Examinando por Materia "Systematics"
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- PublicaciónSólo datosFrom the river to the ocean: mitochondrial DNA analyses provide evidence of spectacled caimans (Caiman crocodilus Linnaeus 1758) mainland–insular dispersal(Biological Journal of the Linnean Society, 2021-06-22) Balaguera-Reina, Sergio A .; Konvalina, John D.; Mohammed, Ryan S.; Gross, Brandon; Vazquez, Ryan; Moncada, Juan Felipe; Ali, Saiyaad; Hoffman, Eric A.; Densmore, Llewellyn D.There are few studies that have investigated the evolutionary history of large vertebrates on islands off the Caribbean coast of South America. Here we use the spectacled caiman (Caiman crocodilus) to investigate among- and within-population patterns of genetic diversity to understand connectivity between island and mainland populations. The spectacled caiman is naturally distributed across Central and South America including the islands of Trinidad and Tobago, which are considered to have the only natural insular populations of the species. Because of this apparent isolation, we sought to determine whether caimans on Trinidad and Tobago comprise a unique lineage and have reduced genetic diversity compared to mainland caimans. We test these hypotheses by using mitochondrial DNA variation to assess the phylogenetic and phylogeographical relationships of the C. crocodilus populations inhabiting these islands within the evolutionary context of the entire spectacled caiman complex. Phylogenetic analyses placed the Trinidad and Tobago samples together with samples from Colombia, Venezuela and Brazil into one well-supported clade, which corresponds to the defined Orinoco/upper Negro lineage. Interestingly, the majority of sequences from Trinidad and Tobago are similar or identical to haplotypes reported from Venezuela and Colombia, supporting the idea of a dispersal process from the Orinoco River to these islands. We discuss the implications of our findings for systematics and the conservation of the species and how these dispersal movements could shape the current phylogeographical structure depicted for C. crocodilus.
- PublicaciónSólo datosSpecies delimitation reveals an underestimated diversity of Andean catfishes of the family Astroblepidae (Teleostei: Siluriformes)(Neotropical Ichthyology, 2020-12-04) Ochoa, Luz E.; Melo, Bruno F.; García-Melo, Jorge E.; Maldonado-Ocampo, Javier A.; Souza, Camila S.; Albornoz-Garzón, Juan G.; Villa-Navarro, Francisco; Conde-Saldaña, Cristhian C.; Ortega-Lara, Armando; Oliveira, ClaudioCatfishes of the family Astroblepidae form a group composed by 82 valid species of the genus Astroblepus inhabiting high-gradient streams and rivers throughout tropical portions of the Andean Cordillera. Little has been advanced in the systematics and biodiversity of astroblepids other than an unpublished thesis, a single regional multilocus study and isolated species descriptions. Here, we examined 208 specimens of Astroblepus that apparently belong to 16 valid species from several piedmont rivers from northern Colombia to southern Peru. Using three single-locus approaches for species delimitation in combination with a species tree analysis estimated from three mitochondrial genes, we identified a total of 25 well-delimited lineages including eight valid and 17 potential undescribed species distributed in two monophyletic groups: the Central Andes Clade, which contains 14 lineages from piedmont rivers of the Peruvian Amazon, and the Northern Andes Clade with 11 lineages from trans- and cis-Andean rivers of Colombia and Ecuador, including the Orinoco, Amazon, and Magdalena-Cauca basins and Pacific coastal drainages. Results of species delimitation methods highlight several taxonomical incongruences in recently described species denoting potential synonymies.
- PublicaciónSólo datosUnveiling the mystery: assessing the evolutionary trajectory of the Apaporis caiman population (Caiman crocodilus apaporiensis, Medem 1955) via mitochondrial molecular makers(Biological Journal of the Linnean Society, 2020-07-31) Balaguera-Reina, Sergio A.; Vargas-Ramírez, Mario; Ordóñez-Garza, Nicté; Hernández-González, Felipe; Densmore, Llewellyn D.The Apaporis caiman (Caiman crocodilus apaporiensis) has been of particular interest due to its highly differentiated morphology. However, no molecular research has been done to clarify its taxonomy. We characterized the genetic variation within C. crocodilus by assessing the evolutionary trajectory of Apaporis caiman populations using mitochondrial molecular markers. We collected ten Apaporis caiman samples from the middle basin of the Apaporis River, Colombia, sequenced two mitochondrial genes [cytochrome oxidase I (COI) and cytochrome B (CytB)], and analysed them together with all available sequences from homologous gene fragments at GenBank for the species. Phylogenetic reconstructions revealed three main clades clearly differentiated across the C. crocodilus complex. These clades matched genetically and geographically with three of the four subspecies currently recognized (C. c. chiapasius, C. c. fuscus and C. c. crocodilus). However, we found low to almost non-existent genetic differentiation between C. c. crocodilus and the until-now morphologically recognized C. c. apaporiensis, suggesting that the latter is part of the genetic spectrum present within C. c. crocodilus. We reject the hypothesis of an expected elevated level of genetic variation due to isolation (supported by morphological differentiation) and support the idea of Apaporis caiman populations as a C. crocodilus ecomorph.