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The black-horned capuchin (Sapajus nigritus) is a neotropical primate with wide distribution from southeastern Brazil to northeastern Argentina. Although this species has been described with coat pattern variation, even with intrapopulational differences, and characterized as having the greatest genetic diversity among Sapajus species, there are still few studies on natural populations that contribute to the knowledge of this intraspecific variability. We examined individuals from an as yet unstudied population of Ilha da Marambaia, Rio de Janeiro (RJ) state, Brazil, compared with published data for S. nigritus. We sought to confirm the species through phenotypic and genetic characterization using C-banding and fluorescence in situ hybridization with #11qHe+/21WCP probes for chromosomal constitutive heterochromatin (He+) patterns, and cytochrome c oxidase I and II gene sequences for phylogenetic analysis. The coat presented two color patterns, varying from brown to blackish on the body, yellow to brown on the chest, and white to yellow on the face, besides the presence and shape of the tufts on the head, corresponding to S. nigritus. He+ was identified in pairs 4, 12, 13 and 17, and less consistently in pairs 6, 19 and 21, already described for this species. While most Sapajus species have a large He+ block, here pair 11 was identified without extracentromeric He+, the same as reported for S. nigritus from Argentina. Molecular analysis showed divergence of this population from other S. nigritus sequences, reinforcing a trend already demonstrated when samples from RJ are compared with the rest of the distribution, which may represent an evolutionary deviation. [ABSTRACT FROM AUTHOR]

The genus Atelognathus is composed of five species that occur in the southernmost regions of Argentina and Chile. It belongs to the Batrachylidae, one of the few endemic anuran families from Patagonia. More than 50 yr ago, it was concluded that A. reverberii had a diploid chromosomal complement of 2N = 26, a feature later reported for other congenerics. In this work, we describe the cytogenetics of all known species of Atelognathus (A. nitoi, A. patagonicus, A. praebasalticus, A. reverberii, and A. solitarius) and two additional undetermined populations. Unexpectedly, our analyses showed that all have a diploid chromosomal complement 2N = 24, which contrasts with conclusions of previous studies. We conclude that a karyotype of 2N = 24 is shared in Atelognathus as a derived condition within Batrachylidae. Additionally, we describe and discuss other cytogenetics characters (i.e., nucleolar organizer region location and C-banding patterns) of Atelognathus and related genera of Batrachylidae in an evolutionary framework. [ABSTRACT FROM AUTHOR]

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The genus Pediculus L. that parasitize humans comprise two subspecies: the head lice Pediculus humanus capitis De Geer and the body lice Pediculus humanus humanus De Geer. Despite the 200 yr of the first description of these two species, there is still a long debate about their taxonomic status. Some authors proposed that these organisms are separate species, conspecifics, or grouped in clades. The sequencing of both forms indicated that the difference between them is one gene absent in the head louse. However, their chromosomal number remains to be determined. In this study, we described the male and female karyotypes, and male meiosis of head and body lice, and examined the chromatin structure by means of C-banding. In P. h. humanus and P. h. capitis, the diploid chromosome complement was 2 n = 12 in both sexes. In oogonial prometaphase and metaphase and spermatogonial metaphase, it is evident that chromosomes lack of a primary constriction. No identifiable sex chromosomes or B chromosomes were observed in head and body lice. Neither chiasmata nor chromatin connections between homologous chromosomes were detected in male meiosis. The meiotic behaviour of the chromosomes showed that they are holokinetic. C-banding revealed the absence of constitutive heterochromatin. Our results provide relevant information to be used in mapping studies of genes associated with sex determination and environmental sensing and response., (© The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)