Conditions for establishing fin primary cell cultures in a wide range of ray-finned fishes.

Ray-finned fishes (Actinopterygii) represent the most diverse vertebrate lineage that show extensive variations in physiology, ways of life, and adaptations to marine and freshwater environments, and several species have been established as biological research models. The in vitro culture of cells is fundamental for several fields of biological research, being an alternative for studies that use animals. Hundreds of fish cell lines have been established using specific methods for each cell type and species. Here is described a protocol which can be used commonly for obtaining cell cultures from the caudal fin of a wide range of ray-finned fishes including marine and freshwater species. Conditions for sample collection, microbial disinfection, tissue dissociation, plating and incubation, cryopreservation and thawing, and karyotyping are described in detail. Primary cell cultures were developed for 20 species grouped into 12 different orders. Eleven of these species have been cultivated in vitro for the first time. In the beginning, the fish cell cultures showed different capacities of proliferation among them; however throughout the passages, most cultures began to have a similar proliferation rate. Throughout the passages, it was noticed that cells similar to fibroblasts began to predominate. The great proliferative ability of these cultures reveals their potential to become cell lines. The culture of A. mexicanus, for example, has been proliferating for months and is already in its 65th passage. Moreover, these cell cultures showed conserved diploid chromosome numbers in comparison with in vivo descriptions which suggest these cultures have stable karyotypes. Therefore, these cultures have potential to be used in several fields, such as toxicology, cytogenetics, genomics, pathology, immunology, cellular agriculture, and conservation, and this method has the potential to be expanded to species not yet tested, as well as to other organs.

Soft-tissue fossilization illuminates the stepwise evolution of the ray-finned fish brain.

A complex brain is central to the success of backboned animals. However, direct evidence bearing on vertebrate brain evolution comes almost exclusively from extant species, leaving substantial knowledge gaps. Although rare, soft-tissue preservation in fossils can yield unique insights on patterns of neuroanatomical evolution. Paleontological evidence from an exceptionally preserved Pennsylvanian (∼318 Ma) actinopterygian, Coccocephalus, calls into question prior interpretations of ancestral actinopterygian brain conditions. However, the ordering and timing of major evolutionary innovations, such as an everted telencephalon, modified meningeal tissues, and hypothalamic inferior lobes, remain unclear. Here, we report two distinct actinopterygian morphotypes from the latest Carboniferous-earliest Permian (∼299 Ma) of Brazil that show extensive soft-tissue preservation of brains, cranial nerves, eyes, and potential cardiovascular tissues. These fossils corroborate inferences drawn from ✝Coccocephalus, while adding new information about neuroanatomical evolution. Skeletal features indicate that one of these Brazilian morphotypes is more closely related to living actinopterygians than the other, which is also reflected in soft-tissue features. Significantly, the more crownward morphotype shows a key neuroanatomical feature of extant actinopterygians-an everted telencephalon-that is absent in the other morphotype and ✝Coccocephalus. All preserved Paleozoic actinopterygian brains show broad similarities, including an invaginated cerebellum, hypothalamus inferior lobes, and a small forebrain. In each case, preserved brains are substantially smaller than the enclosing cranial chamber. The neuroanatomical similarities shared by this grade of Permo-Carboniferous actinopterygians reflect probable primitive conditions for actinopterygians, providing a revised model for interpreting brain evolution in a major branch of the vertebrate tree of life.

Metazoan parasites of Hoplias aff. malabaricus, Trachelyopterus galeatus and Schizodon borellii (Osteichthyes) from the Protected Area and its main tributary, Brazil / Metazoários parasitos de Hoplias aff. malabaricus, Trachelyopterus galeatus e Schizodon borellii (Osteichthyes) da Área de Proteção Ambiental e seu principal afluente, Brasil

A study of the parasite-host interactions was conducted in the protected area popularly known as the "Refúgio Biológico de Santa Helena" and its tributary, the São Francisco Falso River. For each of the three host species, Schizodon borellii, Hoplias aff. malabaricus, and Trachelyopterus galeatus, 30 fish were collected from 2018 to 2019. A total of 2172 parasites were identified among the three host species. Among these, the Monogenea class had the highest number of species, with 26 taxa, followed by Copepoda with eight taxa, Digenea with six taxa, and Cestoda and Nematoda with one taxon each. Eleven new records of infection/infestation were found among the host species such as Urocleidoides paradoxus, Urocleidoides ramentacuminatus, Rhinoxenus arietinus, Mymarothecioides sp. (Monogenea), Ergasilus cf. bryconis, Lernaea devastatrix, and Brasergasilus sp. (Copepoda) parasitizing S. borellii. Trinigyrus sp., Vancleaveus sp. (Monogenea), Gamispinus diabolicus (Copepoda) present in T. galeatus, and Gamidactylus jaraquensis (Copepoda) present in H. aff. malabaricus. This study contributes to the record of parasite species occurrence in the vicinity of a protected area and helps fill gaps in the knowledge of fish parasitic fauna in the Neotropical region.(AU)

