RESUMO
Studying species interactions in nature often requires elaborated logistics and intense fieldwork. The difficulties in such task might hinder our ability to answer questions on how biotic interactions change with the environment. Fortunately, a workaround to this problem lies within scientific collections. For some animals, the inspection of preserved specimens can reveal the scars of past antagonistic encounters, such as predation attempts. A common defensive behaviour that leaves scars on animals is autotomy, the loss of a body appendage to escape predation. By knowing the collection site of preserved specimens, it is possible to assess the influence of organismal biology and the surrounding environment in the occurrence of autotomy. We gathered data on tail loss for 8189 preserved specimens of 33 snake and 11 amphisbaenian species to investigate biological and environmental correlates of autotomy in reptiles. We applied generalized linear mixed effect models to evaluate whether body size, sex, life-stage, habitat use, activity pattern, biome, tropicality, temperature and precipitation affect the probability of tail loss in limbless reptiles. We observed autotomy in 23.6% of examined specimens, with 18.7% of amphisbaenian and 33.4% of snake specimens showing tail loss. The probability of tail loss did not differ between snakes and amphisbaenians, but it was higher among large-sized specimens, particularly in adults and females. Chance of tail loss was higher for diurnal and arboreal species, and among specimens collected in warmer regions, but it was unaffected by biome, precipitation, and tropicality. Autotomy in limbless reptiles was affected by size-dependent factors that interplay with ontogeny and sexual dimorphism, although size-independent effects of life-stage and sex also shaped behavioural responses to predators. The increase in probability of tail loss with verticality and diurnality suggests a risk-balance mechanism between species habitat use and activity pattern. Although autotomy is more likely in warmer regions, it seems unrelated to seasonal differences in snakes and amphisbaenians activity. Our findings reveal several processes related to predator-prey interactions involving limbless reptiles, demonstrating the importance of scientific collections to unveil ecological mechanisms at different spatio-temporal scales.
Assuntos
Lagartos , Feminino , Animais , Lagartos/fisiologia , Cauda/fisiologia , Comportamento Predatório , Cicatriz , EcossistemaRESUMO
The brain is one of the most important organs of vertebrates. Over the years, several studies have investigated brain features under different approaches, such as comparative morphology. Although many recent studies use non-invasive methods, such as micro-CT scan, some methods require access to the brain, such as histological analyses and cell count methods. In addition, several researchers do not have access to those expensive devices and rely on the traditional dissection to conduct their studies. Still, for most vertebrates, very few protocols are available for removing the brain, especially those committed to minimizing the damage to the specimen for further examinations. Here we describe in detail a method to dissect the brains of anurans and squamates maintaining the specimen's external morphology as undamaged as possible. This simple method can be performed using few tools and can be achieved in the first trials, representing an incentive for more research on vertebrate's brains. This method contributes to the maximum utilization of each animal collected, a positive practice from both ethical and practical perspectives.(AU)
Assuntos
Animais , Anuros/anatomia & histologia , Metodologias de Avaliação de Danos , Cérebro/anatomia & histologia , Contagem de Células , Anatomia ComparadaRESUMO
Abstract We report a case of envenomation by Dendrobates tinctorius in the northwest of the Amazon Forest. The patients were two men, who presented with numbness in the right arm and slight numbness in the lower lip, respectively. Dendrobates tinctorius secretions contain pumiliotoxin, one of several toxins found in the dendrobatidis skin, which interferes with muscle contraction and causes locomotor difficulties. Although Dendrobatidae is a family of anurans known for their venom, few studies describe the symptoms of envenomation in humans.
Assuntos
Animais , Masculino , Anuros , Venenos , Pele , BrasilRESUMO
We report a case of envenomation by Dendrobates tinctorius in the northwest of the Amazon Forest. The patients were two men, who presented with numbness in the right arm and slight numbness in the lower lip, respectively. Dendrobates tinctorius secretions contain pumiliotoxin, one of several toxins found in the dendrobatidis skin, which interferes with muscle contraction and causes locomotor difficulties. Although Dendrobatidae is a family of anurans known for their venom, few studies describe the symptoms of envenomation in humans.
Assuntos
Anuros , Venenos , Animais , Brasil , Humanos , Masculino , PeleRESUMO
The rare Amazonian snake Eutrachelophis papilio is known from only five individuals, from four localities, belonging to its type-series, the more recent collected over 10 years ago. Here, we expand its distribution and describe its color in life for the first time. We also provide an estimate of its distribution area using the minimum convex polygon method and identify the values of anthropic pressure within its known distribution range with the Human Footprint Index. The new occurrence is located 291 km from the nearest known locality and its distribution is associated with pristine forests. Considering its rarity, and the absence of demographic and biological data, we suggest that the species should be classified as Data Deficient by IUCN criteria. (AU)
Assuntos
Serpentes , Florestas , Distribuição AnimalRESUMO
The rare Amazonian snake Eutrachelophis papilio is known from only five individuals, from four localities, belonging to its type-series, the more recent collected over 10 years ago. Here, we expand its distribution and describe its color in life for the first time. We also provide an estimate of its distribution area using the minimum convex polygon method and identify the values of anthropic pressure within its known distribution range with the Human Footprint Index. The new occurrence is located 291 km from the nearest known locality and its distribution is associated with pristine forests. Considering its rarity, and the absence of demographic and biological data, we suggest that the species should be classified as Data Deficient by IUCN criteria.(AU)
A rara serpente amazônica Eutrachelophis papilio é conhecida por apenas cinco indivíduos provenientes de quatro localidades e pertencentes à sua série-tipo, sendo o mais recente coletado há mais de 10 anos. No presente trabalho, expandimos sua distribuição e descrevemos sua cor em vida pela primeira vez. Calculamos sua área de distribuição usando o método de mínimo polígono convexo e identificamos os valores de pressão antrópica dentro de sua área de distribuição através do Human Footprint Index. A nova ocorrência está a 291 km da localidade conhecida mais próxima e toda sua distribuição é associada a florestas bem preservadas. Devido à sua raridade, carências de dados demográficos e biológicos, sugerimos que a espécie seja categorizada como Dados Insuficientes (DD) pelos critérios da UICN.(AU)
Assuntos
Animais , Serpentes/anatomia & histologia , Serpentes/crescimento & desenvolvimento , FlorestasRESUMO
BACKGROUND: The Atlantic Forest is a hotspot for biodiversity, an area which houses high species richness and endemism, but with high level of threat. With reference to the herpetofauna, until recently there has been no detailed information regarding diversity of snakes recorded in the Atlantic Forest, the number of endemic species and their distribution ranges. While these basic data were missing, large areas of original forest have continued to be lost to increased urbanization and human population, representing a severe threat to the biodiversity. NEW INFORMATION: We recorded 28 snake species in our study area. Dipsadidae was the richest family with 14 species, followed by Colubridae (eight species), Boidae (two species), Viperidae (two species), and Anomalepididae, Elapidae and Typhlopidae (one species each). Most species were forest inhabitants (61%), of which 13 are endemic to the Atlantic Forest. There were no clearly defined species clusters regarding species composition. None of the species recorded in Niterói are listed as threatened in the Brazilian Redlist. However, most of them are strongly associated with forested areas and, perhaps, are not adapted to live in small fragments. Thus, more initiatives should be implemented to evaluate the true conservation status of these species in order to better protect them.