A group led by researchers from the State University of Campinas (Unicamp) described the second smallest vertebrate in the world .
One of the copies of the miniature frog used at work, an adult, is 6.95 millimeters . Before that, a species of the same genus had been described in southern Bahia with one of the individuals measuring 6.45 millimeters.
The study, supported by FAPESP, was published last Friday (25) in PeerJ magazine.
Flea toads or flea frogs, as some species of the genus Brachycephalus are known, have adults less than one centimeter in length.
To give you an idea, they can sit on an adult human’s fingernail or on a 50-cent coin.
The new species was named Brachycephalus dacnis in honor of the Dacnis Project, which maintains private areas of Atlantic Forest in the State of São Paulo, including the one where the animal was found, in Ubatuba, on the north coast.
“There are small frogs with all the characteristics of large frogs, just smaller. This genre is different. Throughout its evolution, it underwent what we call miniaturization. These are characteristics such as fusions and loss of bones, in addition to the lack of digits and other parts of the anatomy”, explains Luís Felipe Toledo, professor at the Institute of Biology (IB) at Unicamp and coordinator of the study.
The work is part of the project “From natural history to the conservation of Brazilian amphibians”, supported by Fapesp, and also included a PhD scholarship for Julia Ernetti, co-author of the study.
This is the seventh species of flea thrush described within the genus Brachycephalus. Until recently, the group was best known for brightly colored and venom-bearing species, such as the golddrop frogs (Brachycephalus rotenbergae and B. ephippium) and the pitanga frog (B. pitanga).
But the small size of flea thrushes is now catching researchers’ attention.
Interestingly, although larger than flea toads, golddrops have fewer anatomical structures, such as the absence of parts of the inner ear that make it impossible for them to hear their own song, for example.
Diversity
The song of the species described now was what caught the attention of researchers. Its morphology is the same as that of another species, B. hermogenesi. Both have yellowish brown skin, live in forest leaf litter, do not have tadpoles (they emerge from eggs walking) and occur in the same region. However, the singing is different.
When they sequenced the gene normally used to differentiate species, the researchers confirmed that it was a new entity.
However, when visiting Picinguaba, in Ubatuba, where the frogs that allowed the description of B. hermogenesi were found, they noticed that B. dacnis also occurs there.
“It is possible that, among the specimens that served as the basis for describing B. hermogenesi in 1998, there are animals of the new species,” says Toledo.
The researcher suggests the use of historical DNA sequencing tools, that contained in specimens deposited a long time ago in zoological collections, in order to resolve the doubt.
In the description of the new species, in addition to the usual anatomical characteristics, the researchers added information about the skeleton and internal organs, as well as molecular and song data.
The idea is that descriptions of new species also contain this information so that it is possible to differentiate them more precisely, since many are cryptic, that is, they cannot be discriminated solely by external anatomy.
“The diversity of these miniature frogs may be much greater than we imagine. Therefore, it is important to have as many characteristics as possible to speed up the description process and, thus, be able to act on conservation”, he concludes.
The article “Among the world’s smallest vertebrates: a new miniaturized flea-toad (Brachycephalidae) from the Atlantic rainforest” can be read here.
This content was originally published in Scientists find the world’s 2nd smallest vertebrate in the Atlantic Forest; see the CNN Brasil website.
Source: CNN Brasil