The Neotropics of Mexico and Central America have a very large range of biodiversity which makes them great for research, especially on salamanders. But, as you probably know if you're reading this post, amphibian populations worldwide are declining, mostly due to habitat destruction for farming and development and diseases such as chytrid fungus. If a species that we thought was extinct is discovered or if a species with a very small range is found in a different region, that tells us that those species have a higher chance of surviving.
This particular salamander, the Finca Chiblac Salamander, which I will abbreviate as the FC Salamander for the purpose of making this post easier to read, has been very difficult as far as being discovered in the Neotropics. Until January of 2009, there was no sign of it until researchers found nine individuals in a survey, the first sighting of the endangered species in 32 years. Another specimen was collected a year later outside of the salamander's range, implying that maybe the FC Salamander wasn't extinct and had a larger range than we thought it did.
In June of 2012, a team of researchers started surveying for vertebrates in a mostly unexplored region of northern Mexico. The herpetologists started looking in plants and under rocks to see if there were any salamanders there. Eight specimens of the FC Salamander were found under assorted kinds of wood. This was surprising. This was far outside the FC's range and the species isn't built for travel. This led to genetic examination to see if the salamanders the herpetologists had found were really FCs or a species that spawned from the FC. The results were in, and they proved that the FC Salamander had a wider range than anyone had expected.
Bouzid, Nassima, Rovito, Sean, Sanchez-Solis, Jorge. "Discovery of the Critically Endangered Finca Chiblac Salamander (Bradytriton silus) in Northern Chiapas, Mexico." Herpetological Review, 46(2), 186-187. 2015.