Three previously unknown species of forest mice have been officially identified in Mindoro, expanding the island’s already impressive roster of endemic mammals and marking a significant leap in our understanding of the region’s biodiversity.
Published in the scientific journal Zootaxa, the discovery confirms that Mindoro is home not to one, but four distinct species of Apomys, or Philippine forest mice. This revelation follows years of fieldwork led by the late Filipino biologist Danilo S. Balete between 2013 and 2017, whose team explored less-studied mountain regions including Mt. Abra de Ilog, Mt. Iglit-Baco National Park, Mt. Wood, and Mt. Alibug.
For decades, the only known endemic forest mouse on the island was A. gracilirostris, found in Mt. Halcon and known for its curved claws and earthworm diet. But Balete’s explorations uncovered three new species that differ in color, fur features, and claw structure—key morphological traits that drew the attention of mammalogists.
The process didn’t end in the field. For nearly a decade, Filipino and American scientists collaborated on genetic analysis and skull morphology, navigating the delays of the COVID-19 pandemic to ensure their findings were robust and conclusive. Their efforts paid off: the mice found on Mt. Abra de Ilog, Mt. Iglit-Baco, and Mt. Wood/Mt. Alibug were confirmed to be entirely new species.
These were named A. veluzi, A. crinitus, and A. minor, respectively. One of them, A. veluzi, honors the late National Museum mammalogist Maria Josefa “Sweepea” Veluz. “We take great pleasure in naming this species in honor of Maria Josefa ‘Sweepea’ Veluz … in recognition of her lifetime of contributions,” wrote the study authors.
Beyond taxonomic excitement, the discovery has deeper evolutionary implications. Genetic data suggests all four species descended from a single ancestral mouse that arrived from Luzon about 4.7 million years ago—likely rafting on debris during a storm. Isolated by Mindoro’s rugged mountains, these mice slowly diverged, leading to today’s distinct species.
This discovery doesn’t just increase the island’s tally of endemic mammals from nine to twelve—a remarkable 33% jump—it also makes Mindoro the smallest known island on Earth where mammal speciation has occurred within its borders. The next smallest is Mindanao, which is over ten times larger.
