RESUMO
A new species of Characidium from southeastern Brazil is described based on morphological and molecular evidence from specimens collected between the rio Jucuruçu and rio Doce basins. The new species belongs to a group of species within Characidium with an unscaled area in the isthmus and is distinguished from these species, except C. alipioi, C. fasciatum, C. hasemani, and C. kamakan, by the greater distance (greater than 10% SL) and presence of 5-7 scales between the anus and the anal fin, and presence of 14 series of scales around the caudal peduncle. The species is distinguished from C. alipioi by having 4 series of scales above the lateral line (vs. 5 series) and greater distance between the anus and the anal fin; from C. fasciatum and C. kamakan, by the smaller body depth at the dorsal-fin origin, at the anal-fin origin, and at the caudal peduncle; from C. hasemani, by the short distances between the tip of the snout and the pelvic fin, the tip of the snout and the anal fin, and the tip of the snout and the tip of anal fin. The new species forms a presumably monophyletic group with C. alipioi and C. kamakan.(AU)
Uma nova espécie de Characidium do sudeste do Brasil é descrita com base em evidências morfológicas e moleculares provenientes de exemplares coletados entre as bacias dos rios Jucuruçu e Doce. A nova espécie pertence a um grupo de espécies de Characidium com área desprovida de escamas no ístmo e difere dessas espécies, exceto C. alipioi, C. fasciatum, C. hasemani e C. kamakan, pela grande distância (maior que 10% do comprimento padrão, CP) e presença de 5-7 escamas entre o ânus e a nadadeira anal, e pela presença de 14 séries de escamas em torno do pedúnculo caudal. A espécie difere de C. alipioi pela presença de 4 séries de escamas acima da linha lateral (vs. 5 séries) e maior distância entre o ânus e a nadadeira anal; de C. fasciatum e C. kamakan, pela menor altura do corpo na origem da nadadeira dorsal, na origem da nadadeira anal, e no pedúnculo caudal; de C. hasemani, pela menor distância entre a ponta do focinho e a nadadeira pélvica, a ponta do focinho e a nadadeira anal, e a ponta do focinho e a ponta da nadadeira anal. A nova espécie forma um grupo presumidamente monofilético com C. alipioi e C. kamakan.(AU)
Assuntos
Animais , Filogeografia/métodos , Caraciformes/anatomia & histologia , Caraciformes/classificaçãoRESUMO
A new species of Characidium from southeastern Brazil is described based on morphological and molecular evidence from specimens collected between the rio Jucuruçu and rio Doce basins. The new species belongs to a group of species within Characidium with an unscaled area in the isthmus and is distinguished from these species, except C. alipioi, C. fasciatum, C. hasemani, and C. kamakan, by the greater distance (greater than 10% SL) and presence of 5-7 scales between the anus and the anal fin, and presence of 14 series of scales around the caudal peduncle. The species is distinguished from C. alipioi by having 4 series of scales above the lateral line (vs. 5 series) and greater distance between the anus and the anal fin; from C. fasciatum and C. kamakan, by the smaller body depth at the dorsal-fin origin, at the anal-fin origin, and at the caudal peduncle; from C. hasemani, by the short distances between the tip of the snout and the pelvic fin, the tip of the snout and the anal fin, and the tip of the snout and the tip of anal fin. The new species forms a presumably monophyletic group with C. alipioi and C. kamakan.(AU)
Uma nova espécie de Characidium do sudeste do Brasil é descrita com base em evidências morfológicas e moleculares provenientes de exemplares coletados entre as bacias dos rios Jucuruçu e Doce. A nova espécie pertence a um grupo de espécies de Characidium com área desprovida de escamas no ístmo e difere dessas espécies, exceto C. alipioi, C. fasciatum, C. hasemani e C. kamakan, pela grande distância (maior que 10% do comprimento padrão, CP) e presença de 5-7 escamas entre o ânus e a nadadeira anal, e pela presença de 14 séries de escamas em torno do pedúnculo caudal. A espécie difere de C. alipioi pela presença de 4 séries de escamas acima da linha lateral (vs. 5 séries) e maior distância entre o ânus e a nadadeira anal; de C. fasciatum e C. kamakan, pela menor altura do corpo na origem da nadadeira dorsal, na origem da nadadeira anal, e no pedúnculo caudal; de C. hasemani, pela menor distância entre a ponta do focinho e a nadadeira pélvica, a ponta do focinho e a nadadeira anal, e a ponta do focinho e a ponta da nadadeira anal. A nova espécie forma um grupo presumidamente monofilético com C. alipioi e C. kamakan.(AU)
Assuntos
Animais , Filogeografia/métodos , Caraciformes/anatomia & histologia , Caraciformes/classificaçãoRESUMO
BACKGROUND: The genetic diversity of Neotropical fish fauna is underrepresented in public databases. This distortion is evident for the order Siluriformes, in which the suborders Siluroidei and Loricarioidei share equivalent proportion of species, although far less is known about the genetics of the latter clade, endemic to the Neotropical Region. Recently, this information gap was evident in a study about the structural diversity of fish mitochondrial genomes, and hampered a precise chronological resolution of Siluriformes. It has also prevented molecular ecology investigations about these catfishes, their interactions with the environment, responses to anthropogenic changes and potential uses. RESULTS: Using high-throughput sequencing, we provide the nearly complete mitochondrial genomes for 26 Loricariidae and one Callichthyidae species. Structural features were highly conserved. A notable exception was identified in the monophyletic clade comprising species of the Hemiancistrus, Hypostomini and Peckoltia-clades, a ~60 nucleotide-long deletion encompassing the seven nucleotides at the 3' end of the Conserved Sequence Block (CSB) D of the control region. The expression of mitochondrial genes followed the usual punctuation pattern. Heteroplasmic sites were identified in most species. The retrieved phylogeny strongly corroborates the currently accepted tree, although bringing to debate the relationship between Schizolecis guntheri and Pareiorhaphis garbei, and highlighting the low genetic variability within the Peckoltia-clade, an eco-morphologically diverse and taxonomically problematic group. CONCLUSIONS: Herein we have launched the use of high-throughput mitochondrial genomics in the studies of the Loricarioidei species. The new genomic resources reduce the information gap on the molecular diversity of Neotropical fish fauna, impacting the capacity to investigate a variety of aspects of the molecular ecology and evolution of these fishes. Additionally, the species showing the partial CSB-D are candidate models to study the replication and transcription of vertebrate mitochondrial genome.
Assuntos
Peixes-Gato/genética , Genoma Mitocondrial , Mitocôndrias/genética , Animais , Sequência de Bases , DNA Mitocondrial/genética , Evolução Molecular , Variação Genética , Genômica , Anotação de Sequência Molecular , Filogenia , RNA Ribossômico/genética , Análise de Sequência de DNARESUMO
In the 1960s, as a part of the construction of the Furnas Hydroelectric Power Dam, Minas Gerais, Brazil, the Rio Piumhi was diverted from the Rio Grande drainage to the São Francisco River basin, with the resulting introduction of species from one basin to the other. Chromosomal characteristics of various populations of Astyanax fasciatus sensu Eigenmann from the transect region were studied using cytogenetic techniques, with the goal to identify and map the dispersal of invasive species in the Rio São Francisco. Populations of the Rio Grande and Rio Piumhi are distinct from those of the São Francisco basin based on chromosome markers associated to the heterochromatin, Ag-NORs, 18S rDNA, 5S rDNA, and As-51 satellite DNA sites. Individuals with karyomorph originally present in the Piumhi drainage are now present in the São Francisco basin, downstream from the transposition channel. This expansion of the distribution corroborates a hypothesis of progressive substitution of native populations by the invasive Piumhi form.