Molecular phylogeny and species delimitation of the genus Schizodon (Characiformes, Anostomidae).

The genus Schizodon is part of a group of headstanders and relatives (Family Anostomidae) that are widespread and ecologically important fishes in South American rivers. Schizodon includes 15 nominal species but their taxonomy has been challenging due to paucity of decisive characters to diagnose species. We present new molecular data to assess species boundaries or molecular operational taxonomic units (MOTUs), and to infer phylogenetic relationships among species. Evidence from two mitochondrial and three nuclear genes was used in these analyses. Mitochondrial DNA data for 112 specimens (from 11 nominal species) supported 13 consensus MOTUs, six of which matched valid nominal species (Schizodon borellii, S. fasciatus, S. intermedius, S. isognathus, S. knerii and S. scotorhabdotus). The nominal species Schizodon vittatus, S. nasutus, and S. dissimilis were subdivided into two MOTUs each, revealing either cryptic species or strong population structuring. In contrast, S. platae and S. jacuiensis constituted a single MOTU, indicating a possible case of synonymy. Our phylogenetic analysis subdivided the genus Schizodon into two large clades that are compatible with observed color patterns and biogeographic distribution. The first clade includes species with three to four conspicuous dark vertical bars on the flanks that originated in the Amazonas region (S. borellii, S. dissimilis, S. intermedius, S. fasciatus, S. scotorhabdotus, S. vittatus, and a cryptic species, Schizodon aff. vittatus). The second clade includes species with a conspicuous dark caudal blotch on the caudal peduncle, with vertical bars absent or inconspicuous, with a biogeographic origin in the La Plata drainage (S. isognathus, S. jacuiensis, S. knerii, S. nasutus and S. platae). Our results reinforce the importance of using molecular analyses to accelerate the study of diversity, particularly in groups with a wide distribution, few variable meristic characters, and high morphological plasticity, which may hide still unknown or underestimated diversity.

Taxonomic revision of Hypostomus albopunctatus (Siluriformes: Loricariidae) reveals a new piece of the Hypostomus jigsaw in the upper Rio Paraná basin.

Hypostomus albopunctatus was described from the Rio Piracicaba, a tributary of the Rio Tietê, upper Rio Paraná basin. Nevertheless, specimens attributed to this species are commonly found throughout other river systems in the upper Rio Paraná basin and present varying degrees of morphological variation. A taxonomic review of H. albopunctatus based on large series of specimens from many localities throughout the upper Rio Paraná basin was carried out. Results support H. lexi, H. niger and H. scaphyceps as junior synonyms. Hypostomus albopunctatus differs from all congeners except H. heraldoi by having pectoral-fin spine equal to or shorter than pelvic-fin spine (v. longer); it differs from H. heraldoi by having white or light yellow spots on the body and fins (v. dark brown or black spots). Despite conspicuous variation related to the shape and size of the spots and snout morphology, both spot and snout patterns overlapped among the examined populations, thus this variation was inferred to be intraspecific within a widely distributed H. albopunctatus.

A new endangered species of Megaleporinus (Characiformes: Anostomidae) from the Rio de Contas basin, eastern Brazil.

A new species of Megaleporinus is described from the Rio de Contas, a coastal drainage of eastern Brazil, and its phylogenetic relationships are studied using molecular data. The new species is unique among Anostomidae by possessing two exclusive features: an irregular dark longitudinal stripe from supracleithrum to second midlateral blotch and anterior cranial fontanel partially closed. In addition, the new species is diagnosed by having three premaxillary teeth, three dentary teeth, 37 or 38 scales in lateral line, 16 scale rows around caudal peduncle, three dark midlateral blotches on body, and red fins in life. The new species is closely related to M. obtusidens from the São Francisco basin, corroborating previous studies that indicated that the latter represents a species complex as currently defined. The new species exhibits the first rib enlarged in mature males, a feature described for some congeners. The new species is herein considered to be Endangered under the IUCN criteria.

Description of a new species of Schizodon (Characiformes: Anostomidae) from the upper rio Tapajs basin, Brazil.

