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1.
Microsc Res Tech ; 85(5): 1845-1855, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-34978358

RESUMO

The present study was done on 20 adult specimens of Nile catfish (Clarias gariepinus) to demonstrate the morphological characteristics of the cardiac region of the stomach. The cardiac mucosa was characterized by a large number of well-defined long folds. The surface epithelial cells were simple columnar type covered with distinct microvilli and connected by desmosomes. Few PAS- and AB- positive goblet cells were found between the surface epithelium. In addition, many lymphocytes, macrophages, and blood capillaries were seen in the epithelial layer. The lamina propria was exclusively occupied by simple branched gastric (cardiac) glands that fill most of the thickness of the mucosa and open into gastric pits. The gastric glands were composed of numerous secretory tubules that were lined with one type of cells with a cytoplasm containing numerous electron-dense granules, well-developed rER, mitochondria, and a large number of free ribosomes. Moreover, macrophages were distributed in the lamina propria and submucosa. Telocytes were observed in the cardiac region for the first time around the glands, blood vessels, between the muscular layer, and in the serosa. A large number of mast cells could be identified in the submucosa around the blood vessels. The presence of many immune cells in the wall of the cardiac stomach suggests involvement in immune response in addition to its digestive function. RESEARCH HIGHLIGHTS: The study exposed many cell types in the wall of the cardiac stomach of Nile catfish including mast cells, lymphocytes, and neutrophils that suggests an involvement in the immune response. The current study is the first one to highlight the distribution of telocytes in the fish stomach.


Assuntos
Peixes-Gato , Animais , Peixes-Gato/anatomia & histologia , Células Epiteliais/ultraestrutura , Epitélio , Membrana Mucosa , Estômago
2.
Nat Commun ; 13(1): 377, 2022 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-35046391

RESUMO

In nature, living organisms evolve unique functional components with mechanically adaptive compatibility to cater dynamic change of interface friction/lubrication. This mechanism can be used for developing intelligent artificial lubrication-regulation systems. Inspired by the muscle hardening-triggered lubrication of longsnout catfish, here we report a modulus adaptive lubricating hydrogel prototype consisting of top mucus-like hydrophilic lubricating layer and muscle-like bottom hydrogel that can stiffen via thermal-triggered phase separation. It exhibits instant switch from soft/high frictional state (~0.3 MPa, µ~0.37) to stiff/lubricating state (~120 MPa, µ~0.027) in water upon heating up. Such switchable lubrication is effective for wide range of normal loads and attributed to the modulus-dominated adaptive contact mechanism. As a proof-of-concept, switchable lubricating hydrogel bullets and patches are engineered for realizing controllable interface movements. These important results demonstrate potential applications in the fields of intelligent motion devices and soft robots.


Assuntos
Peixes-Gato/fisiologia , Lubrificação , Músculos/fisiologia , Fenômenos Fisiológicos da Pele , Adesividade , Animais , Peixes-Gato/anatomia & histologia , Módulo de Elasticidade , Hidrogéis/farmacologia , Temperatura
3.
Mol Biol Rep ; 49(1): 351-361, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34724129

RESUMO

BACKGROUND: The taxonomic status and geographical distribution of M. tengara are vague. No genetic diversity and phylogenetic study have been done till now to resolve its identity and distribution. In the present study, an integrated taxonomic approach has been applied to clarify the taxonomic status, identity, and distribution of bagrid catfish, Mystus tengara. METHODS AND RESULTS: Comparative morphometric evaluation of M. tengara identified in the present study from distant geographical locations revealed variations of the traits in response to body length and environment, without significant genetic distance. The observed morphometric traits of M. tengara were found to be overlapping with available morphometric traits of M. tengara, M. carcio and M. vittatus. Maximum likelihood and Bayesian phylogenetic analysis based on mitochondrial cytochrome c oxidase (COI) gene also could not resolve their identity, and five paraphyletic clades comprising of M. tengara, M. vittatus, and M. carcio from India, Nepal, and Bangladesh were observed. Morphological and genetic evidence along with comparative evaluation of M. tengara, from its type locality, we consider M. tengara identified in the present study to be true, with its distribution extending from North East India to West Bengal, North India, Central India, Northern peninsular India, and Bangladesh. CONCLUSION: The observation of paraphyletic subclades and evaluation of genetic distance between subclades reveals the presence of four cryptic species. Further confirmation on the identity of M. vittatus and M. carcio, by an integrated taxonomic approach based on fresh specimens collected from the type locality, is required.


