Posted by Kromey at 9:41pm Sep 7 '10Here we have the Australian yellow-bellied three-toed skink.
Nothing too special, except that if you look closely, you can spot a few light orbs in the body -- those, folks, are live embryos.
This lizard species is presently evolving into one that gives live birth.
That's actually not that unusual -- there are some 20% of all snake and lizard species today that give birth to live young, and fossil records show nearly 100 reptile species independently evolving to give live birth. What makes this skink unique is that the species is currently in transition: members of the same species in warmer coastal lowlands are still laying eggs, but almost all of those in the colder highlands are giving live birth!
This is a rare opportunity to study how the transition from laying eggs to giving live birth can actually happen -- only two other known species (another skink, and a European lizard) use both methods of reproduction.
The really shocking part? The transition from laying eggs to live birth is a lot simpler than previously thought.
Nothing too special, except that if you look closely, you can spot a few light orbs in the body -- those, folks, are live embryos.
This lizard species is presently evolving into one that gives live birth.
That's actually not that unusual -- there are some 20% of all snake and lizard species today that give birth to live young, and fossil records show nearly 100 reptile species independently evolving to give live birth. What makes this skink unique is that the species is currently in transition: members of the same species in warmer coastal lowlands are still laying eggs, but almost all of those in the colder highlands are giving live birth!
This is a rare opportunity to study how the transition from laying eggs to giving live birth can actually happen -- only two other known species (another skink, and a European lizard) use both methods of reproduction.
The really shocking part? The transition from laying eggs to live birth is a lot simpler than previously thought.
Evolution caught in the act! - Kromey