Lifeon earth is astonishingly diverse, and how diversity varies geographically,among different taxonomic groups and through time, is intriguing. There are fewstudies that investigated which evolutionary processes might explain currentmacroalgae distribution patterns, or which traits might have been involved intheir evolutionary success. These studies have mainly focused on thermal affinities,as it has been suggested that temperature is the most relevant abiotic factorin survival and distribution of macroalgae. The main goal of this project wasto test macroevolutionary hypotheses of trait evolution in macroalgae acrossgeological timescales. The focus was drawn to two distinct taxonomic groups:the green algal genus Codium, andthe red algal order Nemaliales. The first is a highly diverse genus, andpresents a variety of distinct morphologies. The latter comprises bothcalcified and uncalcified taxa.
Both groups are distributed from cold-temperatewaters to tropical regions. This latitudinal distribution range makes themgreat models to investigate evolutionary dynamics over thermal gradients. Theresults corroborate the strong influence of temperature in macroalgaeevolutionary history, but they also show that other traits may play anevolutionary role. In the genus Codium itwas shown that taxa with higher temperature affinities present higherdiversification rates. However, morphology was also correlated with theserates. In the order Nemaliales a correlation was found between the uncalcifiedderived character, and the exploration of wider climatic niches during itsradiation. Projects like this one allow us to test hypotheses about theevolutionary past, yielding exciting insights into the hidden history of theevolution of life.