This was a difficult species to identify, because the taxonomy of whiptail lizards in this precise area is so complex and confusing that a number of journal articles have been written about it. There are two sexually-reproducing species in this general area: A. tigris and A. sexlineata. Then there several "pattern classes" of unisexual (all-female) whiptails, with tricky visible and genetic differences. These unisexual groups elicit strong philosophical debates over the definition of species, so that can make it hard to see past the terminology differences in the literature. Also, which sets of whiptails are in which precise locales seems to have changed quite a bit over the past few decades, adding to the confusion.

In 1997 herpetologists James Walker, James Cordes, and Harry Taylor published a paper carefully examining the historic confusion and disagreements and the current status of the various populations. I tracked down a copy of this paper at the always-helpful Bibliomania! herpetological literature site. It turns out that Vogel Canyon is in the only area where two very similar-looking unisexual species coexist, A. tesselata and A. neotesselata. Fortunately, Walker, Cordes, and Taylor's paper includes a series of photographs of several specimens of each of the different types, along with very detailed descriptions. From these, I was able to confidently conclude that the two whiptails I photographed were A. tesselata, based mostly on the appearance of the vertebral and paravertebral stripes.

This large whiptail was obviously a campground veteran, and we saw it on multiple occasions over a couple of days. It was typically poking slowly around within about twenty feet of the picnic table at our campsite, and would race off as whiptails do when I went to get my camera. Our dogs thought this lizard was awesome entertainment. Eventually, after pointing out a nearby rattlesnake to me, it finally settled down for a few moments nearby and let me get a photo.

After spending many long minutes hoping that a nearby whiptail of a different species would sit still for a moment, I was very pleasantly surprised to come across this motionless fellow in the middle of the slot canyon trail.

Palo Duro Canyon State Park is one of the most beautiful state parks in the U.S., and home to a large variety of interesting herps. Most of whom were tucked well out of sight on the cold and windy days when we visited. In fact, these two whiptails were both hiding under rocks and too chilly to run off quickly the way whiptails are typically wont to do.