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A new species of Gelanoglanis from the Orinoco and Amazon River basins, with comments on miniaturization within the genus (Siluriformes: Auchenipteridae: Centromochlinae)
... The Auchenipteridae, known as driftwood catfishes, is a monophyletic group with 116 valid species known to date, arranged in 22 genera (updated from Ferraris, 2007). Gelanoglanis Böhlke 1980 is a very distinctive genus and currently known as a monophyletic taxonomic unit of the subfamily Centromochlinae, diagnosed by 15 morphological synapomorphies (Böhlke, 1980; Soares-Porto et al., 1999; Calegari et al., 2014). Gelanoglanis has four valid species distributed in the Orinoco River (Gelanoglanis stroudi Böhlke 1980), middle Negro River and upper Orinoco River (Gelanoglanis nanonocticolus Soares-Porto, Walsh, Nico & Netto 1999), upper Amazon River basin (Gelanoglanis ‡Author to whom correspondence should be addressed. ...
... Gelanoglanis Böhlke 1980 is a very distinctive genus and currently known as a monophyletic taxonomic unit of the subfamily Centromochlinae, diagnosed by 15 morphological synapomorphies (Böhlke, 1980; Soares-Porto et al., 1999; Calegari et al., 2014). Gelanoglanis has four valid species distributed in the Orinoco River (Gelanoglanis stroudi Böhlke 1980), middle Negro River and upper Orinoco River (Gelanoglanis nanonocticolus Soares-Porto, Walsh, Nico & Netto 1999), upper Amazon River basin (Gelanoglanis ‡Author to whom correspondence should be addressed. Tel.: +55 (51) 3353 4413; email: reis@pucrs.br ...
... The new species shares with congeners all synapomorphies previously proposed for the genus (Böhlke, 1980; Soares-Porto et al., 1999; Calegari et al., 2014), except for the absence of serrae on the anterior margin of the pectoral-fin spine. Gelanoglanis varii also shares with congeners the presence of a series of soft and rounded papillae along the maxillary barbel, corroborating that feature as a potential additional synapomorphy for the genus [a complete description of this structure was given by Calegari et al. (2014)]. ...
A new species of Gelanoglanis is described based on specimens collected in the Tocantins River, a tributary of the Amazon Basin. The new species is distinguished from congeners by unusual features to the genus such as the pelvic fin falling short of the urogenital opening by a distance larger than the anal‐fin length, the first unbranched dorsal and pectoral‐fin rays not ossified as spines, the dorsal‐fin spinelet absent and the adipose fin in adults preceded by a long fleshy ridge. The new species is further distinguished from congeners by its soft, sinuous snout tip and morphometric proportions of the body and head. The new species shares most putative synapomorphies of the genus, as well as the miniaturized condition evidenced by a diminutive body size and reduced ossifications and lateral sensory system. An elongate dorsal process of the cleithrum is posited as an additional synapomorphy for the genus. An osteological description of Gelanoglanis nanonocticolus based on high‐resolution X‐ray computed tomography is also provided.
http://zoobank.org/urn:lsid:zoobank.org:pub:BA3FE72D‐FEF84‐7A7‐B751‐2A15EA52C203 .
... single pair in Gelanoglanis), and having a vomer (v. vomer absent) (see Soares-Porto et al., 1999 for additional features exclusive to Gelanoglanis). ...
A new species of the catfish genus Centromochlus (Auchenipteridae, Centromochlinae) is described. The new species is diagnosed by having numerous dark rounded blotches over the body and fins, dorsal-fin spine with serrations anteriorly and smooth posteriorly, anal fin of mature males with three unbranched and seven branched rays, anterior nuchal plate absent and posterior nuchal plate not extended ventrally. The new species is described from a small stream in the Estação Ecológica Serra Geral de Tocantins, a natural reserve in the centre of the Brazilian Cerrado, close to the watershed between the Rio Tocantins and the Rio São Francisco basins. The new species is possibly the sister taxon to the recently described Centromochlus meridionalis from the upper Rio Tapajós. Those two species share with Centromochlus perugiae, from the upper Amazon and upper Paraguay, derived features associated with the modified anal fin in sexually mature males.
© 2015 The Fisheries Society of the British Isles.
