Amphibians
Comal Blind Salamander
Eurycea tridentifera · also called Comal blind salamanders
Deep within a flooded Texas cave passage, a Comal blind salamander drifts through total darkness, its skin pale and translucent, its useless eyes hidden beneath the surface, its feathery gills the only feature it will ever need.
Overview
The Comal blind salamander, Eurycea tridentifera, is a permanently aquatic, cave-dwelling salamander confined to groundwater passages within the Cibolo Sinkhole Plain of Comal and Bexar counties, Texas. Its complete lack of eyes and pigment, lifelong retention of external gills, and total dependence on a narrow underground water system make it one of the more specialized and vulnerable amphibians in North America.
A life that never sees the surface
Unlike most salamanders, which spend at least part of their life on land, the Comal blind salamander never leaves the water and never grows functional eyes, evolution having stripped away everything a creature living in permanent darkness simply does not need.
Status
Vulnerable — confined to a small cluster of central Texas caves and highly dependent on groundwater quality.
Comal Blind Salamander: common questions
Why doesn't the Comal blind salamander have eyes?
The Comal blind salamander has only vestigial, non-functional eyes hidden beneath its skin, an adaptation to a permanently lightless underground existence where the ability to see offers no survival advantage and the energy needed to maintain functional eyes is better spent elsewhere.
Does the Comal blind salamander ever leave the water or grow lungs?
No, this species retains feathery external gills and an aquatic lifestyle for its entire life, a permanently larval condition called neoteny, meaning it never undergoes the metamorphosis into a land-dwelling adult that many other salamander species complete.
Why is the Comal blind salamander considered vulnerable?
The species survives only within a small cluster of caves and sinkholes in the Cibolo Sinkhole Plain of central Texas, living entirely within the Edwards Aquifer groundwater system, which makes it acutely vulnerable to pollution, contamination, or depletion of the very water it depends on for survival.
How is the Comal blind salamander related to other Texas cave salamanders?
The Comal blind salamander belongs to the genus Eurycea, the same group that includes several other highly localized central Texas cave and spring salamanders such as the Georgetown salamander, the Salado salamander, and the Blanco blind salamander, each confined to its own small stretch of the Edwards Aquifer system.