A new species of Schizodon with five dark transverse blotches on the body and a large black blotch at the end of the caudal peduncle is described from the rio Arinos, upper rio Tapajs basin, in the Brazilian Amazon. The new species shares a color pattern composed by transverse brown bars and a caudal fin blotch with Schizodon fasciatus and S. trivittatus but possess twelve rows of scales around the caudal peduncle, a unique character among the species of genus.

Description of a new species of Leporinus (Characiformes: Anostomidae) from the Rio Tapajós basin, Brazil.

A new species of Leporinus is described from the rio Teles Pires, rio Tapajós basin, Amazon basin, Brazil. The new species is diagnosed based on dental formula 3/4, a dark midlateral stripe on body and a series of transversal dark bars on the dorsum. The new species is similar to a handful of congeners based on the color pattern, including L. britski, L. microphysus, L. parvulus, and L. vanzoi, all of which also occur at the rio Tapajós basin. The new species is distinguished from the aforementioned congeners based on number of premaxillary teeth, number of scales in lateral line and/or around caudal peduncle. The new species is apparently endemic to the rio Teles Pires near the Sete Quedas rapids and upstream.

Poor taxonomic sampling undermines nomenclatural stability: A reply to Roxo et al. (2019).

A recent study based on genomic data by Roxo et al. (2019) provided a phylogeny of the Loricariidae, the largest catfish family and second largest Neotropical fish family with approximately 1,000 species. The study represents a valuable and innovative contribution for understanding higher-level relationships within the family. The phylogenetic tree inferred by Roxo et al. (2019) thoroughly corroborates the monophyly and relationships of most currently accepted subfamilies of Loricariidae, based on a fair taxon sampling (nearly 14% of the species in the family) representing most genera of each but one of the subfamilies, the Lithogeninae, the sister-group of the remaining members of the family (Pereira & Reis, 2017; Reis et al., 2017). In addition to a hypothesis of relationships, Roxo et al. (2019) also proposed a series of lower-level taxonomic changes, which are deemed premature considering that the taxonomic sampling of the study targeted higher-level clades, and go against one of the pillars of biological classification: nomenclatural stability (e.g., Heterick & Majer, 2018; Beninger & Backeljau, 2019). Here we (1) discuss implications of inadequate taxonomic sampling as a basis for changes in classification of species; (2) explain why the taxonomic sampling design of Roxo et al. (2019) is inadequate for the proposed nomenclatural changes; and (3) advocate that changes to classifications must be grounded on phylogenies with dense sampling of taxa at the relevant level.

Hypostomus velhochico, a new keeled Hypostomus Lacépède, 1803 (Siluriformes: Loricariidae) from the rio São Francisco basin in Brazil.

Hypostomus velhochico sp. n., is described from the rio São Francisco basin, in the states of Minas Gerais and Bahia, Brazil. The new species is mainly distinguished from its congeners by a combination of characters such as slender bicuspid teeth, dentaries angled more than 90 degrees, conspicuous keels along lateral series of plates, small roundish dark spots, one plate bordering supraoccipital, spots aligned along lateral series of plates, and by attaining small to medium size. Hypostomus velhochico is widespread in the rio São Francisco basin and has a more similar general pattern of external morphology to species from the Northeastern Brazilian Coastal drainages than to species of the rio São Francisco basin. Aspects about its ecology and its putative relationship are discussed.

Integrative taxonomy reveals a new species of Neotropical headstanding fish in genus Schizodon (Characiformes: Anostomidae)

Abstract Schizodon encompasses approximately 15 species of Neotropical headstanding fishes. Integrative taxonomy, combining molecular and morphometric analyses with traditional taxonomic methods, was used to investigate Schizodon vittatus and its potential new sister species. Molecular differences between the two species in the barcode are greater than intra-specific variation recovered in species of Schizodon, and the two species represent distinct lineages for approximately one million years. The two species are morphologically very similar, and the meristic data showed great overlap. Morphometric analyses also showed overlap among the putative species but indicated differences in caudal-peduncle depth, orbital diameter, and length of anal-fin rays. Color pattern seems to provide a clear diagnostic feature for the two species. Schizodon vittatus usually has four dark brown transversal bars on body, and its sister species has three conspicuous bars, with the fourth, if present, inconspicuous and dorsal to the lateral line. Schizodon vittatus is redescribed based on the type and recently collected specimens, its type locality is revisited, and its known distribution restricted to the Araguaia and Tocantins drainages. The new species, sister to S. vittatus, distributed in the Xingu and Tapajós drainages, is described. A key for the identification of the Amazon clade species of Schizodon is provided.

