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. Additional details from Hutchins et al. (2021).

Well Depth (m) Notes

Verstraeten Well No 1, Bexar County


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 Pump Station Well No.4, Bexar County 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. (2017) 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. This group of four is the sister group to all other ictalurids in the analysis and they presumably share a last common ancestor which lived in the northern Mexico area.

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

Trogloglanis pattersoni mitochondrion, complete genome

Prietella phreatophila mitochondrion, complete genome

Powerpoint slides of a lecture

The lecture as a pdf file

Fishes of Texas website

Key References

Eigenmann, C.H. Journal Article 1919 Trogloglanis pattersoni, a new blind fish from San Antonio, Texas
Hubbs, C.L. and Bailey, R.M. Journal Article 1947 Blind catfishes from artesian waters of Texas
Taylor, W. R. Thesis 1955 A revision of the genus Noturus Rafinesque with a contribution to the classification of the North American catfishes
Suttkus, R. D. Journal Article 1961 Additional information about blind catfishes from Texas
Reddell, J. R. Journal Article 1967 A checklist of the cave fauna of Texas. III Vertebrates
Reddell, J.R. and Mitchell, R.W. Journal Article 1969 A checklist and annotated bibliography of the subterranean aquatic fauna of Texas
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
Reddell, J. R. Journal Article 1971 A checklist of the cave fauna of Texas. 6 Additional records of vertebrates
Hubbs, C. Book Section 1971 Fishes of Texas caves
Lundelius, E. L. and Slaughter, B. H. Book 1971 Natural history of Texas caves
Species, Texas Organisation for Endangered Journal Article 1975 T.O.E.S. watchlist of endangered, threatened and peripheral vertebrates of Texas
Winograd, I.J. and Pearson, F.J. Journal Article 1976 Major Carbon-14 anomaly in a regional carbonate aquifer: Possible evidence for megascale channeling, south-central Great Basin
Longley, G. Journal Article 1977 Preliminary report of biological investigations: Valdina Farms sinkhole, Medina County, Texas
Karnei, H. Thesis 1978 Survey of the subterranean fauna, Bexar County, Texas
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
Longley, G. Journal Article 1979 Subterranean aquatic fauna of the Edwards aquifer in Texas, as indicated by samples from wells and springs
Longley, G. and Karnei, H. Journal Article 1979 Status of Satan eurystomus Hubbs and Bailey, the widemouth blindcat
Cooper, J.E. and Longley, G. Book Section 1980 Trogloglanis pattersoni Eigenmann Toothless blindcat
Cooper, J.E. and Longley, G. Book Section 1980 Satan eurystmus Hubbs and Bailey Widemouth blindcat
Longley, G. Journal Article 1981 The Edwards aquifer: Earths most diverse groundwater ecosystem ?
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
Winograd, I. J. and Roberston, F. N. Journal Article 1982 Deep oxygenated groundwater: anomaly or common occurence ?
Edwards, R.J., Beaty, H.E., Longley, G., Riskind, D.H., Tupa, D.D. and Whiteside, B.G. Book 1984 The San Marcos recovery plan
Longley, G. Book Section 1986 The biota of the Edwards Aquifer and the implications for zoogeography
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)
Woodruff, C. M. and Abbott, P. L. Book Section 1986 Stream piracy and the evolution of the Edwards Aquifer along the Balcones escarpment, central Texas
Moravec, 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
Edwards, R.J., Longley, G., Moss, R., Ward, G., Matthews, R. and Stewart, B. Journal Article 1989 A classification of Texas aquatic communities with special consideration toward the conservation of enangered and threatened taxa
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
Kroschewsky, J. R. Journal Article 1990 The Edwards Aquifer Research and Data Centre: Objectives and accomplishments
Kuehn, K.A. and Koehn, R.D. Journal Article 1991 Fungal populations isolated from Ezells Cave in south Texas
Langecker, T.G. and Longley, G. Book Section 1992 Blind catfish (Trogloglanis pattersoni and Satan eurystomus) from deep 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 eurystomus) from deep artesian waters: A study on convergant adaptation to cave and deep sea biotas
