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1.
Knodus dorsomaculatus, a new species, is described from Teles Pires River, a tributary of the Tapajós River, Brazil. It can be distinguished from its congeners by the presence of a conspicuous dark blotch on the base of the first five branched dorsal fin rays and the presence of ii,9 dorsal fin rays. Additional comparisons between K. dorsomaculatus and its congeners are presented. 相似文献
2.
A new species of Astyanax from the Rio Paraguaçu basin, Bahia, Brazil, is described. This new species is distinguished from its congeners known to occur in Brazilian drainages by the presence of small bony hooks on all fins of mature males. Furthermore, the new species can be diagnosed by its colour pattern, which consists of a unique vertically elongated humeral blotch, a conspicuous dark drop‐shaped horizontal blotch over the caudal peduncle, tapering anteriorly and not extending to the median caudal‐fin rays, and by the absence of a conspicuous broad dark midlateral stripe. The new species differs further by having the greatest body depth just anterior to the dorsal‐fin origin, 32–35 perforated scales in the lateral line and a reduced number of branched anal‐fin rays (16–20). Apparently, the new species does not fit into any species complex of Astyanax. The occurrence of bony hooks on all fins of Astyanax is discussed. 相似文献
3.
Three species that Navás described - Leucochrysa (Nodita) azevedoi Navás, 1913, Leucochrysa (Nodita) camposi (Navás, 1933) and Leucochrysa (Nodita) morenoi (Navás, 1934) - have received recent taxonomic attention. All three have many similar external features; indeed Navás himself, as well as subsequent authors, have confused the species with each other. Here, (a) misidentifications are corrected; (b) a neotype of Leucochrysa azevedoi is designated; (c) Leucochrysa (Nodita) morenoi, previously synonymized with Leucochrysa (Nodita) camposi, is recognized as a valid species [Reinstated status] All three species are redescribed and illustrated, with special emphasis on the types. Leucochrysa (Nodita) azevedoi was found to be relatively common in agricultural areas along Brazil's Atlantic coast. The two other species are known only from their type localities: Leucochrysa (Nodita) camposi - coastal Ecuador, and Leucochrysa (Nodita) morenoi - Quito, Ecuador. 相似文献
4.
5.
Cetopsis varii sp. nov. Cetopsidae (Cetopsinae) is described from the Río Meta basin in eastern Colombia, at middle portions of the Río Orinoco basin. The new species differs from congeners by a combination of features: the absence of a humeral spot, presence of eye, conical teeth on vomer and dentary and rounded posterior nares, along with details of body, dorsal and caudal‐fin pigmentation. The osteology of the new species is investigated through high‐resolution X‐ray computed tomography and cleared and stained specimens. Data thus obtained are used to code the new species for character states utilized in a previous phylogenetic analysis of Cetopsidae. Analysis of the expanded matrix shows that C. varii is the sister group to C. orinoco. 相似文献
6.
José L. O. Birindelli Heraldo A. Britski Jorge L. Ramirez 《Journal of fish biology》2020,96(6):1349-1359
A new species of Megaleporinus is described from the Rio de Contas, a coastal drainage of eastern Brazil, and its phylogenetic relationships are studied using molecular data. The new species is unique among Anostomidae by possessing two exclusive features: an irregular dark longitudinal stripe from supracleithrum to second midlateral blotch and anterior cranial fontanel partially closed. In addition, the new species is diagnosed by having three premaxillary teeth, three dentary teeth, 37 or 38 scales in lateral line, 16 scale rows around caudal peduncle, three dark midlateral blotches on body, and red fins in life. The new species is closely related to M. obtusidens from the São Francisco basin, corroborating previous studies that indicated that the latter represents a species complex as currently defined. The new species exhibits the first rib enlarged in mature males, a feature described for some congeners. The new species is herein considered to be Endangered under the IUCN criteria. 相似文献
7.
