Geez, Mark. . . so much to learn. I wasn't aware of different location species. I'll have to see if my friend Google can teach me the difference.
It is confusing. What used to be more obvious reasons for species and genus differentiation - obvious morphological differences and inability to produce fertile offspring has long been abandonded. Now it's mostly genetic differences. But then geologic isolation or behavioral isolation in that males selectively breed with only their specific selection still comes into play.This is what I learned:
Many taxonomic authorities now split what had been considered one species of turtle into two species. The southern species is named Actinemys pallida, or the southwestern pond turtle. Its range is southern California and Mexico. The northern species remains Actinemys marmorata, with a range of northern California northward. It is then usually referred to as the northwestern pond turtle.
So if I'm understanding correctly, it's only a regional thing. They look exactly the same. One would have no way of knowing what species the turtle was if, for instance, someone found it in Idaho. Because the turtle here in this thread is in SoCal, we are to assume it is the Southwestern Pond Turtle. Geez! Why? Why can't 'they' just leave the names alone? What was wrong with calling all of the Western Pond Turtles, or Actinemys marmorata?
I used to receive quite a few of them in the spring, people finding them in town. I know the females were nest location hunting and the males were female hunting, but, come on. . . Fresno? Where are they coming from in Fresno? The San Joaquin River is quite far from town, so is the Kings River.It is confusing. What used to be more obvious reasons for species and genus differentiation - obvious morphological differences and inability to produce fertile offspring has long been abandonded. Now it's mostly genetic differences. But then geologic isolation or behavioral isolation in that males selectively breed with only their specific selection still comes into play.
With the Pond Turtles - I see both species here in my general area. For the most part the northern species does tend to have a much lighter throat and chin while the southern species is uniformly dark and speckled - especially when older.
Canals and Ponding Basins. When I was in the Operating Heavy Equipment phase of my life we were required to dig "Ponding Basins" at EVERY housing tract we built. Both for street runoff to go and to "Reintroduce" ground water. Full O Turtles they are, always. Why? People put em there. Little johnny catches a turtle at Avocado Lake and takes it home. A week later parents say no way Jose and the turtle is in the Basin.I used to receive quite a few of them in the spring, people finding them in town. I know the females were nest location hunting and the males were female hunting, but, come on. . . Fresno? Where are they coming from in Fresno? The San Joaquin River is quite far from town, so is the Kings River.
It was my experience with them ( I was allowed to keep several that were 'disabled' and would die if released) that they were able to eat out of water.The southern species is fairly common in my area. I found one in Acton a few years back, and Acton is only about 10-15 miles from Palmdale/Lancaster where that shelter is. Oddly, they often occur where there is no obvious water, and appear to survive with only season ponds that form in the rain. I would guess they aestivate underground during our hot summers?
The one I found was just walking around on dry ground under some dappled shade from trees, and there was no body of water anywhere near there. I searched for a few hundreds yards in each direction and even put a drone up to look for water, and I found nothing.