have revealed substantial karyotype differentiation among the nine investigated elephantfish species and genera (a single species studied per each genus). In the present study, karyotypes of five species representing five mormyrid genera (four unexplored ones) collected from the White Nile system in southwestern Ethiopia are described for the first time. The results show substantial variety of the diploid chromosome and fundamental numbers: 2n = 48 and FN = 54 in Brevimyrus niger (Günther, 1866), 2n = 50 and FN = 72 in Cyphomyrus petherici (Boulenger, 1898), 2n = 50 and FN = 78 in Hippopotamyrus pictus (Marcusen, 1864), 2n = 50 and FN = 76 in Marcusenius cyprinoides (Linnaeus, 1758), 2n = 52 and FN = 52 in Mormyrops anguilloides (Linnaeus, 1758). Karyotype structure in the latter species seems to be close to the ancestral condition for the family. This hypothesis is discussed in the light of available data on karyotype diversity and phylogeny of mormyrids.
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Affiliation(s)
- Sergey Simanovsky
- Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, 33 Leninskij prosp., Moscow, 119071, RussiaRussian Academy of SciencesMoscowRussia
| | - Dmitry Medvedev
- Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, 33 Leninskij prosp., Moscow, 119071, RussiaRussian Academy of SciencesMoscowRussia
| | - Fekadu Tefera
- National Fishery and Aquatic Life Research Center, Ethiopian Institute of Agricultural Research, Sebeta, P.O. Box 64, EthiopiaEthiopian Institute of Agricultural ResearchSebetaEthiopia
| | - Alexander Golubtsov
- Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, 33 Leninskij prosp., Moscow, 119071, RussiaRussian Academy of SciencesMoscowRussia
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17
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Calegari BB, Vari RP, Reis RE. Phylogenetic systematics of the driftwood catfishes (Siluriformes: Auchenipteridae): a combined morphological and molecular analysis. Zool J Linn Soc 2019. [DOI: 10.1093/zoolinnean/zlz036] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
A comprehensive phylogeny of species relationships of the Auchenipteridae is reconstructed here with a large-scale taxon sampling based on combined morphological and molecular datasets. The hypothesized phylogeny includes most species of Auchenipteridae (97 of 124 valid species) and multiple members of siluriform families as an outgroup (32 species) to embrace the diversity of forms among related catfishes. As the first large-scale phylogeny of the Auchenipteridae, comparison between taxa included information from both morphology (264 characters) and mitochondrial and nuclear molecular markers (3490 nucleotides) from five genes: coI, 16S, rag2, myh6 and SH3PX3. Trees were generated under two different optimality criteria (Maximum Parsimony and Bayesian Inference). A new classification for the family is presented herein to bring the taxonomy more in line with the new phylogenetic hypothesis. The strict consensus tree corroborates the monophyly of superfamily Doradoidea, family Auchenipteridae and its two subfamilies, Centromochlinae and Auchenipterinae. The new classification scheme proposes nine tribes in Auchenipteridae, based on the monophyly of major groups in both subfamilies. Centromochlus, Glanidium and Tatia are each recovered as paraphyletic. To maintain a monophyletic classification, some species treated as Tatia and Centromochlus are assigned to genera not previously recognized as valid.
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Affiliation(s)
- Bárbara B Calegari
- Laboratório de Sistemática de Vertebrados, Pontifícia Universidade Católica do Rio Grande do Sul. Avenida Ipiranga, Brazil
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | - Richard P Vari
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | - Roberto E Reis
- Laboratório de Sistemática de Vertebrados, Pontifícia Universidade Católica do Rio Grande do Sul. Avenida Ipiranga, Brazil
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18
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Stoddard PK, Tran A, Krahe R. Predation and Crypsis in the Evolution of Electric Signaling in Weakly Electric Fishes. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00264] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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19
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Crampton WGR. Electroreception, electrogenesis and electric signal evolution. JOURNAL OF FISH BIOLOGY 2019; 95:92-134. [PMID: 30729523 DOI: 10.1111/jfb.13922] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 02/05/2019] [Indexed: 05/06/2023]
Abstract
Electroreception, the capacity to detect external underwater electric fields with specialised receptors, is a phylogenetically widespread sensory modality in fishes and amphibians. In passive electroreception, a capacity possessed by c. 16% of fish species, an animal uses low-frequency-tuned ampullary electroreceptors to detect microvolt-range bioelectric fields from prey, without the need to generate its own electric field. In active electroreception (electrolocation), which occurs only in the teleost lineages Mormyroidea and Gymnotiformes, an animal senses its surroundings by generating a weak (< 1 V) electric-organ discharge (EOD) and detecting distortions in the EOD-associated field using high-frequency-tuned tuberous electroreceptors. Tuberous electroreceptors also detect the EODs of neighbouring fishes, facilitating electrocommunication. Several other groups of elasmobranchs and teleosts generate weak (< 10 V) or strong (> 50 V) EODs that facilitate communication or predation, but not electrolocation. Approximately 1.5% of fish species possess electric organs. This review has two aims. First, to synthesise our knowledge of the functional biology and phylogenetic distribution of electroreception and electrogenesis in fishes, with a focus on freshwater taxa and with emphasis on the proximate (morphological, physiological and genetic) bases of EOD and electroreceptor diversity. Second, to describe the diversity, biogeography, ecology and electric signal diversity of the mormyroids and gymnotiforms and to explore the ultimate (evolutionary) bases of signal and receptor diversity in their convergent electrogenic-electrosensory systems. Four sets of potential drivers or moderators of signal diversity are discussed. First, selective forces of an abiotic (environmental) nature for optimal electrolocation and communication performance of the EOD. Second, selective forces of a biotic nature targeting the communication function of the EOD, including sexual selection, reproductive interference from syntopic heterospecifics and selection from eavesdropping predators. Third, non-adaptive drift and, finally, phylogenetic inertia, which may arise from stabilising selection for optimal signal-receptor matching.
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20
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Extreme Enlargement of the Cerebellum in a Clade of Teleost Fishes that Evolved a Novel Active Sensory System. Curr Biol 2018; 28:3857-3863.e3. [PMID: 30449664 DOI: 10.1016/j.cub.2018.10.038] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 09/26/2018] [Accepted: 10/15/2018] [Indexed: 11/23/2022]
Abstract
Brains, and the distinct regions that make up brains, vary widely in size across vertebrates [1, 2]. Two prominent hypotheses have been proposed to explain brain region scaling evolution. The mosaic hypothesis proposes that changes in the relative sizes of particular brain regions are the result of selection acting independently on those regions [2, 3]. The concerted hypothesis proposes that the brain evolves as a coordinated structure due to developmental constraints [4]. These hypotheses have been widely debated [3-7], and recent studies suggest a combination of the two best describes vertebrate brain region scaling [8-10]. However, no study has addressed how the mosaic and concerted models relate to the evolution of novel behavioral phenotypes. We addressed this question using African mormyroid fishes. The mormyroids have evolved a novel active electrosensory system and are well known for having extreme encephalization [11] and a large cerebellum [2, 12], which is cited as a possible example of mosaic evolution [2]. We found that compared to outgroups without active electrosensing, mormyroids experienced mosaic increases in the sizes of the cerebellum and hindbrain, and mosaic decreases in the sizes of the telencephalon, optic tectum, and olfactory bulb. However, the evolution of extreme encephalization within mormyroids was associated with concerted changes in the sizes of all brain regions. This suggests that mosaic evolutionary change in the regional composition of the brain is most likely to occur alongside the evolution of novel behavioral functions, but not with the evolution of extreme encephalization.
