| parasitism of cichlasoma paranaense kullander, 1983 and gymnotus carapo linnaeus, 1814 by clinostomum complanatum (rudolphi, 1814) metacercariae in the taquari river. | the infection, known as yellow spot disease, produced by metacercariae of clinostomum spp. was studied in fishes of the taquari river, located in jataizinho, paraná state, brazil. a total of 1,582 specimens, belonging to 36 species, were collected between march 1999 and april 2001. yellow spot disease was observed only in gymnotus carapo linnaeus, 1814 (gymnotiformes, gymnotidae) and cichlasoma paranaense kullander, 1983 (perciformes, cichlidae). this parasitism was generated by metacercariae of ... | 2005 | 16341430 |
| neotropical monogenoidea. 52. diechodactylus joaberi n. g., n. sp. from the banded knifefish gymnotus carapo (gymnotiformes: gymnotidae) in southeastern brazil. | diechodactylus joaberi n. g., n. sp. is described from the body surface of the banded knifefish gymnotus carapo l. (gymnotiformes: gymnotidae) from southeastern brazil. the new genus is proposed to accommodate species with five pairs of hooks in anterior bilateral clusters on the haptor, three pairs of hooks in a single cluster on the posterior margin of the haptor, sclerites r1 associated with the superficial bar, and confluent intestinal caeca. the presence of five pairs of hooks in two bilate ... | 2008 | 18030601 |
| [ultrastructure of the ampullary organ of gymnotus carapo (gymnotidae) nature and origin of its polysaccharides]. | | 2014 | 4251200 |
| structural and functional aspects of the fast electrosensory pathway in the electrosensory lateral line lobe of the pulse fish gymnotus carapo. | the fast electrosensory pathway (fep) of gymnotiform fish is mediated by tuberous electroreceptor organs innervated by ganglion cells that synapse with spherical cells of the electrosensory lateral line lobe (ell). spherical cells project to the magnocellular mesencephalic nucleus. the electrosensory environment was represented somatotopically within ell. the mandibular (mn) and the supraorbital (son) nerves projected to rostral ell (occupying 19-28% and 4-10%, respectively), and the posterior b ... | 1998 | 9826277 |
| the spinal cord of gymnotus carapo: the electromotoneurons and their projection patterns. | the electric organ of gymnotus carapo lies parallel to the spinal cord and extends from the pectoral girdle to the tip of the tail. the spinal electromotoneurons are distributed in a relatively consistent pattern: there is a peak at 17% of the fish's length and an irregular distribution beyond 25%. horseradish peroxidase injections into the electric organ not exceeding 5% of the fish's length labeled electromotoneuron arrays occupying 20% of the fish's length. injections made in four discrete ro ... | 1994 | 7987665 |
| some aspects of the structural organization of the spinal cord of gymnotus carapo (teleostei, gymnotiformes). i. the electromotor neurons. | the spinal electromotor neurons (emns) of gymnotus carapo from a distinct column dorsal to the central canal. when massively retrograde-labeled with horseradish peroxidase, these neurons show a well-developed dendritic arborization. dendrites run along the longitudinal axis of the cord and also project toward the dorsal gray and dorsolateral funiculi. input to the emns is mediated by scarce synaptic contacts which show the fine structural characteristics of the so-called "morphologically mixed" ... | 2006 | 3453366 |
| automated pulse discrimination of two freely-swimming weakly electric fish and analysis of their electrical behavior during dominance contest. | electric fishes modulate their electric organ discharges with a remarkable variability. some patterns can be easily identified, such as pulse rate changes, offs and chirps, which are often associated with important behavioral contexts, including aggression, hiding and mating. however, these behaviors are only observed when at least two fish are freely interacting. although their electrical pulses can be easily recorded by non-invasive techniques, discriminating the emitter of each pulse is chall ... | 2017 | 28188835 |
| new approach data in electric fish (teleostei: gymnotus): sex chromosome evolution and repetitive dna. | antagonist sexual selection is the driving force behind the origin and diversification of sex chromosomes such as xx/xy and zz/zw. however, chromosome mobility, mainly in fishes, may result in the formation of chromosomes of recent origin, a process known as turnover. the family gymnotidae, which is composed of the genera electrophorus+gymnotus, presents a multiple system of the type x1x1x2x2/x1x2y, which has been described for gymnotus pantanal. this article describes the karyotype of three ama ... | 2014 | 25264714 |
