Discovery of a new species of Coendou (Rodentia: Erethizontidae) within the hyper-diverse mammalian community of Sangay National Park in Ecuador

The tropical Andes harbor high levels of undocumented biodiversity, often hidden within complex ecological communities that require sustained sampling efforts to be fully characterized. Here, we describe a new species of porcupine of the genus Coendou , discovered within the hyper-diverse mammalian assemblage of Sangay National Park (Sangay) in Ecuador. The description is based on an adult specimen collected at 2,400 m on the eastern slopes of the Andes. Phylogenetic analyses using mitochondrial Cytochrome b (Cytb) place the new species as a distinct lineage within the Clade B ( sensu (Voss, Hubbard & Jansa, 2013)), showing significant genetic divergence (p-distance > 6.0%) from its closest congeners, C. speratus, C. nycthemera and C. bicolor . Morphologically, Coendou sangay sp. nov. is diagnosed by its medium body size, a remarkably short tail (approx. 26% of head-and-body length), tricolored bristle-quills with brownish-red tips, and distinct cranial features, including a long nasal bone and a mesopterygoid fossa that does not reach the second upper molar. This discovery is contextualized within a comprehensive mammalian inventory of Sangay, compiled over 15 years of fieldwork. Despite an intensive sampling effort totaling 12,800 trap-nights and 2,400 camera-trap days, only a single specimen was obtained, highlighting the species status as a rare, canopy-dwelling specialist. We report 170 mammal species within the park, including 18 endemic and 35 threatened taxa. With a richness of 0.03 species per km 2 , Sangay ranks as the most mammal-diverse protected area per unit area in the Tropics. Our results demonstrate that intensive, long-term inventories are essential for identifying cryptic arboreal lineages that remain “invisible” to traditional terrestrial sampling. Finally, we emphasize the urgent need for conservation policies, including the strengthening of biological corridors and the limitation on road and mining expansion, to safeguard this high-elevation biodiversity hotspot.