Phoneutria boliviensis is a very well studied type of banana spider because, like other species of the same genus, it produces a venom with strong neurotoxic action that is very interesting for its medical applications. The behavior, habitat, ecology of this spider, considered one of the most dangerous in the world, has been analyzed, as well as the treatment of its bites and the properties of the venom it produces. The animal usually inhabits environments disturbed by man, and is very common in banana plantations (hence the name).
Now a team of scientists at George Washington University has published a paper reviewing ancient specimens collected for museum collections that had been identified as P. boliviensis . The work shows that, in reality, P. boliviensis does not represent a single species, but two.
The starting point was the identification of two well-defined morphological groups that had been collected in areas separated by the Andes mountain range, a natural geographic barrier that has led to the separation of many other species. To test their hypothesis, the scientists conducted field sampling in the Amazon, the Andes, and Central America, collecting spiders from different locations to explore their genomic signal.
They found that indeed the genetic differences that separate the two forms were similar compared to the genetic differences that separate other recognized species of banana spiders. Using morphological, genomic, and geographic distribution data, the authors concluded that P. boliviensis does not represent a single species, but two different ones. They found that the true P. boliviensis is only found in the Amazon region, and the second species, P. depilata (an old name now revalidated by the research team), is found in the Andes, Chocó, and Caribbean regions. Their findings are published in the journal ZooKeys .
A camouflaged species
The authors have found that P. depilata has been mislabelled as P. boliviensis in many studies, including some on venom composition and toxicity, ecology, geographic distribution, and human epidemiology of bites. Records of human bites of this species have been reported in Costa Rica and in banana plantations in Colombia, most of them with mild to moderate poisoning symptoms. Except for brief anecdotal mentions by field explorers in the Amazon, little is known about P. depilata .
“Our information is very valuable, as it will help to identify areas of risk for accidental bites and will help health professionals to determine the identity of the species involved, especially for P. depilata . This is a significant discovery that will affect the studies on toxicology, opening new opportunities to compare the venom composition and effect of these two species “, conclude the authors.
Citizen science provided key information
In the world there are thousands of amateur naturalists who in their free time go on field trips in which they collect a lot of valuable information. Thanks to the generalization of the internet and social networks, citizen science platforms have proliferated that allow to centralize all those data that were formerly scattered here and there in field notebooks. Altruistically, many of these naturalists provide a lot of information that, once analyzed, is key to advancing the knowledge and conservation of species and ecosystems.
In this case, the authors used the citizen science platform iNaturalist to obtain more records of the distribution of species, since both can be visually identified thanks to exclusively morphological characteristics.
Data presented by the iNaturalist community helped identify where the two Phoneutria species are found. Interestingly, for these two species, iNaturalist presented higher and more widely distributed records than the scientists’ own database. “To our knowledge, this is the first study that iNaturalist has used to collect records of the occurrence of poisonous species to estimate distribution patterns,” say the researchers.
