Hiding in plain sight: Koshicola spirodelophila gen. et sp. nov. (Chaetopeltidales, Chlorophyceae), a novel green alga associated with the aquatic angiosperm Spirodela polyrhiza

A resurgence of green algal taxonomy over the last decade has resulted from investigations of unusual and previously poorly sampled habitats (e.g., Neustupa et al., 2011 ; Ramos et al., 2015 ; Caisova et al., 2015 ), from the application of molecular methods to resolve cryptic taxa (e.g., Fucikova et al., 2014a ), and through taxonomic clarifi cation of known species (e.g., Sanchez-Puerta et al., 2006 ; Caisova et al., 2011 ; Hegewald et al., 2013 ; Skaloud et al., 2013b ). Even aquatic habitats, historically more commonly sampled for algae, have yielded new species of green algae ( Perez et al., 2014 ). Together, these recent studies illustrate that our understanding of green algal diversity is incomplete and that new, and even deeply diverging, phylogenetic lineages are yet to be discovered. Microscopic green algae frequently colonize other algae and emerged and submersed embryophytes. Two phylogenetically distinct genera of microscopic green algae known to be endophytic on freshwater aquatic plants were highlighted in a recent morphological and molecular systematic investigation by Skaloud et al. (2013a) : Chlorochytrium Cohn (Chlamydomonadales, Chlorophyceae), and Scotinosphaera Klebs (Scotinosphaerales, Ulvophyceae). A lineage of recently investigated green epiphytes comprises the genera Chaetopeltis Berthold and Pseudulvella Wille ( Sanchez-Puerta et al., 1 Manuscript received: 13 November 2015; revision accepted: 4 March 2016. 2 Department of Biology, Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan; and 3 Department of Ecology and Evolutionary Biology, University of Connecticut, 75 North Eagleville Road, Storrs, Connecticut 06269 USA 4 Author for correspondence (e-mail: louise.lewis@uconn.edu) doi:10.3732/ajb.1500481 Hiding in plain sight: Koshicola spirodelophila gen. et sp. nov. (Chaetopeltidales, Chlorophyceae), a novel green alga associated with the aquatic angiosperm Spirodela polyrhiza 1