Assuntos
Peixes-Gato/anatomia & histologia , Peixes-Gato/classificação , Complexo IV da Cadeia de Transporte de Elétrons/genética , Animais , Bangladesh , Teorema de Bayes , Peixes-Gato/genética , Proteínas de Peixes/genética , Índia , Funções Verossimilhança , Proteínas Mitocondriais/genética , Nepal , Filogenia , Filogeografia
4.
Zootaxa ; 4969(3): 453491, 2021 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-34186920

RESUMO

The Glyptothorax species inhabiting the Euphrates and Tigris drainages are reviewed and six species are recognised, one of which is described herein as new species. Glyptothorax armeniacus is endemic to headwater streams in the Euphrates drainage. Glyptothorax kurdistanicus is endemic to the upper Tigris downstream to the Lesser Zab drainage. Glyptothorax cous and G. steindachneri are riverine species widespread in both the Euphrates and Tigris drainages. Glyptothorax silviae is endemic to Iran. Glyptothorax daemon, new species, from the Greater Zab and Yanarsu in the upper Tigris drainage, is distinguished by having the thoracic adhesive apparatus strongly elevated, 1.11.2 times longer than wide, without tubercles on the head, well developed anteromedial striae, the medial pit without striae, and a short adipose fin. Glyptothorax daemon is separated into two mitochondrial lineages, externally indistinguishable and separated by a minimum K2P distance of 2.0% in the DNA barcode region. These lineages are paraphyletic in our analysis indicating past introgressive hybridisation with G. cous. All six species are diagnosed and all, except unstudied G. steindachneri, form distinct mitochondrial clades with between 1.2% and 3.4% minimum K2P distance between them. Species from the Euphrates and Tigris form a monophyletic mitochondrial group separated from 53 other Glyptothorax species studied from India and areas further east.


Assuntos
Peixes-Gato/anatomia & histologia , Peixes-Gato/classificação , Animais , DNA Mitocondrial , Irã (Geográfico)
5.
Fish Physiol Biochem ; 47(4): 1033-1052, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33987812

RESUMO

Ontogeny of the digestive tract and its accessory organs and their further development in the Indian walking catfish (Clarias magur) were examined in larvae, starting from the day of hatching until 35 days post-hatching (dph) reared at 28-29 °C. Many organs at their primordial stage were seen on the day of hatching. These include opened oral cavity with monolayered epithelial lining and very few newly emerging taste buds and goblet cells, primordial pharyngeal teeth on slightly stratified epithelia of the pharyngeal plate, stomach anlage with some degree of the mucosal fold, and a few newly forming gastric glands embedded under its mucosa, primordial anterior and posterior intestine with the smooth mucosal surface, anal opening, and primordial liver and pancreas. At 1 dph, the stomach appeared to be bilobed with the first evidence of food particle in it, and the intestine had some initial folding. On the day of hatching, goblet cells appeared in all lengths of the gut, but not densely, except in the stomach; on it, they appeared at 2 dph. Pancreatic zymogen granules also appeared on this day. Supranuclear vesicles first appeared on 4-5 dph (7.9 ± 0.5-8.6 ± 0.8 mm TL), and they continue to exist until 35 dph. The developmental sequence in this fish confirmed it as an altricial species with some major histomorphological events after the onset of feeding; these include-the appearance of fully developed-pharyngeal teeth at 4 dph and onwards, pyloric sphincter, anterior to posterior intestinal sphincter at 6 dph, and the continuous development of buccopharyngeal cavity and stomach in their shape, size, and functionality until the completion of metamorphosis. Overall, the information on gastrointestinal development in the early life stage of C. magur will be useful for understanding its larval digestive physiology, and this, in turn, will help in designing effective larval feed for growth and survival.