Resumo Schizodon engloba aproximadamente 15 espécies de peixes neotropicais. A taxonomia integrativa, combinando análises moleculares e morfométricas com métodos taxonômicos tradicionais, foi utilizada para investigar Schizodon vittatus e sua potencial espécie irmã. As diferenças moleculares (DNA barcoding) entre as duas espécies são maiores do que a variação intraespecífica observada em espécies congêneres, e as duas espécies representam linhagens distintas por aproximadamente um milhão de anos. As duas espécies são morfologicamente muito similares e os dados merísticos mostram grande sobreposição. As análises morfométricas também mostraram sobreposição entre as duas espécies, mas indicaram diferenças na altura do pedúnculo caudal, no diâmetro interorbital, e no comprimento dos raios da nadadeira anal. O padrão de colorido parece fornecer uma característica diagnóstica clara para as duas espécies. Schizodon vittatus normalmente possui quatro faixas escuras transversais no corpo e sua espécie irmã tem três faixas, com a quarta, se presente, inconspícua e dorsal à linha lateral. Schizodon vittatus é redescrita com base no tipo e em espécimes coletados recentemente; sua localidade tipo é revisitada e a sua distribuição conhecida é restringida às drenagens do Araguaia e Tocantins. A nova espécie, irmã de S. vittatus e distribuída nas drenagens do Xingu e Tapajós, é descrita. Uma chave para a identificação das espécies do clado amazônico de Schizodon é apresentada.

Revalidation and redescription of Steindachnerina nigrotaenia and redescription of S. insculpta (Characiformes: Curimatidae)

Steindachnerina nigrotaenia is resurrected from the synonym of S. brevipinna and considered a valid species. The previous designation of the lectotype of S. nigrotaenia is considered invalid and a new lectotype is designated herein. Steindachnerina nigrotaenia and S. insculpta are redescribed based on type specimens and on additional material from the rio Paraguai and the upper rio Paraná basins, respectively. The two species can be separated by the number of scales of the lateral line and of the transverse series and by phylogenetic analyses of molecular data.(AU)

Steindachnerina nigrotaenia é retirada da sinonímia de S. brevipinna e considerada uma espécie válida. A designação do lectótipo de S. nigrotaenia é considerada inválida e um novo lectótipo é aqui designado. Steindachnerina nigrotaenia e S. insculpta são redescritas com base no material tipo e em exemplares adicionais das bacias do rio Paraguai e alto rio Paraná, respectivamente. As duas espécies se diferenciam pelo número de escamas da linha lateral e da série transversal e por análises filogenéticas de dados moleculares.(AU)

New species of Leporinus (Characiformes: Anostomidae) from the highlands of the Guiana Shield in Venezuela

A new species of Leporinus is described using morphological data and compared to all other species of the family. Specimens were illustrated using digital photograph, measured using digital calipers, and had teeth, scales, and fin rays counted under a stereomicroscope. The new species is distinguished from all other Anostomidae, except Anostomus anostomus, A. brevior, A. ternetzi, Hypomasticus despaxi, Leporinus arcus, and L. striatus, by having four dark longitudinal stripes on body. The new species is distinguished from aforementioned species by having terminal mouth with four teeth on the premaxilla, 12 series of scales around caudal peduncle, and 34 to 36 scales in the lateral line. The new species is remarkably similar to Leporinus arcus, which occurs on the opposite side of Guyana Shield highlands. The new species and L. arcus are possibly closely related to Leporinus gomesi, L. granti, L. lebaili, L. melanostictus, L. nijsseni, and L. santosi.(AU)

