Hemiodus jatuarana, a new species of Hemiodontidae from the rio Trombetas, Amazon Basin, Brazil (Teleostei, Characiformes)

Hemiodus jatuarana, a new species of the Hemiodontidae from Oriximina, rio Trombetas, Amazon Basin, Brazil, is described. The new species can be readily distinguished from its congeners by the presence of a horizontally elongated dark spot on the caudal peduncle, and by the absence of any other dark pigmentation pattern on the body. Hemiodus jatuarana is readily separated from H. immaculatus, another species without dark pigmentation on the body, by having 25 - 27 epibranchial and 36 - 37 ceratobranchial gill rakers on the first branchial arch, and caudal-fin lobes without longitudinal stripes, vs. 14 - 16 and 21 - 25 gill rakers, and a conspicuous longitudinal stripe on each caudalfin lobe in H. immaculatus. The new species is only known from its type-locality, where it cooccurs with H. immaculatus.

Hisonotus bocaiuva, a new species from the rio São Francisco basin, Brazil (Teleostei: Loricariidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Hemiodus iratapuru, a new species of Hemiodontidae from the Rio Jari, Amazon Basin, Brazil (Teleostei, Characiformes)

Hemiodus iratapuru, a new species of the Hemiodontidae from the Rio Iratapuru, a left bank tributary of the Rio Jari, Amazon Basin, Brazil, is described. The new species is diagnosed from other species of Hemiodus by modifications in the ectopterygoid, tooth form, scale counts, dorsal-fin form and colour pattern. The new species is proposed to be related to the Hemiodus quadrimaculatus species group. © 2013 The Authors. Journal of Fish Biology © 2013 The Fisheries Society of the British Isles.

A new species of Hemigrammus from the upper Rio Tapajos basin in Brazil (Teleostei : Characiformes : Characidae)

Hemigrommus silimoni is described from the Rio Juruena, upper Rio Tapajos basin, Mato Grosso State, Brazil. The new species is distinguished from all congeners, and in fact from the remaining Characidae, by the autapomorphic presence of an ocellus-like blotch on the caudal-fin dorsal lobe. The high level of fish endemicity In the Rio Juruena (upper Rio Tapajos basin) is discussed.

Evolution of time-control mechanisms in subterranean organisms: cave fishes under light-dark cycles (Teleostei: Siluriformes, Characiformes)

Subterranean organisms are excellent models for chronobiological studies, yet relatively few taxa have been investigated with this focus. Former results were interpreted as a pattern of regression of circadian locomotor activity rhythms in troglobitic (exclusively subterranean) species. In this paper we report results of experiments with cave fishes showing variable degrees of troglomorphism (reduction of eyes, melanic pigmentation and other specializations related to the hypogean life) submitted to light-dark cycles, preceded and followed by several days in constant darkness. Samples from seven species have been monitored in our laboratory for the detection of significant circadian rhythms in locomotor activity: S. typhlops, an extremely troglomophic species, presented the lowest number of significant components in the circadian range (only one individual out of eight in DD1 and three other fish in LD), all weak (low values of spectral power). Higher incidence of circadian components was observed for P. kronei - only one among six studied catfish without significant circadian rhythms under DD1 and DD2; spectral powers were generally high. Intermediate situations were observed for the remaining species, however all of them presented relatively strong significant rhythms under LD. Residual oscillations (circadian rhythms in DD2) were detected in at least part of the studied individuals of all species but S. typhlops, without a correlation with spectral powers of LD rhythms, i.e., individuals exhibiting residual oscillations were not necessarily those with the strongest LD rhythms. In conclusion, the accumulated evidence for troglobitic fishes strongly supports the hypothesis of external, environmental selection for circadian locomotor rhythms.

A systematic review of diapoma (teleostei: characiformes: characidae: stevardiinae: diapomini) with descriptions of two new species from southern Brazil

Diapoma is reviewed and four species are recognized: (1) Diapoma thauma, new species, from streams of the rio Jacuí basin, state of Rio Grande do Sul; (2) D. pyrrhopteryx, new species collected from the rio Canoas and streams flowing into this basin in the states of Rio Grande do Sul and Santa Catarina, Brazil; (3) Diapoma terofali, from streams flowing into rio Uruguay in Uruguay and Rio Grande do Sul, Brazil and streams flowing into rio de la Plata, Argentina; and (4) Diapoma speculiferum, from lowland coastal streams in Rio Grande do Sul, Brazil and Uruguay. Diapoma pyrrhopteryx possess the posteroventral opercular elongation typical of D. speculiferum, type species of the genus, but which is absent in D. thauma and D. terofali. Nonetheless, all the diapomin species have the caudal pouch organ about equally developed in both sexes and the dorsal portion of the pouch opening bordered by a series of 3 to 8 elongated scales, the two derived features that characterize the group. The two previously described species, D. speculiferum and D. terofali, are redescribed. Previous hypotheses of relationships among the diapomin genera Planaltina, Diapoma and Acrobrycon are discussed on the basis of preliminary morphological information. It is proposed that the Diapomini is a monophyletic group. An identification key, information on sexual dimorphism, gonad anatomy, reproductive mode and distribution of the species of Diapoma are provided.

