Junior Chuctaya, Cristina M. Bührnheim & Luiz R. Malabarba

ABSTRACT

Specimens historically identified as Odontostilbe microcephala from the upper rio Paraná and Andean piedmont tributaries of the río Paraguay are reviewed and split in three species. We found that the distribution of O. microcephala is restricted to the Andean slope of the río Paraguay basin. The species is distinguished from congeners with subterminal mouth by the elongate body, usually 10-12 gill rakers on upper branch and smaller horizontal orbital diameter (24.6-32.8 % HL, mean 28.7%). Specimens from upper rio Paraná constitute two new species, diagnosed from other Cheirodontinae by the presence of mesopterygoid teeth, grouped on median portion and forming a continuous row. The new species are distinguished from each other by having premaxillary teeth with five cusps vs. nine cusps and by the number of lamellae in left and right sides of central median raphe of olfactory rosette with 20-21 vs. 11-12.

Keywords: Biodiversity; Characidae; La Plata River basin; Mesopterygoid teeth; Taxonomy

Link: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252018000100205&lng=en&nrm=iso&tlng=en

KARINE O. BONATO, PRISCILLA C. SILVA & LUIZ R. MALABARBA

Fish diets have been traditionally studied through the direct visual identification of food items found in their stomachs. Stomach contents of Vandeliinae and Stegophilinae (family Trichomycteridae) parasite catfishes, however, cannot be identified by usual optical methods due to their mucophagic, lepidophagic, or hematophagic diets, in such a way that the trophic interactions and the dynamics of food webs in aquatic systems involving these catfishes are mostly unknown. The knowledge about trophic interactions, including difficult relation between parasites and hosts, are crucial to understand the whole working of food webs. In this way, molecular markers can be useful to determine the truly hosts of these catfishes, proving a preference in their feeding behavior for specific organisms and not a generalist. Sequences of cytochrome oxidase subunit 1 (COI) were successfully extracted and amplified from mucus or scales found in the stomach contents of two species of stegophilines, Homodiaetus anisitsi, and Pseudostegophilus maculatus, to identify the host species. The two species were found to be obligatory mucus-feeders and occasionally lepidophagic. Selection of host species is associated to host behavior, being constituted mainly by substrate-sifting benthivores. Characiformes are preferred hosts, but host choice depends on what characiform species are available in their environments, usually corresponding to the most abundant species. This is the first time that host species of parasitic fishes bearing mucophagous habits are identified, and demonstrates the effectiveness of the extraction and amplification of mitochondrial DNA from the ingested mucus in gut contents. The molecular markers effectively allowed determine parasite preferences and helps in better understanding the food web and trophic interaction on which fish species are involved. Despite, the methodology applied here can be used for an infinitive of organisms improving ecological trophic studies.

Link: https://www.frontiersin.org/articles/10.3389/fevo.2018.00022/full

Figure 1. Studied species of Stegophilinae. (a) Homodiaetus anisitsi, 32 mm standard length, specimen from Lagoa dos Quadros, rio Tramandaí basin, Rio Grande do Sul State, Brazil. (b) Pseudostegophilus maculatus, 38 mm standard length, specimen from rio Ibicuí, rio Uruguay basin, Rio Grande do Sul State, Brazil. Arrows indicate the digestive tract, visible by transparency as a relatively straight tube from the mouth to the anus.

Figure 2. Host species of Homodiaetus anisitsi represented in scale. (A) Mugil liza; (B) Cyphocharax voga; (C) Bryconamericus iheringii; (D) Astyanax fasciatus; (E) Astyanax jacuhiensis; (F) Homodiaetus anisitsi represented in black. Scale bar 50 mm.

FONTANA, J.L.V., NETO, A.B.R.,  TAVARES, J.D.,  DE OLIVEIRA, M.D., LINHARES, T.,  SILVA, P.C & BONATO. K.O.

A espécie de água doce Microglanis cibelae Malabarba & Mahler, 1998 é um exemplo de que ainda há muito que se fazer (Figura 1b). Essa espécie pertence a família Pseudopimelodidae, ocorre nas bacias costeiras dos estados do Rio Grande do Sul e Santa Catarina. Especificamente para o Rio Grande do Sul, a distribuição da espécie ocorre na bacia do rio Tramandaí (que inclui as sub-bacias do Rio Maquiné, Três Forquilhas e Mampituba) habitando áreas marginais com vegetação de rios, lagoas e canais, e não há dados sobre sua biologia alimentar e reprodutiva (Malabarba et al. 2013). Trachinotus carolinus (Linnaeus, 1766) é uma espécie marinha da família Carangidae (Figueiredo, Menezes, 1980) (Figura 1a). Popularmente conhecidos como pampo, distribuemse no Oceano Atlântico de Massachusetts (EUA) ao Sudeste do Brasil, os adultos vivem em águas abertas e os jovens ocupam as zonas de arrebentação de praias arenosas (Muller et al. 2002; Vasconcellos et al. 2007).

