5.1 Endangered Species
Krejca and Reddell (2019, Table 2 therein) list 66 threatened, endangered, and petitioned spring and cave species in the state of Texas, which are either state-listed, federally-listed, or have been petitioned for listing as endangered. Table 4 lists the nine federally-listed endangered species that live in the Edwards Aquifer or its major springs. Of these, the Peck’s Cave amphipod, the Comal Springs dryopid beetle, and the Texas and Austin blind salamanders are stygobites that are living in the aquifer. The others live primarily in spring discharge systems. The EAA (2020) is also considering three additional species that have been petitioned for endangered species status in its habitat conservation plan, the Edwards Aquifer diving beetle, the Comal Springs salamander, and the Texas troglobitic water slater. The EAA has established two refugia for the breeding and maintenance of endangered species should re-introduction to the spring systems be necessary.
Table 4 – Federally-listed endangered species in the Edwards Aquifer.
| Common name | Species name | Group |
| Texas wild rice | Zinzania texana | plant |
| Peck’s Cave amphipod | Stygobromus pecki | invertebrate |
| Comal Springs riffle beetle | Hetereimus comalensis | invertebrate |
| Comal Springs dryopid beetle | Stygoparnus comalensis | invertebrate |
| Fountain darter | Etheostoma fonticola | fish |
| San Marcos gambusia | Gambusia georgei | fish |
| Texas blind salamander | Eurycea rathbuni | amphibian |
| Barton Springs salamander | Eurycea sosorum | amphibian |
| Austin blind salamander | Eurycea waterlooensis | amphibian |
Two other fishes are listed as threatened by the State of Texas, the toothless blindcat fish (Trogloglanis patersoni) and the wide-mouthed blindcat (Satan eurystomas). The latter has not been observed since 1978 (Krejca and Reddell, 2019; Hendrickson, 2019). It may be extinct, but the wells in the limited area south of downtown San Antonio, where the fish was known to occur, are now part of the San Antonio city water system and are no longer accessible for sampling. Another fish species, the San Marcos gambusia, was last collected in 1983 and is now listed as extinct (EAA, 2020). The endangered species listing will continue to evolve. Figure 33 shows some of the endangered species.
Figure 33 – Endangered species of the Edwards Aquifer (figure provided by Juliana Apolonio): a) Texas wild rice; b) Peck’s Cave amphipod; c) Comal Springs riffle beetle; d) Comal Springs dryopid beetle; e) Fountain darter; f) the now extinct San Marcos gambusia; g) Texas blind salamander; h) Barton Springs salamander (photo provided by Nathan Bendik); and, i) Austin blind salamander.