Assuntos
Peixes-Gato/crescimento & desenvolvimento , Sistema Digestório/crescimento & desenvolvimento , Animais , Peixes-Gato/anatomia & histologia , Sistema Digestório/anatomia & histologia , Feminino , Larva/anatomia & histologia , Larva/crescimento & desenvolvimento , Masculino
6.
PLoS One ; 16(3): e0247747, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33720930

RESUMO

We present a combined molecular and morphological phylogenetic analysis of the Loricariinae, with emphasis on the Harttiini (Cteniloricaria, Harttia, and Harttiella) and Farlowellini (Aposturisoma, Farlowella, Lamontichthys, Pterosturisoma, Sturisoma, and Sturisomatichthys). Character sampling comprised seven molecular markers (the mitochondrial Cytb, nd2, 12S and 16S, and the nuclear MyH6, RAG1 and RAG2) and 196 morphological characters. A total of 1,059 specimens, and 159 tissue samples were analized, representing 100 species. A Bayesian Inference analysis was performed using the concatenated data matrix, which is comprised of 6,819 characters. The Loricariinae were found to comprise the tribes (Hartiini (Loricariini, Farlowellini)), the latter two elevated from subtribes. A Maximum Parsimony analysis was also performed using the same data matrix in order to reveal phenotypical synapomorphies to diagnose each clade. Two MP trees were found with a length of 14,704 steps, consistency index of 0.29 and retention index of 0.61, which were summarized in a strict consensus tree. Harttiini includes (Harttiella (Cteniloricaria, Harttia), and Farlowellini includes (Lamontichthys (Pterosturisoma (Sturisoma (Sturisomatichthys, Farlowella)))). Aposturisoma was recovered nested within Farlowella and is synonymyzed to the latter. Sturisoma was corroborated as strictly cis-Andean, while Sturisomatichthys encompasses, besides the valid species already included in the genus, the trans-Andean species once belonging to Sturisoma sensu lato. Identification keys and phylogenetic diagnoses of family-group taxa and genera of both the Harttiini and the Farlowellini are provided.


Assuntos
Peixes-Gato/genética , Proteínas de Peixes/genética , Filogenia , Animais , Teorema de Bayes , Peixes-Gato/anatomia & histologia , Peixes-Gato/classificação , Núcleo Celular/genética , DNA Mitocondrial/genética , Marcadores Genéticos , Mitocôndrias/genética
7.
Mol Phylogenet Evol ; 159: 107117, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33609705

RESUMO

The uplift of the Tibetan Plateau altered the environmental conditions of the local area substantially. Here, we conducted a comprehensive investigation based on morphometrics, population genomics, and climatic factors to evaluate phenotypic and genome-level variations in a radiation of Chimarrichthys catfish endemic to the Plateau. Discriminant function analysis showed phenotypic differences of Chimarrichthys between rivers with respect to elevation. Genetic structure analysis based on 6606 single nucleotide polymorphisms (SNPs) deduced genetic differences between rivers, and species delimitation indicated that the Chimarrichthys fish complex could be divided into three species. Restriction site-associated DNA tags were mapped to the gene sets of Glyptosternon maculatum, and matches were searched against databases for Gene Ontology annotation. Genomic regions exhibiting marked differences among localities represented a range of biological functions, including growth (gdf11), bone development (bmp8a), cellular response to light stimulus (opn3), regulation of the rhodopsin-mediated signalling pathway (grk1), immune response (rag1 and ung), reproductive process (antxr2), and regulation of intracellular iron levels (ireb2). The tag44126, where gene gdf11 is located, was identified as an outlier exhibiting divergence between rivers with altitude differences, and the SNP is thymine (T) in Dadu and Yalong River (~2700 m), but guanine (G) in Jinsha and Qingyi rivers (~2200 and ~ 684 m), suggesting a possible effect of altitude on its differentiation.


Assuntos
Peixes-Gato/classificação , Especiação Genética , Genética Populacional , Filogenia , Altitude , Animais , Peixes-Gato/anatomia & histologia , Clima , Fluxo Gênico , Genoma , Metagenômica , Polimorfismo de Nucleotídeo Único , Rios , Tibet
8.
J Fish Biol ; 98(5): 1371-1384, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33440014

RESUMO

Environmental disasters affecting Brazilian rivers have been frequent recently, especially involving mining activities. Two recent dam-rupture events suddenly released millions of cubic meters of iron tailings downstream into two major Brazilian watersheds. These events generated major losses to the environment and human life. Additionally, the biodiversity in both watersheds was still incompletely known. Two new species of the armoured catfish genus Hypostomus were discovered in the Rio Paraopeba and surrounding rivers of the Rio São Francisco Basin. The species share some main characteristics including a depressed body, large dark spots on a clearer background and the absence of keels on flanks. However, while one species (Hypostomus freirei sp. n.) has a large mandibular ramus and numerous slender teeth, the other (Hypostomus guajupia sp. n.) has a shorter mandibular ramus and few robust teeth. The discovery of these two new mid-sized fish species emphasizes the presumption that the effects of major environmental disasters cannot be fully estimated as local biodiversity is not completely known. This discovery in a recently devastated area also shows that tough environmental laws for the protection, supervision and mitigation of major impacts are urgently needed in developing countries.


Assuntos
Biodiversidade , Peixes-Gato/anatomia & histologia , Peixes-Gato/classificação , Animais , Brasil , Desastres , Mandíbula/anatomia & histologia , Mineração , Rios , Especificidade da Espécie , Dente/anatomia & histologia
9.
PLoS One ; 16(1): e0244894, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33471818

RESUMO

Hopliancistrus is an Ancistrini genus diagnosed by having few and very strong cheek odontodes on interopercular area, and a patch of strong and stiff odontodes on the antero-lateral border of the snout. The type species is herein redescribed based on types and recently collected specimens. In addition, four new congeneric species are described based on specimens collected in other parts of the Rio Xingu and Rio Tapajós basins. Hopliancistrus tricornis is distributed in the lower Rio Tapajós and is diagnosed by the possession of four branched anal-fin rays and relatively large white to yellow spots on trunk and pectoral and pelvic fins, and dark brown spots on dorsal, caudal and anal fins. Hopliancistrus munduruku is described based on specimens from Rio Jamanxim (Rio Tapajós basin) and Rio Curuá (Rio Xingu basin) and is diagnosed by the possession of five branched anal-fin rays and large yellow blotches on trunk and dark brown to black spots over the fins. Hopliancistrus wolverine is distributed in the rapids of the lower and middle Rio Xingu and is diagnosed by the possession of five branched anal-fin rays and conspicuous small yellow dots on head, trunk and fins. Hopliancistrus xikrin is distributed in medium- to small-sized tributaries of the lower portion of Rio Xingu basin, and is diagnosed by absence of contact between the transverse process of the first dorsal-fin pterygiophore and the transverse process of the second pterygiophore. Hopliancistrus xavante is distributed in the tributaries of upper Rio Xingu basin, and is diagnosed by having a thick skin covering the nuchal plate; by having large white spots on trunk and fins; and by the possession of five branched anal-fin rays. An osteological description and a key for species identification are also provided.


Assuntos
Peixes-Gato/classificação , Nadadeiras de Animais , Animais , Peixes-Gato/anatomia & histologia
10.
J Morphol ; 282(4): 489-499, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33432686

RESUMO

The gross brain morphology and the peripheral olfactory organ of Microglanis garavelloi are described throughout development, and the relationship of these organs to the general behaviour of the species is discussed. During the development, the main brain subdivisions undergo a series of morphological changes keeping a relatively constant volume increase. However, we observed different growth rates in the brains of males and females when these were compared. During the maturation process, a series of hormonal events result in the development of some secondary sexual traits in the brain of male specimens, like faster growth rate of brain areas linked to motor control, olfactory and visual responses. The number of olfactory-organ lamellae increases continuously in both males and females, during their maturation period. These results suggest that changes may be caused by cognitive demands that this species is exposed to throughout its lifespan. The gross morphological arrangement of the central nervous system indicates shared patterns with other members of the family Pseudopimelodidae.


Assuntos
Encéfalo/anatomia & histologia , Peixes-Gato/anatomia & histologia , Animais , Encéfalo/embriologia , Peixes-Gato/classificação , Feminino , Masculino , Bulbo Olfatório/anatomia & histologia , Tamanho do Órgão , Fenótipo , Caracteres Sexuais
11.
J Fish Biol ; 98(1): 154-167, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32990952

RESUMO

Loricaria cuffyi n. sp. is described based on 36 specimens from the Essequibo and upper Negro River drainages in western Guyana and the upper Orinoco River drainage in Venezuela. The new species can be distinguished from sympatric and geographically proximate congeners by a postorbital notch that is inconspicuous, shallow and rounded, odontode ridges on the dorsum of head and predorsal weakly developed, abdominal plates tightly joined and completely covering the median abdominal space and pectoral girdle, higher anterior lateral plate counts, and coloration characteristics. The distribution of the new species adds to an interesting and well-documented biogeographical pattern exhibited by other Guiana Shield loricariids influenced by the proto-Berbice during the Cenozoic and recent configuration of drainages in the Guiana Shield. We present an update on the taxonomy of Loricaria, and discuss the biogeography and conservation status of the new species.


Assuntos
Peixes-Gato/anatomia & histologia , Peixes-Gato/classificação , Animais , Conservação dos Recursos Naturais , Guiana , Filogeografia , Rios , Especificidade da Espécie , Venezuela
12.
J Fish Biol ; 98(2): 430-444, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33044745

RESUMO

Silonia silondia is a commercially important fish distributed in Asian countries, which is under threat due to overexploitation. This study focuses on the morphological analysis and genetic variation of S. silondia individuals, through truss network and sequencing of two mitochondrial regions, respectively, from six wild populations of the Ganga and Mahanadi river systems in India. A total of 38 haplotypes was observed by analysing combined mitochondrial genes (cytochrome b + ATPase 6/8) in 247 individuals of S. silondia collected from six populations. Average haplotype and nucleotide diversities were 0.8508 and 0.00231, respectively. Genetic structure analysis showed the predominant cause of genetic variation to be within populations. The two clades were observed among the haplotypes and time of divergence from their most probable ancestor was estimated to be around 0.3949 mya. Analysis of combined mitochondrial genes in six populations of S. silondia resulted into three management units or genetic stocks. The truss network analysis was carried out by interconnecting 12 landmarks from digital images of specimens to identify phenotypic stocks. Sixty-five truss morphometric variables were analysed for geometric shape variation which revealed morphological divergence in River Son specimens. The present study presents molecular markers and genetic diversity data which can be critical input for conservation and management of differentiated populations and future monitoring of the genetic bottleneck. The morphological shape analysis clearly shows that variation in the insertion of adipose fin is an important parameter influencing the morphological discrimination.


Assuntos
Peixes-Gato/anatomia & histologia , Peixes-Gato/genética , Variação Genética , Adenosina Trifosfatases/genética , Animais , Citocromos b/genética , Genes Mitocondriais/genética , Genética Populacional , Haplótipos , Índia , Rios
13.
J Fish Biol ; 98(4): 1091-1104, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33277920

RESUMO

Chaetostoma chimu sp. nov. is described from 119 specimens collected in the Andean foothills of the Orinoco River in Colombia. The new species can be distinguished from congeners by a combination of characters, including shape of cheek odontodes, presence of a supraoccipital excrescence, sexual dimorphism characters and colour pattern. In addition, this species can be distinguished from the sympatric and geographically close congeners of the Orinoco that have curved cheek odontodes (i.e., Chaetostoma anale, Chaetostoma formosae and Chaetostoma joropo), by presenting a generally larger orbital diameter and interorbital distance, details of sexual dimorphism and colour pattern. The type locality of specimens collected by Kjell von Sneidern in the mid-twentieth century in the Colombian Amazon is also clarified. Chaetostoma alternifasciatum and Chaetostoma vagum are proposed as junior synonyms of C. anale. An identification key for the species of Chaetostoma from cis-Andean drainages in Colombia is provided. The new species is herein categorized as Vulnerable (Vu) B1a (i, iii), following the IUCN criteria.


Assuntos
Peixes-Gato/classificação , Caracteres Sexuais , Distribuição Animal , Animais , Peixes-Gato/anatomia & histologia , Peixes-Gato/fisiologia , Colômbia , Rios , Especificidade da Espécie
14.
J Comp Neurol ; 529(8): 1787-1809, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33070328

RESUMO

Mochokid catfish offer a distinct opportunity to study a communication system transitioning to a new signaling channel because some produce sounds and others electric discharges. Both signals are generated using an elastic spring system (ESS), which includes a protractor muscle innervated by motoneurons within the protractor nucleus that also has a motoneuron afferent population. Synodontis grandiops and S. nigriventris produce sounds and electric discharges, respectively, and their ESSs show several morphological and physiological differences. The extent to which these differences explain different signal types remains unclear. Here, we compare ESS morphologies and behavioral phenotypes among five mochokids. S. grandiops and S. nigriventris were compared with Synodontis eupterus that is known to produce both signal types, and representative members of two sister genera, Microsynodontis cf. batesii and Mochokiella paynei, for which no data were available. We provide support for the hypothesis that peripheral and central components of the ESS are conserved among mochokids. We also show that the two nonsynodontids are only sonic, consistent with sound production being an ancestral character for mochokids. Even though the three sound producing-only species differ in some ESS characters, several are similar and likely associated with only sound production. We propose that the ability of S. eupterus to generate both electric discharges and sounds may depend on a protractor muscle intermediate in morphology between sound producing-only and electric discharge-only species, and two separate populations of protractor motoneurons. Our results further suggest that an electrogenic ESS in synodontids is an exaptation of a sound producing ESS.


Assuntos
Comunicação Animal , Peixes-Gato/anatomia & histologia , Peixe Elétrico/anatomia & histologia , Órgão Elétrico/anatomia & histologia , Neurônios Motores/citologia , Animais , Peixes-Gato/fisiologia , Peixe Elétrico/fisiologia , Órgão Elétrico/fisiologia , Neurônios Aferentes/citologia , Especificidade da Espécie
15.
J Fish Biol ; 98(3): 668-679, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33128401

RESUMO

The Neotropical catfish genus Kronichthys contains three species distributed along coastal rivers of southern and southeastern Brazil. Although phylogenetic hypotheses are available, the molecular and morphological diversity and species boundaries within the genus remain unexplored. In this study, the authors generated mitochondrial data for 90 specimens combined with morphometric and meristic data to investigate species diversity, species boundaries and putative morphological signatures in Kronichthys. Phylogenetic and species delimitation results clearly show the presence of four genetic lineages, three within Kronichthys heylandi along the coast from Rio de Janeiro to southern São Paulo and a single lineage encompassing both the nominal species Kronichthys lacerta and Kronichthys subteres from the Ribeira de Iguape basin to Santa Catarina in southern Brazil. Nonetheless, morphological data show overlapped ranges in morphometrics and a definition of only two morphotypes, with clear phenotypic differences in the teeth number: K. heylandi differs from K. subteres + K. lacerta by the higher number of premaxillary teeth (30-52 vs. 19-28) and higher number of dentary teeth (28-54 vs. 17-28). Headwater captures and connections of paleodrainages because of sea-level fluctuations represent the two major biogeographic processes promoting species diversification and lineage dispersal of Kronichthys in the Atlantic coastal range of Brazil.


Assuntos
Biodiversidade , Peixes-Gato/classificação , Animais , Brasil , Peixes-Gato/anatomia & histologia , Peixes-Gato/genética , Variação Genética , Filogenia , Rios
16.
J Fish Biol ; 98(4): 1186-1191, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33244758

RESUMO

Two specimens of Micromyzon akamai, an eyeless and miniaturized species previously known only from the deep channels of the eastern Amazon basin in Brazil, are reported from the Curaray River, a tributary of the Napo River in Ecuador. The new specimens are the first records of Micromyzon in the headwaters of the Amazon River and the first records of M. akamai outside Brazil. External morphological characters and a phylogenetic analysis of cytochrome c oxidase I (coI) gene support the identification of the new specimens as M. akamai. Nevertheless, the new specimens also indicate that some features previously hypothesized to be apomorphic for M. akamai are intraspecifically variable.


