Parablechnum shuariorum (Blechnaceae), a new fern species from the Cordillera del Cóndor

Parablechnum is the most diverse genus in the fern family Blechnaceae, with about 70 species, mainly from Central and South America, the Austropacific, and a few in Africa. Species delimitation in Parablechnum is challenging, and regional studies vary in species recognized. This genus is generally found in humid mid- to high-elevation forests, especially in the Andes. Ecuador is notable for its high species richness, particularly in the poorly explored Cordillera del Cóndor, a sub-Andean range with a distinctive geology contributing to high plant diversity and endemism. Since the early 2000s, botanical expeditions have revealed numerous endemic species, highlighting the region's significance. In 2006, an unusual Parablechnum species was collected in the Cordillera del Cóndor. Here, we describe it as a new species, Parablechnum shuariorum. It grows on sandstone cliffs along small rivers and can be distinguished by its fertile fronds, which are shorter than its sterile ones, and its densely scaly rachis. This species, endemic to the Cordillera del Cóndor, is found at elevations of 900–1,600 m. It is named after the Shuar people, whose lands include the collection sites. Preliminary conservation assessment suggests that P. shuariorum is endangered due to a limited area of occupancy and threats from human activities, such as mining.