Like other central Texas Eurycea salamanders, the San Marcos salamander is strictly aquatic and retains its external gills throughout life. The Texas blind salamander was listed as endangered on March 11, 1967 under the Endangered Species Preservation Act of 1966 (32 FR 4001). The species was subsequently incorporated into the list of species threatened with extinction on October 13, 1970 (35 FR 16047) after the passage of the Endangered Species Conservation Act of 1969, and was again confirmed as an endangered species on September 26, 1975 (40 FR 44412) after the Endangered Species Act of 1973 superseded the earlier endangered species statues. Threats to the species include groundwater overconsumption and contamination. We work with our partners to ensure that the springs and groundwater continue to provide clean and healthy freshwater to their microhabitats and important life history. We also collaborate on biological research to address the needs for the species.
Juveniles have been collected throughout the year, making it likely that this species is sexually active year-round. The species does not have reliable external characters that can be used to distinguish between the sexes. Captive female Texas blind salamanders are reported to become gravid at 1.5 to 2 years of age, but the presence of eggs does not necessarily result in the production of offspring.
The species continues to grow throughout their life span, which is estimated to be 10 years in the wild.
Adults have a large, broad head and reduced eyes and attain an average length of about 4.7 inches (12 centimeters). The limbs are slender and long with four toes on the forefeet and five toes on the hind feet.
The Texas blind salamander is a smooth, unpigmented, aquatic subterranean species.
The Texas blind salamander is adapted to the relatively constant temperatures of the water-filled subterranean caverns of the Edwards Aquifer in the San Marcos area.
A natural chamber or series of chambers in the earth or in the side of a hill or cliff. An irregular limestone region with sinkholes, underground streams and caverns.
A natural body of running water.
Observations indicate that this salamander moves through the aquifer by traveling along submerged ledges and may swim short distances before spreading its legs and settling to the bottom of the pool.
The Texas blind salamander is an active predator. It moves its head from side to side as it searches for food and hunts by sensing water pressure waves that are created by prey in the still underground waters where it lives. Prey items include amphipods, blind shrimp (Palaemonetes antrorum), daphnia, small snails and other invertebrates. Observations of captive individuals indicate that Texas blind salamanders feed indiscriminately on small aquatic organisms and do not appear to exhibit an appreciable degree of food selectivity.
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