Foi realizado um estudo das interações parasitas-hospedeiros na área de proteção popularmente conhecida como "Refúgio Biológico de Santa Helena" e seu afluente, o Rio São Francisco Falso. Para cada uma das três espécies hospedeiras, Schizodon borellii, Hoplias aff. malabaricus e Trachelyopterus galeatus, foram coletados 30 peixes entre 2018 e 2019. Foi identificado um total de 2.172 parasitos entre as três espécies hospedeiras. Dentre estes, a classe Monogenea apresentou o maior número de espécies, com 26 táxons, seguida por Copepoda com oito táxons, Digenea com seis táxons, e Cestoda e Nematoda com um táxon cada. Foram encontrados onze novos registros de infecção/infestação entre as espécies hospedeiras tais como Urocleidoides paradoxus, Urocleidoides ramentacuminatus, Rhinoxenus arietinus, Mymarothecioides sp. (Monogenea), Ergasilus cf. bryconis, Lernaea devastatrix e Brasergasilus sp. (Copepoda) parasitando S. borellii. Trinigyrus sp., Vancleaveus sp. (Monogenea), Gamispinus diabolicus (Copepoda) presentes em T. galeatus, e Gamidactylus jaraquensis (Copepoda) em H. aff. malabaricus. Este estudo contribui para o registro da ocorrência de espécies de parasitos nas proximidades de uma área protegida, e ajuda a preencher lacunas no conhecimento da fauna parasitária de peixes na região Neotropical.(AU)

Fish-parasite interactions: A dataset of continental waters in Mexico involving fishes and their helminth fauna.

Most of the available knowledge in the literature on Mexican fishes and their parasites refers to information within political divisions and/or hydrological basins in the country. Indeed, only a few studies have analyzed the helminth fauna of these vertebrates as a biological group distributed nation-wide. This lack of available knowledge prevents the study of several basic and applied aspects involving fish-parasite interactions at different spatial and temporal scales. In this dataset, we compiled all the available geographic information on fish-helminth parasite interactions involving native and exotic fish species recorded in continental waters throughout the Mexican territory. After an exhaustive filtering and the curation of information, our data set contains 5999 records of 361 freshwater fish species (roughly 70% of known freshwater fish species occurring in Mexico) and 483 endo- and ectoparasitic helminths collected over an 85-year period (from 1936-2021) in 1070 localities distributed throughout Mexico. These records are mainly concentrated in only a few states located to the south and east of the country; although all states have been sampled and all major basins in Mexico are represented. The fish order with the highest number of records was Perciformes (n = 2325, 38.75%) while the fish family with the highest number of records was Cichlidae (n = 1741, 29.02%). Native species of fishes corresponded to 92.14% of the records (n = 5528) and fish-associated parasites were found in 41 habitat types in/on their host bodies. Regarding fish parasites, we found that most of the records are from the phylum Platyhelminthes (n = 4495, 74.92%). At the class level, we observed that Trematoda reached the highest number of records (n = 2965, 49.42%). Moreover, we found that Diplostomidae (n = 917, 15.25%) were the family of trematodes with the highest number of records. Most parasites were registered in their adult stage (n = 3730, 62.17%), followed by larval stages (n = 2267, 37.78%). We hope that the fish-parasite interactions data set will encourage researchers worldwide to explore different ecological and coevolutionary aspects of fishes and their helminth parasites, as well as provide useful information for the better implementation of conservation initiatives. There are no copyright restrictions; please cite this data paper when using its data in publications or teaching events.

Lung evolution in vertebrates and the water-to-land transition.

A crucial evolutionary change in vertebrate history was the Palaeozoic (Devonian 419-359 million years ago) water-to-land transition, allowed by key morphological and physiological modifications including the acquisition of lungs. Nonetheless, the origin and early evolution of vertebrate lungs remain highly controversial, particularly whether the ancestral state was paired or unpaired. Due to the rarity of fossil soft tissue preservation, lung evolution can only be traced based on the extant phylogenetic bracket. Here we investigate, for the first time, lung morphology in extensive developmental series of key living lunged osteichthyans using synchrotron x-ray microtomography and histology. Our results shed light on the primitive state of vertebrate lungs as unpaired, evolving to be truly paired in the lineage towards the tetrapods. The water-to-land transition confronted profound physiological challenges and paired lungs were decisive for increasing the surface area and the pulmonary compliance and volume, especially during the air-breathing on land.

