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Intra- and interspecific genetic diversity of the lizard species Plica plica (9 localities) and Plica umbra (19 localities) from the Brazilian Amazon was analysed using two mitochondrial (16S rDNA and CO1) and one nuclear (prolactin receptor – PRLR) genes. We generated a maximum-likelihood and Bayesian hypotheses of phylogenetic relationships, and using the bPTP and ABGD lineage delimiting methods inferred the most likely number of lineages within each species. Both methods delimited five distinct lineages in Plica plica and six lineages within Plica umbra. The nominal subspecies of Plica umbra was comprised of one lineage, while Plica umbra ochrocollaris was comprised of five lineages. In majority of the cases, lineages were restricted to the interfluves of major Amazonian rivers, and different lineages occupied distinct areas of endemism. Phylogenetic relationships of the lineages are largely concordant with the hypothesized formation of the areas of endemism. The geographic structuring of the clades and the delimitation of these clades as distinct lineages suggest the possibility that these lineages represent species. If the observed diversity of lineages within the genus Plica is characteristic of squamate reptiles of the Amazon region, the diversity of squamates is grossly underestimated.

We used a microsatellite enriched library to isolate and characterize 12 di-nucleotide microsatellite loci of Caiman crocodilus. Microsatellites were characterized in populations of C. c. crocodilus from Piagacu-Purus, Amazonas, Brazil and C. c. yacare from Caceres, Mato Grosso, Brazil. Results of characterization were comparable between the two subspecies, with number of alleles varying from three to 20 and one to 14 per locus in C. c. crocodilus and C. c. yacare, respectively. Observed heterozygosities ranged from 0.088 to 0.816 and 0.115 to 0.833, respectively. Joint paternity exclusion (QC) was >0.999 in both subspecies, and probability of genetic identity varied from 4.631 × 10−13 in C. c. crocodilus to 2.233 × 10−8 in C. c. yacare. All loci are unlinked, and with the exception of three loci in C. c. crocodilus all loci were at Hardy–Weinberg equilibrium. The characteristics of these loci makes them an excellent tool set for the study of mating systems, and fine-scaled population structuring in the Caiman crocodilus species complex.

We used a microsatellite-enriched library to isolate and characterize 16 di-nucleotide microsatellite loci in Semaprochilodus insignis. Microsatellites were characterized in a population sample from Piagacu-Purus (Purus River, Amazonas, Brazil) and in eight individuals each of S. brama from Itaipavas (Araguaia River, Para, Brazil), S. taeniurus from Novo Airao (Negro River, Amazonas, Brazil), S. kneri (Caura River, Venezuela), and Prochilodus nigricans also from Piagacu-Purus. In S. insignis observed heterozygosities ranged from 0.516 to 0.968, expected heterozygosities from 0.574 to 0.973, and the number of alleles per locus varied from 4 to 32 in 31 analyzed individuals. All loci were unlinked and three loci showed significant deviations from Hardy–Weinberg equilibrium. Most markers could be successfully transferred to the other four prochilodontids, making them potentially useful for conservation genetic studies of Semaprochilodus spp.

The mating system of the spectacled caiman (Caiman crocodilus) was investigated in the Piagacu-Purus Sustainable Development Reserve, Amazonas, Brazil. We used 6 polymorphic microsatellite loci to genotype 13 females and 174 hatchlings representing 20 nests sampled over 4 consecutive reproductive seasons (2007-2010). Paternity was determined by 2 methods: simple counts, and statistical analysis using Gerud 2.0. Results were congruent between the 2 approaches, and the null hypothesis of single paternity was rejected in 19 of the 20 nests analyzed, thereby demonstrating that C. crocodilus females are polyandrous and that the breeding system of the species can be characterized as polygamous. The data suggest that 1-4 fathers were responsible for the paternity of the offspring, and that the males contributed differently (9-100%) to each of the 20 nests. A total of 53 males copulated with the 20 females mothering the nests. This is the first study on the mating system of C. crocodilus and the frequency of multiple paternity is among the highest values (95%) reported thus far for crocodilians.

Este trabajo tuvo como objetivo comparar y estandarizar un protocolo eficiente para la extracción de ADN de fragmentos de tejido de Podocnemis expansa y evaluar el poder informativo de los marcadores moleculares RAPD e ISSR para el análisis de la estructura genética de la especie colectada en el entorno del parque Nacional do Araguaia, Tocantins, Brasil. El método de extracción fue estandarizado a partir de la evaluación de tres diferentes protocolos permitiendo la obtención de ADN de buena calidad y en cantidad adecuada para las reacciones de RAPD e ISSR. La razón A de las muestras presentó un valor entre 1.8 a 2.3, indicando que estas presentan baja contaminación por proteínas y que los ADNs podrían ser utilizados para evaluar el poder informativo de los marcadores RAPD e ISSR. Los dos marcadores demostraron ser una herramienta eficiente para estudios genéticos de P. expansa