Four types of body cavity arrangement were found in 20 species of fish (see Materials and Methods). The body cavities of fishes were also compared with those of mammals and birds. It was concluded that higher vertebrates utilized only the Tinca type for their evolution, while the other types were dead-end evolutionary forms which terminated at fish level, or possibly with amphibians and reptiles. The necessary research in these groups still remains to be done.

• MeSH
• Fishes anatomy & histology   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH

BACKGROUND: Smell abilities differ greatly among vertebrate species due to distinct sensory needs, with exceptional variability reported in the number of olfactory genes and the size of the odour-processing regions of the brain. However, key environmental factors shaping genomic and phenotypic changes linked to the olfactory system remain difficult to identify at macroevolutionary scales. Here, we investigate the association between diverse ecological traits and the number of olfactory chemoreceptors in approximately two hundred ray-finned fishes. RESULTS: We found independent expansions producing large gene repertoires in several lineages of nocturnal amphibious fishes, generally able to perform active terrestrial exploration. We reinforced this finding with on-purpose genomic and transcriptomic analysis of Channallabes apus, a catfish species from a clade with chemosensory-based aerial orientation. Furthermore, we also detected an augmented information-processing capacity in the olfactory bulb of nocturnal amphibious fishes by estimating the number of cells contained in this brain region in twenty-four actinopterygian species. CONCLUSIONS: Overall, we report a convergent genomic and phenotypic magnification of the olfactory system in nocturnal amphibious fishes. This finding suggests the possibility of an analogous evolutionary event in fish-like tetrapod ancestors during the first steps of the water-to-land transition, favouring terrestrial adaptation through enhanced aerial orientation.

• Keywords
• Amphibious fishes, Evolutionary transition, Olfactory receptors, Sensory evolution,
• MeSH
• Acclimatization MeSH
• Biological Evolution * MeSH
• Adaptation, Physiological MeSH
• Vertebrates * genetics   MeSH
• Fishes genetics   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

This study investigated microplastic (MP) contamination in six tropical fish species of different mouth sizes and trophic levels from Saint Martin's Island, Bay of Bengal. A total of 309 microplastics (MPs) were extracted from the gastrointestinal tract (GT) of these selected fishes, where the presence of MPs was 100 %. The mean abundance of MPs was significantly varied among the species and ranged from 4.38 to 10 MPs/GT (p < 0.05). This study revealed that MP incidence was strongly correlated with the mouth-to-body ratio of the selected fishes (r = 0.424, p = 0.003) and trophic levels (r = 0.458, p = 0.002). Results suggest that fish with larger mouths are more likely to ingest MPs, intentionally or unintentionally, compared to those with smaller mouths.

• Keywords
• Feeding behaviour, MPs contamination, Mouth-to-body ratio, Tropical fishes,
• MeSH
• Water Pollutants, Chemical * analysis   MeSH
• Microplastics * MeSH
• Environmental Monitoring methods   MeSH
• Plastics MeSH
• Eating MeSH
• Fishes MeSH
• Mouth MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Water Pollutants, Chemical * MeSH
• Microplastics * MeSH
• Plastics MeSH

Nothobranchius fishes (Cyprinodontiformes), known for their genetically encoded extremely compressed lifespan, are considered an excellent vertebrate model for the research of aging. Unlike the rapid accumulation of data concerning their biology, ecology and genome, knowledge of their age-related diseases, including tumours, is still very limited. This Note reports spontaneous neoplastic lesions in the swim bladder gas glands of Nothobranchius furzeri, N. kadleci and N. orthonotus. Based on light and transmission electron microscopy, the neoplastic proliferation of gas gland cells was classified as adenocarcinoma. There was a concurrent proliferation of haemopoietic cells in the kidney interstitium in all individuals diagnosed with this type of primary neoplasia.

• Keywords
• Gas gland adenocarcinoma, Nothobranchius fishes, Spontaneous neoplasia,
• MeSH
• Adenocarcinoma * veterinary   MeSH
• Cyprinodontiformes * MeSH
• Longevity MeSH
• Aging MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH

The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large-scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications.

• Keywords
• Neotropical region, biodiversity hotspot, conservation, data paper, ichthyology, occurrence, species distribution,
• MeSH
• Biodiversity MeSH
• Ecosystem MeSH
• Fishes * MeSH
• Fresh Water * MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Caribbean Region MeSH
• Mexico MeSH

Asymmetrical localization of biomolecules inside the egg, results in uneven cell division and establishment of many biological processes, cell types and the body plan. However, our knowledge about evolutionary conservation of localized transcripts is still limited to a few models. Our goal was to compare localization profiles along the animal-vegetal axis of mature eggs from four vertebrate models, two amphibians (Xenopus laevis, Ambystoma mexicanum) and two fishes (Acipenser ruthenus, Danio rerio) using the spatial expression method called TOMO-Seq. We revealed that RNAs of many known important transcripts such as germ layer determinants, germ plasm factors and members of key signalling pathways, are localized in completely different profiles among the models. It was also observed that there was a poor correlation between the vegetally localized transcripts but a relatively good correlation between the animally localized transcripts. These findings indicate that the regulation of embryonic development within the animal kingdom is highly diverse and cannot be deduced based on a single model.

