One of the many fascinating aspects of evolution is the way that, when a new capability evolves, it can lead to a rapid radiation of new species as that capability opens access to new niches. For example, the evolution of flight in mammals and birds led to rapid radiation and speciation into all the bats and flying birds, respectively.
In the case of fish, the ability to bite rather than suck is a relatively recently evolved ability that led to a radiation of new species of fish that graze on surfaces such as the feeding method seen in very many different species of fish living on coral reefs, within the last 60 million years.
There may have been some biting done by teleosts before the end-Cretaceous, but our reconstructions suggest that it was very uncommon.
Graduate student
Department of Evolution and Ecology and Center for Population Biology
University of California Davis Davis, CA, USA.
As the article by in UCDavis News by Andy Fell explains: