Central American burrowers out of Belize and southern Mexico, small to moderate, and with a blue cast on some species that is subtle rather than dramatic.
Genuinely fossorial. Give one depth and it will build and stay in it, and casual observers will conclude the enclosure is empty. Not defensive so much as absent.
The genus is under-collected and under-bred, so supply comes from a handful of European breeders in irregular batches. Prices hold steady through the gaps rather than spiking, which suggests a small, stable pool of buyers rather than any speculative interest. That is a healthier market than a hype curve, and it means there is rarely a wrong time to buy.