Uma espécie nova de Leporinus é descrita usando dados morfológicos e comparações entre todas as espécies da família. Exemplares foram ilustrados com fotografia digital, medidos com paquímetro digital e seus dentes, escamas e raios das nadadeiras foram contados sob estereomicroscópio. A espécie nova distingue-se dos demais Anostomidae, exceto Anostomus anostomus, A. brevior, A. ternetzi, Hypomasticus despaxi, Leporinus arcus e L. striatus, por apresentar quatro faixas longitudinais no corpo. A nova espécie distingue-se das espécies mencionadas por ter boca terminal com quatro dentes no osso pré-maxilar, 12 séries de escamas ao redor do pedúnculo caudal e 34 a 36 escamas na linha lateral. A espécie nova é particularmente similar à Leporinus arcus, que ocorre no lado oposto das terras altas do Escudo da Guiana. A espécie nova e L. arcus, possivelmente, são relacionadas proximamente à Leporinus gomesi, L. granti, L. lebaili, L. melanostictus, L. nijsseni e L. santosi.(AU)

Ichthyofauna of streams of the Rio Sapucaí basin, upper Rio Paraná system, Minas Gerais, Brazil / Ictiofauna de riachos da bacia do Rio Sapucaí, sistema do alto Rio Paraná, Minas Gerais, Brasil

Abstract: The Rio Sapucaí basin, in Minas Gerais State, Brazil, is one of the many watersheds of the upper Rio Paraná system. Ichthyofauna surveys in this basin, in general, are scarce. In addition, small rivers and streams of the region have been targets of anthropogenic actions (e.g., pollution) - which suggest that more ichthyological studies must be performed within the watershed. In this study we provide a survey of species that occur within three streams of the lower Rio Sapucaí basin. Samples were collected in April, July, and November 2017 and in May 2018. Collections resulted in 349 individuals belonging to 28 species, five orders, and 12 families. Among our findings are three putatively undescribed species and the first record of Oligosarcus argenteus and Pareiorhina hyptiorhachis within the Rio Paraná system.

Resumo: A bacia do Rio Sapucaí, no Estado de Minas Gerais, Brasil, é uma das muitas bacias hidrográficas do sistema do alto Rio Paraná. Levantamentos de ictiofauna nessa bacia, em geral, são escassos. Além disso, rios de pequeno porte e córregos da região têm sido alvos de ações antrópicas (e.g., poluição) - o que sugere que mais estudos ictiológicos devem ser realizados na bacia. Neste trabalho nós fornecemos um levantamento de espécies que ocorrem em três riachos da porção baixa da bacia do Rio Sapucaí. As amostras foram coletadas em Abril, Julho, e Novembro de 2017 e em Maio de 2018. As coletas resultaram em 349 indivíduos pertencentes a 28 espécies, cinco ordens e 12 famílias. Dentre os nossos achados estão três espécies possivelmente não descritas e o primeiro registro de Oligosarcus argenteus e Pareiorhina hyptiorhachis no sistema do Rio Paraná.

Comparative morphology of the gas bladder in driftwood catfishes (Siluriformes: Auchenipteridae).

The gross morphology of the gas bladder is described and illustrated for representatives of most species and all valid genera of the Auchenipteridae (Siluriformes). Although, a simple cordiform gas bladder is present in some species of the family, others are characterized by their distinctive gas-bladder shape and diverticula disposition. An acute posterior end of the gas bladder characterizes Centromochlus heckelii and C. macracanthus, and is variably present in specimens of Auchenipterus. Tocantinsia piresi and Asterophysus batrachus have distinctive gas bladders differing in number of diverticula (two or many). The two species of Trachycorystes are diagnosed based on their gas bladder morphology: T. menezesi has a simple cordiform bladder, whereas T. trachycorystes has a pair of lateral diverticulum and, usually, a well-developed terminal diverticulum. Species of Auchenipterichthys are characterized by having a secondary bladder with simple chamber. Short or elongate and divergent terminal diverticula are exclusive to most cis-andine species of Trachelyopterus. Tetranematichthys and trans-andine species of Trachelyopterus share a well-developed secondary chamber or terminal diverticula ventrally or dorsally connected to the posterior chambers. The small-sized species of Ageneiosus have well-developed gas bladders with a pair of posterior diverticula, whereas large-sized species have a reduced gas bladder with tunica externa varying from non-, partially, or completely ossified. Eight phylogenetic characters are proposed based on the morphology of the gas bladder and associated structures in species of Auchenipteridae, and the evolution of those characters in the family discussed.

