Hi, Kaichos Man.
Kaichos Man writes:
Although the presence of cecal valves and large heads in hatchlings and juveniles suggests a genetic basis for these differences, further studies investigating the potential role of phenotypic plasticity and/or maternal effects in the divergence between populations are needed...
Our old friend phenotypic plasticity. Made all the more likely by the fact that other lizards belonging to the same family possess cecal valves.
You really like phenotypic plasticity, don't you?
First, phenotypic plasticity is very unlikely to be able to explain why
hatchlings have cecal valves, and it seems odd that two islands with very similar environments would select for two very different phenotypes.
Maternal effects are most viable option here. But, the problem with that is that maternal effects cannot realistically explain the origin of the cecal valve in the first Pod Mrcaru lizard to develop one. So, you need
two changes: one to explain the first cecal valve in the population, and one to explain how it was passed to the offspring.
Second, you’re talking about a
family of lizards: the family Lacertidae (70 species). Lumping them all as one creationist kind might explain away the cecal valve by atavism, but then you’ve got some other things to explain: like two unique reproductive/development modes (parthenogenesis and vivipary); transparent, fused eyelids (genus
Ophisops); and air-pockets in the bones that allow gliding (genus
Holaspis).
If you feel that all of this is possible within a creationist kind, I guess I have no argument for you, except to ask you what the difference is (in terms of complexity) between air-pockets in the bones and a new muscular valve in the cecum.
-Bluejay (a.k.a. Mantis, Thylacosmilus)
Darwin loves you.