<abstract abstract-type="main"> <title>Summary</title> <p>A new subgenus, <italic>Microsquama</italic>, is proposed for <italic>Nephroselmis pyriformis</italic> based on its phylogenetic position and some ultrastructural characters, such as the absence of large stellate scales. Other species of the genus are classified in the subgenus <italic>Nephroselmis</italic>.</p> </abstract>