All life on Earth started out under water. However, around 400 million years ago some vertebrates, such as fish, started developing limbs and other characteristics that allowed them to explore life on land. One of the most pivotal features to evolve was the lungs, which gave vertebrates the ability to breathe above water. Most land-living vertebrates, including humans, have two lungs which sit on either side of their chest. The lungs extract oxygen from the atmosphere and transfer it to the bloodstream in exchange for carbon dioxide which then gets exhaled out in to the atmosphere. How this important organ first evolved is a hotly debated topic. This is largely because lung tissue does not preserve well in fossils, making it difficult to trace how the lungs of vertebrates changed over the course of evolution. To overcome this barrier, Cupello et al. compared the lungs of living species which are crucial to understand the early stages of the water-to-land transition. This included four species of lunged bony fish which breathe air at the water surface, and a four-legged salamander that lives on land. Cupello et al. used a range of techniques to examine how the lungs of the bony fish and salamander changed shape during development. The results suggested that the lungs of vertebrates started out as a single organ, which became truly paired later in evolution once vertebrates started developing limbs. This anatomical shift increased the surface area available for exchanging oxygen and carbon dioxide so that vertebrates could breathe more easily on land. These findings provide new insights in to how the lung evolved into the paired structure found in most vertebrates alive today. It likely that this transition allowed vertebrates to fully adapt to breathing above water, which may explain why this event only happened once over the course of evolution.

Does genome size increase with water depth in marine fishes?

A growing body of research suggests that genome size in animals can be affected by ecological factors. Half a century ago, Ebeling et al. proposed that genome size increases with depth in some teleost fish groups and discussed a number of biological mechanisms that may explain this pattern (e.g., passive accumulation, adaptive acclimation). Using phylogenetic comparative approaches, we revisit this hypothesis based on genome size and ecological data from up to 708 marine fish species in combination with a set of large-scale phylogenies, including a newly inferred tree. We also conduct modeling approaches of trait evolution and implement a variety of regression analyses to assess the relationship between genome size and depth. Our reanalysis of Ebeling et al.'s dataset shows a weak association between these variables, but the overall pattern in their data is driven by a single clade. Although new analyses based on our "all-species" dataset resulted in positive correlations, providing some evidence that genome size evolves as a function of depth, only one subclade consistently yielded statistically significant correlations. By contrast, negative correlations are rare and nonsignificant. All in all, we find modest evidence for an increase in genome size along the depth axis in marine fishes. We discuss some mechanistic explanations for the observed trends.

A bioinformatics analysis of the CatSper channel in the class Actinopterygii.

The regulation of sperm motility is controlled by several variables, including mainly ion concentrations. In fish, Ca2+ concentrations play an important role in the regulation of sperm motility, and several reports highlight the importance of certain Ca2+ channels in the regulation of this cell function. CatSper is a calcium channel scarcely studied in fish. In the species Salmo salar, it has been shown that it is key in the regulation of sperm motility. Taking into account the relevance of this channel in sperm activation in fish, in this study we evaluated the presence and probable functionality of this channel in the class Actinopterygii. For this purpose, a rational bioinformatic analysis was carried out, which had been previously validated using in vitro techniques by our group. The bioinformatic analysis of the present work revealed that the functionality of CatSper of the species of the class Actinopterygii could be exclusive to freshwater and anadromous fish species. The results of this study showed that only some anadromous and freshwater fish species contain 11 subunits of the CatSper channel, which are enough to trigger sperm motility. Consequently, this study provides new data for a better understanding of the sperm activation mechanism in fish.

Taxonomy of Centropomus Lacépède, 1802 (Perciformes: Centropomidae), with focus on the Atlantic species of the genus.

Centropomus Lacépède, 1802 comprises 13 species of the fishes popularly knows as snooks, distributed in both Atlantic and Pacific coasts of America. Despite several studies on the group, conflicting taxonomic classifications still exist, including overlapping diagnostic characters, rendering species diagnoses extremely difficult. Herein, we review the taxonomy of Centropomus to elucidate species identities, redefine their diagnoses and to assess interspecific relationships based on the examination of 376 specimens. The study included complementary approaches, as analyses of external morphologic characters, linear and geometric morphometrics, and molecular analyses. Forty-nine characters were used for external morphology, 17 discrete plus 32 linear measurements. Shape and size were analyzed through geometric morphometrics of 185 specimens in lateral view. Partial sequences of the gene cytochrome c oxidase I were obtained for 129 specimens representing 11 species. Based on the consistent results retrieved from the morphologic and molecular analyses, we recognized six species of Centropomus from the Atlantic coast (C. ensiferus, C. irae, C. parallelus, C. pectinatus, C. poeyi and C. undecimalis). Centropomus mexicanus is treated as a junior synonym of C. parallelus. Six species from the Pacific coast are also tentatively recognized (C. armatus, C. medius, C. nigrescens, C. robalito, C. unionensis, and C. viridis), however further studies on the Pacific species are still needed. Information on type material, diagnosis, distribution, and taxonomic comments are provided for each species. An identification key to the species of Centropomus is presented.