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21
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Hatanaka T, de Oliveira EA, Ráb P, Yano CF, Bertollo LAC, Ezaz T, Jegede OOI, Liehr T, Olaleye VF, de Bello Cioffi M. First chromosomal analysis in Gymnarchus niloticus (Gymnarchidae: Osteoglossiformes): insights into the karyotype evolution of this ancient fish order. Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly098] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Terumi Hatanaka
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, SP, Brazil
| | - Ezequiel A de Oliveira
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, SP, Brazil
- Secretaria de Estado de Educação de Mato Grosso – SEDUC-MT, Cuiabá, MT, Brazil
| | - Petr Ráb
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Liběchov, Czech Republic
| | - Cassia F Yano
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, SP, Brazil
| | - Luiz A C Bertollo
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, SP, Brazil
| | - Tariq Ezaz
- Institute for Applied Ecology, University of Canberra, Bruce, Canberra, ACT, Australia
| | | | - Thomas Liehr
- Jena University Hospital, Institute of Human Genetics, Jena, Germany
| | - Victor F Olaleye
- Department of Zoology, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Marcelo de Bello Cioffi
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, SP, Brazil
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22
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Nagel R, Kirschbaum F, Hofmann V, Engelmann J, Tiedemann R. Electric pulse characteristics can enable species recognition in African weakly electric fish species. Sci Rep 2018; 8:10799. [PMID: 30018286 PMCID: PMC6050243 DOI: 10.1038/s41598-018-29132-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 06/21/2018] [Indexed: 12/02/2022] Open
Abstract
Communication is key to a wide variety of animal behaviours and multiple modalities are often involved in this exchange of information from sender to receiver. The communication of African weakly electric fish, however, is thought to be predominantly unimodal and is mediated by their electric sense, in which species-specific electric organ discharges (EODs) are generated in a context-dependent and thus variable sequence of pulse intervals (SPI). While the primary function of the electric sense is considered to be electrolocation, both of its components likely carry information regarding identity of the sender. However, a clear understanding of their contribution to species recognition is incomplete. We therefore analysed these two electrocommunication components (EOD waveform and SPI statistics) in two sympatric mormyrid Campylomormyrus species. In a set of five playback conditions, we further investigated which components may drive interspecific recognition and discrimination. While we found that both electrocommunication components are species-specific, the cues necessary for species recognition differ between the two species studied. While the EOD waveform and SPI were both necessary and sufficient for species recognition in C. compressirostris males, C. tamandua males apparently utilize other, non-electric modalities. Mapped onto a recent phylogeny, our results suggest that discrimination by electric cues alone may be an apomorphic trait evolved during a recent radiation in this taxon.
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Affiliation(s)
- Rebecca Nagel
- Unit of Evolutionary Biology and Systematic Zoology, Institute of Biochemistry/Biology, University of Potsdam, 14476, Potsdam, Germany
| | - Frank Kirschbaum
- Faculty of Life Sciences, Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Unit of Biology and Ecology of Fishes, Humboldt University of Berlin, 10115, Berlin, Germany
| | - Volker Hofmann
- Active Sensing, Faculty of Biology, Cognitive Interaction Technology - Center of Excellence, Bielefeld University, 33602, Bielefeld, Germany
- Faculty of Medicine, Department of Physiology, McGill University, H3G1Y6 Montreal, Quebec, Canada
| | - Jacob Engelmann
- Active Sensing, Faculty of Biology, Cognitive Interaction Technology - Center of Excellence, Bielefeld University, 33602, Bielefeld, Germany
| | - Ralph Tiedemann
- Unit of Evolutionary Biology and Systematic Zoology, Institute of Biochemistry/Biology, University of Potsdam, 14476, Potsdam, Germany.
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23
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Baron VD, Orlov AA, Golubtsov AS. Electric Organ Discharges of Cyphomyrus petherici (Mormyridae, Osteoglossiformes) from the White Nile Basin. DOKLADY BIOLOGICAL SCIENCES : PROCEEDINGS OF THE ACADEMY OF SCIENCES OF THE USSR, BIOLOGICAL SCIENCES SECTIONS 2018; 481:142-145. [PMID: 30171467 DOI: 10.1134/s0012496618040038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Indexed: 06/08/2023]
Abstract
The waveform and some characteristics of the electric organ discharges have been studied in 11 individuals of Cyphomyrus petherici, the only representative of the genus in the Nilotic fauna. The discharge is characterized by three to five phases with a prevalence of the second phase in terms of the relative amplitude and a wide variability of the total duration of discharge (from 212 to 558 μs). The comparison of the discharges of the species under study with those in the congeneric species and representatives of the genus Pollimyrus (which previously encompassed C. petherici) demonstrates a general similarity of the C. petherici discharges with those of Cyphomyrus, but not Pollimyrus. This is in agreement with the correspondence of the discharge characteristics observed in other mormyrids to the phylogenetic position and taxonomic status of the species.
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Affiliation(s)
- V D Baron
- Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, 117071, Russia
| | - A A Orlov
- Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, 117071, Russia.
| | - A S Golubtsov
- Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, 117071, Russia
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24
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Sukhum KV, Freiler MK, Wang R, Carlson BA. The costs of a big brain: extreme encephalization results in higher energetic demand and reduced hypoxia tolerance in weakly electric African fishes. Proc Biol Sci 2017; 283:rspb.2016.2157. [PMID: 28003448 DOI: 10.1098/rspb.2016.2157] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 11/28/2016] [Indexed: 12/29/2022] Open
Abstract
A large brain can offer several cognitive advantages. However, brain tissue has an especially high metabolic rate. Thus, evolving an enlarged brain requires either a decrease in other energetic requirements, or an increase in overall energy consumption. Previous studies have found conflicting evidence for these hypotheses, leaving the metabolic costs and constraints in the evolution of increased encephalization unclear. Mormyrid electric fishes have extreme encephalization comparable to that of primates. Here, we show that brain size varies widely among mormyrid species, and that there is little evidence for a trade-off with organ size, but instead a correlation between brain size and resting oxygen consumption rate. Additionally, we show that increased brain size correlates with decreased hypoxia tolerance. Our data thus provide a non-mammalian example of extreme encephalization that is accommodated by an increase in overall energy consumption. Previous studies have found energetic trade-offs with variation in brain size in taxa that have not experienced extreme encephalization comparable with that of primates and mormyrids. Therefore, we suggest that energetic trade-offs can only explain the evolution of moderate increases in brain size, and that the energetic requirements of extreme encephalization may necessitate increased overall energy investment.