Jade Luiza de Viegas Fontana, Antônio Barth da Rocha Neto, Jonathan Dutra Tavares, Matheus Dotto de Oliveira, Tarcísio Linhares, Priscilla Caroline Silva & Karine Orlandi Bonato. 2017. Dieta de Microglanis cibelae (Actinopterygii, Pseudopimelodidae) da bacia costeira do Rio Maquiné e de Trachinotus carolinus (Actinopterygii, Carangidae) de praias arenosas na costa do Rio Grande do Sul. Boletim Sociedade Brasileira de Ictiologia, No124. http://www.sbi.bio.br/images/sbi/boletim-docs/2017/december_124.pdf

Figura 1. (a) Trachinotus carolinus 39,9 mm CP, Praia de Imbé; e (b) Microglanis cibelae 57,6 mm CP, rio Maquiné.

CHUCTAYA, J., DONIN L.M.  VALENZUELA, S & HIDALGO, M.

Orestias Valenciennes 1839 pertence à família Cyprinodontidae Gill, 1865, endêmico dos sistemas aquáticos do Altiplano andino entre os países de Perú, Bolivia e Chile, desde o lago Lacsha nos andes centrais do Peru até o Salar de Ascotán no Norte de Chile (Parenti, 1984; Costa, 2003; Ortega et al., 2012; Cruz-Jofré et al., 2013). O gênero inclui 45 espécies válidas e uma species inquerenda (Eschemeyer et al., 2017), mais da metade das espécies pertencentes à bacia do lago Titicaca. Orestias alba foi descrita por Valenciennes (1846) como Orestias albus posteriormente, o nome foi corregido por Cruz-Jofré et al. (2013). Segundo Parenti (1984) Orestias alba é uma espécie de grande porte pertencente ao grupo luteus [atualmente lutea] do complexo agassii. O grupo lutea é composto por cinco espécies do gênero (O. lutea, O. rotundipinnis, O. farfani, O. alba e O. olivaceus) compartilhando um padrão derivado de escamas grossas e cobertas de granulações entre o focinho e a base da nadadeira dorsal, nas regiões preopercular e opercular e na região dorsal da nadadeira peitoral.

LINK: CHUCTAYA, JUNIOR A. ; DONIN, LAURA M. ; VALENZUELA, S. ; HIDALGO, M. . Peixes da Vez: Orestias alba Valenciennes 1846. Boletim Sociedade Brasileira de Ictiologia, Londrina, PR, , v. 124, p. 41 – 41. https://www.researchgate.net/publication/323294773_PEIXE_DA_VEZ_Orestias_alba_Valenciennes_1846

Orestias alba Valenciennes 1846

ANGRIZANI, R. C.; MALABARBA, LUIZ R

The eustatic movements triggered by glaciations during the Quaternary have shaped the landscape of Brazilian Atlantic Coast. Cyclic sea-level changes either isolated or connected freshwater fish populations, impacting their distribution and diversification. Rhamdia quelen has been widely recorded from the Brazilian Atlantic Coastal rivers, but it is also considered a species complex. A phylogeographic study carried out using three molecular markers of mtDNA and one of nDNA in the populations of Rhamdia from the hydrographic basins of Southern Atlantic Coast of Brazil recovered three evolutionarily distinct groups: one represented by the populations found in lowlands of all studied watersheds; the second group composed of populations found in the upper tributaries of the rio Araranguá, rio Mampituba and rio Tramandaí; and a third group found exclusively in the upper portions of rio Tubarão. The genetic divergences among these three lineages of Rhamdia is discussed according to sea level changes in the Quaternary. Two new species of Rhamdia are diagnosed and described based on morphological and molecular evidence.

Angrizani, R. C. ; Malabarba, Luiz R. . Morphology and molecular data reveal the presence of two new species under Rhamdia quelen (Quoy & Gaimard, 1824) (Siluriformes: Heptapteridae) species complex. Zootaxa, v. 4388, p. 44, 2018. http://dx.doi.org/10.11646/zootaxa.4388.1.3

Figure Left: Holotype of Rhamdia gabrielae (UFRGS 20010), holotype, 194 mm SL. In dorsal, lateral, and ventral views. Figure Right: Rhamdia eurycephala (UFRGS 19908), holotype, 246.6 mm SL. In dorsal, lateral, and ventral views.

CHUCTAYA, J. A.; DONIN, L. M. ; VIEIRA, C. S. ; FAUSTINO-FUSTER, D. ; CARVALHO, T. P.

The first occurrence of Phallotorynus victoriae is reported from the Uruguay River basin associated to the grasslands of the Pampa Biome, southern Brazil. The record include only one specimen from a tributary to Ibicuí River located in the municipality of Uruguaiana, Rio Grande do Sul State.

