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The article highlights the potential threat of the Peters's Rock Agama, a non-native species from sub-Saharan Africa, to reptile diversity in the Lesser Antilles. The introduction of non-native species is causing a loss of biodiversity in the region, which is known for its unique and endemic species. The Peters's Rock Agama has already been sighted in Florida, the Bahamas, and Tortola, and if it establishes a population in the Lesser Antilles, it could negatively impact native species through predation and competition. The article urges local stakeholders to be vigilant and report any sightings to relevant authorities. Additionally, the text emphasizes the importance of state authorities, transport providers, and shipping providers in preventing the spread of invasive species and calls for collaboration between Florida-based conservationists and alien species experts to address this threat. [Extracted from the article]

Multivariate statistical methods were used to elucidate which environmental factors influence the activity patterns of free-living Malayan pit vipers, Calloselasma rhodostoma. Fourteen adult snakes were implanted with miniature radio transmitters and located a total of 887 times in 5 months. The pit vipers usually remained coiled on the ground for several consecutive days before moving at night to a new site. Partial correlation tests revealed that the frequency and distance ofmovements to new sites by tagged snakes were highly positively correlated with ambient relative humidity, but not with rainfall, ambient temperature or the lunar cycle. This finding was corroborated by the frequency with which active non-tagged C. rhodostoma were encounteredat night. In each site, the proportion of the snakes' bodies exposedto view was positively correlated with ambient humidity, and the snakes retreated to areas with deeper undergrowth when ambient humidity was low. Overt thermoregulatory behaviour was not observed, and implanted thermosensitive transmitters revealed that the snakes were passive thermoconformers. These findings seem to contradict much of the current literature which shows temperature to be the dominant abiotic factor affecting reptilian activity, but most herpetologists have considered only temperate forms. Ambient temperature in our tropical study site was warm and relatively constant throughout the year (mean daily range = 24--31 deg.C). so the pit vipers could passively maintain body temperature within a fairly narrow range, with a daytime mean of29.4 deg.C. Ambient relative humidity, on the other hand, was very variable, and confining exposure and activity to periods of high ambient humidity may be necessary to avoid dehydration. [ABSTRACT FROM AUTHOR]

Venom composition within snake species can show considerable geographical variation, an important consideration because bites by conspecific populations may differ in symptomatology and require different treatments. The underlying causes of this phenomenon have never been explained. Here we present evidence that the variation in the venom of the pitviper Calloselasma rhodostoma (Serpentes: Viperidae) is closely associated with its diet. We also evaluated other possible causes of geographic variation in venom using partial Mantel tests and independent contrasts, but rejected both contemporary gene flow (estimated from geographical proximity) and the phylogenetic relationships (assessed by analysis of mitochondrial DNA) among populations as important influences upon venom evolution. As the primary function of viperid venom is to immobilize and digest prey and prey animals vary in their susceptibility to venom, we suggest that geographical variation in venom composition reflects natural selection for feeding on local prey.

The Malayan pit viper (Calloselasma rhodostoma) is of major clinical significance both as a leading cause of snakebite and as the source of ancrod (Arvin). Although its venom has been extensively studied, the degree to which venom composition varies between individuals is poorly known. We individually analysed the venoms of over 100 C. rhodostoma using isoelectric focusing. In all populations, females produced an intense band that was absent from all males, and significant ontogenetic variation was detected. Principal components analysis of the banding profiles also revealed strong geographic variation, which was significantly congruent with variation in the biological activities of the venom (phosphodiesterase, alkalinephosphoesterase, L-amino acid oxidase, arginine ester hydrolase, 5'-nucleotidase, thrombin-like enzyme, haemorrhagic activity). Studies of captive-bred snakes indicate that the intraspecific variation in venom is genetically inherited rather than environmentally induced. The intraspecific variation in venom composition and biological activity could be of applied importance to snakebite therapy, both in correct diagnosis of the source of envenomation and in the development of a more effective antivenom. Greater attention should be given to the source of C. rhodostoma venom used in research to ensure reproducibility of results.