In proximity of shelters, grazing by sea urchins plays a fundamental role in establishing and maintaining areas dominated by encrusting corallines. Much attention has been given to the effects of urchins on algal assemblages in shallow subtidal reefs, but few studies attempted to clarify the role played by encrusting coralline algae in this system. It has been shown that encrusting corallines a...

Ulva intestinalis and Ulva compressa are two bloom-forming morphologically-cryptic species of green seaweeds widely accepted as cosmopolitan in distribution. Previous studies have shown that these are two distinct species that exhibit great morphological plasticity with changing seawater salinity. Here we present a phylogeographic assessment of tubular Ulva that we considered belonging to this ...

Two new species of Hisonotus are described from the rio Paraná-Paraguay basin in Brazil. The most remarkable features of the new species are the odontodes forming longitudinally aligned rows (one odontode after the other, but not necessarily forming parallel series) on the head and trunk (vs. odontodes not forming longitudinally aligned rows), a pair of rostral plates at the tip of the snout (v...