The oldest Devonian circumpolar ray-finned fish?

Actinopterygians (ray-finned fishes) are the most diverse group of living fishes, but have a sparse Devonian fossil record restricted to low palaeolatitudes. Here we report a new actinopterygian from the Paraná Basin of Brazil, which occupied a circumpolar position in the Palaeozoic. Available geological evidence supports a Middle Devonian or older age for this taxon, which shares features of the mandibular symphysis with the latest Devonian Tegeolepis. A phylogenetic analysis resolves these two as sister taxa. This new record expands the palaeogeographic distribution of Devonian ray-fins and suggests that gaps in their fossil record might be filled by exploring poorly sampled high-latitude localities within the Malvinokaffric Realm.

A new species of Bryconamericus (Characidae: Stevardiinae: Diapomini) from the upper rio Paraná basin, Brazil

Bryconamericus is the most diverse genus within Stevardiinae, comprising 61 valid species distributed in Cis- and Trans-Andean basins from Panama in Central America to northern Argentina in South America. Three species are known from the upper rio Paraná basin: B. exodon, B. iheringii, and B. turiuba. Herein we describe a new species of Bryconamericus from the upper rio Paraná basin inhabiting tributaries of Ivaí, Piquiri, and Tibagi basins, Paraná State, Brazil. The new species differs from its congeners by the presence of unaligned teeth in the outer tooth row of the premaxilla; a single, vertical, dorsally expanded and rounded humeral spot; 36-39 pored scales in the longitudinal series; body depth 31.6-37.9% SL; anal-fin base length 24.8-30.1% SL; number of branched anal-fin rays 19-22, and bony hooks on pelvic- and anal-fin rays of sexually dimorphic males. The new species is syntopic with other Stervadiinae in the upper rio Paraná basin such as B. iheringii, B. turiuba, Piabarchus stramineus, and Piabina argentea.(AU)

Bryconamericus é o gênero de Stevardiinae mais diverso, com 64 espécies válidas distribuídas nas bacias Cis- e Trans-Andinas, do Panamá na América Central à região norte da Argentina na América do Sul. Dessas espécies, três são conhecidas da bacia do alto rio Paraná: B. exodon, B. iheringii e B. turiuba. Neste trabalho descrevemos uma espécie nova de Bryconamericus da bacia do alto rio Paraná, habitando tributários das bacias dos rios Ivaí, Piquiri e Tibagi, Estado do Paraná, Brasil. A espécie nova difere dos seus congêneres pela presença de dentes desalinhados na fileira externa de dentes do pré-maxilar; uma única mancha umeral vertical, expandida e arredondada dorsalmente; 36-39 escamas perfuradas na série longitudinal; altura do corpo 31,6-37,9% CP; base da nadadeira anal 24,8-30,1% CP; 19-22 raios ramificados na nadadeira anal e ganchos ósseos nas nadadeiras pélvica e anal de machos sexualmente dimórficos. A espécie nova é sintópica com outros Stervadiinae na bacia do alto rio Paraná, como B. iheringii, B. turiuba, Piabarchus stramineus e Piabina argentea.(AU)

A new species of Bryconamericus (Characidae: Stevardiinae: Diapomini) from the upper rio Paraná basin, Brazil

Bryconamericus is the most diverse genus within Stevardiinae, comprising 61 valid species distributed in Cis- and Trans-Andean basins from Panama in Central America to northern Argentina in South America. Three species are known from the upper rio Paraná basin: B. exodon, B. iheringii, and B. turiuba. Herein we describe a new species of Bryconamericus from the upper rio Paraná basin inhabiting tributaries of Ivaí, Piquiri, and Tibagi basins, Paraná State, Brazil. The new species differs from its congeners by the presence of unaligned teeth in the outer tooth row of the premaxilla; a single, vertical, dorsally expanded and rounded humeral spot; 36-39 pored scales in the longitudinal series; body depth 31.6-37.9% SL; anal-fin base length 24.8-30.1% SL; number of branched anal-fin rays 19-22, and bony hooks on pelvic- and anal-fin rays of sexually dimorphic males. The new species is syntopic with other Stervadiinae in the upper rio Paraná basin such as B. iheringii, B. turiuba, Piabarchus stramineus, and Piabina argentea.(AU)

