LAUSR

ABSTRACT The Laguna Madre-Tamaulipas is the world’s largest hypersaline lagoon and is equally located in south Texas, USA, and Tamaulipas, Mexico. Over 40% of its American surface area is covered by wind-tidal sand flats containing cyanobacteria as the major autotrophic component of the microbial community. A recent laboratory examination of these microbial mats revealed the presence of a boring, filamentous cyanobacterium which, in culture, ‘drilled’ through an agar substrate. The observed clockwise/counterclockwise rotation, gliding, and boring ability of the filaments was atypical for any known cyanobacterium. The isolate from Laguna Madre produces nine toxins that were originally described from both marine and freshwater habitats. Presence of a diverse array of bioactive metabolites in our unialgal culture agrees with earlier work demonstrating diverse toxin production by marine cyanobacteria. Initial comparison of this new taxon with its polyphasically closest genus, Oxynema, showed several morphological, physiological, and phylogenetic differences, warranting establishment of a new family Laspinemaceae, containing Perforafilum tunnelli gen. & sp. nov.