What are the Crustaceans in caliche ponds in the hill country of Texas?

Answer 1

They go by a few different names, but they are all the same critter: crayfish, craw-dad, craw-fish.

Answer 2

Assuming that the caliche ponds are temporary, drying up part of the year, there are several
kinds of crustaceans that would be found in them.
These include: fairy shrimp (Anostraca), clam
shrimp (Conchostraca), tadpole shrimp (Notostraca) and some smaller ones such as
seed shrimp (Ostracoda) and copepods. Crayfish
are possible, but unlikely.

Answer 3

small, little clamlike creatures.