Mexican fawnsfoot occur in medium to large rivers, in or adjacent to riffle and run habitats, as well as in stream bank habitats. Small-grained material, like clay, silt or sand, gathers in crevices and provides suitable habitat and great flow refuges from the large flood events that occur regularly. Mexican fawnsfoot use flow refuges to avoid being swept away as large volumes of water move through the system, as there is relatively little particle movement in these refuges, even during flooding.

Like all other freshwater mussel species, Mexican fawnsfoot are filter feeders that feed and survive on organic particulate matter, bacteria and algae which they filter from the water column. Juvenile mussels live in the sediment and most likely feed interstitially rather than from the water column, meaning that they use the relatively large muscular foot to sweep organic and inorganic particles that they find among the substrate and bring into the shell opening.

The shell of the Mexican fawnsfoot is elongated and laterally inflated, with a narrow and elevated beak. The beak contains a shallow cavity with short and lateral teeth.

Measurements
Length: Up to 45 mm have been collected

The shell of the Mexican fawnsfoot is yellow-green to gray-green in color with darker chevron like markings.

There is a lot that we don't know about the life cycle of the Mexican fawnsfoot. It is believed that males release sperm into the water column, which is taken in by the female fertilizing her eggs. The developing larvae are held by the female until they mature and are ready for release. The mature larvae, called glochidia, may be released in proximity to a fish host and attach to the host’s gills or fins. It is believed that some Mexican fawnsfoot may self-sacrifice and release mature glochidia immediately preceding being predated upon by the species host fish. Glochidia that fail to attach to a suitable host or attach to the wrong location will die. Attached glochidia encyst, or implant into the host, and develop into juvenile mussels over a period of weeks or months. Once fully developed, the juveniles excyst, or break away, from the host and settle on the stream bottom leaving their host relatively unharmed. It is also possible that some females from this species do not self-sacrifice, and instead use secondary reproductive strategies, like broadcast of free glochidia or cryptic lures for glochidia dispersal.

While the life span of the Mexican fawnsfoot is not yet known, similar species of mussels have a maximum of eight to 18 years.

The primary host fishes for the Mexican fawnsfoot are unknown. However, based on other Truncilla spp., it is likely freshwater drum.