Made available in DSpace on 2015-04-17T14:55:22Z (GMT). No. of bitstreams: 1 ArquivoTotal.pdf: 2362893 bytes, checksum: 7beba6948bd6e28831af22fe71b56260 (MD5) Previous issue date: 2013-02-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The genus Achirus Lacépède, 1802 is anphiamerican, occurring in marine, estuarine and fresh waters. In Brazil, the species of this genus are known as linguado, sóia, solha, tapa and aramaçá. As other Achiridae, they are carnivores, eating fishes and benthonic invertebrates. As most of Achiridae, they are eurihaline, tending to adopt a marine-estuarine (A. lineatus, ex.), estuarine-freshwater (A. achirus, ex.) and freshwater-estuarine life, the only species with this behavior being A. novoae, which occurs from high portions of the Orinico basin to areas around the delta. Nineteen nominal species are referred to the genus Achirus, eight of them considered valid. This work has the object of deal a taxonomic review of the Western Atlantic species of Achirus. Morphometrics and meristics data of 450 specimens were taken, including that of known type specimens. All the four species occurring in Western Atlantic were considered: Achirus achirus, A. declivis, A. lineatus, A. novoae. Redescriptions reconstruction of synonymies and clarification of geographic distributions of these species are presented. A fifth species of the genus, whose description was recently submitted to the publication by other authors, was included in this work. An identification key for the Western Atlantic Achirus species is provided. / O gênero Achirus Lacépède, 1802 tem distribuição anfiamericana, ocorrendo em águas marinhas, estuarinas e doces. No Brasil, as espécies deste gênero são conhecidas vulgarmente como linguado, sóia, solha, tapa e aramaçá. Como outros Achiridae, são animais carnívoros, alimentam-se de peixes e invertebrados bentônicos e, como a maioria dos Achiridae, suas espécies são eurihalinas, tendendo a ser marinho-estuarinas (A. lineatus, p. ex.), estuarino-dulcicolas (A. achirus, p. exemplo) e dulcícola-estuarina, a única espécie registrada com este comportamento sendo A. novoae, que ocorre desde porções altas da bacia do Orinoco até áreas no entorno do delta. Dezenove espécies nominais são atribuídas ao gênero Achirus, oito consideradas válidas. O trabalho teve como objetivo desenvolver uma revisão taxonômica das espécies do gênero Achirus no Atlântico Ocidental. Foram tomados dados morfométricos e merísticos de 450 espécimes, dentre eles os espécimes-tipo conhecidos. As quatro espécies que ocorrem no Atlântico Ocidental foram consideradas válidas: Achirus achirus, A. declivis, A. lineatus, A. novoae. Redescrições destas espécies, reconstrução de suas sinonímias e esclarecimento de suas distribuições geográficas foram realizados. Uma quinta espécie do gênero, cuja descrição foi recentemente submetida à publicação por outros autores, foi incluída neste trabalho. Uma chave para identificação das espécies do gênero Achirus do Atlântico Ocidental é provida.

The fish order Pleuronectiformes (flatfishes) include over 800 fish species, and are generally considered to be monophyletic. Phylogenetic relationships within the order remain largely unresolved, particularly for the Paralichthyidae, a very poorly defined family. In addition to the lack of consensus on intrarelationships within this order, flatfish diversification patterns are still poorly understood. Here we want to test the hypothesis that (i) a densely sampled phylogenetic tree will help to unravel the phylogenetic relationships within flatfish, and (ii) that the formation of the Isthmus of Panama has played a role in the diversification of flatfish, following their distribution in both oceans, Atlantic and Pacific. Maximum likelihood and Bayesian analyzes were performed on a dataset consisting of nine mitochondrial and nuclear loci on a set of 309 flatfish species. The heterogeneity of substitution rates, known to cause phylogenetic errors in large multigene alignments, can be corrected by data partitioning, or by using heterogeneous site models. Very few studies have compared the effects of using these approaches. We present a robust phylogenetic tree with different heterogeneous and well-supported models, and the intraordinal relationships of flatfish are discussed in light of these results. We present evidence for three new suborders within the flatfishes. The monophyletic status of most families is corroborated. The family Paralichthyidae and the family Poecilopsettidae were found to be polyphyletic. Heterogeneous models have not been able to solve the deeper relationships between flatfish. We also show that flatfish diversification occurred in a few families in at least two stages, related to distinct geological events.

Ray-finned fish from a diversity of distantly related lineages have remarkably large visual opsin repertoires. Starry flounder (Platichthys stellatus) development, morphology, life history, and behavior make this species especially suitable for experiments designed to determine why fish have so many opsins. Human and bird colour vision uses three and five opsins, respectively. Fish often have many more opsins. We sequenced an eye transcriptome to determine the starry flounder opsin repertoire, and used high performance liquid chromatography to determine the chromophore content of the retina. We found eight visual opsins that utilize only 11-cis-retinal (vitamin A1). This species’ entire visual opsin toolkit appears to be functional. The number of distinct cone and rod cell absorbance profiles determined using microspectrophotomery are consistent with the number of visual opsins in the transcriptome. RH2 transcripts were more abundant and SWS1 and SWS2 transcripts were less abundant in the dorsal retina, where cone density was highest, outer segments the longest, and where we observed double cones with outer segments that differed in their wavelength of maximum absorbance. Regions of fish retinas appear to be specialized and I predict that this fine-tuning is enhanced by photoreceptor plasticity and opsin gene duplication and divergence. Studies that compare opsin expression patterns among individuals, populations, or species typically assume that the differences observed influence vision. Direct connections between opsin expression and quantitative behaviours are rare. This thesis aimed to test whether varying opsin expression affects vision by modifying opsin expression and characterizing vision in starry flounder. We held starry flounder in aquaria exposed to either broad spectrum sunlight or green-filtered light. We tested vision by quantifying the visually-mediated camouflage response and we measured opsin expression using digital-PCR. Granularity analysis of photographs of the camouflage response revealed higher overall pattern energy at each of the seven spatial frequency bands in fish exposed to broad spectrum sunlight compared to the green-filtered fish. However, no statistical difference in typical measurements of pattern or contrast (e.g., maximum filter size, the standard deviation of pattern energy, and the proportional power) was observed between the two groups. Opsin expression was different between fish held in the green light environment compared to those exposed to broad spectrum light. SWS1 (UV sensitive) and SWS2B (blue sensitive) were significantly down regulated in response to the green light environment. Surprisingly, this difference was lost after only three hours under a white LED light, suggesting rapid changes in opsin expression in response to the light environment. We found tantalizing, albeit not statistically significant evidence that fish with higher expression of UV- and blue-wavelength sensitive opsins could see more contrast in colour on blue-green checkerboards. / Graduate