Redescription of leporinus jamesi (characiformes: anostomidae), a poorly known species of leporinus from the lowlands of the central Amazon, Brazil

The poorly known Leporinus jamesi is redescribed. The species was originally described based on a single specimen collected in the rio Solimões at Manacapuru, in the central Amazon, Brazil. The holotype went missing before the species description was finished and published, and remained lost for more than a hundred years. Leporinus jamesi is distinguished from its congeners by having pectoral and pelvic fins dark, 42 to 45 scales on the lateral line, 16 scale series around the caudal peduncle, a body with two conspicuous dark midlateral blotches (the blotch on the caudal peduncle absent or inconspicuous), and four teeth on the premaxilla and dentary, including a bicuspid symphyseal tooth on the premaxilla. A principal component analysis on morphometric traits between combined samples of L. jamesi and L. amazonicus was performed showing significant morphometric differences between these species. In addition, inaccuracies in Borodin's descriptions of various species of the genus Leporinus are discussed.

Leporinus jamesi, uma espécie pouco conhecida, é redescrita. A espécie foi originalmente descrita com base em um único exemplar procedente do rio Solimões em Manacapuru, na Amazônia central, Brasil. O holótipo da espécie foi perdido antes de sua descrição ter sido concluída e publicada, assim permanecendo por mais de cem anos. Leporinus jamesi distingue-se dos congêneres por apresentar as nadadeiras peitorais e pélvicas escuras, 42 a 45 escamas na linha lateral, 16 séries de escamas ao redor do pedúnculo caudal, duas manchas escuras conspícuas na lateral do corpo (mancha do pedúnculo caudal ausente ou inconspícua) e quatro dentes no pré-maxilar e no dentário , incluindo um dente bicúspide sinfisiano. Uma análise de componentes principais de características morfológicas realizada entre amostras combinadas de L. jamesi e L. amazonicus revelou diferenças significativas entre estas espécies. Além disso, imprecisões nas descrições de diversas espécies de Leporinus apresentadas por Borodin são discutidas.

A new species of Leporinus Agassiz, 1829 (Characiformes: Anostomidae) from the rio Tocantins, Brazil

A new species of Leporinus is described based on specimens from the lower rio Tocantins, Pará State, Brazil. The new species is diagnosed by having conspicuous dark spots on center of scales on anterolateral portion of body, 33 or 34 scales in lateral line, 16 scales rows around caudal peduncle, four scale rows between dorsal-fin origin and lateral line and four between lateral line and pelvic-fin origin, and four teeth on premaxilla and four on dentary. The new species is similar to Leporinus gomesi, L. granti, and L. nijsseni for having three prominent dark midlateral blotches, smaller blotches formed by dermal pigment, five of which form an interrupted "X" between head and first midlateral blotch, small dark spots formed by epidermal pigment, terminal mouth with four teeth on premaxilla and four on dentary, and relatively few scales on lateral line (less than 36). In addition, new data is provided for the type specimens of Leporinus granti and L. megalepis (=Hypomasticus megalepis),, and L. badueli is confirmed as a junior synonym of L. granti.

Uma espécie nova de Leporinus é descrita a partir de exemplares do baixo rio Tocantins, estado do Pará, Brasil. A espécie nova é diagnosticada por possuir conspícuos pontos escuros no centro de cada escama da porção anterolateral do corpo, 33 ou 34 escamas na linha lateral, 16 séries de escamas ao redor do pedúnculo caudal, quatro séries de escamas entre a origem da nadadeira dorsal e a linha lateral e quatro entre a linha lateral e a origem da nadadeira pélvica, quatro dentes no pré-maxilar e quatro no dentário. A espécie nova se assemelha a Leporinus gomesi, L. granti e L. nijsseni por apresentar três manchas escuras laterais no corpo, manchas menores no corpo formadas por pigmentos dérmicos dispostas num "X" entre o opérculo e a primeira mancha lateral, pontos escuros formados por pigmentos epidérmicos, boca terminal com quatro dentes no pré-maxilar e quatro no dentário, e relativamente poucas escamas na linha lateral (menos de 36). Além disso, dados novos sobre as séries de exemplares-tipo de Leporinus granti e L. megalepis (=Hypomasticus megalepis) são apresentados, e L. badueli é confirmado como um sinônimo júnior de L. granti .