Lundberg, J.G. Book Section 1992 The phylogeny of ictalurid catfishes: a synthesis of recent work
Kuehn, K.A., O'Neil, R.M. and Koehn, R.D. Journal Article 1992 Viable photosynthetic microalgal isolates from aphotic environments of the Edwards Aquifer (central Texas)
Bowles, D.E. and Arsuffi, T.L. Journal Article 1993 Karst aquatic ecosystems of the Edwards Plateau region of central Texas, USA: A consideration of their importance, threats to their existence, and efforts for their conservation
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
Walsh, S.J. and Gilbert, C.R. Journal Article 1995 New species of troglobitic catfish of the genus Prietella (Siluriformes, Ictaluridae) from Northeastern Mexico
Maclay, R.W. Report 1995 Geology and hydrology of the Edwards Aquifer in the San Antonio area, Texas
Campbell, L. Book 1995 Endangered and threatened animals of Texas: Their life history and management.
Longley, G. and Jordan, W.R. Journal Article 1997 Management of the Edwards Aquifer region - How the Endangered Species Act influenced action
Hendrickson, D.A., Krejca, J. and Rodriguez Martinez, J.M. Journal Article 1998 Blind catfish (Prietella: Ictaluridae) phylogenies and troglobitic invertebrates as indicators of international (Mexico-USA) subterranean aquatic interconnections, and as tools for environmental risk assessment
Hendrickson, D.A. and Krejca, J. Book Section 2000 Subterranean freshwater diversity in northeastern Mexico and Texas
Krejca, J., Hendrickson, D.A. and Taylor, S.J. Journal Article 2000 Using stygobites to follow groundwater in Texas and Mexico
Northup, D.E. and Lavoie, K.H. Journal Article 2001 Geomicrobiology of caves: A review
Hendrickson, D.A., Krejca, J. and Rodriguez Martinez, J.M. Journal Article 2001 Mexican blindcats genus Prietella (Siluriformes: Ictaluridae): An overview of recent explorations
Wilcox, T.P., Garcia de Leon, F.J., Hendrickson, D.A. and Hillis, D.M. Journal Article 2004 Convergence among cave catfishes: long-branch attraction and a Bayesian relative rates test
Boghici, R. Report 2004 Hydrogeology of Edwards and Trinity Aquifer of Texas and Coahuila in the Border Region
Krejca, J. Journal Article 2005 Stygobite phylogenetics as a tool for determining aquifer evolution
Sullivan, J.P., 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
Taylor, S.J., Weckstein, J.D., Takiya, D.M., Krejca, J.K., Murdoch, J.D., Veni, G., Johnson, K.P. and Reddell, J.R. Report 2007 Phylogeography of cave crickets (Ceuthophilus spp.) in central Texas: A keystone taxon for the conservation and management of federally listed endangered cave arthropods
Engel, A.S. Journal Article 2007 Observations on the biodiversity of sulfidic karst habitats
Bendik, N.F., Gluesenkamp, A.G. and Chippindale, P.T. Conference Paper 2009 The biogeography and rapid radiation of central Texas neotenic salamanders
Chippindale, P.T., Gluesenkamp, A.G. and Bendik, N.F. Conference Paper 2009 Texas cave and spring salamanders (Eurycea): new discoveries and new surprises
White, K., Davidson, G.R. and Paquin, P. Journal Article 2009 Hydrologic evolution of the Edwards Aquifer recharge zone (Balcones fault zone) as recorded in the DNA of eyeless Cicurina cave spiders, south-central Texas
Egge, J.J.D. Book Section 2010 Systematics if ictalurid catfishes: a review of the evidence
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
Zara Environmental LLC Report 2010 Final Report for deep aquifer biota study of the Edwards Aquifer
Edwards Aquifer Authority Web Page 2011 Drop inside the Edwards Aquifer
Edwards Aquifer Authority Web Page 2011 How an aquifer works
Gary, M.O., Gary, R.H. and Hunt, B.B. Journal Article 2011 Interconnection of the Trinity (Glen Rose) and Edwards Aquifers along the Balcones Fault Zone and related topics
McDermid, K. Conference Paper 2013 Biological sampling through wells as windows into the Edwards Aquifer
Bendik, N.F., Meik, J.M., Gluesenkamp, A.G., Roelke, C.E. and Chippindale, P.T. Journal Article 2013 Biogeography, phylogeny, and morphological evolution of central Texas cave and spring salamanders
Bishop, R., Humphreys, W.F. and Longley, G. Journal Article 2014 Epigean and hypogean palaemonetes sp. (Decapoda, Palaemonidae) from Edwards Aquifer: an examination of trophic structure and metabolism.
Zara Environmental LLC Report 2014 Fauna of wells near the saline waterline of the Edwards Aquifer, Texas
