Trogloglanis pattersoni

Eigenmann 1919







Only a holotype has been assigned: CAS 58675 (ex IU 15240) female 68.0mm SL This species is the type species by monotypy of the cave‑restricted genus Trogloglanis.


This species (and its confamilial Satan eurystomus) is restricted to very deep artesian waters (up to 600m) in the Central, or San Antonio, Pool of the Edwards Aquifer, Bexar County, Texas, USA (29o30’N, 98o30’W). It is distributed over an area of at least 500km2 but has only been collected from man‑made wells which penetrate the aquifer. The collection localities are given below.

Well Depth (m) Notes
Verstraeten Well 513

Well still in use. One specimen collected by Longley and Karnei (1979:18).

O. R. Mitchell Well 582

Third specimen collected here (Suttkus 1961), Well no. AY‑68‑43‑601 of the USGS, still in use. Three specimens collected by Longley and Karnei (1979:18). S. eurystomus also recorded from this site.

El Patio Foods Well 430

S. eurystomus also recorded from this site. Now capped.

Artesia Well 402

Well still in use. Twenty two specimens collected by Longley and Karnei (1979:19).S. eurystomus also recorded from this site.

Josef Boecke Well 308

Second specimen collected here (Hubbs and Bailey 1947). Now covered byroad.S. eurystomus also recorded from this site.

George W. Brackenridge Well 308

Probable TYPE LOCALITY. Probably now capped.

Alamo Dressed Beef Company Well ? Location unknown. Fishes collected may have been T. pattersoni or S. eurystomus.
Persyn Well ?

Location unknown. Fishes collected may have been T. pattersoni or S. eurystomus.



The underground cavities inhabited by this species and Satan eurystomus are probably the most extreme of any  from which subterranean fishes are known. Details of the actual haibitat are of course unknown and will probably remain so. What little is known has been gleaned from samples taken at the wells. Longley (1981) considered the aquifer to be the earths most diverse groundwater ecosystem and summarised its fauna. Kuehn and Koehn (1991) and Kuehn, O’Neil and Koehn (1992) isolated various fungi and algae which may play an important role in the trophic economy of the system. Northup and Lavoie (2001) suggest that bacteria growing at the interface between saline and freshwater may take part in the food web within this aquifer.  Moraver and Huffman (1988) report the parasitic nematode Rhabdochona longleyi from both species of fishes. The most detailed account of the animals and their environs is that of Longley and Karnei (1979) and (1979).



Lundberg (1982) made a very thorough study of the anatomy of T. pattersoni and from it he concluded that the species is not a relict but is probably the sister group of a major lineage containing Ameiurus, Noturus, Pylodictis and two troglobitic genera Satan and Prietella. Lundberg suggests that the immediate ancestor of T. pattersoni arose in the Oligocene and that it may have been evolving in the deep aquifer for 15 million years. The phylogenetic relationships of Noturus are covered by Hardman (2004). Detailed studies the four North and Central American troglobitic ictalurids Satan eurystomus, Trogloglanis pattersoni, Prietella phreatophila and P. lundbergi  by Arce et al. 2(016) suggest that they form a monophyletic group with fifteen synapomorphies: 1. Absence of eyes, 2. depigmentation, 3. Fifth vertebra, 4. Lateral line extent, 5. Mesethmoid cornua, 6. Anterior cranial fontanel, 7. Descending wing of frontal, 8. Supraoccipital posterior process, 9. Pterotic wings, 10. Parasphenoid and orbitosphenoid, 11. Abductor arcus palatine scars, 12. Anterior ceratohyal-ventral hypohyal joint, 13. Dorsal hypohyal, 14. Upper hypurals, 15. Transcapular ligament ossification. It would be highly valuable to compare these anatomical synapomorphies with those from molecular markers.

Conservation Status

MG [VU D2:3.1:2013]

(NatureServe. 2013. Trogloglanis pattersoni. The IUCN Red List of Threatened Species 2013: Downloaded on 07 July 2017). his species is potentially threatened by overpumping of the aquifer, which is the primary source of water for people in the region. In the 1990s the world's largest water well (at that time) was drilled close to the known habitat of the species, and the water was briefly used to support a catfish farm; subsequently the well and water rights were purchased by the San Antonio Water System, which now uses the well for aquifer monitoring purposes. Depletion of the aquifer poses a threat to the Toothless Blindcat by possibly allowing the poor-quality anaerobic water of the "bad water" zone to replace good-quality water where the fish now resides (G. Longley, The Handbook of Texas Online).

Pollution from industrial and agricultural sources is a potential threat, but protection of the aquifer for human uses likely will also protect the blindcat.

V (Miller 1977), R (IUCN 1988), V (IUCN 1990), V (IUCN 1993), VU D2 (IUCN 1996, 2000). T1 (Williams, Johnson, Hendrickson, Contreras-Balderas, Williams., Navarro-Mendoza, McAllister and Deacon 1989). G1 (NatureServe 2002).

A thorough study by Longley and Karnei (1979) has shown that, at present, there appears to be no danger to this fish because: "Based on population estimates, there appears to be a large population of [the species] in the San Antonio Pool of the Edwards Aquifer". In 1977 a total of 6.4 x 106m3 of water was pumped from the Artesia Well with the (estimated) loss of only 98 fishes. Longley and Karnei (1979:41) point out, however, that the greatest threat to this animal is from depletion of the groundwater by pumping. Groundwater pollution could also pose a serious threat, especially in the light of the evidence gathered by Winograd and Robertson (1982) that the residence time of water in very deep aquifers may be as much as 10000 years. See also the San Marcos Recovery Plan (Edwards, Beaty, Longley, Riskind, Tupa and Whiteside, 1984).

Internet Resources

Powerpoint slides of a lecture

The lecture as a pdf file

Key References

Eigenmann, C. H. Journal Article 1919 Trogloglanis pattersoni, a new blind fish from San Antonio, Texas
Taylor, W. R. Thesis 1955 A revision of the genus Noturus Rafinesque with a contribution to the classification of the North American catfishes
Taylor, W. R. Journal Article 1969 A revision of the catfish genus Noturus Rafinesque, with an analysis of higher groups in the Ictaluridae
Lundberg, J.G. Thesis 1970 The evolutionary history of north American catfishes, family Ictaluridae
Longley, G. and Karnei, H. Journal Article 1979 Status of Satan eurystomus Hubbs and Bailey, the widemouth blindcat
Longley, G. and Karnei, H. Journal Article 1979 Status of Trogloglanis pattersoni Eigenmann, the toothless blindcat
Karnei, H. Journal Article 1979 Status of the troglobitic blind catfishes, Trogloglanis pattersoni and Satan eurystomus, in Bexar County, Texas
Cooper, J.E. and Longley, G. Book Section 1980 Trogloglanis pattersoni Eigenmann Toothless blindcat
LeGrande, W. H. Journal Article 1981 Chromosomal evolution in North American catfishes (Siluriformes, Ictaluridae) with particular emphasis on the Madtoms, Noturus
Lundberg, J. G. Journal Article 1982 The comparative anatomy of the toothless blindcat, Trogloglanis pattersoni Eigenmann, with a phylogenetic analysis of the ictalurid fishes
Amemiya, C.T., Kelsch, S.W., Hendricks, F.S. and Gold, J.R. Journal Article 1986 The karyoptype of the Mexican blindcat, Prietalla phreatophila Carranza (Ictaluridae)
Moraver, F. and Huffman, D. G. Journal Article 1988 Rhabdochona longleyi sp. n. (Nematoda, Rhabdochonidae) from the blind catfishes, Trogloglanis pattersoni and Satan eurystomus (Ictaluridae) from the subterranean waters of Texas
Williams, J. E., Johnson, J. E., Hendrickson, D. A., Conteras-Balderas, S., Williams, J. D., Navarro-Mondoza, M., McAllister, D. E. and Deacon, J. E. Journal Article 1989 Fishes of North America endangered, threatened or of special concern 1989
Langecker, T. G. and Longley, G. Book Section 1992 Blind catfish (Trogloglanis pattersoni and Satan eurystomus) from dep artesian waters. A study on convergent adaptations to cave and deep sea biota
Langecker, T. G. and Longley, G. Journal Article 1992 Blind catfish (Trogloglanis pattersoni and Satan eurystomas) from deep artesian waters: A study on convergant adaptation to cave and deep sea biotas
Langecker, T. G. and Longley, G. Journal Article 1993 Morphological adaptations of the Texas blind catfishes Trogloglanis pattersoni and Satan eurystomus (iluriformes, Ictaluridae) to their underground environment
Hendrickson, DA and Krejca, J Book Section 2000 Subterranean freshwater diversity in northeastern Mexico and Tewas
Krejca, J, Hendrickson, DA and Taylor, SJ Journal Article 2000 Using stygobites to follow groundwater in Texas and Mexico
Wilcox, TP, Garcia de Leon, FJ, Hendrickson, DA and Hillis, DM Journal Article 2004 Convergence among cave catfishes: long-branch attraction and a Bayesian relative rates test
Boghici, R. Report 2004 Hydrogeology of Edwards–Trinity Aquifer of Texas and Coahuila in the Border Region
Sullivan, JP, Lundberg, J. G. and Hardman, M Journal Article 2006 A phylogenetic analysis of the major groups of catfishes (Teleostei: Siluriformes) using rag1 and rag2 nuclear gene sequences
Zara Environmental LLC Report 2010 Final Report for deep aquifer study of the Edwards Aquifer
Dahdul, W.M., Lundberg, J.G., Midford, P.E., Balhoff, J.P., Lapp, H., Vision, T.J., Haendel, M.A., Westerfield, M. and Mabee, P.M. Journal Article 2010 The Teleost anatomy ontology: Anatomocal representation for the genomics age
Egge, JJD Book Section 2010 Systematics if ictalurid catfishes: a review of the evidence
Zara Environmental LLC Report 2014 Fauna of wells near the saline waterline of the Edwards Aquifer, Texas
Arce, M, Lundberg, J. G. and O'Leary, MA Journal Article 2016 Phylogeny of the North American catfish Family Ictaluridae (Teleostei: Siluriformes) combining morphology, genes and fossils
Lundberg, J.G., Hendrickson, D.A., Luckenbill, K.R. and Arce M Journal Article 2017 Satan's skeleton revealed: a tomographic and comparative osteology of Satan eurystomus, the subterranean Widemouth Blindcat (Siluriformes, Ictaluridae)
Nissen, B.D., Devitt, T.J., Bendik, N.F., Gluesenkamp, A.G., Gibson, R. Journal Article 2018 New occurrence records for stygobiontic invertebrates from the Edwards and Trinity aquifers in west-central Texas, USA
Devitt, T.J., Wright, A.M., Cannatella, D. and Hillis, D. Journal Article 2019 Species delimitation in endangered groundwater salamanders: Implications for aquifer management and biodiversity conservation
Nair, P. Thesis 2019 Ecophysiology and food web dynamics of spring ecotone communities in the Edwards Aquifer, USA