Texas Fawnsfoot. The Field Guide to Texas Freshwater Mussels (Xxxxxxx, 2014) describes the Texas Fawnsfoot as summarized below: A rare, elongate oval shaped mussel with adults reaching up to 60 mm in length. They have pseudocardinal (pseudo = false) teeth (two left, one right), 2 lateral teeth, and are generally unsculptured with an exterior color of dull green, tan, yellowish brown, or xxxxxxx-xxxxx with broken rays. The nacre (inner shell layer) is white to bluish-white. Until recently, the current range of the Texas Fawnsfoot was thought to be limited to the Brazos and Colorado river basins (Xxxxxxx, 2014). Though they historically occurred in the Trinity River Basin, they were presumed extirpated (Xxxxxxx et al., 1996). Recent genetic work on mussels previously classified as Fawnsfoot (Truncilla donaciformis) from the Middle and Lower East Fork of the Trinity River (Xxxxxxxx, 2017) indicate that those mussels are actually Texas Fawnsfoot (Inoue et al., 2018). This 2019 range expansion for the Texas Fawnsfoot resulted in the Trinity River Basin (previously considered only as part of the USFWS’ status review for East Texas Mussels) now also being affected by the status review for the Central Texas Mussels. In addition to the Texas Fawnsfoot, the Central Texas Mussels Species Status Assessment (SSA) includes five additional species of mussels (which are not thought to co-occur with the Eastern Texas mussels) currently under consideration by the USFWS for ESA protections. The Texas Fawnsfoot is a rare species (Xxxxxxxx et al., 2010; Xxxxxxxxx et al., 2019) and little is known about its life history. In other river basins, Texas Fawnsfoot prefers deep bank habitats but they are also found in backwaters and on the upstream end of point bars (Xxxxxxxx et al., 2014). Conversely, in the Trinity River Basin, Texas Fawnsfoot are primarily found in xxxxxx habitats (Xxxxxxxx et al, 2017). Texas Fawnsfoot are known to bury in up to 15-20 cm of sand, or in a mixture of sand and gravel, near the shore in riffles (Xxxxxxxxx et al., 2019), making it difficult to locate using tactile sampling methods. The presumed host fish for this species is the Freshwater Drum (Aplodinotus grunniens)(Xxxx, 2012; Xxxxxxx, 2014).