Two new species of Leporinus Agassiz (Characiformes: Anostomidae) from eastern basins of Brazil, and redescription of L. melanopleura Günther

Two new species of Leporinus are described from coastal rivers of southern Bahia, Brazil. One of the new species has a bright red blotch immediately dorsal to the pectoral-fin origin in life, three dark blotches along the lateral line that distinctly increase in size posteriorly, and dark longitudinal lines between scale rows on the side of body. The second new species possesses a single broad dark midlateral stripe, encompassing one or two scale rows of depth on the body and centered on the scale row below the lateral line, a dark adipose fin, and a conspicuous dark blotch on the caudal peduncle. The first new species is known only from the rio de Contas and the second from the rio das Almas and rio Jiquiriçá. In addition, Leporinus melanopleura is redescribed based on a designated lectotype and additional specimens collected in the rio Una. Leporinus melanopleura has a single broad dark midlateral stripe, encompassing one or two scale rows of depth on the body, centered on the scale row below lateral line, a hyaline adipose fin (red in life), and an inconspicuous dark blotch on the caudal peduncle.

Duas espécies novas de Leporinus são descritas com base em exemplares de rios costeiros do sudeste da Bahia, Brasil. Uma das espécies novas possui uma mancha vermelho-viva imediatamente dorsal à origem da nadadeira peitoral em vida, três manchas escuras sobre a linha lateral que aumentam de tamanho para trás, e linhas escuras longitudinais entre as séries de escamas na lateral do corpo. A segunda espécie nova apresenta uma única faixa escura sobre o corpo, com altura de uma ou duas fileiras de escamas e centrada na série de escamas da linha lateral, nadadeira adiposa escura, e uma conspícua mancha escura sobre o pedúnculo caudal. A primeira espécie nova é conhecida somente do rio de Contas e a segunda dos rios das Almas e Jiquiriçá. Além disso, Leporinus melanopleura é redescrita com base no lectótipo, designado no presente trabalho, e outros exemplares coletados no rio Una. Leporinus melanopleura possui uma única faixa escura sobre o corpo, com altura de uma ou duas fileiras de escamas e centrada na série de escamas abaixo à linha lateral, nadadeira adiposa hialina (vermelha em vida), e uma mancha escura inconspícua sobre o pedúnculo caudal.

Parotocinclus seridoensis, a new hypoptopomatine catfish (Siluriformes: Loricariidae) from the upper rio Piranhas-Açu basin, northeastern Brazil

A new species of Parotocinclus is described from the upper rio Piranhas-Açu basin, northeastern Brazil. The new species differs from all its congeners, except P. bidentatus, P. muriaensis (both from rio Paraíba do Sul basin, southeastern Brazil), and P. spilurus (rio Jaguaribe basin, northeastern Brazil) by presenting the adipose fin rudimentary or absent. The new species differs from P. bidentatus, P. muriaensis, and P. spilurus mainly by presenting the abdomen region extensively naked, with few reduced rounded dermal platelets between the pectoral girdle and the anus. Parotocinclus seridoensis is probably an endemic species of the semi-arid Caatinga, region where the genus presents high species richness.

Uma espécie nova de Parotocinclus é descrita da bacia do alto rio Piranhas-Açu, nordeste do Brasil. A espécie nova difere de todas as congêneres, exceto P. bidentatus, P. muriaensis (ambas da bacia do rio Paraíba do Sul, sudeste do Brasil) e P. spilurus (bacia do rio Jaguaribe, nordeste do Brasil), por apresentar nadadeira adiposa rudimentar ou ausente. A espécie nova difere de P. bidentatus, P. muriaensis e P. spilurus principalmente por apresentar no abdômen extensas áreas nuas, com poucas placas dérmicas reduzidas e arredondadas entre a cintura peitoral e o ânus. Parotocinclus seridoensis é provavelmente uma espécie endêmica da Caatinga semi-árida, região onde o gênero apresenta elevada riqueza de espécies.

