Nanoflagellates from coastal waters of southern Brazil (32°S)

Abstract

A taxonomic survey of nanoflagellates in the extreme southern Brazilian coastal waters of the Patos Lagoon estuary and adjacent coastal shelf was undertaken using transmission electron microscopy. A total of 44 species was recorded including 42 nanoflagellates, one scale-bearing amoeba and two species incertae sedis. Scale-bearing haptophytes predominated (27 species), followed by prasinophytes (7), chrysophytes (6), pedinellids (2), incertae sedis (2) and one scale-bearing amoeba. Most of the species (42) are new records for Brazilian marine waters. Among the haptophytes, Chrysochromulina was the most species-rich genus, occurring mainly in high salinity waters, and C. simplex was the most frequent species. Scales of undescribed Chrysochromulina species were observed and documented. Other haptophytes present were Prymnesium parvum and Phaeocystis scrobiculata. Five scale-bearing prasinophytes of the genus Pyramimonas were observed including the uncommon species P. longicauda, in addition to Micromonas pusilla and Nephroselmis pyriformis. Among the chrysophytes, the scale-bearing Paraphysomonas species (4) and the loricate Dinobryon belgica were recorded. The pedinellids (Apedinella radians and Parapedinella reticulata), the amoeba Rabdiophrys sp. and the incertae sedis (Meringosphaera mediterranea, Thaumatomastix sp.) are all scale-bearing protists. The 44 taxa (mostly scale-bearing flagellate species) identified and the finding of further undescribed Chrysochromulina species indicate that only a fraction of the species present in the region are known, and that an effort must be made to increase general knowledge of biodiversity in these southern waters.