Leatheralgae
As populations of Ovalgae (Primophytorus ovalus) faced increasing predation pressures from the Ciliaurrg (Primoplanus lavancilia), individuals that had a thicker cell wall would survive for longer and have better chances to reproduce than their ancestors. This eventually led to the evolution of Primophytorus paellius.
7 millimeters wide 15 millimeters tall
Originated in Zone 31
The most distinguishing trait the Leatheralgae (Primophytorus paellius) has compared to its ancestors is their thicker cell walls which are more resistant to the Ciliaurrg when they attempt to feed on it, although they don't hold back a hungry Litorincolus maritimus if they come across it. Another, albeit minor, difference it has compared to its ancestors is their larger size which means a larger surface area to catch more sunlight for their photosynthesis. Their larger size and tougher cells walls do mean, however, that the Leatheralgae takes longer grow compared to their ancestors and as such can't spread as quickly. They still reproduce via budding with the new leather algae growing from the base of the parent polyph before splitting off and growing to full size in about 10 days (compared to the ancestral time of a week).