A new Poptella from the rio Xingu basin, Brazil (Characiformes: Characidae)

A new species of Poptella is described from the rio Xingu basin, Pará and Mato Grosso states, Brazil. The new species is distinguished from all congeners by having a greater number of scales around the caudal peduncle (15­18 vs. 13­14). Furthermore, this species can be easily distinguished from P. brevispina, P. longipinnis, and P. fuscata by the lower number of branched rays in the dorsal fin (9 vs. 10­11). The description of new taxon represents the third species of the genus Poptella described in the last five years.(AU)

Uma nova espécie de Poptella é descrita da bacia do rio Xingu, estados do Pará e Mato Grosso, Brasil. A nova espécie é distinguida de todas as espécies congêneres por apresentar maior número de escamas ao redor do pedúnculo caudal (15­18 vs. 13­14). Além disso, esta espécie pode ser facilmente distinguida de P. brevispina P. longipinnis e P. fuscata pelo menor número de raios ramificados na nadadeira dorsal (9 vs.10-11). A descrição do novo táxon representa a terceira espécie do gênero Poptella descrita nos últimos cinco anos.(AU)

Poptella fuscata, a new Stethaprionini from the upper Amazon basin, Peru (Characiformes: Characidae).

A new species of Poptella is described from the Río Putumayo, Upper Río Amazon basin, Peru. The new species is distinguished from congeners by having a dense field of dark chromatophores homogeneously spread over the posterior half of the body, posterior humeral blotch extending to three to four horizontal scale rows below the lateral line, and a higher number of branched dorsal-fin rays. The new species can be readily distinguished from P. paraguayensis by having a comparatively shorter predorsal spine.

A new Amazonian species of Brachychalcinus (Characiformes: Characidae) from the Trombetas River basin, Brazil.

A new species of Brachychalcinus is described from the Rio Trombetas basin, Brazil. It differs from congeners by possessing a conspicuous rounded second humeral spot. Additionally, our new species differs from Brachychalcinus nummus, B. orbicularis and B. reisi by having a higher number of branched dorsal-fin rays, and from Brachychalcinus parnaibae by having a lower head depth.

A new species of Poptella (Characiformes: Characidae: Stethaprioninae) from the Rio Juma, Rio Madeira basin, Brazil

A new species of Poptella is described from the Rio Juma, a tributary of the lower Rio Aripuanã, Rio Madeira basin, Amazonas, Brazil. The new species is distinguished from all congeners, except P. brevispina, by having a lower number of scale rows between the lateral line and dorsal-fin origin (7 vs. 8-10). The new species can be readily distinguished from P. brevispina by the lower number of branched dorsal-fin rays (9 vs. 10). This is the first description of a new species of Poptella since the revisionary study of the Stethaprioninae, published 30 years ago.(AU)

Uma nova espécie de Poptella é descrita do Rio Juma, tributário do baixo Rio Aripuanã, bacia do rio Madeira, Amazonas, Brasil. A nova espécie é distinguida de todas suas congêneres, exceto P. brevispina, por apresentar menor número de séries de escamas entre a linha lateral e origem da nadadeira dorsal (7 vs. 8-10). A nova espécie pode ser facilmente diferenciada de P. brevispina pelo menor número de raios ramificados na nadadeira dorsal (9 vs. 10). Esta é a primeira descrição de uma nova espécie de Poptella desde a última revisão taxonômica de Stethaprioninae, publicada há trinta anos.(AU)

A new species of Poptella (Characiformes: Characidae: Stethaprioninae) from the Rio Juma, Rio Madeira basin, Brazil

A new species of Poptella is described from the Rio Juma, a tributary of the lower Rio Aripuanã, Rio Madeira basin, Amazonas, Brazil. The new species is distinguished from all congeners, except P. brevispina, by having a lower number of scale rows between the lateral line and dorsal-fin origin (7 vs. 8-10). The new species can be readily distinguished from P. brevispina by the lower number of branched dorsal-fin rays (9 vs. 10). This is the first description of a new species of Poptella since the revisionary study of the Stethaprioninae, published 30 years ago.(AU)

Uma nova espécie de Poptella é descrita do Rio Juma, tributário do baixo Rio Aripuanã, bacia do rio Madeira, Amazonas, Brasil. A nova espécie é distinguida de todas suas congêneres, exceto P. brevispina, por apresentar menor número de séries de escamas entre a linha lateral e origem da nadadeira dorsal (7 vs. 8-10). A nova espécie pode ser facilmente diferenciada de P. brevispina pelo menor número de raios ramificados na nadadeira dorsal (9 vs. 10). Esta é a primeira descrição de uma nova espécie de Poptella desde a última revisão taxonômica de Stethaprioninae, publicada há trinta anos.(AU)

A new species of Brachychalcinus (Characiformes: Characidae) from the rio Xingu basin, Serra do Cachimbo, Brazil.

Brachychalcinus reisi, a new species of characid fish, is described from the rio Curuá, tributary of rio Iriri, rio Xingu basin, Serra do Cachimbo, Pará State, Brazil. The new species can be distinguished from its congeners by the presence of a series of longitudinal black wavy stripes on the entire body and by a lower number of longitudinal scale rows between dorsal-fin origin and lateral line (7-8 vs. 8-12). Additionally, the new species differs from B. copei, B. parnaibae, and B. retrospina by the lower number of branched dorsal-fin rays (9 vs.10). This is the first description of a new species of the subfamily since the revisionary study of Stethaprioninae, published almost 30 years ago.