• Keywords
• Amphibians, Egg, Fishes, RNA localization, TOMO-Seq, evo devo,
• MeSH
• Biological Evolution MeSH
• Zebrafish MeSH
• Oocytes * metabolism   MeSH
• RNA * genetics   metabolism   MeSH
• Xenopus laevis genetics   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• RNA * MeSH

Morphological and molecular evaluation of tapeworms of the genus Bothriocephalus Rudolphi, 1808 (Cestoda: Bothriocephalidea), based on newly collected and uniformly fixed worms from freshwater fishes in Canada and the United States has revealed unexpected diversity. With a combination of selected morphological features and 4 molecular markers (18S rDNA V8 region, ITS1, ITS2, and COI gene sequences), the following morphotypes and lineages of the Bothriocephalus cuspidatus Cooper, 1917 complex were identified, several of which are specific to their respective fish definitive hosts and may represent separate species: B. cuspidatus sensu stricto from walleye, Sander vitreus (type host), which likely includes a miniature morphotype from Johnny darter, Etheostoma nigrum (both Percidae); Bothriocephalus morphotype from pumpkinseed, Lepomis gibbosus (Centrarchidae); and Bothriocephalus morphotype from rock bass, Ambloplites rupestris (Centrarchidae). The Bothriocephalus morphotype from goldeye, Hiodon alosoides (Hiodontidae), may also represent a separate lineage (possibly Bothriocephalus texomensisSelf, 1954) but requires additional studies. A morphotype from smallmouth bass, Micropterus dolomieu, based on a single specimen, is morphologically and genetically very similar to the morphotype from rock bass. Morphological study of the scolex and strobila of heat-killed and fixed specimens has revealed consistent differences, often subtle, that allowed us to differentiate between these morphotypes.

• Keywords
• Bothriocephalus, Cestoda, Diversity, Freshwater Fishes, Host Specificity, North America, Tapeworms,
• MeSH
• Cestoda anatomy & histology   genetics   ultrastructure   MeSH
• Cestode Infections parasitology   veterinary   MeSH
• Microscopy, Electron, Scanning veterinary   MeSH
• Fish Diseases parasitology   MeSH
• Perches parasitology   MeSH
• Perciformes parasitology   MeSH
• Likelihood Functions MeSH
• DNA, Ribosomal analysis   chemistry   MeSH
• RNA, Ribosomal, 18S genetics   MeSH
• Fishes MeSH
• Base Sequence MeSH
• Sequence Alignment veterinary   MeSH
• Fresh Water MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Canada MeSH
• United States MeSH
• Names of Substances
• DNA, Ribosomal MeSH
• RNA, Ribosomal, 18S MeSH

"The piscine respiratory system is represented by gills. Gill diseases are extremely common and may be caused by a large variety of etiologic agents. The gills are in direct contact with water and reflect its quality, for example, pollution, and they also must face the presence of biotic agents, such as viruses, bacteria, fungi, and parasites. Evolution has established many defense mechanisms to combat these agents. Failure of these mechanisms is life-threatening for the fish, due to impaired respiration. Gills are relatively easily accessible for clinical examination and sampling, which facilitates intravital diagnosis."

• Keywords
• Branchitis, Gill illness, Ichthyopathology, Parasites,
• MeSH
• Bacterial Infections microbiology   pathology   veterinary   MeSH
• Fish Diseases parasitology   MeSH
• Parasitic Diseases, Animal parasitology   pathology   MeSH
• Fishes MeSH
• Virus Diseases pathology   veterinary   virology   MeSH
• Gills microbiology   parasitology   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Review MeSH

• Keywords
• Acheilognathinae, coevolution, ecological speciation, freshwater mussels, oviposition,
• MeSH
• Cyprinidae * MeSH
• Fishes MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

The present paper comprises a systematic survey of nematodes found in 88 specimens of 24 species of freshwater fishes in Venezuela in 1992 and 1994. The following 13 species of nematodes were recorded: Adults; Guyanema longispiculum Moravec, Prouza et Royero, 1996, Guyanema sp., Procamallanus (Spirocamallanus) inopinatus Travassos, Artigas et Pereira, 1928, P. (S.) krameri (Petter, 1974) comb. n., P.(S.) pintoi (Kohn et Fernandes, 1988) comb, n., Procamallanus (Spirocamallanus) sp., Raphidascaris (Sprentascaris) mahnerti (Petter et Cassone, 1984). Larvae: Anisakidae gen. sp., Brevimulticaecum sp., Contracaecum sp. Type 1, Contracaecum sp. Type 2, Contracaecum sp. Type 3, Eustrongylides sp. All these parasites are reported from Venezuela for the first time and all findings represent new host records. Brevimulticaecum larvae are reported from fishes for the first time. Almost all parasites are briefly described and illustrated and problems concerning their morphology, taxonomy, hosts and geographical distribution are discussed. A new name, Terranova diazungriai nom.nov. is proposed for T. caballeroi Díaz-Ungría, 1968 (a junior homonym of T. caballeroi Barus et Coy Otero, 1966).

• MeSH
• Nematoda anatomy & histology   classification   MeSH
• Nematode Infections veterinary   MeSH
• Fish Diseases parasitology   MeSH
• Fishes MeSH
• Data Collection MeSH
• Fresh Water MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Comparative Study MeSH
• Geographicals
• Venezuela MeSH