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Affiliation(s)
- Kimberley V Sukhum
- Department of Biology, Washington University in Saint Louis, 1 Brookings Drive, Campus Box 1137, St. Louis, MO 63130-4899, USA
| | - Megan K Freiler
- Department of Biology, Washington University in Saint Louis, 1 Brookings Drive, Campus Box 1137, St. Louis, MO 63130-4899, USA
| | - Robert Wang
- Department of Biology, Washington University in Saint Louis, 1 Brookings Drive, Campus Box 1137, St. Louis, MO 63130-4899, USA
| | - Bruce A Carlson
- Department of Biology, Washington University in Saint Louis, 1 Brookings Drive, Campus Box 1137, St. Louis, MO 63130-4899, USA
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25
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Levin BA, Golubtsov AS. New insights into the molecular phylogeny and taxonomy of mormyrids (Osteoglossiformes, Actinopterygii) in northern East Africa. J ZOOL SYST EVOL RES 2017. [DOI: 10.1111/jzs.12186] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Boris A. Levin
- Institute of Biology of Inland Waters; Russian Academy of Sciences; Borok Yaroslavl District Russia
- Cherepovets State University; Vologda Region Cherepovets Russia
| | - Alexander S. Golubtsov
- Institute of Biology of Inland Waters; Russian Academy of Sciences; Borok Yaroslavl District Russia
- A.N. Severtsov Institute of Ecology and Evolution; Russian Academy of Sciences; Moscow Russia
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26
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Vélez A, Kohashi T, Lu A, Carlson BA. The cellular and circuit basis for evolutionary change in sensory perception in mormyrid fishes. Sci Rep 2017. [PMID: 28630408 PMCID: PMC5476679 DOI: 10.1038/s41598-017-03951-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Species differences in perception have been linked to divergence in gross neuroanatomical features of sensory pathways. The anatomical and physiological basis of evolutionary change in sensory processing at cellular and circuit levels, however, is poorly understood. Here, we show how specific changes to a sensory microcircuit are associated with the evolution of a novel perceptual ability. In mormyrid fishes, the ability to detect variation in electric communication signals is correlated with an enlargement of the midbrain exterolateral nucleus (EL), and a differentiation into separate anterior (ELa) and posterior (ELp) regions. We show that the same cell types and connectivity are found in both EL and ELa/ELp. The evolution of ELa/ELp, and the concomitant ability to detect signal variation, is associated with a lengthening of incoming hindbrain axons to form delay lines, allowing for fine temporal analysis of signals. The enlargement of this brain region is also likely due to an overall increase in cell numbers, which would allow for processing of a wider range of timing information.
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Affiliation(s)
- Alejandro Vélez
- Department of Biology, Washington University in St. Louis, St. Louis, MO, USA
| | - Tsunehiko Kohashi
- Department of Biology, Washington University in St. Louis, St. Louis, MO, USA.,Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Anan Lu
- Department of Biology, Washington University in St. Louis, St. Louis, MO, USA
| | - Bruce A Carlson
- Department of Biology, Washington University in St. Louis, St. Louis, MO, USA.
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27
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Rich M, Sullivan JP, Hopkins CD. Rediscovery and description of Paramormyrops sphekodes (Sauvage, 1879) and a new cryptic Paramormyrops (Mormyridae: Osteoglossiformes) from the Ogooué River of Gabon using morphometrics, DNA sequencing and electrophysiology. Zool J Linn Soc 2017. [DOI: 10.1093/zoolinnean/zlw004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Madeline Rich
- College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA
- Cornell University Museum of Vertebrates, 159 Sapsucker Woods Road, Ithaca, NY 14850, USA
| | - John P. Sullivan
- Cornell University Museum of Vertebrates, 159 Sapsucker Woods Road, Ithaca, NY 14850, USA
| | - Carl D. Hopkins
- Cornell University Museum of Vertebrates, 159 Sapsucker Woods Road, Ithaca, NY 14850, USA
- Department of Neurobiology and Behavior, 265 Seeley G. Mudd Hall, Cornell University, Ithaca, NY 14853-2702, USA
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Kirschbaum F, Nguyen L, Baumgartner S, Chi HWL, Wolfart R, Elarbani K, Eppenstein H, Korniienko Y, Guido-Böhm L, Mamonekene V, Vater M, Tiedemann R. Intragenus (Campylomormyrus) and intergenus hybrids in mormyrid fish: Physiological and histological investigations of the electric organ ontogeny. ACTA ACUST UNITED AC 2017; 110:281-301. [PMID: 28108418 DOI: 10.1016/j.jphysparis.2017.01.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 01/04/2017] [Accepted: 01/14/2017] [Indexed: 11/24/2022]
Abstract
African weakly electric mormyrid fish show a high diversity of their electric organ discharge (EOD) both across and within genera. Thanks to a recently developed technique of artificial reproduction in mormyrid fish, we were able to perform hybridizations between different genera and within one genus (Campylomormyrus). The hybrids of intergenus hybridizations exhibited different degrees of reduced survival related to the phylogenetic distance of the parent species: hybrids of the crosses between C. rhynchophorus and its sister genus Gnathonemus survived and developed normally. Hybrids between C. rhynchophorus and a Mormyrus species (a more basal clade compared to Campylomormyrus s) survived up to 42days and developed many malformations, e.g., at the level of the unpaired fins. Hybrids between C. numenius and Hippopotamyrus pictus (a derived clade, only distantly related to Campylomormyrus) only survived for two days during embryological development. Eight different hybrid combinations among five Campylomormyrus species (C. tamandua, C. compressirostris, C. tshokwe, C. rhynchophorus, C. numenius) were performed. The aim of the hybridizations was to combine species with (1) either caudal or rostral position of the main stalk innervating the electrocytes in the electric organ and (2) short, median or long duration of their EOD. The hybrids, though they are still juveniles, show very interesting features concerning electrocyte geometry as well as EOD form and duration: the caudal position of the stalk is prevailing over the rostral position, and the penetration of the stalk is dominant over the non-penetrating feature (in the Campylomormyrus hybrids); in the hybrid between C. rhynchophorus and Gnathonemus petersii it is the opposite. When crossing species with long and short EODs, it is always the long duration EOD that is expressed in the hybrids. The F1-Hybrids of the cross C. tamandua×C. compressirostris are fertile: viable F2-fish could be obtained with artificial reproduction.
