The morphological data (form of the oral jaws and size of the fish) were subjected to models which describe different types of phenotypical diversification: (1) high rate of diversification followed by a slow down (early burst), (2) constant/variable rate, and random diversification, (3) constant/variable rate, and diversification driven by diet or farming behavior. In the case of the Pomacentridae, the data does not at all fit with an early burst of phenotypical diversification. The model that best fits to morphological data was typically a constant speed of diversification driven by adaptation to diet. The farming behavior did not constrain the evolution of the morphological traits studied here but could influence others not dealt with in this work.

Conclusion.

The three trophic groups of damselfishes therefore appeared repeatedly during evolution. Each sub-family represents a similar ecological and phenotypical diversity. We are speaking about iterative adaptive radiation that leads to convergences.

Several phenomena can cause these convergences. For example, the regionalization of coral reefs by the apparition of physical barriers such as the Isthmus of Panama (due to the emergence of land), the formation of the Atlantic barrier (large stretch of ocean) or the appearance of volcanic islands made possible the colonization of new reefs. Competition in the natural environment and other functional constraints, linked for example with the processes necessary for the appearance of particular morphological traits, can also lead to such convergences.

In the context of macroevolution, that is to say on the long scales of geological periods, the iterative adaptive radiations towards a limited number of ecological niches is not rare. This reveals the importance of constraints in evolution. Thus, for example, the radiation of Anolis in the Caribbean islands follows a typical pattern of unique adaptive radiation when we consider the islands separately, but their evolution appears to be very convergent when we consider them as part of a whole.

Damselfishes illustrate one of the first demonstrated such iterative ecological radiations occuring in the oceans.