... Centromochlus simplex also lacks the features used to diagnose Glanidium (Soares-Porto, 1998;Sarmento-Soares & Martins-Pinheiro, 2013), such as voluminous section A2 of the adductor mandibulae muscle associated with a deep concavity between sphenotic and pterotic, and anterior nuchal plate present. Centromochlus simplex does not share the unique features present in Gelanoglanis described in Soares-Porto et al. (1999) and Rengifo et al. (2008), already mentioned in the introduction. ...
Centromochlus abriga doze espécies, com registros para os principais
sistemas fluviais de águas interiores da América do Sul, como o Orinoco, Essequibo,
rios costeiros do Suriname, Amazonas, alto Paraná e São Francisco. A nova espécie é
descrita do alto rio Paraná, a partir de material coletado em 1965 durante a
construção da UHE Ilha Solteira, São Paulo, Brasil. A espécie nova distingue-se
facilmente de todas as suas congêneres pela ausência de nadadeira adiposa, uma
condição até então restrita à Gelanoglanis nanonocticolus, dentre os
bagres centromochlíneos. A nova espécie inclui pequenos bagres (adultos entre 35 e 39
mm CP), nos quais a nadadeira anal modificada em machos é desprovida de dentículos ou
espinhos, e com os raios mais posteriores de tamanho reduzido. Adicionalmente,
Tatia simplex Mees é transferida para Centromochlus
e é fornecida uma discussão acerca de seu posicionamento genérico.
... Para a família Cetopsidae, Oliveira (1988) cita o prolongamento dos primeiros raios da peitoral para a maioria dos gêneros. O mesmo é citado para Gelanoglanis nanonocticolus (Porto et al., 1999 DIMORFISMO SEXUAL EM SILURIFORMES E GYMNOTIFORMES (OSTARIOPHYSI) DA AMAZÔNIA. alargado e achatado. ...
The present paper aims to summarize cases of sexual dimorphism in Siluriformes and Gymnotiformes. This summary focuses on Neotropical representatives, with emphasis on Amazonian fish. Fishes from this region exhibit high species-level diversity, although the intraspecific limits of many of these forms are unknown. In Loricariidae (Siluriformes), mapping of dimorphic traits on cladograms has helped to demonstrate that patterns of sex dimorphism are consistent with hypotheses of monophyly, thus reinforcing its role as an important evolutionary phenomenon. In Apteronotidae (Gymnotiformes), mapping of characters on phylogenetic trees suggests that sexual dimorphism (regarding snout size, form, and presence/absence of teeth) has evolved independently in multiple taxa. Recently in Gymnotiformes, detected taxonomic errors are attributed to extreme differences between males and females in their morphology.
... single pair in Gelanoglanis), vomer present (vs. absent) and by other diagnostic features stated in Soares-Porto et al. (1999). Centromochlus is under long term revisionary studies (LMSS), and investigation regarding its monophyly it out of the scope of present paper. ...
Centromochlus actually comprises eleven species, being the most problematic genus among the Centromochlinae, including morphologically heterogeneous taxa. The Centromochlus species have a wide distributional area on northern South America. Centromochlus meridionalis, new species, is described from headwaters of rio Teles Pires, contributor of rio Tapajós, Mato Grosso State, Brazil, and represents one of the southernmost records of a centromochlin catfish for Meridional Amazon rivers. Centromochlus meridionalis is promptly distinguished from its congeners by the small orbital diameter (relative to head length), and also by the combination of absence of first nuchal plate, anterior margin of dorsal-fin spine smooth, six branched rays in anal fin, seven pairs of ribs and 34 vertebrae. They are small sized catfishes with adults between 33 to 61 mm in standard length. The modified male anal fin is conspicuous, with the third unbranched ray enlarged, about twice the width of first unbranched ray. The new species inhabits a region strongly endangered by environmental changes due to expansion of agropecuary activities on Brazilian Amazon, which include this species in an uncertain situation regarding the conservation status of its natural population.
A comprehensive phylogeny of species relationships of the Auchenipteridae is reconstructed here with a large-scale taxon sampling based on combined morphological and molecular datasets. The hypothesized phylogeny includes most species of Auchenipteridae (97 of 124 valid species) and multiple members of siluriform families as an outgroup (32 species) to embrace the diversity of forms among related catfishes. As the first large-scale phylogeny of the Auchenipteridae, comparison between taxa included information from both morphology (264 characters) and mitochondrial and nuclear molecular markers (3490 nucleotides) from five genes: coI, 16S, rag2, myh6 and SH3PX3. Trees were generated under two different optimality criteria (Maximum Parsimony and Bayesian Inference). A new classification for the family is presented herein to bring the taxonomy more in line with the new phylogenetic hypothesis. The strict consensus tree corroborates the monophyly of superfamily Doradoidea, family Auchenipteridae and its two subfamilies, Centromochlinae and Auchenipterinae. The new classification scheme proposes nine tribes in Auchenipteridae, based on the monophyly of major groups in both subfamilies. Centromochlus, Glanidium and Tatia are each recovered as paraphyletic. To maintain a monophyletic classification, some species treated as Tatia and Centromochlus are assigned to genera not previously recognized as valid.