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Affiliation(s)
- Frank Kirschbaum
- Humboldt University, Faculty of Life Sciences, Unit of Biology and Ecology of Fishes, Philippstr. 13, Haus 16, D-10115 Berlin, Germany.
| | - Linh Nguyen
- Humboldt University, Faculty of Life Sciences, Unit of Biology and Ecology of Fishes, Philippstr. 13, Haus 16, D-10115 Berlin, Germany; University of Potsdam, Institute of Biochemistry and Biology, Unit of Evolutionary Biology/Systematic Zoology, Karl-Liebknecht-Str. 24-25, Haus 26, D-14476 Potsdam-Golm, Germany
| | - Stephanie Baumgartner
- Humboldt University, Faculty of Life Sciences, Unit of Biology and Ecology of Fishes, Philippstr. 13, Haus 16, D-10115 Berlin, Germany
| | - Hiu Wan Linda Chi
- Humboldt University, Faculty of Life Sciences, Unit of Biology and Ecology of Fishes, Philippstr. 13, Haus 16, D-10115 Berlin, Germany
| | - Rene Wolfart
- Humboldt University, Faculty of Life Sciences, Unit of Biology and Ecology of Fishes, Philippstr. 13, Haus 16, D-10115 Berlin, Germany
| | - Khouloud Elarbani
- Humboldt University, Faculty of Life Sciences, Unit of Biology and Ecology of Fishes, Philippstr. 13, Haus 16, D-10115 Berlin, Germany
| | - Hari Eppenstein
- Humboldt University, Faculty of Life Sciences, Unit of Biology and Ecology of Fishes, Philippstr. 13, Haus 16, D-10115 Berlin, Germany
| | - Yevheniia Korniienko
- Humboldt University, Faculty of Life Sciences, Unit of Biology and Ecology of Fishes, Philippstr. 13, Haus 16, D-10115 Berlin, Germany
| | - Lilian Guido-Böhm
- Humboldt University, Faculty of Life Sciences, Unit of Biology and Ecology of Fishes, Philippstr. 13, Haus 16, D-10115 Berlin, Germany
| | - Victor Mamonekene
- Ecole Nationale Supérieure d'Agronomie et de Foresterie, Université Marien Ngouabi, B.P. 69, Brazzaville, People's Republic of Congo
| | - Marianne Vater
- University of Potsdam, Institute of Biochemistry and Biology, Unit of General Zoology, Karl-Liebknecht-Str. 24-25, Haus 26, D-14476 Potsdam-Golm, Germany
| | - Ralph Tiedemann
- University of Potsdam, Institute of Biochemistry and Biology, Unit of Evolutionary Biology/Systematic Zoology, Karl-Liebknecht-Str. 24-25, Haus 26, D-14476 Potsdam-Golm, Germany
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Pitchers WR, Constantinou SJ, Losilla M, Gallant JR. Electric fish genomics: Progress, prospects, and new tools for neuroethology. ACTA ACUST UNITED AC 2016; 110:259-272. [PMID: 27769923 DOI: 10.1016/j.jphysparis.2016.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 09/06/2016] [Accepted: 10/16/2016] [Indexed: 01/01/2023]
Abstract
Electric fish have served as a model system in biology since the 18th century, providing deep insight into the nature of bioelectrogenesis, the molecular structure of the synapse, and brain circuitry underlying complex behavior. Neuroethologists have collected extensive phenotypic data that span biological levels of analysis from molecules to ecosystems. This phenotypic data, together with genomic resources obtained over the past decades, have motivated new and exciting hypotheses that position the weakly electric fish model to address fundamental 21st century biological questions. This review article considers the molecular data collected for weakly electric fish over the past three decades, and the insights that data of this nature has motivated. For readers relatively new to molecular genetics techniques, we also provide a table of terminology aimed at clarifying the numerous acronyms and techniques that accompany this field. Next, we pose a research agenda for expanding genomic resources for electric fish research over the next 10years. We conclude by considering some of the exciting research prospects for neuroethology that electric fish genomics may offer over the coming decades, if the electric fish community is successful in these endeavors.
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Affiliation(s)
- William R Pitchers
- Dept. of Integrative Biology, Michigan State University, 288 Farm Lane RM 203, East Lansing, MI 48824, USA.
| | - Savvas J Constantinou
- Dept. of Integrative Biology, Michigan State University, 288 Farm Lane RM 203, East Lansing, MI 48824, USA
| | - Mauricio Losilla
- Dept. of Integrative Biology, Michigan State University, 288 Farm Lane RM 203, East Lansing, MI 48824, USA
| | - Jason R Gallant
- Dept. of Integrative Biology, Michigan State University, 288 Farm Lane RM 203, East Lansing, MI 48824, USA.
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Markham MR, Ban Y, McCauley AG, Maltby R. Energetics of Sensing and Communication in Electric Fish: A Blessing and a Curse in the Anthropocene? Integr Comp Biol 2016; 56:889-900. [PMID: 27549201 DOI: 10.1093/icb/icw104] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Weakly electric freshwater fish use self-generated electric fields to image their worlds and communicate in the darkness of night and turbid waters. This active sensory/communication modality evolved independently in the freshwaters of South America and Africa, where hundreds of electric fish species are broadly and abundantly distributed. The adaptive advantages of the sensory capacity to forage and communicate in visually-unfavorable environments and outside the detection of visually-guided predators likely contributed to the broad success of these clades across a variety of Afrotropical and neotropical habitats. Here we consider the potentially high and limiting metabolic costs of the active sensory and communication signals that define the gymnotiform weakly electric fish of South America. Recent evidence from two well-studied species suggests that the metabolic costs of electrogenesis can be quite high, sometimes exceeding one-fourth of these fishes' daily energy budget. Supporting such an energetically expensive system has shaped a number of cellular, endocrine, and behavioral adaptations to restrain the metabolic costs of electrogenesis in general or in response to metabolic stress. Despite a suite of adaptations supporting electrogenesis, these weakly electric fish are vulnerable to metabolic stresses such as hypoxia and food restriction. In these conditions, fish reduce signal amplitude presumably as a function of absolute energy shortfall or as a proactive means to conserve energy. In either case, reducing signal amplitude compromises both sensory and communication performance. Such outcomes suggest that the higher metabolic cost of active sensing and communication in weakly electric fish compared with the sensory and communication systems in other neotropical fish might mean that weakly electric fish are disproportionately susceptible to harm from anthropogenic disturbances of neotropical aquatic habitats. Fully evaluating this possibility, however, will require broad comparative studies of metabolic energetics across the diverse clades of gymnotiform electric fish and in comparison to other nonelectric neotropical fishes.