Chuctaya, J. A. ; Donin, L. M. ; Vieira, C. S. ; Faustino-Fuster, D. ; Carvalho, T. P. . First record of Phallotorynus victoriae Oliveros, 1983 (Cyprinodontiformes, Poeciliidae) for Uruguay river basin and Rio Grande do Sul, southern Brazil. Check List, Journal of species list and distribution, v. 14, p. 159-162, 2018. http://dx.doi.org/10.15560/14.1.159

Figure 1. Male ofPhallotorynus victoriae, UFRGS 23645, 15.3 mm SL, captured in Uruguay river basin, Rio Grande do Sul, Brazil. Left to right image for better visualization of the gonopodium. Scale bar = 2 mm.

CRAIG, J. M. ; MALABARBA, LUIZ R. ; CRAMPTOM, W. G. R. ; ALBERT, J. S

Banded Knifefishes (Gymnotus, Gymnotidae) comprise the most species-rich, ecologically tolerant (eurytopic), and geo- graphically widespread genus of Neotropical electric fishes (Gymnotiformes), with 40 valid species occupying most hab- itats and regions throughout the humid Neotropics. Despite substantial alpha-taxonomic work in recent years, parts of the genus remain characterized by taxonomic confusion. Here we describe and delimit species of the G. carapo and G. tigre clades from the southern Neotropics, using body proportions (caliper-based morphometrics), fin-ray, scale and laterosen- sory-pore counts (meristics), quantitative shape differences (geometric morphometrics), osteology, color patterns and electric organ discharges. We report these data from 174 Gymnotus specimens collected from 100 localities throughout the southern Neotropics, and delimit species boundaries in a multivariate statistical framework. We find six species of the G. carapo clade (G. carapo australis, G. cuia n. sp., G. chimarrao, G. omarorum, G. pantanal, and G. sylvius), and two species of the G. tigre clade (G. inaequilabiatus and G. paraguensis) in the southern Neotropics. The new species G. cuia is readily distinguished from the morphologically similar and broadly sympatric G. c. australis by a shorter head and deep- er head and body, and from the morphologically similar and sympatric G. omarorum by fewer lateral-line ventral rami and fewer pored lateral-line scales anterior to the first ventral ramus. We also review the geographic distributions of all eight species of the G. carapo and G. tigre clades in the southern Neotropics, showing that G. cuia is the most widespread species in the region. These results affirm the importance of understanding the structure of variation within and between species, both geographic and ontogenetic, in delimiting species boundaries.

Link: Craig, J. M. ; Malabarba, Luiz R. ; Cramptom, W. G. R. ; Albert, J. S. . Revision of Banded Knifefishes of the Gymnotus carapo and G. tigre clades (Gymnotidae Gymnotiformes) from the Southern Neotropics. Zootaxa, v. 4379, p. 47, 2018. http://dx.doi.org/10.11646/zootaxa.4379.1.3

FIGURE 7. Variation within the type series of Gymnotus cuia. A. The holotype, UFRGS 23700 (193 mm). B. Four specimens of the paratype series, UFRGS 9794 (171-217 mm). FIGURE 1. Geographic distributions of the materials examined from six species of the G. carapo clade clade of the southern Neotropics including the new species G. cuia. White star indicates the type locality for G. cuia. Note G. cf. carapo from Rio de Janeiro could not be positively identified due to age (collected 1865) and condition. Specimens from all localities were personally examined and identified by the authors.

DUTRA G.M., MELO, B.F & NETTO-FERREIRA, A.L.

ANDRE L. NETTO-FERREIRA  & CRISTIANO R. MOREIRA

Creagrutus yudja is described from the Rio Xingu basin, Brazil. It is distinguished from its congeners by the lack of infraorbital 6, the shallower body (13.7–19.2% of SL), the presence of 34–36 perforated lateral line scales, and the presence of 4–6 post-anal scales. The inclusion of the new species on the available, morphology-based phylogenetic study of Creagrutus placed C. yudja as the sister-species of C. nigrotaeniatus, but the clade including those species is not recovered as sister to the pair C. cracentis + C. maxillaris, suggesting independent modifications of the dentition pattern typical of Creagrutus to a condition similar to the plesiomorphic characid condition within the genus.

Netto-Ferreira, A. L.; Moreira, C. R. . New species of Creagrutus (Ostariophysi; Characiformes; Characidae) from the Rio Xingu drainage, Brazil. Zootaxa, v. 4375, p. 250, 2018. http://dx.doi.org/10.11646/zootaxa.4375.2.4

FIGURE 1. Creagrutus yudja, new species, holotype, MNRJ 48662, 26.7 mm SL, Brazil, Pará, Altamira, Praia do Levi, Rio Iriri, Rio Xingu basin.

FIGURE 3. Consensus tree of 274464 fundamental trees with 178 steps. Character numbers as in Vari & Harold (2001).