After decades of study, the team of international experts believe that these salamanders, which are no bigger than a matchstick, are the smallest tailed tetrapods from the enigmatic genus Thorius. Their tiny bodies, albeit uncommon for vertebrates, are equipped with structures for feeding, reproduction. They named them: Thorius pinicola ("pine-dwelling minute salamander"), Thorius longicaudus ("long-tailed minute salamander"), and Thorius tlaxiacus ("heroic minute salamander").

According to the peer-reviewed paper published on PeerJ, the new species were discovered using a combination of sophisticated molecular analyses (including DNA sequencing), digital imaging (X-ray computed tomography), and statistical analysis of external and internal anatomy.

Thorius were first discovered in the 19th century, and scientists believed there was only a single species for the next 75 years. Nine more species were discovered between 1940 and 1960, but because of their miniscule size, they found it difficult to tell them apart.

It wasn't until the 1970s when biologists have finally learned that many species, while anatomically similar, could be readily told apart by using molecular techniques, which then revealed subtle anatomical features that differentiate them. Following that breakthrough, several new species of Thorius have been identified. Currently, with these three newly named species, the total is 29, Eureka Alert reports.

Unfortunately, like other amphibians, the once-abundant population of Thorius have tragically diminished, that it is extremely rare to see one in nature. As a matter of fact, of the nearly 30 species of Thorius now recognized, almost all are regarded as Endangered or Critically Endangered by the International Union for the Conservation of Nature.

Despite the progressive discovery and documentation of amphibians, there are more awaiting to be discovered and hopefully saved before they are lost. To learn more about other strange-looking salamanders, check out the video below.