Naércio A. Menezes, Katiane M. Ferreira & André L. Netto-Ferreira

ABSTRACT

A new species of the characid genus Knodus is described from the rio Aripuanã (rio Madeira basin). It can be distinguished from its congeners by its very low body depth, the presence of tri- to pentacuspid teeth on the outer premaxillary series, with the median cuspid larger than the lateral ones, the teeth of the inner premaxillary series pentacuspid, distinctly larger than those of the outer series, the maxillary teeth tri- to pentacuspid, with the median cusp slightly larger than the lateral ones, the four anteriormost dentary teeth pentacuspid, the smaller posterior teeth tri- to pentacuspid, a complete lateral line with 36-38 scales, 3 longitudinal scale series from pelvic fin origin to lateral line, and 11-12 circumpeduncular scales. The new species is also compared to incertae sedis species of ‘Bryconamericus’ from northern South America since phylogenetic studies suggest a closer relationship of those species with Knodus.

Link: https://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252020000200208&lng=en&nrm=iso&tlng=en

FIGURE 1 | Knodus angustus, MZUSP 122222, female. 36 mm SL, Brazil, Amazonas, rio Aripuanã, tributary of rio Madeira.

FIGURE 2 | Knodus angustus, MZUSP 124932, C&S, jaws and dentition, lateral view, left side, anterior at left.

Uma reportagem de Fernanda Wenzel, sobre a coleta de peixes na Calha Norte, onde participou membros do laboratório de ictiologia da UFRGS. A região paraense é um dos tesouros da biodiversidade amazônica

De fato, a Calha Norte tem mais similaridades ambientais com esses vizinhos do que com o resto da Amazônia, ao sul. É uma área montanhosa, de maiores altitudes, o que faz com que os peixes dali sejam diferentes daqueles de zonas mais baixas. “A Calha Norte tem uma história geológica compartilhada com os rios da região ao norte”, explica André Netto Ferreira, professor do departamento de Zoologia da Universidade Federal do Rio Grande do Sul e um dos autores do estudo.

Das seis novas espécies de peixes, a mais recente foi identificada em 2019: é o Curimatopsis melanura, que mede cerca de 38 mm e tem uma cauda escura, que o diferencia das outras espécies do gênero. “Os curimatídeos se alimentam de algas que vivem no lodo, promovendo um serviço ecossistêmico formidável de limpeza da água”, explica Ferreira.

Nota completa: https://www.uol.com.br/ecoa/colunas/noticias-da-floresta/2020/06/11/pesquisadores-identificam-novos-peixes-em-area-preservada-da-amazonia.htm

Curimatopsis melanura, uma das novas espécies identificadas na Calha Norte. Fotografia Lorena S. Vieira (aluna PPGBAN-UFRGS)

Muddula Krishna Naranji, Ronald Fricke, Andre Luiz Netto-Ferreira & Govinda Rao Velamala

Abstract

In this paper, we report finding of 74 specimens of Neomerinthe amplisquamiceps  (Scorpaendiae) and field observations of this species from the Indian coast. Specimens of N. amplisquamiceps were captured between 150 and 300 m depth with a 38 m high speed demersal trawl (crustacean version, codend, mesh size 40 mm) and 46 m Expo model demersal trawl (mesh size 30 mm). This rare, poorly known species is the only member of the genus Neomerinthe in the Indian ichthyofauna. The new records improve the current knowledge on N. amplisquamiceps, and refine the limits of its geographical distribution and habitat preference. Analyses of morphometric and meristic characters confirmed the identity of the specimens and are described, compared and summarized.

link: https://link.springer.com/article/10.1007/s41208-020-00210-2

Fresh specimen of Neomerinthe amplisquamiceps, DMLRAU, 128/2016, 78 mm TL, off Visakhapatnam coast, Andhra Pradesh, India

Map of northeastern coast of India where Neomerinthe amplisquamiceps were sampled between 50 and 100 m deep near the coast of Visakhapatnam

Rafael Costa Angrizani, Luiz Roberto Malabarba

Abstract

More than 100 species have been referred to Rhamdia since its description, but in the last revision of the genus more than two decades ago, only eleven species have been considered as valid. Rhamdia quelen was then redefined to include 47 junior synonyms, resulting in a species with a large distribution in the Neotropics, from Mexico to Argentina. Populations of Rhamdia from west of the Andes have been recently removed from the synonymy of R. quelen, and currently there are 27 species recognized in the genus. Most cis-Andean populations, however, remain referred to the R. quelen species complex. In this paper, we use species delimitation methods and multilocus phylogenetic analyses to delimit the species contained in the R. quelen species complex in cis-Andean river drainages. Eighteen MOTUs in the gene tree were recovered with high support. We further demonstrate that the previous designation of a neotype for R. quelen is invalid, and has to be replaced by the proper designation of a neotype from the type locality of the species. The neotype is designated herein and R. quelen is diagnosed and redescribed.

