We've seen many photos of gray and dusty-looking tortoises in the media over the last two days, as a result of the newly announced tortoise species. But check out this photo taken by biologist Cecil Schwalbe of the USGS Southwest Biological Science Center, one of our sister offices:
This is a tortoise from the Sonoran Desert -- the population now recognized as its own species, Gopherus morafkai. Dashes of sienna and orange sets it visually apart from typical photos of adult desert tortoises.
Kristin Berry, a tortoise biologist at the USGS Western Ecological Research Center and coauthor on the new tortoise species study, says that this coloration is a good example of the Morafka's tortoise. "This coloration becomes more distinct in Morafka's tortoises further south in the Sonoran Desert into Mexico," says Berry.
The explanation for the differences in coloration within the geographic range of Morafka's tortoises remains to be determined. Berry says some possibilities include genetics or possibly mineral uptake via diet.
For a comparison, have a look at an Agassiz's desert tortoise (Gopherus agassizii) -- the species which Morafka's desert tortoises were previously grouped with. This individual from Nevada shows the more uniform gray-beige we picture desert tortoises as having:
The photo is taken by Ken Nussear, another USGS tortoise specialist. Along with Todd Esque, Nussear, Berry, Schwalbe and other USGS scientists are conducting desert ecology research in America's southwest, providing independent scientific data to inform resource management offices in federal, military, state and local branches of government.
-- Ben Young Landis
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