Listed as Critically Endangered given that its extent of occurrence (EOO) and area of occupancy (AOO) are 4 km², it is known from one threat-defined location, and there is continuing decline in the quality of its habitat around the headwaters of the San Marcos River.

This species is known only from a pool at the source of the San Marcos River (San Marcos Springs, Spring Lake), Hays County, Texas, United States at an elevation of 174 m asl, and a short distance downstream (Chippindale et al. 2000, Green et al. 2014). A second, smaller subpopulation of this species was thought to occur in the Comal River (Springs), slightly to the west in Comal County; however, this population has been determined to not be E. nana (Chippindale et al. 1994, Chippindale et al. 1998, Chippindale et al. 2000). Its extent of occurrence (EOO) is 0.22 km² measured by a minimum convex polygon of its known range; however the EOO has been adjusted to 4 km² as area of occupancy (AOO) values should not exceed EOO (IUCN Standards and Petitions Subcommittee 2019).

This species has been reported as abundant within its limited range, with Spring Lake and the two sites below the dam supporting large and relatively stable subpopulations (NatureServe 2021). However, overall the population is inferred to be in decline due to the increasing pressures of urbanization.

This species can be found in shallow alkaline springs carved out of limestone. They have been found in mats of blue-green algae (Lyngbya sp.), under rocks, and in gravel substrate at water depths of less than 1m to several metres. Clean, clear, flowing water of constant temperature is required for suitable habitat, as this species has not been found in areas where the bottom is muddy or bare (TPWD 2021). A study by Diaz et al. (2015) found that this species occurred almost exclusively in mesohabitats containing cobble and gravel with coverage of Amblystegium and filamentous algae, and indicated that individuals selected mesohabitats based on benthic substrate rather than the biotic communities present. This species is completely aquatic and does not metamorphose. Eggs have never been observed in the wild. In captivity, ovipositioning has occurred on aquatic moss, filamentous algae, rocks, and glass marbles. This species is paedomorphic, which may limit dispersal and gene flow between subpopulations (Niemiller et al. in press).

Reduced spring flow is the greatest threat to the survival of this species, and the growth of nearby cities has led to higher water use by people as well as increased problems with water pollution and silt accumulation. The introduction of non-native species is also a threat, as these species may destroy important aquatic vegetation, prey on this species, or compete for food (TPWD 2021). Climate change is also thought to pose a threat, as warmer and drier conditions will likely contribute to increased groundwater take. 

Additionally, disease may pose a future threat to this species as the emergence of the salamander chytrid fungus (Batrachochytrium salamandrivorans, “Bsal”) as an amphibian pathogen has caused dramatic declines in European fire salamanders since its apparent arrival in 2008 through the international pet trade (Feldmeier et al. 2016). Carter et al. (2020) found that Eurycea wilderae and E. lonicauda were susceptible to Bsal, and in lab tests altered their behavior upon infection and developed clinical chytridiomycosis. A separate study found that E. sosorum was a suitable host for Bsal, but upon infection did not alter behavior or experience mortality (M. Gray unpub. data 2021). The response of this species is not known, but the genus does appear to be susceptible to infection. Although the presence of the fungus has not been confirmed in the Americas, it is spreading in Europe and risks spreading further. Should Bsal be introduced to the US, the impacts on salamander populations could be rapid and severe if immediate mitigation action is not taken.

There are no records of this species being utilized.

Conservation Actions In-Place
The range of this species is protected at both the state and federal level. It is listed as Threatened by the state of Texas and Threatened by the Federal government. The primary management concern is limiting the amount of water that is pumped out of the ground. The owner of Spring Lake has cooperated in protection efforts (Matthews and Moseley 1990, NatureServe 2021).

In an effort to prevent the introduction of Bsal into the US, an Interim Rule of the Lacey Act has been enacted that bans the importation of 201 species of salamanders (USFWS 2016). Additionally, a temporary voluntary trade moratorium of imports of Asian salamander species that are known to carry the disease until such time as effective testing and treatment regimens can be developed and distributed has been recommended to all exporters, shippers, sellers and buyers by the Pet Industry Joint Advisory Council (PIJAC). A North America Bsal Task Force has also been created, with working groups designed to address a variety of disease prevention and mitigation goals (North America Bsal Task Force 2021).

Conservation Needed
Continued enforcement of protected areas will be important for maintaining the quality of critical aquatic habitat within this species' range.

Research Needed
There is a need for close monitoring of the population status of this species.