Assuntos
Distribuição Animal , Peixes-Gato/fisiologia , Animais , Brasil , Peixes-Gato/anatomia & histologia , Equador , Filogenia , Rios , Especificidade da Espécie
17.
Neotrop. ichthyol ; 19(2): e200101, 2021. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1279493

RESUMO

he age and growth of Pseudoplatystoma corruscans, is analyzed on specimens landed in Puerto Antequera, Province of Chaco, Argentina. The study is based on length frequency distribution of 1192 individuals and growth marks of 293 pectoral spines. Previously to age assignation based on spines readings, we performed analyses that ruled out age-associated resorption of rings and corroborated the annual periodicity of mark formation. The average sizes of the radius of each ring were obtained, and the total length of fish were back-calculated to the time of the ring formation, by the regression model fitted between the total radius of the spines to the respective sizes of each fish. Such data showed a good fitting to growth models of von Bertalanffy, Gompertz and logistic for both sexes separately. Results indicate that the study of the species growth must be carried out for each sex separately and that the fishing regulations must consider this characteristic of the species since the current management guidelines could be promoting differential capture by sexes.(AU)


En este trabajo se analiza el crecimiento y la edad del Pseudoplatystoma corruscans, a partir de ejemplares desembarcados en el Puerto Antequera, provincia de Chaco, Argentina. El estudio se basó en la distribución de frecuencias de tallas de 1192 individuos y marcas de crecimiento en 293 espinas pectorales. Para asignar las edades a partir de las lecturas se realizaron análisis que permitieron descartar la reabsorción de anillos asociada a la edad y corroborar la periodicidad anual de la formación de marcas. Se obtuvieron los tamaños medios de los radios de cada anillo y se retrocalcularon las tallas al momento de su formación, mediante la relación del radio total de las espinas con las tallas respectivas de cada pez. Dichos datos mostraron un buen ajuste a las curvas de crecimiento de von Bertalanffy, Gompertz y logística para ambos sexos por separado. Los resultados demostraron que el estudio del crecimiento de la especie debe realizarse para cada sexo por separado y que las normas pesqueras deben contemplar esta característica de la especie ya que las actuales pautas de manejo podrían estar promoviendo la captura diferencial por sexos.(AU)


Assuntos
Animais , Peixes-Gato/anatomia & histologia , Peixes-Gato/crescimento & desenvolvimento , Efeito Idade , Crescimento , Controle Social Formal
18.
Neotrop. ichthyol ; 19(2): e200128, 2021. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1279482

RESUMO

The coastal basins of southeastern Brazil are influenced by climatic changes that caused sea-level oscillations during the Pleistocene. These marine transgressions and regressions can generate isolation and connection among coastal rivers. In this region, freshwater fishes are excellent models for phylogeographic studies because their distributions may have been affected by geographical and ecological changes resulting from these processes. Therefore, the main objective of this study was to evaluate the effects of Pleistocene sea-level changes on the genetic structure of the loricariid Hisonotus leucofrenatus throughout its area of occurrence. Two genes were sequenced: Cytochrome Oxidase subunit 1 (mitochondrial gene) and rpS7 ribosomal protein gene intron 1 (nuclear gene) from specimens representing 14 river drainages. The genetic data corroborate a divide for freshwater fish by the Serra do Tabuleiro mountain in Santa Catarina State. This divide determines two main genetic groups in H. leucofrenatus: one group to the south and one to the north of this mountain range. The genetic structure observed coincide with the limits of estimated paleodrainage systems for the region, supporting that marine transgressions and regressions during the Pleistocene influenced the biogeographical history of H. leucofrenatus.(AU)


As bacias costeiras do sul do Brasil são influenciadas pelas mudanças climáticas que causaram oscilações no nível do mar durante o Pleistoceno. Essas transgressões e regressões marinhas geraram isolamento e conexão entre os rios. Nessa região, as espécies de peixe são excelentes modelos para estudos filogeográficos, pois suas distribuições podem ter sido afetadas por mudanças históricas e ecológicas decorrentes desses processos. Portanto, o objetivo principal deste estudo foi testar os efeitos das alterações do nível do mar durante o Pleistoceno na estrutura genética das populações do loricarídeo Hisonotus leucofrenatus ao longo de sua área de ocorrência. Dois genes foram sequenciados: Citocromo Oxidase subunidade 1 (gene mitocondrial) e o intron 1 da proteína ribossomal rpS7 (gene nuclear) de espécimes representando 14 bacias de drenagens. A estrutura genética observada corrobora uma divisão para peixes de água doce separada pela Serra do Tabuleiro, em Santa Catarina. Essa divisória determina dois grupos principais genéticos em H. leucofrenatus: um grupo ao sul e outro ao norte desse divisor. A estrutura genética também coincide com os limites dos sistemas de paleodrenagens estimados para a região, sustentando que as transgressões e regressões marinhas durante o Pleistoceno influenciaram a história biogeográfica de H. leucofrenatus.(AU)


