New Colombian frogs discovered by scrutinizing known species

Colombia is home to large variety of animals and plants, partly due to the very different geographic features in the country’s landscapes, like the Andes and the Amazon, creating a myriad of habitats for species to live in. And while the Amazonian rainforest is renowned for its spectacular diversity of life, the lesser known cloud forests of the Andes rival this rainforest in biodiversity. The Andean part of Colombia and surrounding countries like Brazil, Ecuador and Venezuela, might even be the place with the highest amphibian diversity in the world and is definitely a hotspot in terms of amphibian species. No surprise then that two new frog species have been recently found in these Andean cloud forests in Colombia. Though certainly not the only new species that have been identified recently in this region, their ‘discovery’ is remarkable, because these species had been known to science longer, but after careful examination they have received the status of ‘new species’ .

 

We might have the impression that discoveries of new species are ever only made through the work of adventurous biologists that simply venture where no man (or at least scientist) has gone before, but plain hard work and of course diligent scrutinization can lead to such a discovery as well. And by really paying good attention to the call of a frog, morphological features and DNA analysis in the laboratory it is even possible to discover a new species of frog in the midst of a megacity like New York. This has to do with the fact that species are not so easily distinguishable, at least not always. The theoretical discussion about what a species is, adds to the difficulty of the task: there are multiple versions of how a species is defined and even such a widely applied definition as the ‘biological species concept’ (in which interbreeding individuals should produce viable offspring and only then are considered members of the same species) leaves room for ample discussion. In the field, mostly morphology (appearances) is used and with frogs in particular vocalization, but sometimes the human senses aren’t developed enough to tell the difference between two very similar species.

In the northwestern Colombian Andes a new poison frog has been found, named Andinobates cassidyhornae. The group of the Andinobates frogs has only recently been recognized as a new genu and it consists of minute, very small, frogs that reside, mainly, in the Colombian Andes, Pacific lowlands of Colombia and Panama. The researchers found this particular Andinobates population that was assigned to the species A. opisthomelas in the Colombian Andes during fieldwork. Closer inspection of body morphology, specifically the coloration and color patterns of the animals, suggested that this might well be a different and entirely new species.

Through the use of bioacoustics, recording and subsequent analyzing the male call, and molecular methods, analyzing the overlap in DNA between this population and one of the Andinobates opisthomelas, revealed that indeed the researchers had come across a species, unknown to science. Andinobates cassidyhornae was found at four different localities at around 2000 meters altitude in heavily disturbed cloud forests. Because of intensive agriculture many of the forests there have been cut down, so only small patches of suitable habitat remain. As well this activity has had a profound impact on the habitat quality through the use of pesticides, fertilizer and other pollutants. Therefore the researchers  express their concerns about the future of the species.

In the same region of Colombia, in the department of Antioquia, another new species has been ‘discovered’, this time hiding a bit higher up in the Andes, at around 2200 to 3200 meters. The species has been named Hyloscirtus antioquia, in the honor of the bicentennial celebration of the department. Although individuals had been spotted since some years ago, first they had been falsely ascribed to H. larinipygion. Again, closer examination of the color pattern and morphological features like their nuptial pads (a secondary sex characteristic) revealed that these frogs differed distinctively from their  presumed ‘conspecifics’. They belong to the genus of Hyloscirtus, a group of stream-dwelling treefrogs, just like the recently discovered and beautifully colored Hyloscirtus princecharlesi. Individuals of the species have been found at eight localities in the Andean cloud forests of Colombia and their conservation status is not clear at the moment, but species of this genus have mostly restricted elevational ranges, making them vulnerable to any threat that enters their habitat. Hopefully they will not succumb to the chytrid fungus, as is feared by scientists.