ABSTRACT.—A hypothesis of phylogenetic relationships is presented for species of the South American catfish subfamily Centromochlinae (Auchenipteridae) based on parsimony analysis of 133 morphological characters in 47 potential ingroup taxa and one outgroup taxon. Of the 48 species previously considered valid in the subfamily, only one, Centromochlus steindachneri, was not evaluated in the present study. The phylogenetic analysis generated two most parsimonious trees, each with 202 steps, that support the monophyly of Centromochlinae composed of five valid genera: Glanidium, Gephyromochlus, Gelanoglanis, Centromochlus and Tatia. Although those five genera form a clade sister to the monotypic Pseudotatia, we exclude Pseudotatia from Centromochlinae. The parsimony analysis placed Glanidium (six species) as the sister group to all other species of Centromochlinae. Gephyromochlus contained a single species, Gephyromochlus leopardus, that is sister to the clade Gelanoglanis (five species) + Centromochlus (eight species). Based on the new taxonomic arrangement herein, Balroglanis Grant 2015 and Sauronglanis Grant 2015 are placed in the synonymy of Centromochlus. Tatia is the most diverse genus within Centromochlinae, with twenty-six species in three monophyletic clades. The species composition of Tatia differs from that of Calegari et al. (2019). Duringlanis Grant 2015 and Ferrarissoaresia Grant 2015 are considered synonyms of Tatia. All generic taxa within Centromochlinae are diagnosed based on synapomorphic morphological characters. An identification key for Centromochlinae is provided.
A phylogenetic analysis based on 311 morphological characters is presented for most species of the Doradidae, all genera of the Auchenipteridae, and representatives of 16 other catfish families. The hypothesis that was derived from the six most parsimonious trees support the monophyly of the South American Doradoidea (Doradidae plus Auchenipteridae), as well as the monophyly of the clade Doradoidea plus the African Mochokidae. In addition, the clade with Sisoroidea plus Aspredinidae was considered sister to Doradoidea plus Mochokidae. Within the Auchenipteridae, the results support the monophyly of the Centromochlinae and Auchenipterinae. The latter is composed of Tocantinsia, and four monophyletic units, two small with Asterophysus and Liosomadoras, and Pseudotatia and Pseudauchenipterus, respectively, and two large ones with the remaining genera. Within the Doradidae, parsimony analysis recovered Wertheimeria as sister to Kalyptodoras, composing a clade sister to all remaining doradids, which include Franciscodoras and two monophyletic groups: Astrodoradinae (plus Acanthodoras and Agamyxis) and Doradinae (new arrangement). Wertheimerinae, new subfamily, is described for Kalyptodoras and Wertheimeria. Doradinae is corroborated as monophyletic and composed of four groups, one including Centrochir and Platydoras, the other with the large-size species of doradids (except Oxydoras), another with Orinocodoras, Rhinodoras, and Rhynchodoras, and another with Oxydoras plus all the fimbriate-barbel doradids. Based on the results, the species of Opsodoras are included in Hemidoras; and Tenellus, new genus, is described to include Nemadoras trimaculatus, N. leporhinus and Nemadoras ternetzi. Due to conflicting hypotheses of the phylogenetic position of Acanthodoras, Agamyxis, and Franciscodoras, these are considered as incertae sedis in Doradidae. All suprageneric taxa of the Doradoidea are diagnosed based on synapomorphic morphological characteristics.
Previously proposed synapomorphies for the genus Gelanoglanis of the catfish family Auchenipteridae are evaluated and four additional features involving the relationship between the mesethmoid and premaxilla, the very fleshy anterior portion of the snout, the lack of ossification of the second through fourth infraorbitals, and the incomplete poring of the lateral line are hypothesized as synapomorphic for the members of the genus. A new species of Gelanoglanis is described based on a series of specimens collected in the rio Teles Pires, a tributary of the rio Tapajós in the southern reaches of the Amazon basin. The new species demonstrates a number of features unusual within Gelanoglanis including a fontanel bordered by the frontals, a particularly elongate gonopodium in mature males, reductions in the dentition on the premaxilla, and a shorter posterior extension of the maxilla inside the maxillary barbel. The new species is a miniature as evidenced both by its body size and the reductions of various ossifications of the head, the number of fin rays and of the laterosensory canal system on the head and body.
