A new species of Characidium Reinhardt, 1867 endemic to tributaries of the upper rio Paraguaçu in the Chapada Diamantina, Bahia, Brazil, is described. The new species can be distinguished from its congeners except C. bahiense, C. bimaculatum, C. laterale, C. nana, C. nupelia, and C. xavante, by having a conspicuous peduncular blotch in addition to the basicaudal spot on the base of the middle caudal-fin rays. Among other features, the new species differs from C. bahiense, C. laterale, C. nana, C. nupelia, and C. xavante by having a complete lateral line with 32-36 perforated scales (vs. lateral line short, with 9-11 perforated scales), and from C. bimaculatum by the body pigmentation pattern, with secondary bars present (vs. absent), total bars 11-16 (vs. 10-12), peduncular blotch rounded (vs. horizontally elongated), and mature males not having a darker dorsal fin (vs. proximal third of dorsal fin darker in mature males). Characidium bimaculatum, a poorly known species from Northeastern Brazil, is redescribed.

A new species of Hyphessobrycon is described from the Rio Juma, a tributary of the lower Rio Aripuanã-Rio Madeira basin, Amazonas, Brazil. Hyphessobrycon platyodus can be distinguished from its congeners by the: presence of an elongated dorsal fin in adult males, 25-28 branched anal-fin rays and absence of dark blotches from the dorsal fin and caudal peduncle. The presence of multicuspid teeth in species of Characidae and its relation with feeding habits are briefly commented on.

A new species of Corydoras is described from tributaries of the rio Arinos, rio Teles Pires and rio Preto, all in the rio

A new species of the armoured catfish genus Corydoras is described from the Xingu-Tapajos ecoregion, Brazilian Amazon. The new species can be distinguished from its congeners by having the following combination of features: short mesethmoid, with anterior tip poorly developed, smaller than 50% of bone length; posterior margin of pectoral spine with serrations directed towards spine tip or perpendicularly oriented; infraorbital 2 only in contact with sphenotic; ventral laminar expansion of infraorbital 1 poorly or moderately developed; flank midline covered by small dark brown or black saddles with similar size to remaining markings on body; relatively larger, scarcer and more sparsely distributed dark brown or black spots on body; absence of stripe on flank midline; caudal fin with conspicuous dark brown or black spots along its entire surface; slender body; and strongly narrow frontals. A more comprehensive description of poorly-explored internal character sources, such as the gross morphology of the brain, Weberian apparatus and swimbladder capsule elements is presented.

The teleost order Anguilliformes, true eels, comprises more than 1000 described species in 20 families, commonly known as eels, congers, morays, and gulper eels.Comprehensive studies of Anguilliformes are limited, resulting in a lack of consensus for morphology-based phylogenetic hypotheses. A detailed morphological analysis of the cephalic and opercular myology offers a promising new source of characters to help elucidate the intrarelationships of Anguilliformes. Our study is the most extensive myological analysis for the group and includes 97 terminal taxa, with representatives from each of the 20 families of Anguilliformes plus outgroup clades. Results demonstrate that muscle characters inform phylogenetic relationships withinAnguilliformes, and we propose two new synapomorphies for all extant members, including Protanguilla palau, the "living fossil"-adductor mandibulae originating on the parietal (vs. restricted to suspensorium) and segmentum mandibularis absent (vs. present). Exceptions for the first condition characterize highly modified saccopharyngoids, and for the second one, Notacanthidae. More importantly, we suggest three new synapomorphies for the remaining extant anguilliforms (except in highly modified saccopharyngoids)-adductor mandibulae originates on the frontals (vs. frontals naked), adductor mandibulae stegalis is separated from the rictalis (vs. rictostegalis fused into a single piece), and the levator operculi inserts on the lateral surface of the opercle (vs. medial surface of the opercle). Our phylogenetic optimization strongly corroborates the hypothesis that Protanguilla is the sister group of all other extant eels. A further goal of this paper is to clearly document the substantive conflicts between the available molecular data and the extensive and diverse morphological evidence.

The family Myrocongridae comprises some of the rarest and least known benthopelagic eel species. It is composed of a single genus, Myroconger Günther, 1870, and five valid species: M. compressus Günther, 1870, from the Atlantic Ocean; M. gracilis Castle, 1991, M. prolixus Castle & Béarez, 1995, and M. nigrodentatus Castle & Béarez, 1995, from the Pacific Ocean; and M. seychellensis Karmovskaya, 2006, from the Indian Ocean. Herein, we report on an additional species from the Atlantic Ocean, Myroconger pietschi n. sp., based on a specimen obtained on the Aracati Bank, North Brazilian ridge, off Ceará State, western South Atlantic. Myroconger pietschi can be diagnosed by having 190 anal-fin rays, a short pectoral fin (16.6% HL), the posterior portion of the ethmovomerine teeth arranged in a single row, teeth on lower and upper pharyngeal tooth plate 24 and 27, and 10 branchiostegal rays.

