Blood Biochemical Reference Intervals of Black Caimans (Melanosuchus niger) and Spectacled Caimans (Caiman crocodilus) in the Brazilian Amazon Region.

Reference intervals for physiologic parameters, crucial for assessing the health status of animals, have been documented for various crocodilian species across the globe. Nonetheless, the establishment of plasma biochemical reference intervals specific to Amazonian crocodilians remains incomplete. In an effort to address this gap, we procured blood samples from 65 black caimans (Melanosuchus niger) and 58 spectacled caimans (Caiman crocodilus) during the period of September-December 2019 within the Anavilhanas National Park in the Brazilian Amazon region We aimed to define reference intervals for 11 key plasma variables measured, namely glucose, triglycerides, total cholesterol, calcium, magnesium, sodium, potassium, albumin, total protein, uric acid, and urea.

Physiological stress response in free-living Amazonian caimans following experimental capture.

When captured, free-living crocodilians respond by hyperstimulation of the hypothalamic-pituitary-adrenal (HPA) axis, which triggers a cascade of downstream events of physiological stress. We examined these responses in two unstressed, and stressed Amazonian caimans, Caiman crocodilus and Melanosuchus niger. Plasma corticosterone levels increased in both stressed caiman species.

Looking for genetic effects of polluted anthropized environments on Caiman crocodilus crocodilus (Reptilia, Crocodylia): A comparative genotoxic and chromosomal analysis.

The Amazon aquatic ecosystems have been modified by the human population growth, going through changes in their water bodies and aquatic biota. The spectacled alligator (Caiman crocodilus crocodilus) has a wide distribution and adaptability to several environments, even those polluted ones. This study aimed to investigate if a Caiman species living in urban streams of Manaus city (Amazonas State, Brazil) is affected by environmental pollution.

Evidence of cryptic lineages within a small South American crocodilian: the Schneider's dwarf caiman (Alligatoridae: Caimaninae).

Schneider's dwarf caiman is one of the smallest living crocodilians. Due to its broad distribution, cryptic behavior, and small home range, the species is well suited for the study of phylogeographic patterns on a continental scale. Additionally, this species is under threat due to habitat loss, trade and harvest, but is considered at low conservation risk by the IUCN.

Correction to: The metabolic cost of nesting: body condition and blood parameters of Caiman crocodilus and Melanosuchus niger in Central Amazonia.

Although nesting ecology is well studied in several crocodilian species, it is not known how nest attendance influences physiology and body condition of nesting females. In this study, we describe body condition and serum biochemical values of nesting female, non-nesting female and male spectacled caiman (Caiman crocodilus) and black caiman (Melanosuchus niger) in two areas of Central Amazonia. We also evaluated the effect of nest age and nest distance to water on body condition and blood parameters of nesting females.

The metabolic cost of nesting: body condition and blood parameters of Caiman crocodilus and Melanosuchus niger in Central Amazonia.

Although nesting ecology is well studied in several crocodilian species, it is not known how nest attendance influences physiology and body condition of nesting females. In this study, we describe body condition and serum biochemical values of nesting female, non-nesting female and male spectacled caiman (Caiman crocodilus) and black caiman (Melanosuchus niger) in two areas of Central Amazonia. We also evaluated the effect of nest age and nest distance to water on body condition and blood parameters of nesting females.

Mercury concentrations in different tissues of turtle and caiman species from the Rio Purus, Amazonas, Brazil.

Total mercury (Hg) concentrations of muscle, liver, blood, and epidermal keratin were measured in typically consumed, economically and culturally important species of turtle (Podocnemis unifilis and Podocnemis expansa) and caiman (Melanosuchus niger and Caiman crocodilus) from the Rio Purus in the Amazon basin, Brazil. Methylmercury (MeHg) concentrations were also measured in muscle tissue, representing the first analysis of MeHg concentrations in Amazonian reptile species. In muscle tissues Hg was mostly MeHg (79-96%) for all species.

Morphological and molecular identification of ticks infesting Boa constrictor (Squamata, Boidae) in Manaus (Central Brazilian Amazon).

The Boa constrictor is one of the world's largest vertebrate carnivores and is often found in urban areas in the city of Manaus, Brazil. The morphological identification of ticks collected from 27 snakes indicated the occurrence of Amblyomma dissimile Koch 1844 on all individuals sampled. In contrast, Amblyomma rotundatum Koch was found on only two snakes.

An evaluation of the use of reptile dermal scutes as a non-invasive method to monitor mercury concentrations in the environment.

Reptiles are ideal organisms for the non-invasive monitoring of mercury (Hg) contamination. We have investigated Hg bioaccumulation in tissue layers of reptile dermis as a basis for establishing a standardized collection method for Hg analysis. Tissue samples from freshwater turtle species Podocnemis unifilis and Podocnemis expansa and caiman species Melanosuchus niger and Caiman crocodilus, all from the Amazonian region, were analysed in this study.

Mercury concentration in the spectacled caiman and black caiman (Alligatoridae) of the Amazon: implications for human health.

Mercury (Hg) concentrations in the Amazon are generally high, but no studies have been published on Hg concentrations in caimans (Alligatoridae) from the region. Aiming for sizes representative of caimans traded for food in the Amazon, we measured Hg concentration in tail muscle of spectacled caiman (Caiman crocodilus crocodilus) and black caiman (Melanosuchus niger) from the Purus River basin. The information on Hg concentration in caimans from this area is important because of the potential health risk to humans and other animals that eat them as well as the potential use of these top-level predators as bioindicators.

Phylogeographic and conservation genetic analysis of the black caiman (Melanosuchus niger).

We assessed the spatial distribution of the genetic variability of Melanosuchus niger from 11 localities in South America using 1,027 base pairs of the mitochondrial cytochrome b gene. Screening 132 animals, we found 41 haplotypes, high values of genetic diversity, low values of nucleotide diversity and significant deviations from neutral expectation of allelic frequencies in some localities. Mantel test and nested-clade analysis indicated that isolation-by-distance was an important population dynamic for the species as a whole.