Antonio D. Brescovit 《Studies on Neotropical Fauna and Environment》2013,48(2):149-156
New data on the genus Anyphaenoides are presented. A. paraguana Brescovit and A. lecta (Chickering) are synonymized with A. irusa Brescovit and Sillus placens (O.P.-Cambridge), respectively. The latter species is transferred to Anyphaenoides. The first records of an anyphaenine, A. pacifica (Banks), are given from Chile. Four new species are described: A. volcan from Panama; A. xiboreninho and A. coddingtoni from Brazil; and A. samiria from Peru. 相似文献
8.
MÔNICA TOLEDO-PIZA 《Zoological Journal of the Linnean Society》2007,151(4):691-757
A total of 104 osteological and external morphological features were examined in 13 species of Acestrorhynchus and 15 outgroup taxa to advance a hypothesis of relationships within the genus. Two most parsimonious hypotheses corroborate the monophyly of Acestrorhynchus but differ in the hypothesized relationships of Acestrorhynchus heterolepis . Three proposed supraspecific assemblages are at least partially correlated with groups of species previously diagnosed on the basis of colour pattern: (1) Acestrorhynchus britskii , Acestrorhynchus grandoculis , Acestrorhynchus microlepis , and Acestrorhynchus minimus ; (2) Acestrorhynchus falcirostris , Acestrorhynchus isalineae , and A. Acestrorhynchus nasutus ; and (3) Acestrorhynchus abbreviatus , Acestrorhynchus altus , Acestrorhynchus falcatus , Acestrorhynchus lacustris , and Acestrorhynchus pantaneiro . In one hypothesis A. heterolepis is proposed as the closest relative of the clade formed by A. falcirostris , A. isalineae , and A. nasutus , and in the alternative hypothesis it is proposed as a sister species of the clade formed by A. abbreviatus , A. altus , A. falcatus , A. lacustris , and A. pantaneiro . Relationships among species of the latter clade remain unresolved. Two independent episodes of reduction of body size are hypothesized to have occurred within the genus: one associated with the clade formed by A. grandoculis and A. minimus , and the other with the clade formed by A. isalineae and A. nasutus . © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society , 2007, 151 , 691–757. 相似文献
9.
Zaqueu Santos Lucas S. Oliveira Ruineris A. Cajado Fabíola K. S. Silva Lenise V. F. Silva Diego M. Zacardi 《Journal of fish biology》2023,102(1):214-224
The initial development of the red-bellied pacu Piaractus brachypomus is described using morphological, meristic and morphometric characteristics. A total of 127 individuals were analysed (47 in the yolk-sac, 35 in pre-flexion, five in flexion, 20 in post-flexion and 20 in juvenile) with standard length varying between 2.92 and 48.61 mm. The larvae are born poorly developed and have a discoidal yolk at ~6.33 mm standard length. During early ontogeny, the mouth passes from terminal to subterminal and the anal opening reaches the vertical line over the midline region of the body. There are changes in body shape from long and moderate to deep, head length from small to large, and eye diameter from moderate to large. Dendritic chromatophores were present in the ventral, dorsal and upper part of the swim bladder in the early larval stages. Rounded spots are evident all over the body in juveniles. The total number of myomeres ranges from 39 to 41 (20–23 pre-anal, 17–20 post-anal). Through the morphometric relationships, it was evidenced that the greatest changes during the initial ontogeny of P. brachypomus occur in the transition from the post-flexion stage to the juvenile period, indicating changes in behaviour, foraging and physiology. 相似文献
10.
Riguel Feltrin Contente Carmen Lucia del Bianco Rossi‐Wongtschowski 《Zeitschrift fur angewandte Ichthyologie》2019,35(6):1189-1196
We investigated the combined use of cast net (CN), otter trawl (OT), and encircling gill net (EG) to characterize the richness, composition, and abundance of species and functional groups of the subtidal fish assemblage in a subtropical shallow ecosystem in Brazil. Our hypothesis, that this combination would improve faunal characterization, was supported. The CN best sampled small pelagic planktivores (e.g., juvenile sardines) and detritivores (e.g., juvenile mullets); OT, small and large demersal benthivores (e.g., mojarras and croakers); and EG, large fast‐swimming species, such as piscivores (e.g., snooks and weakfishes) and large detritivores (adult mullets). The mean and total richness were best sampled with the OT. The most accurate richness estimate using non‐parametric estimators was reached by combining all three types of gear. Our findings emphasize that the careful sampling gear selection and the use of multiple gears are indispensable for solid characterizations of coastal fish fauna, and consequently, for the success of monitoring and research programs. 相似文献
11.