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Affiliation(s)
- Michael R Markham
- *Department of Biology, The University of Oklahoma, 730 Van Vleet Oval, Norman, OK 73019, USA .,†Cellular & Behavioral Neurobiology Graduate Program, The University of Oklahoma, 730 Van Vleet Oval, Norman, OK 73019, USA
| | - Yue Ban
- *Department of Biology, The University of Oklahoma, 730 Van Vleet Oval, Norman, OK 73019, USA.,†Cellular & Behavioral Neurobiology Graduate Program, The University of Oklahoma, 730 Van Vleet Oval, Norman, OK 73019, USA
| | - Austin G McCauley
- *Department of Biology, The University of Oklahoma, 730 Van Vleet Oval, Norman, OK 73019, USA
| | - Rosalie Maltby
- *Department of Biology, The University of Oklahoma, 730 Van Vleet Oval, Norman, OK 73019, USA
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31
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Picq S, Alda F, Bermingham E, Krahe R. Drift-driven evolution of electric signals in a Neotropical knifefish. Evolution 2016; 70:2134-44. [PMID: 27436179 DOI: 10.1111/evo.13010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 04/12/2016] [Accepted: 07/11/2016] [Indexed: 11/29/2022]
Abstract
Communication signals are highly diverse traits. This diversity is usually assumed to be shaped by selective forces, whereas the null hypothesis of divergence through drift is often not considered. In Panama, the weakly electric fish Brachyhypopomus occidentalis is widely distributed in multiple independent drainage systems, which provide a natural evolutionary laboratory for the study of genetic and signal divergence in separate populations. We quantified geographic variation in the electric signals of 109 fish from five populations, and compared it to the neutral genetic variation estimated from cytochrome oxidase I (COI) sequences of the same individuals, to test whether drift may be driving divergence of their signals. Signal distances were highly correlated with genetic distances, even after controlling for geographic distances, suggesting that drift alone is sufficient to explain geographic variation in electric signals. Significant differences at smaller geographic scales (within drainages) showed, however, that electric signals may evolve at a faster rate than expected under drift, raising the possibility that additional adaptive forces may be contributing to their evolution. Overall, our data point to stochastic forces as main drivers of signal evolution in this species and extend the role of drift in the evolution of communication systems to fish and electrocommunication.
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Affiliation(s)
- Sophie Picq
- Department of Biology, McGill University, Montreal, Quebec, H3A 1B1, Canada. .,Smithsonian Tropical Research Institute, Apartado 0843-03092 Balboa, Ancón, Republic of Panama. .,Current Address: GEOMAR Helmholtz Centre for Ocean Research Kiel, Evolutionary Ecology of Marine Fishes, Düsternbrooker Weg 20, Kiel, 24105, Germany.
| | - Fernando Alda
- Smithsonian Tropical Research Institute, Apartado 0843-03092 Balboa, Ancón, Republic of Panama.,Current Address: Museum of Natural Science, Department of Biological Sciences, Louisiana State University, 119 Foster Hall, Baton Rouge, LA
| | - Eldredge Bermingham
- Department of Biology, McGill University, Montreal, Quebec, H3A 1B1, Canada.,Smithsonian Tropical Research Institute, Apartado 0843-03092 Balboa, Ancón, Republic of Panama.,Current Address: Patricia and Phillip Frost Museum of Science, 3280 South Miami Avenue, Miami, FL
| | - Rüdiger Krahe
- Department of Biology, McGill University, Montreal, Quebec, H3A 1B1, Canada
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32
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Evidence for Non-neutral Evolution in a Sodium Channel Gene in African Weakly Electric Fish (Campylomormyrus, Mormyridae). J Mol Evol 2016; 83:61-77. [PMID: 27481396 DOI: 10.1007/s00239-016-9754-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 07/23/2016] [Indexed: 12/19/2022]
Abstract
Voltage-gated sodium channels, Nav1, play a crucial role in the generation and propagation of action potentials and substantially contribute to the shape of their rising phase. The electric organ discharge (EOD) of African weakly electric fish (Mormyroidea) is the sum of action potentials fired from all electrocytes of the electric organ at the same time and hence voltage-gated sodium channels are one factor-together with the electrocyte's morphology and innervation pattern-that determines the properties of these EODs. Due to the fish-specific genome duplication, teleost fish possess eight copies of sodium channel genes (SCN), which encode for Nav1 channels. In mormyroids, SCN4aa is solely expressed in the electrocytes of the adult electric organ. In this study, we compared entire SCN4aa sequences of six species of the genus Campylomormyrus and identified nonsynonymous substitutions among them. SCN4aa in Campylomormyrus exhibits a much higher evolutionary rate compared to its paralog SCN4ab, whose expression is not restricted to the electric organ. We also found evidence for strong positive selection on the SCN4aa gene within Mormyridae and along the lineage ancestral to the Mormyridae. We have identified sites at which all nonelectric teleosts are monomorphic in their amino acid, but mormyrids have different amino acids. Our findings confirm the crucial role of SCN4aa in EOD evolution among mormyrid weakly electric fish. The inferred positive selection within Mormyridae makes this gene a prime candidate for further investigation of the divergent evolution of pulse-type EODs among closely related species.
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33
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Lavoué S. Was Gondwanan breakup the cause of the intercontinental distribution of Osteoglossiformes? A time-calibrated phylogenetic test combining molecular, morphological, and paleontological evidence. Mol Phylogenet Evol 2016; 99:34-43. [DOI: 10.1016/j.ympev.2016.03.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 03/07/2016] [Accepted: 03/08/2016] [Indexed: 11/16/2022]
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Sullivan JP, Lavoué S, Hopkins CD. Cryptomyrus: a new genus of Mormyridae (Teleostei, Osteoglossomorpha) with two new species from Gabon, West-Central Africa. Zookeys 2016:117-50. [PMID: 27006619 PMCID: PMC4768369 DOI: 10.3897/zookeys.561.7137] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 12/20/2015] [Indexed: 11/14/2022] Open
Abstract
We use mitochondrial and nuclear sequence data to show that three weakly electric mormyrid fish specimens collected at three widely separated localities in Gabon, Africa over a 13-year period represent an unrecognized lineage within the subfamily Mormyrinae and determine its phylogenetic position with respect to other taxa. We describe these three specimens as a new genus containing two new species. Cryptomyrus, new genus, is readily distinguished from all other mormyrid genera by a combination of features of squamation, morphometrics, and dental attributes. Cryptomyrusogoouensis, new species, is differentiated from its single congener, Cryptomyrusona, new species, by the possession of an anal-fin origin located well in advance of the dorsal fin, a narrow caudal peduncle and caudal-fin lobes nearly as long as the peduncle. In Cryptomyrusona, the anal-fin origin is located only slightly in advance of the dorsal fin, the caudal peduncle is deep and the caudal-fin lobes considerably shorter than the peduncle. Continued discovery of new taxa within the “Lower Guinea Clade” of Mormyridae highlights the incompleteness of our knowledge of fish diversity in West-Central Africa. We present a revised key to the mormyrid genera of Lower Guinea.