Bryconamericus é o gênero de Stevardiinae mais diverso, com 64 espécies válidas distribuídas nas bacias Cis- e Trans-Andinas, do Panamá na América Central à região norte da Argentina na América do Sul. Dessas espécies, três são conhecidas da bacia do alto rio Paraná: B. exodon, B. iheringii e B. turiuba. Neste trabalho descrevemos uma espécie nova de Bryconamericus da bacia do alto rio Paraná, habitando tributários das bacias dos rios Ivaí, Piquiri e Tibagi, Estado do Paraná, Brasil. A espécie nova difere dos seus congêneres pela presença de dentes desalinhados na fileira externa de dentes do pré-maxilar; uma única mancha umeral vertical, expandida e arredondada dorsalmente; 36-39 escamas perfuradas na série longitudinal; altura do corpo 31,6-37,9% CP; base da nadadeira anal 24,8-30,1% CP; 19-22 raios ramificados na nadadeira anal e ganchos ósseos nas nadadeiras pélvica e anal de machos sexualmente dimórficos. A espécie nova é sintópica com outros Stervadiinae na bacia do alto rio Paraná, como B. iheringii, B. turiuba, Piabarchus stramineus e Piabina argentea.(AU)

Relative effect of seasonality and body size on the diet of juvenile Lutjanus synagris (Perciformes: Lutjanidae) at a sandy beach in Southeastern Brazil / Efeitos relativos da sazonalidade e do tamanho do corpo na dieta de juvenis de Lutjanus synagris (Perciformes: Lutjanidae) em uma praia arenosa no sudeste do Brasil

The relative effect of seasonality and body size on the diet composition of juvenile Lutjanus synagris was investigated at a sheltered sandy beach (20º18S; 40º16W) on the coast of Espírito Santo state, Brazil. Monthly collections were carried out during the daytime from May 2004 to April 2005, using a beach seine. The specimens captured in each season (e.g. cold/dry, May to October 2004; hot/rainy, November 2004 to April 2005) were separated into three total length (TL) classes (≤ 40; 41–50; ≥ 51 mm). The stomach contents of 540 specimens with TL ranging from 22 to 135 mm were analyzed. Among the 13 food items consumed by L. synagris, the most important were Amphipoda (Index of Relative Importance, IRI = 81.2), Isopoda (IRI = 13.8) and Mysidacea (IRI = 4.4). Significant variations in the diet composition were observed between the seasons (PERMANOVA; P < 0.001), but not between the size classes (P = 0.170). There was, however, a significant interaction between these two factors (P<0,001), but not between the size classes (P = 0.170). There was, however, a significant interaction between these two factors (P<0.001), indicating that the differences between the seasons did not occur in every class. The most important items in the cold/dry and hot/rainy seasons were, respectively, Mysidacea and Amphipoda, for every class. The average length of the preys varied significantly (P<0.05) between the size classes, increasing progressively with the TL of the fishes. Overall, the results indicate a carnivore-opportunist food habit for L. synagris, with significant seasonal changes in the relative importance of the food items.(AU)

O efeito relativo da sazonalidade e do tamanho do corpo na composição da dieta de juvenis de Lutjanus synagris foi avaliado em uma praia arenosa abrigada (20º18S; 40º16W) no litoral do estado do Espírito Santo, Brasil. Coletas mensais diurnas foram conduzidas no período de maio/04 a abril/05, usando uma rede de arrasto de praia. Os espécimes capturados em cada estação (fria/seca, maio a outubro de 2004; quente/chuvosa, novembro de 2004 a abril de 2005) foram separados em três classes de comprimento total (CT) (≤ 40; 41–50; ≥ 51 mm). O conteúdo estomacal de 540 espécimes com CT variando de 22 a 135 mm foi analisado. Entre os treze itens alimentares descritos para a dieta de L. synagris, os mais importantes foram Amphipoda (Índice de Importância Relativa, IIR = 81,2), Isopoda (IIR = 13,8) e Mysidacea (IIR = 4,4). Variações significativas na dieta foram observadas entre as estações do ano (PERMANOVA; P<0,001), mas não entre as classes de tamanho (P = 0,170). Houve, porém, uma interação significativa entre estes dois fatores (P<0,001), indicando que as diferenças entre as estações não ocorreram em todas as classes. Os itens mais importantes nas estações fria/seca e quente/chuvosa foram, respectivamente, Mysidacea e Amphipoda, para todas as classes. O tamanho médio das presas variou significativamente (P<0,05) entre as classes de tamanho, aumentando progressivamente com o CT dos peixes. No geral, os resultados indicam que L. synagris têm um hábito alimentar carnívoro-oportunista e muda sua dieta ao longo do ano. (AU)

Relative effect of seasonality and body size on the diet of juvenile Lutjanus synagris (Perciformes: Lutjanidae) at a sandy beach in Southeastern Brazil / Efeitos relativos da sazonalidade e do tamanho do corpo na dieta de juvenis de Lutjanus synagris (Perciformes: Lutjanidae) em uma praia arenosa no sudeste do Brasil