The recently discovered decapeptide kisspeptin and its G-protein coupled receptor form a signaling system expressed ubiquitously and are implicated in a variety of still poorly characterized functions. In the brain, kisspeptin is secreted by specific neurons and its receptor is localized in GnRH neurons. Kisspeptin signaling has been fully established in the control of the onset of puberty in vertebrates, from fish to mammals. In this study, we characterized the kisspeptin gene in the Senegalese sole and characterized the kisspeptin receptor genes in both the Senegalese sole and in the Atlantic halibut. In contrast to other fish species, the two species analyzed here showed only the presence of one ligand and one receptor, probably as a consequence of the genome reduction characteristic of Pleuronectiformes. However, in both cases we found an alternative splicing mechanism based on intron retention that produces also non-functional isoforms, but whether this is part of a mechanism to control abundance of the active gene product is still not known. We document spatial and temporal changes of expression of kisspeptin and its receptor in the brain, pituitary and gonads related to the annual reproductive cycle. Finally, we present the first evidence of a possible link between energy balance and reproduction mediated by kisspeptin signaling in a non-mammalian vertebrate. / El recentment descobert decapèptid kisspeptina i el seu receptor associat a una proteïna G formen un sistema que s’expressa ubiqüitament i que està implicat en diverses funcions, moltes de les quals encara no estan ben caracteritzades. En el cervell, la kisspeptina és secretada per neurones específiques, mentre que el seu receptor es troba a les neurones GnRH. Aquest sistema s’ha relacionat amb el control de l’inici de la pubertat en diferents vertebrats, des de peixos fins a mamífers. En aquest estudi, hem caracteritzat el gen de la kisspeptina en el llenguado senegalès, i els gens del receptor de la kisspeptina tant a llenguado senegalès com en l’Halibut de l’Atlàntic. Al contrari del que ocorre en moltes altres espècies de peixos, aquestes dues espècies només presenten un gen pel lligand i un gen pel recep- tor. Aquest fet és probable que estigui relacionat amb la reducció de la mida del genoma que han sofert els Pleuronectiformes. Tot i així, en les dues espècies s’hi troba un mecanisme d’empalmament alternatiu conseqüència d’una retenció intrónica que produeix una isoforma no funcional. Ara bé, si aquest mecanisme està relacionat amb el control de l’abundància dels trànscrits de la isoforma funcional encara està per esbrinar. Per altra banda, hem trobat canvis en l’expressió gènica tant en l’espai com en el temps durant un cicle reproductiu dels gens de la kisspeptina i el seu receptor en el cervell, pituïtària i gònades. Finalment, també presentem la primera evidència, en un vertebrat no mamífer, d’una possible relació entre el balanç energètic i la reproducció controlada pel sistema kisspeptina.

The taxonomic status of its 59 nominal species of the genus Bothus (Pleuronectiformes: Bothidae) has been revised, based on a morphological study of 320 type and non-type specimens. Of the 59 nominal species examined in the study, 18 have found to be valid and are re-described. The genus Bothus (pro parte) is considered natural on the basis of two characters previously identified by Hoshino and Amaoka (2006): a ventral expansion of the haemapophyses of the precaudal vertebrae and the bony expansion of the haemal spine of the first caudal vertebrae. These characters were observed in all accepted species of Bothus, excluding B. swio. The morphology of B. swio overlaps with other bothid genera, but its generic placement was not analysed. Engyrprosopon and Crossorhombus are hypothesized as outgroups of Bothus based on the character state identified by Hoshino and Amaoka (2006), an anterior extension of the sciatic part of the urohyal past the main part of the urohyal. A phylogenetic analysis of the Bothidae is needed to substantiate this hypothesis of relationship, to validate the monophyly of Bothus and to resolve the generic position of B. swio. The geographic distribution of each species is mapped and an up-to-date species identification key has been created. The 18 valid species are as follows, with their synonym species in parenthesis: Bothus assimilis, Bothus constellatus, Bothus ellipticus, Bothus guibei (Rhombus heterophthalmus), Bothus leopardinus, Bothus lunatus, Bothus maculiferus, Bothus mancus (Pleuronectes barfi, Rhombus macropterus), Bothus mellissi, Bothus myriaster (Citharicthys aureus), Bothus ocellatus (Platophrys nebularis, Rhomboidichtys spinosus, Rhombus bahianus), Bothus pantherinus, Bothus podas (Bothus rumolo, Bothus tappa, Rhombus gesneri), Bothus robinsi, Bothus swio, Bothus thompsoni, Bothus tricirrhitus, and Bothus ypsigrammus.