Luzon Has the World's Highest Concentration of Unique Mammal Species
Around 20 years ago, an international team of scientists attempted to describe all the existing mammal species in Luzon, the largest of the main islands of the Philippines. The study, led by Lawrence Heaney, was unprecedented in terms of scale and scope. The toilsome task took them to the unexplored corners of the island, which is roughly half the size of the U.K. They never imagined it would take 15 years to finish.
But when they did, what they discovered was immensely satisfying: Luzon had been hiding the world’s highest concentration of unique mammal species.
A Northern Luzon Cloud Rat
The 15-year project was published in 2016 in the scientific journal Frontiers of Biogeography. In the course of their study, the American and Filipino scientists discovered that 52 of the 56 species of non-flying mammal species on the island are found nowhere else in the world. They also discovered 28 new species of mammals during the study.
Why Luzon Has So Many Unique Species
Geographically, Luzon has been isolated from the rest of Asia, allowing unique species of plants and animals to evolve.
“The current island of Luzon is surrounded by deep water and has not been connected to any other land area throughout its existence,” wrote the authors.
Among the unique mammals that Heaney and his team discovered are various species of cloud rats that dwell in trees in the mountains and several species of earthworm mice.
“Nearly all of the new species are restricted to a single mountain or mountain range, most of which had not been sampled previously,” wrote the authors of the study.
The Unique Mammals of Luzon
In the open-source journal, Heaney and his co-authors published photos of the unique mammals they discovered in Luzon. Most of them are tree-dwelling mice, shrew-rats, and worm-eating mice.
In the photos above, the authors described six new species: (A) Apomys musculus, (B) Rhynchomys soricoides, (C) Soricomys montanus, (D) Chrotomys whiteheadi, (E) Archboldomys maximus, and (F) Chrotomys silaceus.
Below are more photos of the other unique mammal species found in Luzon. They are (A) Carpomys melanurus, (B) Batomys granti, (C) Phloeomys pallidus, (D) Carpomys phaeurus, (E) Crateromys schadenbergi, and (F) Musseromys gulantang.
According to Eric Rickart, who is one of the authors of the study, some species are so unique they are found in just one mountain and nowhere else.
“That's more unique species on one mountain than in any country in continental Europe. The concentration of unique biodiversity in the Philippines is really staggering,” Rickart told Phys.org.