Sauropod Vertebra Picture of the Week

Here’s Easty dirty, with a dull-looking shell and a pretty serious ‘tub ring’ of hard-water stains around the crown of her carapace. This shot is a few years old, but she looks about the same now when she’s filthy. But here’s how she cleans up:

On Saturday I gave her a good soak in some warm distilled water and scrubbed her shell with a toothbrush. She shined up beautifully. I should have tried shooting a video, because the keratinous scutes on her shell are a bit translucent, and when full sunlight hits them they take on a depth and luster that I had not previously appreciated (heh).

I shot some reference images in the cardinal directions. If you need dorsal, lateral, or ventral views of an adult female Three-toed box turtle, Terrapene carolina triunguis, it’s your lucky day.

The lateral view is interesting, because you can clearly see the joint between the two halves of her plastron, both of which can raise like drawbridges to completely seal her behind an impenetrable wall of bone and keratin. You can also tell that her posterior plastron is gently convex, which is a female trait. As in many other turtles, male box turtles tend to have at least a gently concave posterior plastron, to help them stay on top of the females during mating.

And a ventral view, giving a good look at her plastron. Note her tiny, tiny tail, with the swelling for the vent just visible in the shadow of the plastron, about even with the edge of the carapace — that’s another female trait, whereas males have longer tails and a more distal vent for mating. You can also see yellow lines cutting across some of the scutes of her plastron — those are the outlines of her plastral bones showing through the overlying keratin. As in carapace, the keratinous scutes overlap the edges of the bones to form a sort of biological plywood. A lot of the growth lines have been worn off of her plastron, which is totally normal, but for the most part you can tell where the growth centers were originally located.

I also gave baby turtle a proper bath, with supervision. Baby box turtles can swim just fine, but if the water is inconveniently deep they can sometimes get flipped over on their backs, be unable to right themselves, and drown. She really did not like not having something to haul out on, so I put in the black jar lid you see in the photo. This particular pic is overexposed, which was a happy accident, because now you can see that the apparently dark and featureless areas of her shell and head are in fact very intricately patterned (compare to her dry photo at the top of this post). I’m really looking forward to seeing how her colors come in over the next few years.

And here’s her plastron. Baby turtle is a different subspecies from Easty — she’s a true Eastern box turtle, Terrapene carolina carolina — so she should have stronger patterns on both her carapace and her plastron when she gets bigger. Her head my also be more vibrantly colored, although Easty is no slouch in that department.

I put the two of them next to each other for a very closely-supervised comparison shot. I had been worried that Easty might have a go at baby turtle, but actually the opposite was true. The wee monster frankly terrorized Easty by nipping at her toes –and this was after eating two small slugs from the back yard — so I brought that experiment to a swift end, and got nipped on the finger for my trouble. I happened to be filming when baby turtle nipped Easty’s toe and my finger, and I will try to get those videos cleaned up and posted soon. Watch this space.

Click to embiggen. Trust me on this.

What I think of as our phylogenetically-extended nuclear family grew by one this week: we got a baby box turtle. We got her from a local hobbyist, who hatched her last summer. We haven’t named her yet, so for now she’s just Baby Tiny Turtle. Unlike Easty, who is the three-toed subspecies, Terrapene carolina triunguis, baby turtle is an Eastern box turtle sensu stricto, Terrapene carolina carolina, so she might end up being quite colorful (f’rinstance). She already has pretty complex patterns of lines and spots on the sides and top of her head and on her beak, but she’s so small that you can’t really see them unless you take a photo and zoom in.

(Aside: how do we know she’s a she and not a he? Personally I’d be lost, but the guy who hatched her says that at this age he can sex the babies correctly about 80% of the time, based on the position of the cloaca — it’s farther from the base of the tail in males. If she turns out to be a he, we’ll love him just the same, we’ll just keep him away from Easty.)

Speaking of her size, here’s an obligatory random-objects-for-scale photo. Baby turtle was closer in size to that US quarter when she hatched. You can tell that she’s grown a bit already because each scute on her shell has a outer rim of smooth new keratin. It’s a bit bittersweet, because I want her to grow big and strong and healthy, but I will miss the tiny turtle days when she is bigger. 

If you just want to die of cuteness, watch this video of her trying to eat some banana. She got it all down eventually, but with a little more adventure than either of us expected. If you turn up the volume, you can hear me talking her through it. That was entirely for my benefit, because I’m a big ole softy who talks to animals a lot, and she got through just fine on her own.

Full bulletins as events warrant.