Abstract
The saccoderm desmids Spirotaenia endospira and Spirotaenia closteridia, species thus far unknown from the southern hemisphere, are described from Serra da Jiboia, northeast Brazil. Spirotaenia filiformis sp. nov. was also recorded in this area and described as new species. In the present study, Spirotaenia species were collected from Alcantarea nahoumii tanks, an endangered Brazilian bromeliad species. The newly described S. filiformis is primarily characterized by a high cell length to breadth ratio (17–31) and a parietal chloroplast with 3.5–8.5 turns. All three species were discussed for possible affiliations with other Spirotaenia taxa. From this study, the knowledge on genus Spirotaenia in Brazil has been expanded to four species currently confirmed: Spirotaenia closteridia, S. condensata, S. endospira, and S. filiformis.