Iheringichthys syi (Siluriformes: Pimelodidae), a new pimelodid species from upper Paraná basin, Brazil

We describe a new species of pimelodid catfish of the genus Iheringichthys from the upper Paraná basin, Brazil. Iheringichthys syi n. sp. is distinguished by the comparatively fine serration along the anterior margin of the pectoral-fin spine, an adpressed dorsal-fin remote from the adipose-fin origin, a large eye (23.2-31.2% of head length), narrow interorbital (16.2-23.0% of head length), long snout (42.0-51.0% of head length), long postorbital length (30.6-34.0% of head length), low adipose fin (4.8-7.8% of standard length), eye diameter 97.0-140.0% of interorbital length, and body with numerous, small dots irregularly scattered on flanks, especially marked on anterior half of flank.

Iheringichthys syi sp. n. é descrita para a bacia do alto rio Paraná, Brasil. A nova espécie diferencia-se das duas outras espécies do gênero pelas seguintes características: margem anterior do acúleo da nadadeira peitoral com serra pouco pronunciada, nadadeira dorsal quando adpressa distante da origem da nadadeira adiposa, olho grande (23,2-31,2% do comprimento da cabeça), interorbital estreito (16,2-23,0% do comprimento da cabeça), focinho longo (42,0-51,0% do comprimento da cabeça), comprimento pós-orbital relativamente longo (30,6-34,0% do comprimento da cabeça), nadadeira adiposa baixa (4,8-7,8% do comprimento padrão), diâmetro do olho 97,0-140,0 % do espaço interorbital, corpo com numerosas manchas pequenas espalhadas pelo flanco, sendo mais conspícuas na metade anterior do corpo.

New species of Trachycorystes Bleeker, with comments on other species of the genus (Ostariophysi: Siluriformes: Auchenipteridae)

A new species of Trachycorystes from the rio Aripuanã, above Dardanelos and Andorinhas falls, is described. The new species is distinguished from the only other species of the genus, T. trachycorystes, by the following characteristics: jaws of equal length (vs. lower jaw prognathous in T. trachycorystes); skull roof covered by thick (vs. thin) integument; inner mental barbel very thin and short not reaching base of outer barbel (vs. extending to or beyond base of outer mental barbel); dorsal-fin spine serrated posteriorly, smooth or rough anteriorly (vs. serrated anteriorly and smooth or rough posteriorly); caudal fin shallowly forked (vs. emarginate); and gas bladder simple, without diverticula (vs. with three posterior diverticula). Comments and data on the nominal species Trachycorystes trachycorystes are provided. Trachycorystes cratensis Miranda Ribeiro, 1937, is allocated to the genus Trachelyopterus Valenciennes, 1840, and another local catfish species, Parotocinclus aripuanensis Garavello, 1988, has its type locality reassigned.

Descreve-se uma espécie nova de Trachycorystes proveniente do curso superior do rio Aripuanã, acima das cachoeiras Dardanelos e Andorinhas. A espécie nova diferencia-se da outra espécie do gênero, T. trachycorystes, pelos seguintes caracteres: maxilas de mesmo comprimento, isto é, mandíbula não prognata (vs. mandíbula prognata em T. trachycorystes); teto do crânio coberto com pele espessa (vs. fina); barbilhão mental muito fino e curto não alcançando a base do barbilhão pós-mental (vs. estendendo-se até a base do barbilhão pós-mental ou além); espinho da nadadeira dorsal com a borda anterior lisa ou rugosa e a posterior com serras retrorsas (vs. borda anterior com serras e a posterior lisa ou rugosa); nadadeira caudal bifurcada (vs. emarginada); bexiga natatória simples, sem divertículos (vs. com três divertículos posteriores). Comentários e dados sobre as outras espécies nominais de Trachycorystes são apresentados. Trachycorystes cratensis Miranda Ribeiro, 1937, é transferido para o gênero Trachelyopterus Valenciennes, 1840, e retificam-se dados sobre a localidade-tipo de Parotocinclus aripuanensis Garavello, 1988.