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Affiliation(s)
- John P Sullivan
- Cornell University Museum of Vertebrates, 159 Sapsucker Woods Road, Ithaca, New York 14850 USA
| | - Sébastien Lavoué
- Institute of Oceanography, National Taiwan University, Roosevelt Road, Taipei 10617, Taiwan
| | - Carl D Hopkins
- Cornell University Museum of Vertebrates, 159 Sapsucker Woods Road, Ithaca, New York 14850 USA; Department of Neurobiology and Behavior, Cornell University, Ithaca, New York 14853 USA
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35
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Carlson BA. Differences in electrosensory anatomy and social behavior in an area of sympatry between two species of mormyrid electric fishes. ACTA ACUST UNITED AC 2015; 219:31-43. [PMID: 26567347 DOI: 10.1242/jeb.127720] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 10/23/2015] [Indexed: 01/15/2023]
Abstract
Sensory systems play a key role in social behavior by mediating the detection and analysis of communication signals. In mormyrid fishes, electric signals are processed within a dedicated sensory pathway, providing a unique opportunity to relate sensory biology to social behavior. Evolutionary changes within this pathway led to new perceptual abilities that have been linked to increased rates of signal evolution and species diversification in a lineage called 'clade A'. Previous field observations suggest that clade-A species tend to be solitary and territorial, whereas non-clade-A species tend to be clustered in high densities suggestive of schooling or shoaling. To explore behavioral differences between species in these lineages in greater detail, I studied population densities, social interactions, and electric signaling in two mormyrid species, Gnathonemus victoriae (clade A) and Petrocephalus degeni (non-clade A), from Lwamunda Swamp, Uganda. Petrocephalus degeni was found at higher population densities, but intraspecific diversity in electric signal waveform was greater in G. victoriae. In the laboratory, G. victoriae exhibited strong shelter-seeking behavior and competition for shelter, whereas P. degeni were more likely to abandon shelter in the presence of conspecifics as well as electric mimics of signaling conspecifics. In other words, P. degeni exhibited social affiliation whereas G. victoriae exhibited social competition. Further, P. degeni showed correlated electric signaling behavior whereas G. victoriae showed anti-correlated signaling behavior. These findings extend previous reports of social spacing, territoriality, and habitat preference among mormyrid species, suggesting that evolutionary divergence in electrosensory processing relates to differences in social behavior.
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Affiliation(s)
- Bruce A Carlson
- Department of Biology, Washington University in St Louis, St Louis, MO 63130-4899, USA
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36
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Decru E, Moelants T, De Gelas K, Vreven E, Verheyen E, Snoeks J. Taxonomic challenges in freshwater fishes: a mismatch between morphology and DNA barcoding in fish of the north-eastern part of the Congo basin. Mol Ecol Resour 2015; 16:342-52. [PMID: 26186077 DOI: 10.1111/1755-0998.12445] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 07/07/2015] [Accepted: 07/13/2015] [Indexed: 11/26/2022]
Abstract
This study evaluates the utility of DNA barcoding to traditional morphology-based species identifications for the fish fauna of the north-eastern Congo basin. We compared DNA sequences (COI) of 821 samples from 206 morphologically identified species. Best match, best close match and all species barcoding analyses resulted in a rather low identification success of 87.5%, 84.5% and 64.1%, respectively. The ratio 'nearest-neighbour distance/maximum intraspecific divergence' was lower than 1 for 26.1% of the samples, indicating possible taxonomic problems. In ten genera, belonging to six families, the number of species inferred from mtDNA data exceeded the number of species identified using morphological features; and in four cases indications of possible synonymy were detected. Finally, the DNA barcodes confirmed previously known identification problems within certain genera of the Clariidae, Cyprinidae and Mormyridae. Our results underscore the large number of taxonomic problems lingering in the taxonomy of the fish fauna of the Congo basin and illustrate why DNA barcodes will contribute to future efforts to compile a reliable taxonomic inventory of the Congo basin fish fauna. Therefore, the obtained barcodes were deposited in the reference barcode library of the Barcode of Life Initiative.
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Affiliation(s)
- Eva Decru
- Department of Biology, Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Charles Deberiotstraat 32, 3000, Leuven, Belgium.,Section Vertebrates, Ichthyology, Royal Museum for Central Africa, Leuvensesteenweg 13, 3080, Tervuren, Belgium
| | - Tuur Moelants
- Department of Biology, Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Charles Deberiotstraat 32, 3000, Leuven, Belgium.,Section Vertebrates, Ichthyology, Royal Museum for Central Africa, Leuvensesteenweg 13, 3080, Tervuren, Belgium
| | - Koen De Gelas
- OD Taxonomy and Phylogeny, Royal Belgian Institute for Natural Sciences, Vautierstraat 29, 1000, Brussels, Belgium
| | - Emmanuel Vreven
- Department of Biology, Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Charles Deberiotstraat 32, 3000, Leuven, Belgium.,Section Vertebrates, Ichthyology, Royal Museum for Central Africa, Leuvensesteenweg 13, 3080, Tervuren, Belgium
| | - Erik Verheyen
- OD Taxonomy and Phylogeny, Royal Belgian Institute for Natural Sciences, Vautierstraat 29, 1000, Brussels, Belgium.,Biology Department, Evolutionary Ecology Group, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerpen, Belgium
| | - Jos Snoeks
- Department of Biology, Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Charles Deberiotstraat 32, 3000, Leuven, Belgium.,Section Vertebrates, Ichthyology, Royal Museum for Central Africa, Leuvensesteenweg 13, 3080, Tervuren, Belgium
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37
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Baker CA, Huck KR, Carlson BA. Peripheral sensory coding through oscillatory synchrony in weakly electric fish. eLife 2015; 4:e08163. [PMID: 26238277 PMCID: PMC4522468 DOI: 10.7554/elife.08163] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 07/08/2015] [Indexed: 01/28/2023] Open
Abstract
Adaptations to an organism's environment often involve sensory system modifications. In this study, we address how evolutionary divergence in sensory perception relates to the physiological coding of stimuli. Mormyrid fishes that can detect subtle variations in electric communication signals encode signal waveform into spike-timing differences between sensory receptors. In contrast, the receptors of species insensitive to waveform variation produce spontaneously oscillating potentials. We found that oscillating receptors respond to electric pulses by resetting their phase, resulting in transient synchrony among receptors that encodes signal timing and location, but not waveform. These receptors were most sensitive to frequencies found only in the collective signals of groups of conspecifics, and this was correlated with increased behavioral responses to these frequencies. Thus, different perceptual capabilities correspond to different receptor physiologies. We hypothesize that these divergent mechanisms represent adaptations for different social environments. Our findings provide the first evidence for sensory coding through oscillatory synchrony.
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Affiliation(s)
- Christa A Baker
- Department of Biology, Washington University in St. Louis, St. Louis, United States
| | - Kevin R Huck
- Department of Biology, Washington University in St. Louis, St. Louis, United States
| | - Bruce A Carlson
- Department of Biology, Washington University in St. Louis, St. Louis, United States
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38
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Comparative histology of the adult electric organ among four species of the genus Campylomormyrus (Teleostei: Mormyridae). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2015; 201:357-74. [PMID: 25752300 DOI: 10.1007/s00359-015-0995-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 02/19/2015] [Accepted: 02/25/2015] [Indexed: 10/23/2022]
Abstract
The electric organ (EO) of weakly electric mormyrids consists of flat, disk-shaped electrocytes with distinct anterior and posterior faces. There are multiple species-characteristic patterns in the geometry of the electrocytes and their innervation. To further correlate electric organ discharge (EOD) with EO anatomy, we examined four species of the mormyrid genus Campylomormyrus possessing clearly distinct EODs. In C. compressirostris, C. numenius, and C. tshokwe, all of which display biphasic EODs, the posterior face of the electrocytes forms evaginations merging to a stalk system receiving the innervation. In C. tamandua that emits a triphasic EOD, the small stalks of the electrocyte penetrate the electrocyte anteriorly before merging on the anterior side to receive the innervation. Additional differences in electrocyte anatomy among the former three species with the same EO geometry could be associated with further characteristics of their EODs. Furthermore, in C. numenius, ontogenetic changes in EO anatomy correlate with profound changes in the EOD. In the juvenile the anterior face of the electrocyte is smooth, whereas in the adult it exhibits pronounced surface foldings. This anatomical difference, together with disparities in the degree of stalk furcation, probably contributes to the about 12 times longer EOD in the adult.
