Texas Fawnsfoot (Truncilla macrodon)- Freshwater mussel

5% of the profits support Endangered & Threatened Species.

Proposed federally endangered mussel

"If you put two of these mussels side by side, they oddly resemble the hooves of a white-tailed deer."

©Juliet Whitsett |Social: @juliet_whitsett_art

Purchase prints HERE



"Texas Fawnsfoot is a freshwater mussel species found only in the Colorado, Brazos and Trinity River basins of Texas. The health of the more than 50 mussel species of Texas, including the Texas Fawnfoot, are of critical importance to maintaining the integrity and function of aquatic ecosystems for other fish and wildlife species and the people of Texas. This is because freshwater mussels help to maintain clean and clear water, cycle nutrients, and provide benefits and balance for other aquatic life. This species is a state-listed threatened species and is currently under review for receiving status as a federally Threatened species under the Endangered Species Act. Researchers and conservation professionals within Texas and across the southeast are working diligently to learn more about this species’ life cycle, habitat requirements, and sensitivity to environmental conditions so that we can work to protect existing populations and restore those that have declined over time."

Information generously provided by:

Kaelyn Fogelman – Assistant Professor of Ecophysiology, Troy University Department of
Biological and Environmental Sciences


various sized mussel shells on biologist’s hand above water.

Image source: https://www.fws.gov/media/texas-fawnsfoot


Hannah Adkins – PhD Student in the Crustacean and Molluscan Ecology Lab, Auburn University
School of Fisheries, Aquaculture, and Aquatic Sciences

At Auburn University, Hannah Adkins and other members of Dr. Jim Stoeckel’s Crustacean and
Molluscan Ecology Lab, are working to assess the sublethal effects of thermal stress on Texas
Fawnsfoot. For conservation, it’s important to know how mussel species are affected
sublethally by temperature in addition to what the lethal tolerance limits are – as mussels may
experience effects that harm populations well before they experience death. Specifically,
Hannah is measuring the relationship between temperature and metaboic rate (i.e. energy
costs), and feeding rate (energy gain) to evaluate Texas Fawnsfoot’s Scope for Growth (SFG).
We can subtract energy cost from energy gains to estimate how SFG changes with increasing
temperature. A positive SFG indicates extra energy available for growth and reproduction
whereas a negative SFG indicates that they don’t have enough energy – requiring them to begin
using internal energy stores. Temperatures with a positive SFG are good for growth and
reproduction, and temperatures with zero or negative SFG tell us where this species is thermally
stressed and will have little to no energy left for growth and reproduction. Once we further
understand what temperatures this species needs to have healthy, growing populations we can
work together with conservation and management professionals in Texas to make sure this
species native range and habitat are meeting these tolerance requirements that have been


Truncilla macrodon range map

Map Image © Copyright Texas A&M NRI


With roughly ~150 threatened and ~75 endangered species in Texas alone, artist Juliet Whitsett has been learning about and sharing the importance of biodiversity. Through the process of developing species-derived color palettes sampled from crowd-sourced images, Whitsett creates original artworks that draw inspiration from these distinctive palettes, as well as the lives and forms of the rarest and most at-risk. Collaborating closely with scientists and leading experts, she continually seeks to deepen her understanding of these species, contributing to both environmental education and conservation.



Additional Links:
Fish and Wildlife species profile: https://www.fws.gov/species/texas-fawnsfoot-trunc...

Shows timeline of petitions for listing – Texas Fawnsfoot was proposed for listing as Threatened under
the Endangered Species Act in 2021, along with proposed designation of critical habitat
Includes species distribution map

Fish and Wildlife article on conservation of San Saba River mussels: https://www.fws.gov/story/2021-

Comprehensive popular news article on freshwater mussels and good figures on imperilment
rates: https://knowablemagazine.org/article/living-world...
Brazos River Authority profile on TX Fawnsfoot (this is who Auburn is working with/ for on their project/
who will use the data we are collecting):