Nessa seção vou agradecer em palavras coisas que não tem como expressar somente em texto, mas tentarei. Aos meus pais, Lodson Espíndola e Anna Corrêa Espíndola (in memoriam), que foram os principais responsáveis pela formação intelectual e afetiva, razão pela qual eles devem vir em primeiro lugar com toda justiça. Assim como meu irmão e minha sobrinha, Lodson e Mariana, os quais me deram apoio em horas alegres e difíceis, com sorrisos e carinho. À minha esposa, Thaisi, sempre com carinho e amor, que em nenhum momento me deixou abaixar a cabeça e levantou sempre a minha motivação em qualquer hora do dia, mesmo nas horas que ficava calado pensando na tese. Os Andias também são meus e me ajudaram demais. Ao meu guia acadêmico e amigo Mário de Pinna (papis), pela oportunidade de trabalhar, estudar, pensar e bater papo sobre cinema, política, comida, filogenia, morfologia, peixes e tudo mais. Ao grande amigo e lenda viva, Náercio, na qual eu já vinha no caminho pensando em conversar sobre todas as atualidades possíveis (eu sempre o interrompia na lupa). Os esportes sempre foram os papos iniciais, nossas paixões por futebol e basquete guiaram esses anos (tiveram mais coisas também). Herr Professor Britski, também teve um grande peso nesses momentos alegres do MZUSP, falando alemão, curiosidades da ictiologia, histórias sobre a ciência, Corumbataí, acordar tarde, qualidades em tomar leite enquanto todos tomavam café. Ao cansado e competente Aléssio, que sempre foi extremamente gentil quando eu chegava com as coisas mais complicadas de Anguilliformes e ele falava: "Cara, esses bichos são muito loucos". Aos amigos e companheiraços: Vaca que ajudou revisando textos, analises, gráficos, fotos e caminhadas até o metrô; Vitin, que mesmo distante me ajudou desde o início; Dagosta que apesar de me chutar, foi amigo de todas as horas (principalmente nas madrugadas); Pay que perdeu mais cabelos do que Paysandu perde jogos por ano; Marcelo Melo, que mesmo discordando de tudo, gosto de falar com ele; Motito que come mais do que do que hiena depois da seca; Sad, que dançava e tossia e pagava seus micos não intencionais; Manu, mesmo sendo brava me ajudou demais; Miguel, sempre disposto a ajudar e ... correr pelo laboratório; Camelier, que sempre me dava bronca pra levantar a cabeça; João Gabriel, que entendia minhas piadas; Paulo, por ser amigaço no Smithsonian e defender depois da minha tese e não me humilhar nas ilustrações; Tulio, que sempre foi mais feio; Cabelinho, sempre me pedindo carregador, caneta, lápis, durex... Marina, por colocar trilha sonora quando eu chegava Arthurzim, por não assistir meus vídeos; Guilhermão, por estar sempre presente e feliz; Pupo, por ser amigaço de todas as horas; Vitor, por reler meu caráteres e me dar excelentes dicas; Rodrigo Caires, por me esclarecer dúvidas e estar sempre presente ao meu lado; Gustavito, quando não assobiava. Aos novos integrantes do MZUSP, Pericles, George e Luz! Posso agradecer ao Osvaldo ou ele vai me xingar? Ao meu primeiro ídolo na ictiologia, o qual tive a realização de...

Triodon macropterus, the Three-tooth Puffer, is the sole extant representative of Triodontidae. It is characterized by a large pelvic fan that it flares when disturbed. Unlike Tetraodontidae (pufferfishes) and Diodontidae (porcupinefishes), T. macropterus has not previously been documented to inflate its abdomen although some nineteenth-century reports implied that it can. Those reports were rejected by a mid-twentieth-century anatomical study, and no new information about inflation in T. macropterus has been reported in the intervening 70 years, in part because the species was rarely collected. In this study, we used a combination of imaging techniques to investigate if T. macropterus can inflate. We examined 13 photographs of T. macropterus in which the pelvic fan was prominently flared; in seven of these, the abdomen was also inflated. We also studied captive T. macropterus at the Okinawa Churaumi Aquarium, which allowed us to make videographic and ultrasound studies of live individuals to confirm inflation behavior in this species. Videography shows that pelvic-fan flaring always preceded inflation. Ultrasound data from four trials of one captive individual show that water is buccal pumped for inflation into the stomach to produce an increase in volume of 30%. Powerful adduction of the suspensorium correlates with stomach inflation. We prepared x-rays and dissected three specimens to evaluate mobility of the long pelvic bone and its role in expanding the ventral abdominal recess during pelvic-fan flaring. We also studied the digestive tract and discovered a thin-walled pyloric region of the stomach that allows inflation to occur. Differences between the inflation mechanism of T. macropterus and those of tetraodontids and diodontids include: (1) inflation is slower and less extreme in T. macropterus; (2) T. macropterus has a pelvic bone that expands the ventral abdominal recess; (3) T. macropterus has smaller folds in the peritoneum and these are ventral to, rather than dorsal to, the digestive tract; (4) the ribs and long postcleithra of T. macropterus limit abdominal inflation; (5) the first branchiostegal ray of T. macropterus is much smaller than in tetraodontids and diodontids, which use the expanded bone to rapidly pump water for inflation; and (6) the pectoral girdle of T. macropterus is larger and much less mobile than that of tetraodontids and diodontids. Although we interpret that inflation serves similar roles in defense, the differences in the inflation mechanism of T. macropterus suggest that it evolved independently, and optimization of inflation behavior on three phylogenetic hypotheses for Tetraodontiformes supports this interpretation.