Reproductive traits of Gymnogeophagus labiatus (Teleostei, Cichlidae), in an upper stretch of Sinos river, Caraá, Brazil

This work describes the reproduction of Gymnogeophagus labiatus (Hensel, 1870) from an upper stretch of Sinos river, southern Brazil, based on the analysis of 174 males and 132 females captured in monthly samples taken from January to December 2007. Results showed that reproductive activity occur in spring and summer although ripe males were found along the year. The standard length of the smallest ripe male was 104.74 mm (Lt) and the smallest ripe female was 55.00 mm (Lt). There was a significant difference in total sex ratio, with 1.32 males to each female (χ2 = 5.76). Males were much more abundant in March (1.75 males: 1 female) and December (5 males: 1 female). Females were more abundant in the 62├77 mm interval (1 male: 2.36 female) while males were more abundant in the 77├92 mm size interval (2.57 males: 1 female). The largest length intervals were composed of only males. Mean absolute fecundity was 113.4 (± 31.24 sd) and mean relative fecundity was 0.0125 (± 0.0026 sd) oocytes/mg. In ripe ovaries, small-diameter oocytes were observed at high frequencies while larger ones occurred at lower frequencies. This pattern is common in fishes with asynchronous oocyte development. Characteristics of G. labiatus, such as low fecundity, asynchrony in oocyte development, multiple spawning, and its well-known parental care behavior, are consistent with an equilibrium strategy, as proposed for other cichlids.

Genetic and morphological characterisation of a new species of the genus Hysterothylacium (Nematoda) from Paralichthys isosceles Jordan, 1890 (Pisces: Teleostei) of the Neotropical Region, state of Rio de Janeiro, Brazil

Taking into account the difficulties of taxonomic identification of larval anisakid nematodes based on morphological characters, genetic analyses were performed, together with those usually applied, in order to identify anisakid larvae found in the flounder Paralichthys isosceles from the littoral of the state of Rio de Janeiro, Brazil. The analysis of 1,820 larvae revealed a new species, similar to Hysterothylacium MD, Hysterothylacium 2, Hysterothylacium KB and Hysterothylacium sp regarding the absence of the larval tooth, an excretory pore situated below the nerve ring level, and slender lateral alae. Moreover, the new species differs from Hysterothylacium fortalezae and Hysterothylacium reliquens with regard to the number and size of spines present on the tail end and from Hysterothylacium patagonicus by the absence of interlabia. The maximum parsimony and neighbour joining tree topologies based on the 18S ribosomal DNA gene, complete internal transcribed spacer region and cytochrome oxidase 2 (COII) gene demonstrated that the Brazilian larvae belong to Raphidascarididae and represent a unique genetic entity, confirmed as a new Hysterothylacium species. Furthermore, the new species presents COII genetic signatures and shares polymorphisms with Raphidascarididae members. This is the first description of a new anisakid species from Brazil through the integration of morphological and molecular taxonomy data.

Allozyme differentiation of two populations of the genus Neoplecostomus Eigenmann & Eigenmann, 1888 (Teleostei, Loricariidae) from the upper Paraná River basin, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Biochemical evidence of a possible new species of Neoplecostomus (Teleostei : Loricariidae) from the upper Rio Parana basin, Brazil

Neoplecostomus paranensis Langeam, 1990, from the upper Rio Parana, is the only Neoplecostomus species described in this basin and is distinguished from its congeners by the lack or reduction of the adipose fin. Neoplecostomus specimens with a normal and always present adipose fin were caught in the Rio Corumba, upper Rio Parana basin. In the present study two samples of populations, one from a tributary of Rio Paranapanema (identified as a typical N. paranensis) and the other from the Rio Corumba were compared through allozyme electrophoresis. Six diagnostic loci were found, Acp-A, Adh-A, Est-A, Gpi-A, Ldh-A and Ldh-B. In addition, the locus Gpi-B showed significant differences between allelic frequencies for the two samples. Nei's genetic identity between the populations was 0.731. The expressive genetic divergence together with the presence of an adipose fin show that the sample from the Rio Corumba is distinct from N. paranensis and probably represents a new species. (C) 2003 Published by Elsevier Ltd.

Follicular diameter range based on morphological features in Synbranchus marmoratus (Bloch, 1795) (Teleostei, Synbranchiformes, Synbranchidae) from the South-central region of Brazil

The morphological characteristics of Synbranchus marmoratus female germ cells in various development stages were described in details; then measurements of ovarian follicle diameters were taken from primary and secondary growth as during these development stages the oocyte size varied considerably along the fish growth. The results were correlated to total fish length, using the individuals division in six size classes. It was possible to group oocytes by stages according to histological characteristics but not according to morphometric diameter, as there was a wide variation in diameter in each stage and overlap between different maturation stages. These data make available new information on the reproductive biology of Synbranchidae. (c) 2004 Published by Elsevier Ltd.

Infection levels of Austrodiplostomum compactum (Digenea, Diplostomidae) metacercariae in Plagioscion squamosissimus (Teleostei, Sciaenidae) from the Nova Avanhandava reservoir, São Paulo State, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comparative cytogenetics of ten species of cichlid fishes (Teleostei, Cichlidae) from the Araguaia River system, Brazil, by conventional cytogenetic methods

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Spawning and parental care in Hoplias malabaricus (Teleostei, Characiformes, Erythrinidae) in the Southern Pantanal, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)