Overview
This species has no formally-recognized common name and is referred to as the Texas Cave or the Edwards Aquifer diving beetle. This species does not live in caves, so the first common name mentioned is not accurate. It is an eyeless, depigmented groundwater diving beetle living within the Edwards Balcones Fault Zone Aquifer where no light is present. In this dark habitat, they swim the interstitial karst limestone spaces and can get caught in conduits of flow up through artesian wells and springs where they can be captured by researchers. This species eats both surface and subsurface derived organic matter. A petition was issued to list this species and the U.S. Fish and Wildlife Service published a 90-day finding in 2009 that stated that this diving beetle may be warranted for listing based on presented substantial scientific or commercial information.
Scientific Name
Identification Numbers
Characteristics
Food
The Edwards Aquifer diving beetle feeds on a combination of surface and subterranean derived organic matter. This species has been observed to feed on a dead cave shrimp or eating the bacteria off the shrimp. This species has body parts to suggest they can catch and feed on other invertebrates, but it is unknown if they engage in group feedings.
Habitat
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.
Similar Species
The larval stage of the Edwards Aquifer diving beetle are similar to Morimotoa phreatica larva, a Japanese subterranean diving beetle. Distinguishing features between the two species are found on the antenna, the cerci and the setae on the maxilla.
There are five known subterranean diving beetle species found in Texas within the Edwards-Trinity Aquifer System: Ereboporus naturaconservatus, Psychopomporus felipi, Comaldessus stygius, Haideoporus texanus and a new species undergoing description as of 2021. All of these species could be mistaken as the Edwards Aquifer diving beetle at a glance and requires microscopic identification.
Physical Characteristics
These small beetles range between 3.4 to 3.7 millimeters in length, with a long body shaped like a ground beetle that is hypothesized to assist them in navigating tight interstitial spaces or gravel beds. They have bristle-like structures on their hind legs called setae and lack hind wings.
The Edwards Aquifer diving beetle is depigmented and lacks the usual colorations and patterns seen in surface-dwelling diving beetles. Subterranean species are usually faded, pale colors like yellow or tan.
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