Length-weight relationships of the main commercial fish species of Tucuruí reservoir (Tocantins/Araguaia Basin, Brazil) / Relação peso-comprimento das principais espécies de peixes comerciais do reservatório de Tucuruí (Bacia do Tocantins/Araguaia, Brasil)

The Tucuruí reservoir has a great ecological and economic importance, but is lacking in basic information of population biology of fishes, especially length-weight relationship. Of the 20 species analyzed, are presented new records of the length-weight relationship for five species, one have record on gray literature and the remaining 14 have records in other studies which was compared to this study. The information generated by this work can contribute to a better environmental and fisheries management in Neotropical region, especially in Tucuruí reservoir.(AU)

O reservatório de Tucuruí tem uma grande importância econômica e ecológica, mas é carente de informações básicas da biologia populacional de peixes, especialmente relação peso-comprimento. Das 20 espécies analisadas, são apresentados novos registros da relação peso-comprimento para cinco espécies, uma tem registro na literatura cinzenta e as 14 restantes apresentam registros em outros estudos, os quais foram comparados com os dados deste trabalho. A informação gerada por este estudo pode contribuir para um melhor manejo ambiental e pesqueiro na região Neotropical, em especial para o reservatório de Tucuruí.(AU)

Length-weight relationships of the main commercial fish species of Tucuruí reservoir (Tocantins/Araguaia Basin, Brazil) / Relação peso-comprimento das principais espécies de peixes comerciais do reservatório de Tucuruí (Bacia do Tocantins/Araguaia, Brasil)

The Tucuruí reservoir has a great ecological and economic importance, but is lacking in basic information of population biology of fishes, especially length-weight relationship. Of the 20 species analyzed, are presented new records of the length-weight relationship for five species, one have record on gray literature and the remaining 14 have records in other studies which was compared to this study. The information generated by this work can contribute to a better environmental and fisheries management in Neotropical region, especially in Tucuruí reservoir.

O reservatório de Tucuruí tem uma grande importância econômica e ecológica, mas é carente de informações básicas da biologia populacional de peixes, especialmente relação peso-comprimento. Das 20 espécies analisadas, são apresentados novos registros da relação peso-comprimento para cinco espécies, uma tem registro na literatura cinzenta e as 14 restantes apresentam registros em outros estudos, os quais foram comparados com os dados deste trabalho. A informação gerada por este estudo pode contribuir para um melhor manejo ambiental e pesqueiro na região Neotropical, em especial para o reservatório de Tucuruí.

Effects of reproductive condition and dominance rank on cortisol responsiveness to stress in free-ranging female rhesus macaques.

The hypothalamic-pituitary-adrenal (HPA) axis modulates individuals' physiological responses to social stress, which is an inevitable aspect of the daily lives of group-living animals. Previous nonhuman primate studies have reported that sex, age, rank, and reproductive condition influence cortisol levels under stressful conditions. In this study we investigated cortisol responses to stress among 70 multiparous, free-ranging female rhesus macaques (Macaca mulatta) on the island of Cayo Santiago, PR. Plasma cortisol samples were collected in two consecutive years under similar conditions. Twenty-two females were sampled both years, and most of those females were lactating in only one of the years. Individual differences in cortisol levels were stable across years, even though reproductive condition changed for most individuals. No relationship was found between age or social rank and cortisol levels. Of the females that changed reproductive conditions, cortisol levels were higher when they were lactating than when they were cycling, and the amount of change in cortisol from cycling to lactating was greatest for low-ranking individuals. Heightened reactivity to stress during lactation may be the result of concerns about infant safety, and such concerns may be higher among low-ranking mothers than among higher ranking mothers. Psychosocial stress and hyperactivation of the HPA axis during lactation can suppress immune function and increase vulnerability to infectious diseases, thus explaining why adult females in the free-ranging rhesus macaque population on Cayo Santiago have a higher probability of mortality during the birth season than during the mating season.

Do females pay attention to secondary sexual coloration in vervet monkeys (Chlorocebus aethiops)?

Several primate species show sexual dichromatism with males displaying conspicuous coloration of the pelage or skin. Studies of scrotal coloration in male vervet monkeys (Chlorocebus aethiops) suggest that it is an important intrasexual signal, with relatively dark, colourful males dominating paler males. To date, no studies have examined the influence of male colour on intersexual social interactions in vervet monkeys. The primary goal of the present study was to evaluate whether female vervet monkeys attend to male coloration. We experimentally introduced females, housed with either "pale" or "dark" males, to stimulus males whose scrota were pale, dark, or pale but painted to look dark. Overall, during introductions, females did not differ in time spent directing affiliative behaviour toward pale, dark, and painted males; however, females, permanently housed with dark males, spent significantly more time directing affiliative behaviour toward pale than painted males. When the stimulus male was pale, affiliative exchanges between males and females were longer than when the stimulus male was painted. Home male colour was not related to female-initiated aggression. Home male colour was also not related to male-initiated aggression, although painted stimulus males were more likely to initiate aggression than pale stimulus males. These findings lead us to conclude that females pay attention to male coloration, but do not bias their interactions toward males solely on the basis of natural male coloration.