Center for Biological Diversity

For Immediate Release, June 22, 2023


Michael Robinson, (575) 313-7017,

Lawsuit Seeks Endangered Species Protections for New Mexico Chipmunk, Six Texas Mussels

Biden Administration Moving Slowly to Protect Endangered Wildlife

SILVER CITY, N.M.— The Center for Biological Diversity filed suit today against the U.S. Fish and Wildlife Service for failing to finalize Endangered Species Act protections for the Peñasco least chipmunk, which lives in New Mexico, and six Texas mussel species suffering from habitat destruction and pollution.

The chipmunks have been reduced to a single population in southern New Mexico. The six mussels are the Texas fatmucket, Guadalupe fatmucket, Texas fawnsfoot, Texas pimpleback, Guadalupe orb and false spike.

“The cute Peñasco least chipmunks and these freshwater mussels that help clean our rivers could disappear forever because the Fish and Wildlife Service is moving too slowly,” said Michael Robinson, a senior conservation advocate at the Center. “We don’t expect the government to move with the speed of a chipmunk dashing up a tree, but with threats looming it’s long past time for these animals to get the strong protections of the Endangered Species Act.”

Following a previous Center lawsuit, the Service proposed protecting the six mussels by designating 1,977 river miles as critical habitat in August 2021 and protecting the Peñasco least chipmunk as endangered with 6,574 acres of critical habitat in September 2021. These proposals triggered one-year deadlines to finalize protections that have not been met.

The Biden administration has consistently missed the Act’s deadlines, which were established to ensure imperiled plants and animals receive timely protections. Thus far, the administration has protected just 11 species per year, compared to 36 species a year under the Obama administration and 65 each year under Clinton.

The Peñasco least chipmunk is imperiled by encroachment of trees into its meadows, desiccation of the meadows due to drought from global warming, unnaturally hot fires that could torch nearby spruce trees, ski area operations, sylvatic plague and feral hogs. The chipmunks originally lived throughout the Sacramento Mountains but lost habitat to logging and livestock grazing. Since 1966, they have only been found in the White Mountains, which are a western spur of the more expansive Sacramentos.

“The Peñasco least chipmunk is one of the most enchanting critters in our Land of Enchantment,” said Robinson. “As we enter another potentially devastating fire season that could threaten the chipmunk’s last home, it’s reckless to keep putting off protections these animals should’ve received many years ago.”

The six mussel species live in the Brazos, Colorado, Trinity and Guadalupe river basins. All face an array of threats, including water pollution, increased sedimentation of their habitats, and changes to the flows of rivers and streams due to diversions and development. Freshwater mussels improve water quality for people by filtering algae, bacteria and pollutants out of rivers.

“Central Texas is lucky to have abundant streams and rivers, but too much is being built and the water quality these mussels need to survive is degrading, driving them toward extinction,” said Robinson. “Mussels are survivors and help keep their aquatic homes clean, but they’re no match for unchecked runoff and pollution. They need Endangered Species Act protection now.”

In addition to the Peñasco least chipmunk and the six mussels, today’s lawsuit includes six other species unduly waiting for protection: the Mt. Rainier white-tailed ptarmigan, tall western penstemon, cactus ferruginous pygmy owl, Humboldt marten, pyramid pigtoe mussel, and four distinct populations of the foothill yellow-legged frog.


The Peñasco least chipmunk forages on insects, seeds, acorns, flowers, and gooseberries and strawberries that are succulent from snowmelt. It is one of 17 subspecies of least chipmunk, which are smaller than most other chipmunk species. The Sacramento Mountains are separated by hot lowlands from other high-elevation mountains, which led to the isolated evolution of subspecies like the Peñasco least chipmunk.

Once common in Texas, the false spike mussel was considered extinct until a single specimen was discovered in 2011 near Gonzales in the Guadalupe River. The species is now found in four populations: the Little River and some tributaries; the lower San Saba and Llano Rivers; and in the lower Guadalupe River. The Service proposed designating 328.2 river miles as protected habitat for the false spike along the Little, San Saba, Llano and Guadalupe rivers.

The Guadalupe fatmucket mussel was recently discovered to be a separate and distinct species from the Texas fatmucket. The mussel is currently found in just one population along 54 miles of the Guadalupe River basin in Kerr and Kendall counties. The Service proposed designating 54.1 river miles along the Guadalupe River, North Fork Guadalupe River and Johnson Creek as protected habitat.

The Guadalupe orb mussel, found in just two populations in the Guadalupe River basin, was also recently discovered to be its own species, separate from the Texas pimpleback, which now occurs only in the Colorado River basin. The Service proposed designating 294.5 river miles of critical habitat for the orb along the Lower and Upper Guadalupe rivers.

For the Texas pimpleback mussel, the Service proposed 494.7 river miles of protected habitat along the Concho, Upper and Lower Colorado, Upper and Lower San Saba and Llano rivers, as well as Elm Creek.

Texas fatmucket mussels also live only in the upper reaches of major tributaries within the Colorado River basin. The Service proposed designating 436 river miles as critical habitat for the Texas fatmucket along the San Saba, Llano and Pedernales rivers, and Cherokee, Elm and Onion creeks.

Texas fawnsfoot mussels are found in the lower reaches of the Colorado and Brazos rivers, and in the Trinity River. The Service proposed designating 917.2 river miles of critical habitat for the fawnsfoot along the Clear Fork Brazos, Upper Brazos, Lower Brazos, Little, Lower San Saba, Upper and Lower Colorado, East Fork Trinity and Trinity rivers.

RSTexas fatmucket
Photo of Texas fatmucket is available for use with appropriate credit. Please credit: USFWS. Image is available for media use.

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 1.7 million members and online activists dedicated to the protection of endangered species and wild places.

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