Priocharax nanus, new species, is described from the rio Negro, Brazil. It is a miniature fish that retains as an adult the larval rayless pectoral fin, a diagnostic character of the genus. Priocharax nanus possesses fewer reductive features compared to congeners, P. ariel and P. pygmaeus, from which it can be distinguished by the presence of i,6 pelvic-fin rays (vs. i,5), the presence of the claustrum (vs. claustrum absent) and the presence of two postcleithra (vs. postcleithra absent). An updated list of 213 species of miniature Neotropical freshwater fishes is presented. The greatest diversity among them is represented by the Characiformes with 87 miniature species.
Priocharax nanus, espécie nova, é descrita do rio Negro, Brasil. É um peixe miniatura que retém no adulto a forma larval da nadadeira peitoral, um caráter diagnóstico do gênero. Priocharax nanus possui um número menor de caracteres redutivos quando comparado aos congêneres, P. ariel and P. pygmaeus, dos quais pode ser distinguida pela presença de i,6 raios na nadadeira pélvica (vs. i,5), presença do claustrum (vs. claustrum ausente) e presença de dois pós-cleitros (vs. pós-cleitros ausentes). Uma lista atualizada de 213 espécies de peixes miniatura de água doce neotropicais é apresentada. A maior diversidade entre eles é representada pelos Characiformes, com 87 espécies miniatura.
Recent studies have described widespread statigraphic units of Late Pleistocene and Holocene age in the western part of the Amazon Basin. The recognition of deltaic sedimentation in the uppermost these units near Rio Branco, Brazil, at a modern elevation of approximately 500 feett leads to the conclusion that this area was situated on the edge of a large Amazonian lake that existed in the recent past when Andean tectonism caused active downwarping of the western edge of the Amazon Basin. The ramifications of this "Lago Anazonas" hypothesis extend into every area of modern Amazonian geology and biology.
A new genus and species of aspredinid catfish, Micromyzon akamai, is described from trawl collections made in river channels of the Brazilian Amazon. This taxon is uniquely diagnosed by several apomorphies including lack of eyes, reduced melanic pigmentation, extremely reduced premaxillae and hypertrophied development of skull roofing elements and body armor. Its sister-group relationship to a clade containing Dupouyichthys and Ernstichthys is supported by the lack of lower jaw dentition, well-developed dorsal armor plates, and an anterior shift in the origin of the anal fin. /// Micromyzon akamai, novo gênero e nova espécie de Aspredinidae, é descrito procedente de coletas de arrasto de fundo nas calhas dos rios da Amazônia brasileira. Este taxon é diagnosticado por várias apomorfias exclusivas, incluindo a ausência de olhos, redução da pigmentação melânica, extrema redução dos prémaxilares e desenvolvimento hipertrofiado dos elementos da base do crânio e da armadura óssea. Possui como grupo mais próximo o clado contendo Dupouyichthys e Ernstichthys, com o qual compartilha a ausência de dentição da mandíbula inferior, placas ósseas dorsais muito desenvolvidas e o deslocamento da origem da nadadeira anal para uma posição mais anterior.
The Auchenipteridae is a neotropical freshwater catfish family composed of over 60 species in 21 genera. It is diagnosed as a monophyletic group on the basis of three synapomorphies: 1) a post-epioccipital process that reaches the nuchal plates or vertebral column: 2) a genital papilla formed with modified rays of the anal fin: and 3) a unique groove that holds the maxillary barbel under the eye. The sister group to the Auchenipteridae is hypothesized to be the Doradidae, a relationship supported by the following five synapomorphies: 1) anterior attachment of the elastic spring apparatus to the wall of the swimbladder; 2) prominent epioccipitals that join the nuchal plates; 3) extreme development of the post-cleithral process; 4) three nuchal plates; and 5) unique arrangement of the neural spines and proximal radials of the dorsal-fin rays. Species representing 19 genera were examined and 24 morphological characters were used in a cladistic analysis of the Auchenipteridae. The most parsimonious tree had only one homoplastic character but it is not completely resolved.