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39
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Lavoué S, Sullivan JP. Petrocephalus boboto and Petrocephalus arnegardi, two new species of African electric fish (Osteoglossomorpha, Mormyridae) from the Congo River basin. Zookeys 2014:43-65. [PMID: 24843255 PMCID: PMC4023242 DOI: 10.3897/zookeys.400.6743] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 03/26/2014] [Indexed: 11/23/2022] Open
Abstract
A specimen of the African weakly electric fish genus Petrocephalus (Osteoglossomorpha, Mormyridae) collected in the Congo River at Yangambi, Orientale Province, Democratic Republic of Congo, is described as a new species. Petrocephalus bobotosp. n. can be distinguished from other Central African species of Petrocephalus by a combination of the following characteristics: three distinct black spots on the body, one at the origin of the pectoral fin, one at the origin of the caudal fin and one below the anterior base of the dorsal fin; Nakenrosette and Khelrosette electroreceptor clusters distinct on head but Augenrosette cluster reduced in size; 23 branched dorsal rays, 34 branched anal rays, and electric organ discharge waveform triphasic. Petrocephalus bobotosp. n. most closely resembles the holotype of Petrocephalus binotatus but is easily distinguished from it by its smaller mouth. A comparative molecular analysis including 21 other Petrocephalus species shows Petrocephalus bobotosp. n. to be genetically distinctive and to represent a deep lineage in the genus. Two specimens of Petrocephalus collected at Yangambi are morphologically similar and genetically closely related to specimens previously assigned to Petrocephalus binotatus, collected in the northwestern Congo River basin within Odzala-Kokua National Park, Republic of the Congo. This prompts us to formally describe a new species from these collections, Petrocephalus arnegardisp. n., that, although similar to the holotype of Petrocephalus binotatus, can be distinguished from it by its smaller mouth and shorter interorbital width.
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Affiliation(s)
- Sébastien Lavoué
- Institute of Oceanography, National Taiwan University, Roosevelt Road, Taipei 10617, Taiwan
| | - John P Sullivan
- Cornell University Museum of Vertebrates, 159 Sapsucker Woods Road, Ithaca, New York 14850 USA
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40
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Krahe R, Fortune ES. Electric fishes: neural systems, behaviour and evolution. ACTA ACUST UNITED AC 2014; 216:2363-4. [PMID: 23761461 DOI: 10.1242/jeb.091322] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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41
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Baker CA, Kohashi T, Lyons-Warren AM, Ma X, Carlson BA. Multiplexed temporal coding of electric communication signals in mormyrid fishes. ACTA ACUST UNITED AC 2014; 216:2365-79. [PMID: 23761462 DOI: 10.1242/jeb.082289] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The coding of stimulus information into patterns of spike times occurs widely in sensory systems. Determining how temporally coded information is decoded by central neurons is essential to understanding how brains process sensory stimuli. Mormyrid weakly electric fishes are experts at time coding, making them an exemplary organism for addressing this question. Mormyrids generate brief, stereotyped electric pulses. Pulse waveform carries information about sender identity, and it is encoded into submillisecond-to-millisecond differences in spike timing between receptors. Mormyrids vary the time between pulses to communicate behavioral state, and these intervals are encoded into the sequence of interspike intervals within receptors. Thus, the responses of peripheral electroreceptors establish a temporally multiplexed code for communication signals, one consisting of spike timing differences between receptors and a second consisting of interspike intervals within receptors. These signals are processed in a dedicated sensory pathway, and recent studies have shed light on the mechanisms by which central circuits can extract behaviorally relevant information from multiplexed temporal codes. Evolutionary change in the anatomy of this pathway is related to differences in electrosensory perception, which appears to have influenced the diversification of electric signals and species. However, it remains unknown how this evolutionary change relates to differences in sensory coding schemes, neuronal circuitry and central sensory processing. The mormyrid electric communication pathway is a powerful model for integrating mechanistic studies of temporal coding with evolutionary studies of correlated differences in brain and behavior to investigate neural mechanisms for processing temporal codes.
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Affiliation(s)
- Christa A Baker
- Department of Biology, Washington University in St Louis, St Louis, MO, USA
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Baker CVH, Modrell MS, Gillis JA. The evolution and development of vertebrate lateral line electroreceptors. ACTA ACUST UNITED AC 2014; 216:2515-22. [PMID: 23761476 DOI: 10.1242/jeb.082362] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Electroreception is an ancient vertebrate sense with a fascinating evolutionary history involving multiple losses as well as independent evolution at least twice within teleosts. We review the phylogenetic distribution of electroreception and the morphology and innervation of electroreceptors in different vertebrate groups. We summarise recent work from our laboratory that has confirmed the homology of ampullary electroreceptors in non-teleost jawed vertebrates by showing, in conjunction with previously published work, that these are derived embryonically from lateral line placodes. Finally, we review hypotheses to explain the distribution of electroreception within teleosts, including the hypothesis that teleost ampullary and tuberous electroreceptors evolved via the modification of mechanosensory hair cells in lateral line neuromasts. We conclude that further experimental work on teleost electroreceptor development is needed to test such hypotheses.
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Affiliation(s)
- Clare V H Baker
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
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Kramer B, van der Bank H, Wink M. Marked differentiation in a new species of dwarf stonebasher,Pollimyrus cuandoensissp. nov. (Mormyridae: Teleostei), from a contact zone with two sibling species of the Okavango and Zambezi rivers. J NAT HIST 2013. [DOI: 10.1080/00222933.2013.807950] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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44
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Carlson BA, Gallant JR. From sequence to spike to spark: evo-devo-neuroethology of electric communication in mormyrid fishes. J Neurogenet 2013; 27:106-29. [PMID: 23802152 DOI: 10.3109/01677063.2013.799670] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Mormyrid fishes communicate using pulses of electricity, conveying information about their identity, behavioral state, and location. They have long been used as neuroethological model systems because they are uniquely suited to identifying cellular mechanisms for behavior. They are also remarkably diverse, and they have recently emerged as a model system for studying how communication systems may influence the process of speciation. These two lines of inquiry have now converged, generating insights into the neural basis of evolutionary change in behavior, as well as the influence of sensory and motor systems on behavioral diversification and speciation. Here, we review the mechanisms of electric signal generation, reception, and analysis and relate these to our current understanding of the evolution and development of electromotor and electrosensory systems. We highlight the enormous potential of mormyrids for studying evolutionary developmental mechanisms of behavioral diversification, and make the case for developing genomic and transcriptomic resources. A complete mormyrid genome sequence would enable studies that extend our understanding of mormyrid behavior to the molecular level by linking morphological and physiological mechanisms to their genetic basis. Applied in a comparative framework, genomic resources would facilitate analysis of evolutionary processes underlying mormyrid diversification, reveal the genetic basis of species differences in behavior, and illuminate the origins of a novel vertebrate sensory and motor system. Genomic approaches to studying the evo-devo-neuroethology of mormyrid communication represent a deeply integrative approach to understanding the evolution, function, development, and mechanisms of behavior.