| automatic realistic real time stimulation/recording in weakly electric fish: long time behavior characterization in freely swimming fish and stimuli discrimination. | weakly electric fish are unique model systems in neuroethology, that allow experimentalists to non-invasively, access, central nervous system generated spatio-temporal electric patterns of pulses with roles in at least 2 complex and incompletely understood abilities: electrocommunication and electrolocation. pulse-type electric fish alter their inter pulse intervals (ipis) according to different behavioral contexts as aggression, hiding and mating. nevertheless, only a few behavioral studies com ... | 2014 | 24400122 |
| structure of the littoral fish assemblage in an impounded tributary: the effects of macrophytes presence (subtropical region, brazil). | to evaluate the effects of macrophytes presence in the structure of littoral fish assemblages in the littoral zone, monthly samples were collected from september, 2006 to august, 2007 in an impounded tributary of the itá reservoir, the fragosos river, located in the upper uruguay river basin. fish were collected using a beach seine and sampling was conducted in the littoral zone inside a macrophyte stand and in an area with no macrophytes. a total of 5,191 fish were captured during the study per ... | 2012 | 22990819 |
| the contribution of air breathing to aerobic scope and exercise performance in the banded knifefish gymnotus carapo l. | the contribution of air breathing to aerobic metabolic scope and exercise performance was investigated in a teleost with bimodal respiration, the banded knifefish, submitted to a critical swimming speed (u(crit)) protocol at 30°c. seven individuals (mean ± s.e.m. mass 89±7 g, total length 230±4 mm) achieved a u(crit) of 2.1±1 body lengths (bl) s(-1) and an active metabolic rate (amr) of 350±21 mg kg(-1) h(-1), with 38±6% derived from air breathing. all of the knifefish exhibited a significant in ... | 2012 | 22442370 |
| two new species of parspina pearse, 1920 (digenea: cryptogonimidae) from freshwater fishes (gymnotiformes) of the paraná river basin in argentina. | two new species of the cryptogonimid genus parspina pearse, 1920 are described from gymnotiform fishes of the paraná river basin, p. carapo n. sp. from the banded knifefish gymnotus carapo linnaeus and p. virescens n. sp. from the glass knifefish eigenmannia virescens (valenciennes). parspina carapo differs from p. virescens in the number of oral spines (32-39 vs 30-33) and their length (28-47 vs 16-28 μm), the distribution of tegumental spines and their anchorage, the types of sensory papillae ... | 2011 | 21805392 |
| pomphorhynchus omarsegundoi sp. n. (acanthocephala:pomphorhynchidae), parasite of the banded knifefish gymnotus carapo (gymnotiformes:gymnotidae) from the paraná river basin, argentina. | pomphorhynchus omarsegundoi sp. n. from gymnotus carapo linnaeus from the paraná river basin in argentina is described in this paper. the new species is characterised by having a small body; a non-spirally twisted long neck forming an inconspicuous asymmetrical bulb more developed dorsally than ventrally; a proboscis almost cylindrical, with 11 to 12 longitudinal rows of 5 to 7 (usually 6) hooks each; presence of an apical organ; a mean neck/body ratio of about 1/8; and a post-equatorial male re ... | 2010 | 21344843 |
| agonistic-like responses from the torus semicircularis dorsalis elicited by gaba(a) blockade in the weakly electric fish gymnotus carapo. | findings by our group have shown that the dorsolateral telencephalon of gymnotus carapo sends efferents to the mesencephalic torus semicircularis dorsalis (tsd) and that presumably this connection is involved in the changes in electric organ discharge (eod) and in skeletomotor responses observed following microinjections of gaba a antagonist bicuculline into this telencephalic region. other studies have implicated the tsd or its mammalian homologue, the inferior colliculus, in defensive response ... | 2006 | 16862286 |
