Elaphoglossum nidusoides (Dryopteridaceae), a New Species of Fern from Madagascar with an Unusual Phylogenetic Position in the Squamipedia Group

A fern from Madagascar is described and illustrated as a new species, Elaphoglossum nidusoides. We investigated its phylogenetic relationships within Elaphoglossum based on analyses of three non-coding plastid loci (trnL-trnF, rps4-trnS, atpB-rbcL) in 30 species representative of the diversity of the sections in the genus. Our results show that E. nidusoides belongs to section Squamipedia. This is an unexpected phylogenetic position because the new species has a short-creeping rhizome, phyllopodia, fronds glabrous or nearly so and more than 15 cm long, and lacks the characteristic peg-like aerophores on the rhizome. Nevertheless, its position as sister to another Malagasy species, E. marojejyense, is supported by the succulent fronds.