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Affiliation(s)
- Bruce A Carlson
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130-4899, USA.
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45
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Leininger EC, Kelley DB. Distinct neural and neuromuscular strategies underlie independent evolution of simplified advertisement calls. Proc Biol Sci 2013; 280:20122639. [PMID: 23407829 DOI: 10.1098/rspb.2012.2639] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Independent or convergent evolution can underlie phenotypic similarity of derived behavioural characters. Determining the underlying neural and neuromuscular mechanisms sheds light on how these characters arose. One example of evolutionarily derived characters is a temporally simple advertisement call of male African clawed frogs (Xenopus) that arose at least twice independently from a more complex ancestral pattern. How did simplification occur in the vocal circuit? To distinguish shared from divergent mechanisms, we examined activity from the calling brain and vocal organ (larynx) in two species that independently evolved simplified calls. We find that each species uses distinct neural and neuromuscular strategies to produce the simplified calls. Isolated Xenopus borealis brains produce fictive vocal patterns that match temporal patterns of actual male calls; the larynx converts nerve activity faithfully into muscle contractions and single clicks. In contrast, fictive patterns from isolated Xenopus boumbaensis brains are short bursts of nerve activity; the isolated larynx requires stimulus bursts to produce a single click of sound. Thus, unlike X. borealis, the output of the X. boumbaensis hindbrain vocal pattern generator is an ancestral burst-type pattern, transformed by the larynx into single clicks. Temporally simple advertisement calls in genetically distant species of Xenopus have thus arisen independently via reconfigurations of central and peripheral vocal neuroeffectors.
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Affiliation(s)
- Elizabeth C Leininger
- Department of Biological Sciences and Program in Neurobiology and Behavior, Columbia University, New York, NY, USA.
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Montaña CG, Winemiller KO. Evolutionary convergence in Neotropical cichlids and Nearctic centrarchids: evidence from morphology, diet, and stable isotope analysis. Biol J Linn Soc Lond 2013. [DOI: 10.1111/bij.12021] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Carmen G. Montaña
- Department of Wildlife and Fisheries Sciences; Texas A&M University; College Station; TX; 77843-2258; USA
| | - Kirk O. Winemiller
- Department of Wildlife and Fisheries Sciences; Texas A&M University; College Station; TX; 77843-2258; USA
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Gallant JR, Hopkins CD, Deitcher DL. Differential expression of genes and proteins between electric organ and skeletal muscle in the mormyrid electric fish Brienomyrus brachyistius. ACTA ACUST UNITED AC 2012; 215:2479-94. [PMID: 22723488 DOI: 10.1242/jeb.063222] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Electric organs (EOs) have evolved independently in vertebrates six times from skeletal muscle (SM). The transcriptional changes accompanying this developmental transformation are not presently well understood. Mormyrids and gymnotiforms are two highly convergent groups of weakly electric fish that have independently evolved EOs: while much is known about development and gene expression in gymnotiforms, very little is known about development and gene expression in mormyrids. This lack of data limits prospects for comparative work. We report here on the characterization of 28 differentially expressed genes between SM and EO tissues in the mormyrid Brienomyrus brachyistius, which were identified using suppressive subtractive hybridization (SSH). Forward and reverse SSH was performed on tissue samples of EO and SM resulting in one cDNA library enriched with mRNAs expressed in EO, and a second library representing mRNAs unique to SM. Nineteen expressed sequence tags (ESTs) were identified in EO and nine were identified in SM using BLAST searching of Danio rerio sequences available in NCBI databases. We confirmed differential expression of all 28 ESTs using RT-PCR. In EO, these ESTs represent four classes of proteins: (1) ion pumps, including the α- and β-subunits of Na(+)/K(+)-ATPase, and a plasma membrane Ca(2+)-ATPase; (2) Ca(2+)-binding protein S100, several parvalbumin paralogs, calcyclin-binding protein and neurogranin; (3) sarcomeric proteins troponin I, myosin heavy chain and actin-related protein complex subunit 3 (Arcp3); and (4) the transcription factors enhancer of rudimentary homolog (ERH) and myocyte enhancer factor 2A (MEF2A). Immunohistochemistry and western blotting were used to demonstrate the translation of seven proteins (myosin heavy chain, Na(+)/K(+)-ATPase, plasma membrane Ca(2+)-ATPase, MEF2, troponin and parvalbumin) and their cellular localization in EO and SM. Our findings suggest that mormyrids express several paralogs of muscle-specific genes and the proteins they encode in EOs, unlike gymnotiforms, which may post-transcriptionally repress several sarcomeric proteins. In spite of the similarity in the physiology and function of EOs in mormyrids and gymnotiforms, this study indicates that the mechanisms of development in the two groups may be considerably different.
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Affiliation(s)
- Jason R Gallant
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, USA.
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Carlson BA, Arnegard ME. Neural innovations and the diversification of African weakly electric fishes. Commun Integr Biol 2012; 4:720-5. [PMID: 22446537 DOI: 10.4161/cib.17483] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
In African mormyrid fishes, evolutionary change in a sensory region of the brain established an ability to detect subtle variation in electric communication signals. In one lineage, this newfound perceptual ability triggered a dramatic increase in the rates of signal evolution and species diversification. This particular neural innovation is just one in a series of nested evolutionary novelties that characterize the sensory and motor systems of mormyrids, the most speciose group of extant osteoglossomorph fishes. Here we discuss the behavioral significance of these neural innovations, relate them to differences in extant species diversity, and outline possible scenarios by which some of these traits may have fueled diversification. We propose that sensory and motor capabilities limit the extent to which signals evolve and, by extension, the role of communication behavior in the process of speciation. By expanding these capabilities, neural innovations increase the potential for signal evolution and species diversification.
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Kramer B, Bills R, Skelton P, Wink M. A critical revision of the churchill snoutfish, genusPetrocephalusMarcusen, 1854 (Actinopterygii: Teleostei: Mormyridae), from southern and eastern Africa, with the recognition ofPetrocephalus tanensis, and the description of five new species. J NAT HIST 2012. [DOI: 10.1080/00222933.2012.708452] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Lavoué S. PetrocephalusMarcusen, 1854 (Osteoglossomorpha: Mormyridae) of the Bangweulu-Mweru ecoregion (Luapula River system, Congo basin), with the description of a new species. J NAT HIST 2012. [DOI: 10.1080/00222933.2012.708449] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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