| potential output pathways for agonistic-like responses resulting from the gaba(a) blockade of the torus semicircularis dorsalis in weakly electric fish, gymnotus carapo. | the purpose of this study is to examine the pathways involved in the electromotor (electric organ discharge interruptions) and skeletomotor responses (defense-like) observed by blockade of gabaergic control of the torus semicircularis dorsalis (tsd) of the awake weakly electric fish gymnotus carapo, described in a former study. microinjection of nmda (5 mm) into the pacemaker nucleus (pm) through a guide cannula previously implanted caused a prolonged interruption of the electric organ discharge ... | 2006 | 16696952 |
| reproductive strategies and developmental aspects in mormyrid and gymnotiform fishes. | comparative data on the reproduction in captivity and ontogenetic development of six of mormyrid species and seven gymnotiform species are reported. mormyrid fishes: egg diameter ranged from 1.8 (petroephalus soudanensis) to 3.0 mm (hippopotamyrus pictus. campylomormyrus phantasticus); fecundity (egg number per spawning) from 28 to 215 (pollimyrus isidori) and 121 to 1662 (campylomormyrus cassaicus); spawning intervals from 5 to 20 days (pollimyrus isidori) and 15 to 80 days (campylomormyrus cas ... | 2006 | 14692503 |
| two new species of nomimoscolex (cestoda: proteocephalidea, monticelliidae) from gymnotus carapo (pisces: gymnotiformes) in argentina. | nomimoscolex guillermoi n. sp. and n. dechambrieri n. sp. are described from the gymnotiform fish gymnotus carapo from argentina. the new species are placed into nomimoscolex based on the cortical position of the vitelline follicles, and medullary position of the testes, ovary, and uterus. both species were compared to the 13 species considered valid in the genus. the combination of features distinguishing n. guillermoi from n. dechambrieri is (1) the position of the vagina to cirrus pouch (ante ... | 2003 | 12886413 |
| biochemical and hematological responses of the banded knife fish gymnotus carapo (linnaeus, 1758) exposed to environmental hypoxia. | oxygen of tropical freshwater environments fluctuates drastically. eutrophic lakes and ponds of warm waters frequently reach very low oxygen concentrations. this is the most common habitat of the banded knife fish "tuvira" gymnotus carapo. this electric fish is reported to present bimodal breathing to cope with low environmental oxygen. biochemical responses can be also observed in fishes facing hypoxia but none were studied in tuvira. in the present study, haematological and metabolic changes w ... | 2002 | 12659013 |
| electrolocation-communication discharges of the fish gymnotus carapo l. (gymnotidae: gymnotiformes) during behavioral sleep. | technical problems have hampered the study of sleep in teleosts. the electrical discharges of gymnotus carapo l. (gymnotidae: gymnotiformes) were monitored to evaluate their ease and reliability as parameters to study sleep. the discharges were detected by electrodes immersed in a glass aquarium and were recorded on a conventional polygraph. g. carapo showed conspicuous signs of behavioral sleep. during these periods, opercular beat rates were counted, electric discharges recorded, and the "shar ... | 1999 | 10510259 |
| retinal projections in gymnotid fishes. | retinal projections were studied in four species of gymnotid fishes, gymnotus carapo, hypopomus artedi, eigenmannia virescens and sternopygus sp. with the aid of cobalt or hrp labelling and autoradiographic techniques. the optic tract gives off a small branch, the axial optic tract and then, after crossing in the midline, splits into a dorsomedial, dorsal and ventral fascicle. e. virescens and sternopygus sp. display in addition an accessory optic tract. in all four species retinal projections a ... | 1987 | 3598174 |
| [reproduction of gymnotus carapo (linnaeus, 1758) in the dam of lobo (sp). morphology and histology of the ovary. seasonal changes. (teleostei, gymnotidae)]. | | 2006 | 4059608 |
| polymorphic nature of nucleolus organizer regions in fishes. | an analysis of the nucleolar organizer region(nor) by silver staining of five species of the order gymnotiformes, gymnotus carapo, apteronotus albifrons, sternopygus macrurus, eigenmannia virescens, and eigenmannia sp., is reported. the five species presented only one pair of homologs bearing nors. in g. carapo, a. albifrons, and s. macrurus the silver-stained nors were present as small black dots over the chromosomes. in e. virescens, the short arm of one of the largest chromosome pairs was ent ... | 1981 | 6173166 |