Abstract:Many species of freshwater fishes are considered miniatures, nevertheless, their identification as miniatures is frequently based only on an arbitrary criterion of small body size. Although some species of Otothyris had been suggested to be miniature, informations about the process and consequences of miniaturization in the genus are lacking. Here, we detail developmental events of loss, fusion, and modifications in several bones, the laterosensory system, and even the brain, that in sum demonstrate miniaturiz… Show more
“…Also it is relevant to note that those species with omnivorous diets herein mentioned seems to have a tendency to a greater development of their liver and pancreas. This means that, in general terms, herbivorous species have a greater portion of its body devoted to feeding and in consequence it may be expected from this, that miniature species are more likely to evolve in "carnivorous clades", or less likely to occur in herbivorous ones, although herbivorous miniatures do occur as in the case of Otothyris (Loricariidae) (Rosa et al, 2014), for example.…”
A compared study of the morphology of the alimentary tract and liver of seven selected species corresponding to the main clades of the Characidae family is presented herein. Three new set of characters corresponding to 1) alimentary tract gross anatomy, 2) alimentary tract histology and 3) liver gross anatomy are evaluated as potential sources of data for future phylogenetic studies of the Characidae. Not considerable interspecific variation was observed at the histological level and therefore this source is not considered to be phylogenetically informative at the taxonomic level analyzed. In contrast, liver and alimentary tract gross anatomy presented important interspecific variation while a relatively homogenous intraspecific morphology was observed. Those characters are optimized in tree-topologies from previous phylogenetic analyses and their evolution and potential relationship with ecological traits are discussed.
“…Also it is relevant to note that those species with omnivorous diets herein mentioned seems to have a tendency to a greater development of their liver and pancreas. This means that, in general terms, herbivorous species have a greater portion of its body devoted to feeding and in consequence it may be expected from this, that miniature species are more likely to evolve in "carnivorous clades", or less likely to occur in herbivorous ones, although herbivorous miniatures do occur as in the case of Otothyris (Loricariidae) (Rosa et al, 2014), for example.…”
A compared study of the morphology of the alimentary tract and liver of seven selected species corresponding to the main clades of the Characidae family is presented herein. Three new set of characters corresponding to 1) alimentary tract gross anatomy, 2) alimentary tract histology and 3) liver gross anatomy are evaluated as potential sources of data for future phylogenetic studies of the Characidae. Not considerable interspecific variation was observed at the histological level and therefore this source is not considered to be phylogenetically informative at the taxonomic level analyzed. In contrast, liver and alimentary tract gross anatomy presented important interspecific variation while a relatively homogenous intraspecific morphology was observed. Those characters are optimized in tree-topologies from previous phylogenetic analyses and their evolution and potential relationship with ecological traits are discussed.
“…The brain anatomy of the Callichthyidae and its relation to the phylogeny of the group was discussed by Pupo (2011), and recently, Rosa et al (2014) detailed the gross morphology of the brain of Neotropical catfi hes. The systematics and anatomy of the Pseudopimelodidae have been the subject of several studies (e.g., Lundberg et al, 1991;Shibatta, 1998Shibatta, , 2003Birindelli & Shibatta, 2011), but descriptions of the gross morphology of the brain in the group (and of the Siluriformes as a whole) remain scarce.…”
The gross morphology of the brain of the pseudopimelodid Pseudopimelodus bufonius is described and compared with congeners. Observations were made on removed brains after elimination of bones from the top of the skull and severing of the cranial nerves and the spinal cord. Nine morphometric characters associated with the major subdivisions of the brain were identified, seven of which revealed significant differences among the species examined. The corpus cerebelli in all examined species of the genus is the largest structure of the brain. The behavior of the species of Pseudopimelodus is still unknown, but in other teleosts that condition is typically correlated with a higher degree of motor coordination. Relative size proportions of the tectum opticum, eminentia granularis, lobus facialis and lobus vagi, might be related to carnivory and an enhanced capacity for food selection.A morfologia externa do encéfalo de Pseudopimelodus bufonius é descrita e comparada com seus congêneres. As análises foram feitas no cérebro removido após a eliminação dos ossos do topo da cabeça e secção dos nervos cranianos e cordão espinhal. Nove caracteres morfométricos foram obtidos das principais subdivisões do encéfalo, dos quais em sete ocorreram diferenças significativas entre as espécies. Em todas as espécies examinadas do gênero o corpus cerebelli é a maior estrutura do encéfalo. O comportamento das espécies de Pseudopimelodus ainda é desconhecido, mas em outros teleósteos esta característica é normalmente correlacionada com uma boa coordenação motora. Além disso, as proporções relativas do tectum opticum, eminentia granularis, lobus facialis e lobus vagi podem ser relacionadas a hábitos carnívoros e boa capacidade de selecionar alimentos.
“…3). Ontogenetic shape changes were already observed in loricariids, including hypoptopomatine catfishes (Aquino & Miquelarena, 2001;Rosa et al, 2014) and must be related to allometric development of bones, muscles and plates structures (Geerinckx et al, 2008(Geerinckx et al, , 2009.…”
Parotocinclus spilurus (Fowler) was originally described as a species of Plecostomus based on six specimens collected in the rio Salgado, Icó Municipality, Ceará State, northeastern Brazil. Because the original description of P. spilurus is brief and uninformative, a detailed redescription of this endangered species based on the type series and on freshly collected topotypes was made. Data on osteology, intraspecific variation, sexual dimorphism and color pattern in life are presented for the first time, aiming at providing the necessary characters to differentiate the species from its congeners, as well as providing data on the distribution, habitat and conservation.Parotocinclus spilurus (Fowler) foi descrita originalmente como uma espécie do gênero Plecostomus com base em seis espécimes coletados no rio Salgado, Município de Icó, Estado do Ceará. Devido à descrição original de P. spilurus ser breve e pouco informativa, uma redescrição detalhada desta espécie ameaçada com base na série tipo e em topótipos recentemente coletados foi feita. Dados de osteologia, variação ontogenética, dimorfismo sexual e padrão de coloração em vida são apresentados pela primeira vez, com o objetivo de fornecer caracteres necessários para distinguir a espécie das suas demais congêneres, assim como fornecer dados de distribuição, habitat e conservação.
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