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Abstract Parablechnumis 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 inParablechnumis 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 unusualParablechnumspecies 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 thatP. shuariorumis endangered due to a limited area of occupancy and threats from human activities, such as mining. 

The name Parablechnum christii (C. Chr.) Gasper & Salino has been applied to a small species with few pairs of short pinnae that is endemic to Costa Rica and Panama. After reviewing type material of this name, we conclude that it has been misapplied and is, in fact, a synonym of P. falciforme (Liebm.) Gasper & Salino, an older name. Because the specimens previously identified as P. christii lack a name, we propose P. talamancanum S. Molino & R. C. Moran for these plants. The species is endemic to the mountains of Costa Rica and Panama, from 1200 to 3350 m. 

Abstract PremiseThe historical biogeography of ferns is typically expected to be dominated by long‐distance dispersal due to their minuscule spores. However, few studies have inferred the historical biogeography of a large and widely distributed group of ferns to test this hypothesis. Our aims were to determine the extent to which long‐distance dispersal vs. vicariance have shaped the history of the fern family Blechnaceae, to explore ecological correlates of dispersal and diversification, and to determine whether these patterns differ between the northern and southern hemispheres. MethodsWe used sequence data for three chloroplast loci to infer a time‐calibrated phylogeny for 154 of 265 species of Blechnaceae, including representatives of all genera in the family. This tree was used to conduct ancestral range reconstruction and stochastic character mapping, estimate diversification rates, and identify ecological correlates of diversification. ResultsBlechnaceae originated in Eurasia and began diversifying in the late Cretaceous. A lineage comprising most extant diversity diversified principally in the austral Pacific region around the Paleocene–Eocene Thermal Maximum. Land connections that existed near the poles during periods of warm climates likely facilitated migration of several lineages, with subsequent climate‐mediated vicariance shaping current distributions. Long‐distance dispersal is frequent and asymmetrical, with New Zealand/Pacific Islands, Australia, and tropical America being major source areas. ConclusionsAncient vicariance and extensive long‐distance dispersal have shaped the history of Blechnaceae in both the northern and southern hemispheres. The exceptional diversity in austral regions appears to reflect rapid speciation in these areas; mechanisms underlying this evolutionary success remain uncertain.