Mobile Studio

I'm fairly certain that this scorpion is Smeringurus aridus. In appearance, this particular example was noticeably large, being by my approximation slightly larger than most adult male mesaensis I've encountered. When I first discovered this individual, it was extending its pedipalps from a shallow burrow. I carefully excavated the surrounding area and gently removed the scorpion from its burrow to examine in more detail.

The weak scalloping of the fingers very closely resembled illustrations depicting S aridus. There appear to be 26 denticles in the sixth row of the fixed finger. I placed plastic wrap over the scorpion and took the included picture of its genital papillae. It's not quite as pronounced as I would have thought, but appears almost identical to the papillae of the Smeringurus vachoni immanis that I came across later in the night, and have also included a picture of. Although not particularly relevant, I also included a single image of the genital operculum of a Smeringurus mesaensis male just for comparison's sake. If you are not certain which one is which, I watermarked the lower left corner of those images with the species name being depicted.

I was feeling fairly fancy that night and decided to bust out my new-fangled mobile photo studio. If you knew what it was actually made of you'd probably have a good laugh at how ridiculous it is, but it was such a pain in the ass to set up that I took a lot of pictures to offset the effort. I hope you'll excuse me for it, lol. This was the only adult male I found that night, so that is why it received special treatment in particular. Now that I have reviewed the pictures produced from my mobile "photo studio" ($4 home depot drop cloth) and I'm happy with the results, I will now keep it set up in my trunk for future use.

I ended up in this particular area after being swarmed by some kind of cicada-like insect at the original spot. I'm obviously not afraid of bugs, but spending half an hour with hundreds of tiny insects constantly crawling all over my skin took its toll on me, not to mention I couldn't even take any photos because the scorpions were chased off by the horde constantly flying into them. I drove around for a while and took a wrong turn and got lost. I eventually ended up in this location where the aridus was found. I can confirm the location is accurate because because I had used GPS to pin where I parked my Jeep. An interesting fact about this locale in particular is that a majority of the surrounding hills are largely featureless and devoid of vegetation. There are little to no rocks or debris for the scorpions to hide amongst, and so the hillside was littered with active burrows. The soil was very soft, which likely accounted for the high density of these burrows. The visibility was amazing, and I found an absolute treasure-trove of other Smeringurus aridus of different sexes and instars, as well as a few Serradigitus joshuaensis hiding in the cracks and pits in the hillside. It is worth noting that although the initial trail which leads into Smoke Tree Wash can be driven on normally, it quickly becomes a very deeply sandy trail which is traversable only by a 4WD vehicle. It is however relatively close to the trailhead, so I imagine those of us without 4x4 could easily walk to this location. It would have added to the mystique if I had found aridus somewhere deep in the wilderness, but I think it's better this way, don't you think? If you're looking for aridus and found any of the info here to be useful, please leave a comment on this post, I would really appreciate it!

I gave my trunk photo studio another run. It's kind of a pain to use, so I only used to take white backdrop pictures of three P luteolus, three P borregoensis borregoensis and a single S mesaensis. I'll post all of those later once I'm not feeling so brain damaged from pulling that all-nighter yesterday. I do have to say that the highlights are completely out of control in these images, but I have a plan for whenever I have to take pictures of similarly shinny scorpions in the future.

This scorpion is a large female, and the largest of the night. There was such a ludicrous number of S mesaensis that I was starting to think I'd never find any Paruroctonus. These scorpions are way smaller than I had anticipated they'd be, but the moment I saw this individual under my flashlight I automatically knew that it wasn't mesaensis. Later in the night I found two adult males featuring prominent scalloping so I knew I had luteolus without needing to confirm it otherwise. These borregoensis group scorpions are now one of my absolute favorites. They are so incredibly docile that I simply picked them up with my hands like I would Catalinia or Superdons with no fear of being stung. At a certain point I began flipping them over to look at their pectines without even using the plastic trick. It really made taking pictures of them totally stress free.

I put a pin on my GPS to mark the scorpion's original location and returned it there once I was done taking pictures.

This scorpion was very poorly behaved and kept trying to run away. I couldn't get it to stay on the translucent stand, but eventually it became hypnotized by the flash and remained still. Thankfully, I had some nice frontal shots which show the internal macrosetae on the patella, and what I'm sure is a prominent MSM. The finger scalloping isn't very impressive, but it's there anyway.
@prakrit

I'm basing the subspecies designation off of a particular locality in Haradon's 1984 paper. Borregoensis is a very goofy and hairy little hairy scorpion. C'mon just look at that face.

Getting a shot of such a pale scorpion without overexposing its thin translucent legs was nearly impossible. Some of the setae were nuked out of existence. Only very few of my pictures were actually salvageable.