The relative effect of seasonality and body size on the diet composition of juvenile Lutjanus synagris was investigated at a sheltered sandy beach (20º18’S; 40º16’W) on the coast of Espírito Santo state, Brazil. Monthly collections were carried out during the daytime from May 2004 to April 2005, using a beach seine. The specimens captured in each season (e.g. cold/dry, May to October 2004; hot/rainy, November 2004 to April 2005) were separated into three total length (TL) classes (≤ 40; 41–50; ≥ 51 mm). The stomach contents of 540 specimens with TL ranging from 22 to 135 mm were analyzed. Among the 13 food items consumed by L. synagris, the most important were Amphipoda (Index of Relative Importance, IRI = 81.2), Isopoda (IRI = 13.8) and Mysidacea (IRI = 4.4). Significant variations in the diet composition were observed between the seasons (PERMANOVA; P < 0.001), but not between the size classes (P = 0.170). There was, however, a significant interaction between these two factors (P<0,001), but not between the size classes (P = 0.170). There was, however, a significant interaction between these two factors (P<0.001), indicating that the differences between the seasons did not occur in every class. The most important items in the cold/dry and hot/rainy seasons were, respectively, Mysidacea and Amphipoda, for every class. The average length of the preys varied significantly (P<0.05) between the size classes, increasing progressively with the TL of the fishes. Overall, the results indicate a carnivore-opportunist food habit for L. synagris, with significant seasonal changes in the relative importance of the food items.

O efeito relativo da sazonalidade e do tamanho do corpo na composição da dieta de juvenis de Lutjanus synagris foi avaliado em uma praia arenosa abrigada (20º18’S; 40º16’W) no litoral do estado do Espírito Santo, Brasil. Coletas mensais diurnas foram conduzidas no período de maio/04 a abril/05, usando uma rede de arrasto de praia. Os espécimes capturados em cada estação (fria/seca, maio a outubro de 2004; quente/chuvosa, novembro de 2004 a abril de 2005) foram separados em três classes de comprimento total (CT) (≤ 40; 41–50; ≥ 51 mm). O conteúdo estomacal de 540 espécimes com CT variando de 22 a 135 mm foi analisado. Entre os treze itens alimentares descritos para a dieta de L. synagris, os mais importantes foram Amphipoda (Índice de Importância Relativa, IIR = 81,2), Isopoda (IIR = 13,8) e Mysidacea (IIR = 4,4). Variações significativas na dieta foram observadas entre as estações do ano (PERMANOVA; P<0,001), mas não entre as classes de tamanho (P = 0,170). Houve, porém, uma interação significativa entre estes dois fatores (P<0,001), indicando que as diferenças entre as estações não ocorreram em todas as classes. Os itens mais importantes nas estações fria/seca e quente/chuvosa foram, respectivamente, Mysidacea e Amphipoda, para todas as classes. O tamanho médio das presas variou significativamente (P<0,05) entre as classes de tamanho, aumentando progressivamente com o CT dos peixes. No geral, os resultados indicam que L. synagris têm um hábito alimentar carnívoro-oportunista e muda sua dieta ao longo do ano.

Chromosome evolution in fishes: a new challenging proposal from Neotropical species

We present a database containing cytogenetic data of Neotropical actinopterygian fishes from Venezuela obtained in a single laboratory for the first time. The results of this study include 103 species belonging to 74 genera assigned to 45 families and 17 out of the 40 teleost orders. In the group of marine fishes, the modal diploid number was 2n=48 represented in 60% of the studied species, while in the freshwater fish group the modal diploid complement was 2n=54, represented in 21.21 % of the studied species. The average number of chromosomes and the mean FN were statistically higher in freshwater fish than in marine fish. The degree of diversification and karyotype variation was also higher in freshwater fish in contrast to a more conserved cytogenetic pattern in marine fish. In contrast to the assumption according to which 48 acrocentric chromosomes was basal chromosome number in fish, data here presented show that there is an obvious trend towards the reduction of the diploid number of chromosomes from values near 2n=60 with high number of biarmed chromosomes in more basal species to 2n=48 acrocentric elements in more derived Actinopterygii.

Se presenta una base de datos que contiene los datos citogenéticos de peces Actinopterigios Neotropicales de Venezuela obtenidos por primera vez en un solo laboratorio. Los resultados de este estudio incluyen 103 especies pertenecientes a 74 géneros de 45 familias contenidas en 17 de los 40 órdenes de teleósteos. En el grupo de peces marinos, el número diploide modal fue 2n=48 representado en 60% de las especies estudiadas, mientras que en el grupo de peces de agua dulce el complemento diploide modal fue 2n=54, representado en el 21,21% de las especies estudiadas. El número de cromosomas y FN promedio fueron estadísticamente superiores en peces dulceacuícolas. El grado de diversificación y variación en el cariotipo también fue mayor en peces de agua dulce en contraste con un patrón citogenético más conservado en peces marinos. En contraposición a la suposición según la cual 48 cromosomas acrocentricos era el número cromosómico basal en los peces, los datos aquí presentados muestran que existe una evidente tendencia hacia la reducción del número de cromosomas desde valores cercanos a 2n=60 con alto número de cromosomas birrámeos en las especies más basales a 2n=48 elementos acrocéntricos en los actinopterigios más derivados.

