Evolutionary novelty at range edges for coral reef organisms

A. F. Budd and J. M. Pandolfi recently concluded that edge zones and peripheral locations represent areas of evolutionary novelty where species fuse (hybridization) or split (peripatric or parapatric speciation) ("Evolutionary novelty is concentrated at the edge of coral species distributions," Reports, 18 June 2010, p. 1558). Their study was limited to corals in the Caribbean, but accumulating evidence from other recent studies indicates that this is a global pattern for coral reef organisms in general.\ud \ud Reef fishes are the most diverse vertebrate assemblages on earth, and the greatest number of hybrids occur at two isolated Indian Ocean locations that represent the range edge for both Indian and Pacific Ocean species (1). Similarly, in the Pacific Ocean, reef fish hybridization is concentrated at peripheral range-edge locations (2). For a variety of coral reef organisms, these peripheral locations also represent concentrations of genetically unique populations and centers of endemicity that are indicative of peripatric speciation (3–5).\ud \ud Coral reefs support the greatest diversity of marine life, but this diversity is under threat from escalating anthropogenic impacts. While conservation efforts aim to minimize biodiversity loss, protecting the processes that generate evolutionary novelty and biodiversity at peripheral range-edge locations should be a priority