RESUMO
During a recent collection expedition to the Rio Negro, in the state of Amazonas, Brazil, eight individuals of an unknown species were collected, with a combination of characteristics that placed the species in the genus Rhadinoloricaria. Furthermore, the presence of two autapomorphic characteristics, including numerous elongated papillae on the lower lip and unbranched barbelets on the margin of lower lip, suggests that it is a new species. From morphological and phylogenetic analyses, including the sequencing of specific genes to calculate the maximum likelihood analyses, coupled with osteological computed tomography (CT) scan analyses, the authors corroborated that the specimens represent a new species of Rhadinoloricaria, described in the present study.
Assuntos
Peixes-Gato , Animais , Brasil , Peixes-Gato/anatomia & histologia , Peixes-Gato/genética , Filogenia , Tomografia Computadorizada por Raios X , Esqueleto/diagnóstico por imagemRESUMO
The Neotropical family Heptapteridae comprises 228 valid species widely distributed in South America. Imparfinis is one of the most diverse genera of this family, with 25 valid species widely distributed, inhabiting streams from Costa Rica to Argentina. Old descriptions coupled with lack of recent systematic studies of the species of Imparfinis from the Upper Paraná river basin have led to a taxonomic impediment and hindered the advancement of studies in other areas, such as ecology, cytogenetic, phylogenetic, and evolution. We conducted the first integrative study analyzing both molecular and morphological data of Imparfinis from the Upper Paraná River basin. Our analyses strongly support the existence of four independent evolutionary lineages in this river system, three of them are the nominal species I. mirini, I. schubarti, and I. piperatus, and a new species from Goiás state described herein.
Assuntos
Peixes-Gato , Rios , Animais , Filogenia , Brasil , Peixes-Gato/genética , CitogenéticaRESUMO
A new species of Poptella is described from the rio Xingu basin, Pará and Mato Grosso states, Brazil. The new species is distinguished from all congeners by having a greater number of scales around the caudal peduncle (1518 vs. 1314). Furthermore, this species can be easily distinguished from P. brevispina, P. longipinnis, and P. fuscata by the lower number of branched rays in the dorsal fin (9 vs. 1011). The description of new taxon represents the third species of the genus Poptella described in the last five years.(AU)
Uma nova espécie de Poptella é descrita da bacia do rio Xingu, estados do Pará e Mato Grosso, Brasil. A nova espécie é distinguida de todas as espécies congêneres por apresentar maior número de escamas ao redor do pedúnculo caudal (1518 vs. 1314). Além disso, esta espécie pode ser facilmente distinguida de P. brevispina P. longipinnis e P. fuscata pelo menor número de raios ramificados na nadadeira dorsal (9 vs.10-11). A descrição do novo táxon representa a terceira espécie do gênero Poptella descrita nos últimos cinco anos.(AU)
Assuntos
Animais , Nadadeiras de Animais/anatomia & histologia , Caraciformes/classificação , Especificidade da Espécie , Brasil , BiodiversidadeRESUMO
In this study, a new species of Moenkhausia is described from the upper rio Juruena, rio Tapajós basin, Brazil. It is distinguished from all congeners by the presence of minute bony hooks in all fins of both mature females and males and combination of a prepelvic region flattened, dorsal portion of the humeral blotch extending two scales horizontally and vertically, lateral line with 28-32 scales, five scale series above and below lateral line; circumpeduncular scales 13-14, anal-fin rays 16-19 and dorsal portion of eyes blue in live specimens. The new species is also supported by high divergence in the mitochondrial gene cytochrome c oxidase subunit I (COI). The presence of minute fin bony hooks in both females and males, population variations and late development of the lateral line in Moenkhausia andrica are discussed.
Assuntos
Characidae , Caraciformes , Nadadeiras de Animais , Animais , Brasil , Characidae/genética , Caraciformes/genética , Feminino , Masculino , RiosRESUMO
The Neotropics harbor the most species-rich freshwater fish fauna on the planet, but the timing of that exceptional diversification remains unclear. Did the Neotropics accumulate species steadily throughout their long history, or attain their remarkable diversity recently? Biologists have long debated the relative support for these museum and cradle hypotheses, but few phylogenies of megadiverse tropical clades have included sufficient taxa to distinguish between them. We used 1288 ultraconserved element loci spanning 293 species, 211 genera, and 21 families of characoid fishes to reconstruct a new, fossil-calibrated phylogeny and infer the most likely diversification scenario for a clade that includes a third of Neotropical fish diversity. This phylogeny implies paraphyly of the traditional delimitation of Characiformes because it resolves the largely Neotropical Characoidei as the sister lineage of Siluriformes (catfishes), rather than the African Citharinodei. Time-calibrated phylogenies indicate an ancient origin of major characoid lineages and reveal a much more recent emergence of most characoid species. Diversification rate analyses infer increased speciation and decreased extinction rates during the Oligocene at around 30 Ma during a period of mega-wetland formation in the proto-Orinoco-Amazonas. Three species-rich and ecomorphologically diverse lineages (Anostomidae, Serrasalmidae, and Characidae) that originated more than 60 Ma in the Paleocene experienced particularly notable bursts of Oligocene diversification and now account collectively for 68% of the approximately 2150 species of Characoidei. In addition to paleogeographic changes, we discuss potential accelerants of diversification in these three lineages. While the Neotropics accumulated a museum of ecomorphologically diverse characoid lineages long ago, this geologically dynamic region also cradled a much more recent birth of remarkable species-level diversity. [Biodiversity; Characiformes; macroevolution; Neotropics; phylogenomics; ultraconserved elements.].
Assuntos
Peixes-Gato , Caraciformes , Animais , Biodiversidade , Fósseis , FilogeniaRESUMO
A new species of Poptella is described from the Río Putumayo, Upper Río Amazon basin, Peru. The new species is distinguished from congeners by having a dense field of dark chromatophores homogeneously spread over the posterior half of the body, posterior humeral blotch extending to three to four horizontal scale rows below the lateral line, and a higher number of branched dorsal-fin rays. The new species can be readily distinguished from P. paraguayensis by having a comparatively shorter predorsal spine.
Assuntos
Characidae/anatomia & histologia , Characidae/classificação , Animais , Peru , Rios , Especificidade da EspécieRESUMO
A new species of Brachychalcinus is described from the Rio Trombetas basin, Brazil. It differs from congeners by possessing a conspicuous rounded second humeral spot. Additionally, our new species differs from Brachychalcinus nummus, B. orbicularis and B. reisi by having a higher number of branched dorsal-fin rays, and from Brachychalcinus parnaibae by having a lower head depth.
Assuntos
Characidae/anatomia & histologia , Characidae/classificação , Nadadeiras de Animais/anatomia & histologia , Animais , Brasil , Cabeça/anatomia & histologia , Rios , Especificidade da EspécieRESUMO
Moenkhausia melogramma is herein redescribed, based on the examination of the holotype plus additional specimens from the western Amazon basin in Brazil, Colombia, Peru, and Ecuador. Moenkhausia melogramma shares with M. collettii, M. conspicua, M. copei, M. venerei, and M. flava a broad dark longitudinal stripe across the eye, and a well-defined dark stripe on the anal-fin base. It can be promptly distinguished from these species by having two humeral blotches. Additionally, we provide comments on the putative relationships of Moenkhausia melogramma with the aforementioned congeners and the Hemigrammus lunatus species-group.(AU)
RESUMO Moenkhausia melogramma é redescrita com base no exame do holótipo e exemplares adicionais da bacia amazônica ocidental no Brasil, Colômbia, Peru e Equador. Moenkhausia melogramma compartilha com M. collettii, M. conspicua, M. copei, M. venerei e M. flava a presença de uma faixa larga longitudinal escura que atravessa os olhos e uma linha escura bem definida na base da nadadeira anal. Ela pode ser prontamente distinguida dessas espécies por ter duas manchas umerais. Adicionalmente, fornecemos comentários sobre as possíveis relações filogenéticas de Moenkhausia melogramma com as congêneres supramencionadas e com o grupo de espécies Hemigrammus lunatus.
Assuntos
Animais , Ecossistema Amazônico , Characidae/classificação , Pinos OrtopédicosRESUMO
Moenkhausia melogramma is herein redescribed, based on the examination of the holotype plus additional specimens from the western Amazon basin in Brazil, Colombia, Peru, and Ecuador. Moenkhausia melogramma shares with M. collettii, M. conspicua, M. copei, M. venerei, and M. flava a broad dark longitudinal stripe across the eye, and a well-defined dark stripe on the anal-fin base. It can be promptly distinguished from these species by having two humeral blotches. Additionally, we provide comments on the putative relationships of Moenkhausia melogramma with the aforementioned congeners and the Hemigrammus lunatus species-group.(AU)
RESUMO Moenkhausia melogramma é redescrita com base no exame do holótipo e exemplares adicionais da bacia amazônica ocidental no Brasil, Colômbia, Peru e Equador. Moenkhausia melogramma compartilha com M. collettii, M. conspicua, M. copei, M. venerei e M. flava a presença de uma faixa larga longitudinal escura que atravessa os olhos e uma linha escura bem definida na base da nadadeira anal. Ela pode ser prontamente distinguida dessas espécies por ter duas manchas umerais. Adicionalmente, fornecemos comentários sobre as possíveis relações filogenéticas de Moenkhausia melogramma com as congêneres supramencionadas e com o grupo de espécies Hemigrammus lunatus.
Assuntos
Animais , Ecossistema Amazônico , Characidae/classificação , Pinos OrtopédicosRESUMO
The species Moenkhausia australis was described based on two specimens from arroyos Trementina and Chagalalina, Rio Paraguai basin, Paraguay. Its taxonomic history is complex and for many years the species was considered a synonym of Moenkhausia sanctaefilomenae. Moenkhausia australis shares a reticulated color pattern with the Moenkhausia oligolepis/M. sanctaefilomenae complex, being more similar within the species included in the complex to M. oligolepis, M. sanctaefilomenae, and M. forestii, with which it shares a prepelvic region laterally compressed, a feature also observed in Bario steindachneri. The laterally compressed prepelvic region is inferred to be putatively synapomorphic for the subgroup herein denominated as Moenkhausia oligolepis group. Our results, based on both molecular and morphological data, support the validity of Moenkhausia australis, which can be readily distinguished from the other members of the group by possessing the following combination of characters: complete lateral line, 23-27 scales in the lateral line, and five scales series above and below the lateral line. Our analysis also indicates three genetic structured populations of M. australis, from Rio Paraguai, upper Rio Paraná, and Rio Madeira basins. Since they are not diagnosable by morphological characters, we conservatively maintain these three genetic lineages as a single species.