Chromosome evolution in fishes: a new challenging proposal from Neotropical species

We present a database containing cytogenetic data of Neotropical actinopterygian fishes from Venezuela obtained in a single laboratory for the first time. The results of this study include 103 species belonging to 74 genera assigned to 45 families and 17 out of the 40 teleost orders. In the group of marine fishes, the modal diploid number was 2n=48 represented in 60% of the studied species, while in the freshwater fish group the modal diploid complement was 2n=54, represented in 21.21 % of the studied species. The average number of chromosomes and the mean FN were statistically higher in freshwater fish than in marine fish. The degree of diversification and karyotype variation was also higher in freshwater fish in contrast to a more conserved cytogenetic pattern in marine fish. In contrast to the assumption according to which 48 acrocentric chromosomes was basal chromosome number in fish, data here presented show that there is an obvious trend towards the reduction of the diploid number of chromosomes from values near 2n=60 with high number of biarmed chromosomes in more basal species to 2n=48 acrocentric elements in more derived Actinopterygii.(AU)

Se presenta una base de datos que contiene los datos citogenéticos de peces Actinopterigios Neotropicales de Venezuela obtenidos por primera vez en un solo laboratorio. Los resultados de este estudio incluyen 103 especies pertenecientes a 74 géneros de 45 familias contenidas en 17 de los 40 órdenes de teleósteos. En el grupo de peces marinos, el número diploide modal fue 2n=48 representado en 60% de las especies estudiadas, mientras que en el grupo de peces de agua dulce el complemento diploide modal fue 2n=54, representado en el 21,21% de las especies estudiadas. El número de cromosomas y FN promedio fueron estadísticamente superiores en peces dulceacuícolas. El grado de diversificación y variación en el cariotipo también fue mayor en peces de agua dulce en contraste con un patrón citogenético más conservado en peces marinos. En contraposición a la suposición según la cual 48 cromosomas acrocentricos era el número cromosómico basal en los peces, los datos aquí presentados muestran que existe una evidente tendencia hacia la reducción del número de cromosomas desde valores cercanos a 2n=60 con alto número de cromosomas birrámeos en las especies más basales a 2n=48 elementos acrocéntricos en los actinopterigios más derivados.(AU)

Hemiodus langeanii (Characiformes: Hemiodontidae), a new species from rio Amana, rio Maués-Açú drainage, Amazon basin, Brazil

Hemiodus langeanii, new species, is described based on 20 specimens collected in the rio Amana, a tributary of rio Maués-Açú, rio Amazonas drainage, Brazil. The new taxon can be distinguished from its congeners by its high body (27.1-35.3%, average 32.3% SL vs. 18.8-28.5% in remaining species). The new species also exhibits a large lateral dark spot that is equal to, or greater than, the eye diameter (vs. smaller in remaining species except for H. microlepis). The lack of conspicuous lateral stripe or transverse bands and the low lateral line scales count (68-74) distinguish H. langeanii from some similar species in the genus (scale counts: 94-123 in H. argenteus, 124-148 in H. microlepis, 86-99 in H. orthonops and 77-92 in H . parnaguae). Finally, the new species can be differentiated from H. unimaculatus (which overlaps in the number of lateral line scales) by the higher number of scales between the lateral line and the pelvic fin origin (9-10 vs. 4-7, respectively), which are similar sized above and below lateral line (vs. scales larger bellow the lateral line in H. unimaculatus).

Hemiodus langeanii, espécie nova, é descrita com base em 20 espécimes coletados no rio Amana, um tributário do rio Maués-Açú na drenagem do rio Amazonas, na Amazônia Brasileira. O táxon novo pode ser diferenciado de seus congêneres devido ao seu corpo muito alto (27,1-35,3%, média 32,3% CP, vs. 18,8-28,5% nas demais espécies). A espécie nova apresenta uma grande mancha lateral escura que é igual ou maior do que o diâmetro do olho (vs. menor nas demais espécies, exceto em H. microlepis). A ausência de faixa longitudinal ou bandas transversais conspícuas, associada a um baixo número de escamas na linha lateral (68-74) distinguem H. langeanii de algumas espécies similares do gênero (94-123 em H. argenteus, 124-148 em H. microlepis, 86-99 em H. orthonops e 77-92 em H . parnaguae). Finalmente, a espécie nova pode ser diferenciada de H. unimaculatus (com a qual apresenta sobreposição na contagem de escamas da linha lateral) devido ao maior número de escamas entre a linha lateral e a origem da nadadeira pélvica (9-10 vs. 4-7, respectivamente), e pelo tamanho similar das escamas acima e abaixo da linha lateral (vs. maiores abaixo da linha lateral em H. unimaculatus).

