MOLECULAR PHYLOGENY OF ANTARCTIC PRASIOLA (PRASIOLALES, TREBOUXIOPHYCEAE) REVEALS EXTENSIVE CRYPTIC DIVERSITY(1)

Area of Science:

• Algology and Phycology
• Molecular Systematics
• Antarctic Marine Biology

Background:

• Prasiola species are key primary producers in Antarctic ecosystems.
• Previous taxonomic classifications relied on morphology, limiting understanding due to cryptic diversity.
• Scarcity of molecular data hindered accurate phylogenetic placement of Antarctic Prasiola.

Purpose of the Study:

• To resolve the taxonomic uncertainty and phylogenetic position of Antarctic Prasiola.
• To identify cryptic species within the Prasiola genus in Antarctica using molecular markers.
• To reassess existing records of Prasiola crispa in Antarctica.

Main Methods:

• DNA sequencing of chloroplast genes (rbcL and psaB) from Antarctic specimens.
• Comparison of obtained sequences with type specimens and existing databases.
• Phylogenetic analyses to determine species relationships.

Main Results:

• Three cryptic species were identified: genuine Prasiola crispa, resurrected Prasiola antarctica, and a new species, Prasiola glacialis sp. nov.
• Prasiola crispa was confirmed in Maritime and Continental Antarctica.
• Prasiola antarctica and P. glacialis were identified in distinct Antarctic regions and Southern Ocean areas.

Conclusions:

• The study uncovers significant cryptic diversity within Antarctic Prasiola, challenging previous identifications.
• A taxonomic revision of Antarctic Prasiola records is essential.
• Marine Prasiola species form a monophyletic group, while freshwater species exhibit greater phylogenetic diversity.