https://www.mapress.com/j/zt/article/view/zootaxa.4801.1.3

Figure 3. Species tree produced by Starbeast in Beast 1.8.4. Dark gray highlight: the trans-Andean clade; light gray highlight: the cis-Andean clade; dark green highlight: the Amazon clade (AM); light green highlight: the Upper Amazon clade (PE); pink highlight: the non-Amazon clade; blue highlight: the Continental clade (CC); orange highlight: the Atlantic clade; red highlight: the Lowland clade (LA); yellow highlight: Highland clade (HA). The terminals are different lineages recovery for the bayesian analyses.

Figure 4. Neotype of Rhamdia quelen by present designation. MNRJ 51746, Brazil, Rio de Janeiro State, Cachoeira de Macacu, tributary of the Rio Soarinho, tributary of the Rio Macacu, Baía de Guanabara (22o38’6”S 42o43’6”W).

Dario Faustino-Fuster, aprovou seu exame de qualificação na última terça feira dia 15 de junho, apresentando seu artigo:

Two new species of the three barbel catfish genus Heptapterus (Siluriformes: Heptapteridae) from the Uruguay River, Brazil

A banca examinadora esteve constituída pelos

Dra. Bárbara Calegari (Museu de Ciências e Tecnologia – PUCRS)

Dr. Tiago Carvalho (Pontificia Universidad Javeriana, Colômbia)

Dr. Carlos Do Nascimiento (Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Colômbia)

Orientado pelo: Prof. Dr. Luiz Roberto Malabarba

Laísa Wociechoski Cavalheiro, defendeu no último sabado, día 13 de junho, sua tese de doutorado

ECOLOGIA TRÓFICA E COMPOSIÇÃO DA ICTIOFAUNA EM RIACHOS DA SUB-BACIA DO RIO IJUÍ, RS, BRASIL

A banca esteve constituída pelos

Prof. Dr Alexander Garcia – FURG

Prof. Dr. Fernando Becker – PPG ECOLOGIA/UFRGS

Prof. Dr Luiz R. Malabarba – PPGBAN/UFRGS

Orientada pelo Prof. Dra. Clarice Bernhardt Fialho

Juliano Ferrer and Luiz R. Malabarba

ABSTRACT

The Neotropical genus Scleronema is revised based on the re-examination of the type specimens and 1,713 newly collected specimens. Scleronema is diagnosed from other trichomycterids by the following unambiguous derived characters: fleshy flap at the base of the maxillary barbell; skin flap in the posterior margin of the opercle; articulation between the autopalatine and the vomer ventrally located, with the medial margins of the autopalatines very close to each other; and autopalatine with an interrupted or not interrupted ossified arch-shaped process on its dorsal surface forming a canal. Scleronema minutum and S. operculatum are redescribed, S. angustirostre is considered a junior synonym of S. minutum, and six new species are described. A lectotype is designated for Trichomycterus minutus. The type localities of S. angustirostre, S. minutum, and S. operculatum are reviewed in order to correct erroneous information cited in articles and catalogs subsequent to the original descriptions. Species of Scleronema are geographically distributed in the La Plata basin and Atlantic coastal drainages from Southern Brazil, Southern Paraguay, Northeastern Argentina and Uruguay. They inhabit rivers or streams with sand- or gravel-bottoms across the Pampa grasslands. We provide evidences to recognize two putative monophyletic units within the genus, namely the S. minutum species group and the S. operculatum species group, and discuss the distribution patterns of their species.

Link: https://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252020000200202&lng=en&nrm=iso&tlng=en

Scleronema operculatum, holotype (FMNH 58080; 65.9 mm SL), Brazil, Rio Grande do Sul, Cacequi, rio Cacequi, tributary to rio Santa Maria, rio Ibicuí basin, lower rio Uruguay. Photograph taken by Sandra Raredon.

Geographical distribution of the genus Scleronema. Circles and squares indicate species of the S. minutum group and S. operculatum group, respectively. Some symbols represent more than one collection locality. AR = Argentina; BR = Brazil; PY = Paraguay; UY = Uruguay.

