Guenons (tribe Cercopithecini) are one of the most diverse groups of primates. They occupy all of sub-Saharan Africa and show great variation in ecology, behavior, and morphology. This variation led to the description of over 60 species and subspecies. Here, using next-generation DNA sequencing (NGS) in combination with targeted DNA capture, we sequenced 92 mitochondrial genomes from museum-preserved specimens as old as 117 years. We infer evolutionary relationships and estimate divergence times of almost all guenon taxa based on mitochondrial genome sequences. Using this phylogenetic framework, we infer divergence dates and reconstruct ancestral geographic ranges. We conclude that the extraordinary radiation of guenons has been a complex process driven by, among other factors, localized fluctuations of African forest cover. We find incongruences between phylogenetic trees reconstructed from mitochondrial and nuclear DNA sequences, which can be explained by either incomplete lineage sorting or hybridization. Furthermore, having produced the largest mitochondrial DNA data set from museum specimens, we document how NGS technologies can “unlock” museum collections, thereby helping to unravel the tree-of-life. [Museum collection; next-generation DNA sequencing; primate radiation; speciation; target capture.]
A new species of Colostethus is described from Kaieteur National Park, Guyana, South America. The new species can be distinguished from close relatives by the presence of a median lingual process, first finger equal to second, Finger III not distinctly swollen but all fingers slightly swollen in males, presence of fringes on fingers, presence of a dorsolateral stripe from posterior corner of eye, absence of an oblique lateral stripe, and differences in tadpole morphology, colouration and pattern, vocalizations and ecology. This is only the second species of Colostethus known to provide maternal care for tadpoles.
A new species of Colostethus (Anura, Dendrobatidae) from French Guiana with a redescription of Colostethus beebei (Noble, 1923) from its type locality. A new species of Colostethus, long mistaken for Colostethus beebei, is described from French Guiana. The new species can be distinguished from congeners by absence of median lingual process, first finger longer than second, third finger not distinctly swollen in males, differences in tadpole morphology, coloration and pattern (e.g. absence of dorsolateral stripe), bioacoustics, and reproductive behavior. A complete redescription of Colostethus beebei plus description of its tadpole and call is provided on the basis of recently collected topotypic specimens. The range of C. beebei is restricted to the Kaieteur plateau, Pakaraima Mountains, Guyana.
Using an in vitro tritiated thymidine nuclear labeling followed by autoradiography, the effects of 17-β-estradiol (E2) or progesterone (Pg) were studied in 30 canine mammary tumors that were incubated and hormonally stimulated in vitro. In 10 of these tumors, the synthetic (S) phase duration was also measured in absence or in presence of E2, by using a double labeling with tritiated thymidine. Our results demonstrate that E2, and, to a lesser degree, Pg can induce cell replication in both estrogen receptor-positive (ER+ PgR+ ) and estrogen receptor-negative (ER–– PgR––) canine mammary tumors. The mitogenic effect of E2 may involve a shortening of the DNA S cell cycle phase. We have also found a significantly positive relationship between, the estrogen and the progesterone receptor concentrations and the basal proliferation rate in these tumors, whereas no correlation was found between steroid receptor contents and the maximal level of stimulation achieved after E2 or Pg exposure.
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