Assuntos
Peixes-Gato/anatomia & histologia , Peixes-Gato/genética , Estruturas Genéticas , Filogeografia , Peixes , Mudança Climática , Nível do Mar
19.
Zoolog Sci ; 37(6): 575-579, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33269873

RESUMO

The morphology and morphometry of the olfactory organ of Korean torrent catfishes, genus Liobagrus, consisting of only five endemic species, were investigated by stereo microscopy, scanning electron microscopy, and statistical analysis. They showed the same morphological structure, externally and internally, including a tubular anterior nostril, a slit posterior nostril, and a rosette structure with several linguiform lamellae. Interestingly, however, the lamellar number (LN) revealed specific characteristics useful to identify the five species anatomically: 16-19 in Liobagrus andersoni (with standard length, SL, 96.8 ± 5.5 mm, mean ± SD), 14-16 in Liobagrus obesus (86.9 ± 13.4 mm), 22-27 in Liobagrus mediadiposalis (99.8 ± 14.7 mm), 19-24 in Liobagrus somjinensis (90.1 ± 6.7 mm), and 14-18 in Liobagrus hyeongsanensis (74.0 ± 6.7 mm). Regarding SL, that of L. andersoni was longer than those of L. somjinensis and L. hyeongsanensis. As opposed to the SL, the LN to SL ratios of L. somjinensis (24.1 ± 2.1%) and L. hyeongsanensis (21.1 ± 1.4%) were greater than that of L. andersoni (18 ± 1.2%). These differences might be considered to reflect an interspecific morphological adaptation to micro-habitat according to olfactory importance and can be used as a taxonomic characteristic for this genus.


Assuntos
Peixes-Gato/anatomia & histologia , Peixes-Gato/classificação , Cavidade Nasal/anatomia & histologia , Animais , Ecossistema , Microscopia Eletrônica de Varredura , Cavidade Nasal/ultraestrutura , República da Coreia , Especificidade da Espécie
20.
J Fish Biol ; 97(6): 1748-1769, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32914431

RESUMO

Epactionotus species are known for inhabiting the rocky-bottom stretches of fast-flowing rivers in a limited geographic area along the Atlantic coast of southern Brazil. These species are endemic to single coastal river drainages (two neighbouring drainages for Epactionotus bilineatus) isolated from each other by the coastal lacustrine environments or the Atlantic Ocean. E. bilineatus is from the Maquiné and Três Forquilhas River basins, both tributaries of the Tramandaí River system, whereas E. itaimbezinho is endemic to the Mampituba River drainage and Epactionotus gracilis to the Araranguá River drainage. Recent fieldwork in the Atlantic coastal drainages of southern Brazil revealed new populations in the Urussanga, Tubarão, d'Una and Biguaçu River drainages. Iterative species delimitation using molecular data (cytochrome c oxidase subunit I) and morphology (morphometrics and meristics) was applied to evaluate species recognition of isolated populations. With regard to new data, the genus was re-diagnosed, the status of Epactionotus species/populations was re-evaluated, formerly described species were supported and population structure was recognized. As for the newly discovered populations, both morphological and molecular data strongly support the population from the Biguaçu River drainage, in Santa Catarina State, as a new species. Molecular data revealed strong per-basin population structure, which may be related to species habitat specificity and low or no dispersal among drainages.


Assuntos
Peixes-Gato/classificação , Variação Genética , Filogenia , Animais , Oceano Atlântico , Brasil , Peixes-Gato/anatomia & histologia , Peixes-Gato/genética , Deriva Genética , Rios , Especificidade da Espécie
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