Clayton Kunio Fukakusa , Talita Sarah Mazzoni and Luiz Roberto Malabarba

ABSTRACT

Most teleosts are externally fertilizing, with internal fertilization occurring as a relatively rare event. Until now, Euteleosteomorpha is the only teleost cohort known to undergo internal fertilization. In the teleost cohort Otomorpha, it has been recorded the presence of sperm in the ovaries of some species of Characiformes and Siluriformes, but no fertilized eggs have been found so far in the female reproductive tract. It has been presumed that oocytes can be released into the water with associated spermatozoa and only there becomes fertilized, and the term insemination has been used to characterize the strategy adopted by these fish. Here, we present the discovery of the first case of internal fertilization in the teleost cohort Otomorpha, in Compsura heterura (Characiformes: Characidae). In the course of spawning, the eggs form the perivitelline space and the animal and vegetative poles within the ovaries, evidencing oocyte fertilization. The newly spawned eggs then continue to form the animal and vegetative poles and increase the perivitelline space. These eggs are in the zygotic stage. These data indicate that fertilized eggs are only retained for a short period, providing evidence that C. heterura is a zygoparous fish

Link: https://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252020000100209&lng=en&nrm=iso&tlng=en

Phylogeny of Teleostei (modified from Betancur-R et al., 2017), showing clades previously known to include species with internal fertilization (dark blue) and the present record in the teleost cohort Otomorpha (light blue). Remaining clades (black) do not contain internally fertilized species.

Oocyte and fertilized eggs of Compsura heterura. A. Unfertilized oocyte in ovary (follicle); B. fertilized egg in ovary (ovarian lumen) and C. gonoduct (Od); D. fertilized spawned egg. Yg, yolk granules; Ca, cortical alveoli; asterisk, chorion; Fe, follicular epithelium; N, nucleus; n, nucleoli; Y, yolk; Cc, cortical cytoplasm; Ps, perivitelline space; arrow, micropyle; Vp, vegetative poles; Ap, animal poles; In, intestine; M, muscle tissue.

Tiago P. Carvalho and Roberto E. Reis

A second species of Acanthobunocephalus is described from tributaries of the lower Purus River in the Amazon Basin, Brazil. Acanthobunocephalus scruggsi, new species, is distinguished from all other aspredinid species by its reduced number of fin rays: four pectoral-fin rays (vs. five or more), two dorsal-fin rays (vs. three or more, except Amaralia hypsiura), five pelvic-fin rays (vs. six), four to five anal-fin rays (vs. six or more, except Bunocephalus verrucosus), and nine caudal-fin rays (vs. 10, except Hoplomyzontinae, Amaralia, Platystacus, Bunocephalus chamaizelus, and Bunocephalus minerim). Osteological aspects of the new species of Acanthobunocephalus are described using cleared and stained specimens and high-resolution x-ray computed tomography (HRXCT), and compared with Acanthobunocephalus nicoi and other aspredinids. Generic assignment is based on putative apomorphic shared features and a morphological diagnosis for Acanthobunocephalus is presented.

Link: https://www.asihcopeiaonline.org/doi/abs/10.1643/CI-19-309

Paratype of Acanthobunocephalus scruggsi, INPA 42229, 20.6 mm SL, Amazonas, Tapauá , Igarapé dos Caetanos, tributary to Rio Ipixuna. Scale bar = 10 mm.

HRXCT model of skull and anterior body of Acanthobunocephalus scruggsi, holotype, INPA 57946, 21.7 mm SL. (A) Dorsal view, (B) lateral view, and (C) ventral view. br = branchiostegal rays; cl = cleithrum; cv=parapophysis of complex vertebrae; db=dorsal blade of complex vertebrae; den=dentary; df =dorsal fin; dp=distal portion of pectoral-fin spine; fr = frontal; hc = hemal canal; me = mesethmoid; mnp=middle nuchal plate; mx=maxilla; op=opercle; p=premaxilla; pcl = posterior process of cleithrum; pfs = pectoral-fin spine; po = preopercle; pp =proximal portion of pectoral-fin spine; psc = posterior process of scapulocoracoid; pso= parieto-supraoccipital; pto=pterotic; pv5 = parapophysis of fifth vertebra; r6 = sixth rib; sco = scapulocoracoid; scl=posttemporal-supracleithrum; spo=sphenotic; tf=temporal fontanel. Limits between selected bones are highlighted in black.

Geographic distributions of species of Acanthobunocephalus. Circles =A. nicoi, squares = A. scruggsi. Black symbols refer to type localities. Amazon River basin highlighted in green.