Pirula versus

Darienko, Tatyana & Pröschold, Thomas, 2017, Toward a monograph of non-marine Ulvophyceae using an integrative approach (Molecular phylogeny and systematics of terrestrial Ulvophyceae II.), Phytotaxa 324 (1), pp. 1-41 : 17

Pirula versus Heterogonium

The genus Pirula with its type species P. gemmata was originally described by Snow (1911, 1912). She observed this species from samples collected in Switzerland and Guatemala. Printz (1927) transferred another species to Pirula , which was described by Dangeard (1911,1912) as Heterogonium salinum from a marine habitat. Pascher (1939, 1944) synonymized the type species of Pirula with Heterococcus , a xanthophycean genus, based on the lack of a pyrenoid and the presence of several chloroplasts per cell. The taxonomic change of Heterogonium salinum to Pirula is not supported. This transfer was also questioned by Gayral and Lepailleur (1969) because of differences in morphology and ecology (freshwater versus marine). However, the generic name Heterogonium is already preoccupied for a tropical fern species by Presl (1851). Therefore, for the species found by Dangeard, the new generic name Halofilum is proposed (see below). In addition, several strains originally assigned as Dilabifilum sp. are closely related to this species and represent new species, which will be erected below.