Typhoctes peculiaris ?
I wonder if this subject had wings at one time because there seems to be evidence of tegula. Although I do not remember having made a mental note of its approximate size, I think that it was less than 10 mm.
Found in semi-arid South Texas. It was a very active small subject, making it difficult to photograph. It looked like an interesting ant because it ran around with its abdomen held up at an angle.
Sorry about the poor images. Thank you.