Zopherus nodulosus haldemani - this subspecies is endemic to TX (possibly ranging into MX), and while not uncommon in the areas in which it occurs, I myself have only ever seen a few of them here in North TX, and it seems that very little is known of their biology. They're in the family Zopheridae, which is part of the superfamily Tenebrionoidea.
https://www.texasento.net/Ironclad.html
https://bugguide.net/node/view/54853