A new species of Trichogenes from the rio Itapemirim drainage, southeastern Brazil, with comments on the monophyly of the genus (Siluriformes: Trichomycteridae)

A new species of the formerly monotypic genus Trichogenes is described from a high-altitude stream of the rio Itapemirim system, an isolated Atlantic drainage in the State of Espírito Santo, southeastern Brazil. Trichogenes claviger, new species, differs from all other trichomycterids by the sexually dimorphic posterior process of the opercle, much elongated in males; the terminal mouth; the deeply bifurcated anterior neural spines and the presence of a large anterodorsal claw-like process on the neural arches of the anterior four free vertebrae. The new species also differs from its only congener, T. longipinnis, by a number of additional traits, including the the lack of branched anal-fin rays in specimens of any size; the broader than long posterior nostril; the deeper head (head depth 72.9-86.6 percent HL); the presence of a fine dark line along the base of the anal fin; the lack of dark spots on cheeks; the shape of the interopercle; the presence of odontodes on a bony expansion on the posterodorsal margin of the interopercle; the fewer vertebrae (35); the absence of an antorbital; and the fewer pleural ribs (eight). Small juveniles of the new species are also strikingly different from those of all other Trichomycteridae, including T. longipinnis, having a very large lateral eye, an upturned mouth, and compressed head. Trichogenes claviger occurs in shaded sectors of a blackwater sluggish stream with sandy substrate and patchy accumulations of vegetable debris, a habitat markedly different from the rocky torrential environment known for T. longipinnis. A comparison of the internal anatomy of the two species provides the basis for a hypothesis of a monophyletic Trichogenes. Data from the new species further support a sister-group relationship between Trichogeninae and Copionodontinae, as well as the position of that clade as sister group to all remaining Trichomycteridae.

Uma espécie nova do gênero previamente monotípico Trichogenes é descrita de um riacho de altitude pertencente à drenagem do rio Itapemirim, uma bacia Atlântica isolada do Estado do Espírito Santo, sudeste do Brasil. Trichogenes claviger, espécie nova, difere de todos os outros Trichomycteridae pela presença sexualmente dimórfica de um processo posterior do opérculo muito alongado nos machos; a boca terminal; os espinhos neurais das vértebras anteriores profundamente bifurcados; e a presença de um grande processo em forma de garra ântero-dorsalmente nos arcos neurais das quatro primeiras vértebras livres. A espécie nova também se diferencia de seu único congenérico, T. longipinnis, por várias outras características, incluindo: a ausência de raios ramificados na nadadeira anal em exemplares de todos os tamanhos; a narina posterior mais larga que longa; a cabeça mais alta (altura da cabeça 72,9-86,6 por cento do seu comprimento); a presença de uma fina linha negra ao longo da base da nadadeira anal; a ausência de manchas negras na face lateral da cabeça; o formato distinto do interopérculo; a presença de odontódeos em uma expansão óssea na margem posterodorsal do interopérculo; o menor número de vértebras (35); a ausência de antorbital; e o menor número de costelas pleurais (oito). Exemplares jovens da espécie nova são notavelmente diferentes daqueles de todos os outros Trichomycteridae, incluindo T. longipinnis, tendo um olho muito grande em posição lateral, a boca inclinada para cima e a cabeça comprimida. Trichogenes claviger ocorre em setores sombreados de um riacho de água preta, de correnteza lenta, com substrato arenoso e aglomerações de matéria vegetal em alguns pontos, um habitat bastante diferente do ambiente rochoso e torrencial de T. longipinnis. Uma comparação da anatomia interna das duas espécies fornece a base para uma hipótese de monofiletismo de Trichogenes. Dados da espécie nova corroboram a hipótese de grupo-irmão entre Trichogeninae e Copionodontinae, assim como a posição deste clado como grupo-irmão de todos os restantes Trichomycteridae.

Structure and evolution of tetraodontoid teeth: An autoradiographic study (pisces, Tetraodontiformes).

For years teeth of tetraodontoid fishes generally have been considered coalescent even though "coalescence," which also is found in fishes of other families, has never been well defined. This paper deals with some aspects of coalescence of the teeth in tetraodontoids and attempts to define this condition. The sites of osteodentinogenesis and the mechanisms by which hard tissues are formed, reabsorbed, and abraded during feeding were analyzed from semiserial decalcified sections and from ground sections, as well as from autoradiographs of the premaxilla and dentary bones of Sphoeroides greeleyi. The observations reported here, taken together with other data we have obtained on members of the Tetraodontoidei, permit clear definitions of "tooth" and "supporting bone," and consequently the structural meaning of coalescence. From these data we hypothesize how coalesced masticatory structures may have evolved in this group.