Evolutionary history of turtles

Researchers examine the history of turtle diversification. As one of the major vertebrate lineages, turtles are ancient, have few extant species, and are highly endangered. Robert Thomson and colleagues investigated the evolutionary history of turtles to identify factors that shaped their diversity through time. The authors collected DNA samples from 591 individual turtles representing 80% of all extant species, estimated their phylogeny, and measured rates of diversification. Species diversification in turtles was associated with historical climate shifts, with most species arising within the last 50 million years; this time-frame coincides with declines in global sea level that reshaped and exposed new continental margins. As new coastal habitats emerged and were independently colonized by several turtle lineages, turtles experienced a three-fold increase in their speciation rate, generating most of the current turtle diversity. The findings suggest that habitats exposed along continental margins were once critical in supporting turtle speciation and remain key to the current persistence of turtles. Furthermore, the loss and degradation of such habitats due to accelerated climate change may also threaten the persistence of other species across the globe, according to the authors.

###

Article #20-12215: "A global phylogeny of turtles reveals a burst of climate-associated diversification on continental margins," by Robert C. Thomson, Phillip Q. Spinks, and H. Bradley Shaffer.

MEDIA CONTACT: Robert C. Thomson, University of Hawaii at Manoa, Honolulu, HI; tel: 808-347-1666; email: <thomsonr@hawaii.edu>