da Rocha Carlos Eduardo Falavigna de Carvalho Bjornberg Maria Helena Gonzaga 《Hydrobiologia》1988,(1):445-448
Allocyclops silvaticus sp. n. is described from cultures of leaf litter collected in Atlantic rain forest in the State of Sergipe, northeastern Brazil. It is the first record of the genus in South America. 相似文献
12.
Prochilodus magdalenae is an endemic freshwater fish that occurs in the Magdalena, Sinú and Atrato hydrographic basins. It has an important economic role and is a food resource for the artisanal fishing communities. Its socioeconomic importance contrasts with the current status of its fisheries, where stocks are being depleted. Considering its importance and lack of information on its genetic structure, we used seven microsatellite markers to assess the genetic structure of wild populations of P. magdalenae. The genetic diversity was assessed and the population genetic structure was estimated through Fst, analysis of molecular variance and Bayesian analysis. A total of 290 alleles were found in all loci throughout all population. The high polymorphism contrasts with the levels of observed heterozygosity (Ho = 0.276), which are the lowest values recorded for the family. We found three populations of bocachico coexisting throughout the studied system, contradicting the hypothesis that freshwater migratory fish form panmictic populations. These results on the genetic structure of P. magdalenae constitute tools for a better understanding of the behavior and biology of this species, contributing to fish management and conservation programs. 相似文献
13.
C. A. Lorscheider C. H. Zawadzki M. R. Vicari I. C. Martins‐Santos R. F. Artoni 《Journal of fish biology》2015,87(4):1099-1110
This study taxonomically reviewed the specimens studied by Artoni & Bertollo (1996) and assimilated species of Hypostomus into three groups according to their cytogenetic characteristics, vagility and occurrence environments. 相似文献
14.
Tatiane C. Mariguela Ricardo C. Benine Kelly T. Abe Gleisy S. Avelino Claudio Oliveira 《Journal of Zoological Systematics and Evolutionary Research》2013,51(4):327-332
Moenkhausia is one of the most speciose genera in Characidae, currently composed of 75 nominal species of small fishes distributed across South American hydrographic basins, primarily the Amazon and Guyanas. Despite the large number of described species, studies involving a substantial number of its species designed to better understand their relationships and putative monophyly are still lacking. In this study, we analysed a large number of species of Moenkhausia to test the monophyly of the genus based on the phylogenetic analysis of DNA sequences of two mitochondrial and three nuclear genes. The in‐group included 29 species of Moenkhausia, and the out‐group was composed of representatives of Characidae and other members of Characiformes. All species of Moenkhausia belong to the same clade (Clade C); however, they appear distributed in five monophyletic groups along with other different genera, which means that Moenkhausia is polyphyletic and indicates the necessity of an extensive revision of the group. 相似文献
15.
A general survey of the occurrence of morphologically differentiated sex chromosomes in the neotropical freshwater fishes is presented. The total number of 32 occurrences involving simple XX-XY and ZZ-ZW, and multiple X1X2Y, XY1Y2 and ZW1W2 sex chromosome systems is described, with comments on the aspects of sex chromosome evolution in this fish fauna. The occurrence of different sex chromosome systems in related species of the same genus, or in different populations of the same nominal species, involving male and sometimes female heterogamety, and differences in the molecular composition of sex-linked heterochromatin, are considered as indicative of the early stage of sex chromosomes evolution in fish. 相似文献
16.
M. L. M. Gomes S. L. P. Matta V. A. Araújo G. M. F. Silva A. A. Zacaro 《Journal of fish biology》2010,76(4):852-861
In the present study, the morphology and behaviour of giant trahira Hoplias lacerdae larvae were investigated, from hatching to complete absorption of the yolk sac, under laboratory conditions. In the first day post‐hatching (dph), the larvae presented a big ovoid‐shaped yolk sac that underwent regression during larval ontogeny. The mouth opened 3 dph, when the pectoral fins were evident. From this day, the larvae were able to perform sudden bursts of activity and appear to be able to swim a few centimetres before sinking again. The branchial apparatus was defined at 5 dph, and by 6 dph the operculum was formed. The internal organs such as intestine, liver, kidney and external sensorial structures were present at 7 dph. The yolk sac remained until 7 dph. 相似文献
17.
Yansacyclops ferrarii, new genus, new species (Copepoda: Cyclopoida) is described from the plankton of Rios Guamá and Acará Grande near Belém, State of Pará, Brazil. 相似文献
18.
J. E. García‐Melo J. G. Albornoz‐Garzón L. J. García‐Melo F. A. Villa‐Navarro J. A. Maldonado‐Ocampo 《Journal of fish biology》2018,92(6):1929-1955
Hemibrycon iqueima sp. nov., is described from small streams in the Magdalena drainage at the foothills of the western slope of the Eastern Cordillera of the Colombian Andes, Suarez municipality, Tolima Department, Colombia. The new species is distinguished from its congeners in the Magdalena–Cauca River basin by a combination of characters related to snout–anal‐fin origin length, head length, dorsal–pectoral fin distance, dorsal‐fin–hypural distance, postorbital distance, orbital diameter, snout length, number of total vertebrae, pre‐dorsal scales, scale rows between anal‐fin origin and lateral line, number of branched rays of the anal fin, maxillary teeth number and number and arrangement of hooks on the branched rays of the pectoral and dorsal fins. In addition, the validity of this species is supported by previous molecular analyses that included specimens of the new species that had been erroneously identified. Phylogenetic relationships between the new species and congeners from Pacific coast basins are discussed. 相似文献
19.
Rayssa de Lima Cardoso Marcelo Henrique Lopes Silva Raimunda Nonata Fortes Carvalho‐Neta Antonio Carlos Leal de Castro Cssia Fernanda Chagas Ferreira Helen Roberta Silva Ferreira Dbora Martins Silva Santos 《Zeitschrift fur angewandte Ichthyologie》2019,35(2):488-500
This study evaluated the annual cycle of biological reproductive aspects of Prochilodus lacustris, a neotropical fish species, in Baixada Maranhense Protection Area in northeastern Brazil. Fish were collected monthly between June of 2015 and June of 2016 using gill nets. In the laboratory, 600 individuals were weighed, measured, and eviscerated to obtain biometric data and data for the microscopic and macroscopic analyses of the maturation stages of the gonads. These analyses allowed the determination of the reproductive period using biological indicators such as the gonadosomatic index and hepatosomatic index, condition factor, stomach repletion index, and spawning season. Abiotic variables were measured in situ during the samplig: temperature, pH, dissolved oxygen, and electrical conductivity. In addition, local rainfall data was also obtained. The results showed that the total body length of individuals varied from 151 to 211 mm in males, and from 142 to 239 mm in females. The sex ratio showed a predominance of females over males, and the species showed negative allometric growth. The annual variation of reproductive indicators and the frequency of individuals in advanced stages of gonadal maturation suggest that the reproductive cycle of the species occurs between November and January, with a reproductive peak in January. This reproductive peak coincides with the beginning of the region's rainy season. Although we did not do the fertility analysis, our results suggest that the species presents partitioned spawning. In conclusion, this results demonstrates that the reproduction of the investigated specie is influenced by associations between environmental variables on a seasonal scale and can be contribute to improve the understanding of the dynamics of the physiological reproductive process in lentic environments. 相似文献
20.
Carlos Eduardo Falavigna da Rocha Maria Helena Gonzaga de Carvalho Bjornber 《Hydrobiologia》1987,153(2):97-107
Cyclopid copepods collected mainly in aquatic microcosms and semiterrestrial habitats in the Juréia Ecological Reserve are studied. Hesperocyclops herbsti and Bryocyclops campaneri are described as new species and their taxonomical relationships discussed. Females of Muscocyclops operculatus (Chappuis) are redescribed and the males described for the first time. An emended diagnosis for Muscocyclops is proposed. 相似文献