Hemiodus langeanii (Characiformes: Hemiodontidae), a new species from rio Amana, rio Maués-Açú drainage, Amazon basin, Brazil

Hemiodus langeanii, new species, is described based on 20 specimens collected in the rio Amana, a tributary of rio Maués-Açú, rio Amazonas drainage, Brazil. The new taxon can be distinguished from its congeners by its high body (27.1-35.3%, average 32.3% SL vs. 18.8-28.5% in remaining species). The new species also exhibits a large lateral dark spot that is equal to, or greater than, the eye diameter (vs. smaller in remaining species except for H. microlepis). The lack of conspicuous lateral stripe or transverse bands and the low lateral line scales count (68-74) distinguish H. langeanii from some similar species in the genus (scale counts: 94-123 in H. argenteus, 124-148 in H. microlepis, 86-99 in H. orthonops and 77-92 in H . parnaguae). Finally, the new species can be differentiated from H. unimaculatus (which overlaps in the number of lateral line scales) by the higher number of scales between the lateral line and the pelvic fin origin (9-10 vs. 4-7, respectively), which are similar sized above and below lateral line (vs. scales larger bellow the lateral line in H. unimaculatus).(AU)

Hemiodus langeanii, espécie nova, é descrita com base em 20 espécimes coletados no rio Amana, um tributário do rio Maués-Açú na drenagem do rio Amazonas, na Amazônia Brasileira. O táxon novo pode ser diferenciado de seus congêneres devido ao seu corpo muito alto (27,1-35,3%, média 32,3% CP, vs. 18,8-28,5% nas demais espécies). A espécie nova apresenta uma grande mancha lateral escura que é igual ou maior do que o diâmetro do olho (vs. menor nas demais espécies, exceto em H. microlepis). A ausência de faixa longitudinal ou bandas transversais conspícuas, associada a um baixo número de escamas na linha lateral (68-74) distinguem H. langeanii de algumas espécies similares do gênero (94-123 em H. argenteus, 124-148 em H. microlepis, 86-99 em H. orthonops e 77-92 em H . parnaguae). Finalmente, a espécie nova pode ser diferenciada de H. unimaculatus (com a qual apresenta sobreposição na contagem de escamas da linha lateral) devido ao maior número de escamas entre a linha lateral e a origem da nadadeira pélvica (9-10 vs. 4-7, respectivamente), e pelo tamanho similar das escamas acima e abaixo da linha lateral (vs. maiores abaixo da linha lateral em H. unimaculatus).(AU)

A fauna de vertebrados do campus da Universidade Estadual de Londrina, região norte do estado do Paraná, Brasil / The vertebrates’ fauna from Universidade Estadual de Londrina campus, northern Paraná State, Brazil

Este trabalho teve como objetivo fazer um levantamento da fauna de vertebrados do campus da Universidade Estadual de Londrina (UEL), pela compilação da literatura, com vistas a auxiliar o seu manejo e preservação. Foram registradas 250 espécies, sendo nove de peixes, 15 de anfíbios, 16 de répteis, 32 de mamíferos e 178 de aves. Duas espécies, o gato-do-mato Leopardus tigrinus e a jandaia-de-testa-vermelha Aratinga auricapillus figuram em listas de fauna ameaçada de extinção. A maioria das espécies, no entanto, não é estenóica ou endêmica da área, o que condiz com um ambiente perturbado e muito freqüentado pela população humana. O assoreamento do ribeirão Esperança, a redução de áreas verdes e a impermeabilização do solo podem reduzir a diversidade de espécies em médio a longo prazos.

This work had the objective to make a survey of vertebrates’ fauna from Universidade Estadual de Londrina (UEL) campus, for the compilation of literature, in order to help its management and preservation. 250 species were identified, being nine of fish, 15 of amphibians, 16 of reptiles, 32 of mammals and 178 of birds. Two species, the gato-do-mato Leopardus tigrinus and the jandaia-da-testa-vermelha Aratinga auricapillus, are in the list of species threatened by extinction. Most species, however, are not stenoecious or endemic to the area, which corresponds to an environment under stress and often visited by humans. Despite UEL’s rich diversity of wild animals, the burying of stream Esperança, the reduction of green areas and waterproofing of the ground can reduce de diversity of species in a medium or long term.