Scientists have discovered a total of three new primate species in Madagascar. The three new species are mouse lemurs and live in the South and East of the island nation.

Mouse lemurs are small, nocturnal primates that can only be found in Madagascar. Just 20 years ago, only two species were known to exist. Now, with the recent findings, that number has jumped to 24 species in total.

The reason for why these various species have gone unnoticed for so long is simple: mouse lemurs look similar. Because they're nocturnal, they're also elusive, and they can only be distinguished reliably with genetic methods.

"By using new, objective methods to assess genetic differences between individuals, we were able to find independent evidence that these three mouse lemurs represent new species," said Peter Kappeler, Head of the Behavioral Ecology and Sociobiology Unit at the German Primate Center and one of the researchers behind the study. "The genetic techniques we used could facilitate species identification, thus also contributing to further new descriptions in other animal groups."

About three years ago, the same research groups described two new mouse lemur species. The closely related Madame Berthe's mouse lemur is actually the smallest primate in the world, weighing in at just 30g.

Finding these different species, although they're closely related, is important. This is largely due to the fact that scientists will be able to better target conservation efforts by knowing the distribution of different species.

"To know the exact distribution area of individual species is necessary to identify functioning protected areas," Kappeler said. "Furthermore, this new information is an important element towards better understanding how biodiversity in Madagascar arose."

More than 100 known species of lemurs are threatened by extinction, according to the IUCN "Red List." In fact, lemurs represent the world's most endangered group of mammals. Both deforestation and hunting have helped reduce population numbers. This, in particular, shows how important it is to monitor these populations of lemurs and understand what species may or may not be vulnerable.

The new findings reveal that mouse lemurs are more diverse than expected. It's likely that scientists will continue to uncover more species in the future with genetic techniques.

The study was recently published in the journal Molecular Ecology.