Engel, A.S. (ed.) Book 2015 Microbial Life of Cave Systems: Unique focus on the microbial life of caves, the ecological processes and geological consequences attributed to microbes in cave environments
Coleman, W.T., Hutchins, B.T. and Schwartz, B.F. Conference Paper 2016 Dynamics of detectability: Insights from high-frequency sampling at a stygobiont hot-spot, Edwards Aquifer, Texas
Hendrickson, D.A., Johnson, J., Sprouse, P.S., Howard, S., Garrett, G.P. Krejca, J.K., Gluesenkamp, W., Paulín, J.A.D., Dugan, L., Cohen, A.E., Espriú, A.H., Sullivan, J.P., Fenol, D.B., Karges, J., Smith, R., García De León, F.J., Wolaver, B. and Reddell Conference Paper 2016 Discovery of the Mexican Blindcat, Prietella phreatophila in the U.S and an update on its rangewide conservation status
Hutchins, B.T., Engel, A.S., Nowlin, W.H. and Schwartz, B.F. Conference Paper 2016 Biodiversity, stability, and trophic complexity in the Edwards Aquifer, United States: The influence of chemolithoautotrophy on stygobiont community structure
Hutchins, B.T. Conference Paper 2016 Conservation status of stygobionts in Texas, United States.
Coleman, W.T. Conference Paper 2016 Dynamics of detectability: Insights from high-frequency sampling at a stygobiont hot-spot, Edwards Aquifer, Texas
Hutchins, B., Engel, A., Nowlin, W., and Schwartz, B. Journal Article 2016 Chemolithoautotrophy supports macroinvertebrate food webs and affects diversity and stability in groundwater communities
Airhart, M.G. Web Page 2017 Scientists on the trail of central Texas' elusive Satan fish
Hendrickson, D.A., Hernández‐ Espriú, A., Dugan, L., Sprouse, P., Dávila Paulín, J.A., Krejca, J., Gluesenkamp, A., Reddell, J., Smith, R., Howard, S., Johnson, J., Garrett, G.P., Cohen, A.E., García De León, F.J., Wolaver, B.P. and Fenolio, D.B. Conference Paper 2017 Discovery of endangered Mexican Blindcat, Prietella phreatophila , in Texas: Implications for international groundwater management and evolution of the regional karst aquifer biota
Gluesenkamp, A., Hendrickson, D., and Sprouse, P. Conference Paper 2017 The Mexican Blindcat project: New discoveries and future efforts
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)
Arce, M., Lundberg, J.G. and O'Leary, M.A. Journal Article 2017 Phylogeny of the North American catfish Family Ictaluridae (Teleostei: Siluriformes) combining morphology, genes and fossils
Gluesenkamp, A. Hendrickson, D.A. and Sprouse, P.S. Journal Article 2018 The Mexican Blindcat Project: new discoveries and future efforts
Hutchins, B.T. Journal Article 2018 The conservation status of Texas groundwater invertebrates
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
Krejca, J. and Reddell, J. Book Section 2019 Biology and ecology of the Edwards aquifer
Niemiller, M.L., Taylor, S.J., Slay, M.E. and Hobbs, H.H. III Book Section 2019 Biodiversity in the United States and Canada
Arroyave, J., Schmitter-Soto, J. and Lyons, T.J. Web Page 2019 Typhlias pearsei. The IUCN Red List of Threatened Species 2019 e.T39296A2896759
Devitt, T.J. Book Section 2019 Evolution of Edwards-Trinity aquifer biodiversity: Insights from phylogeography
Lyons, K.M. Thesis 2019 Exploring the distribution of groundwater salamanders and catfish with environmental DNA
Devitt, T.J., Wright, A.M., Cannatella, D.C. and Hillis, D.M. 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
Green, R.T., Bertetti, F.P., Fratesi, B. and Schinfel, G.M. Book Section 2019 San Antonio Pool of the Edwards (Balcones Fault Zone) aquifer
Devitt, T. Journal Article 2019 Creatures of the deep karst
Sharp, J.M., Green, R.T. and Schindel, G.M. Book 2019 The Edwards Aquifer : the past, present, and future of a vital water resource
Johnson, S., Schindel, G.M., and Van Brahana, J. Book Section 2019 Tracer testing in the Edwards Aquifer
Burr, B.M., Warren, M.L. and Bennett, M.G. Book Section 2020 Ictaluridae: North American catfishes
Warren, M.L. and Burr, B.M. Book 2020 Freshwater fishes of North America. Volume 2 Characidae to Poeciliidae
Lyons, T.J., Máiz-Tomé, L., Tognelli, M., Daniels, A., Meredith, C., Bullock, R. and Harrison, I., Contreras-MacBeath, T., Hendrickson, D.A., Arroyave, J., Mercado Silva, N., Köck, M., Domínguez Domínguez, O., Valdés González, A., Espinosa Pérez et al. Book 2020 The status and distribution of freshwater fishes in Mexico
Gibson, R., Hutchins, B.T., Krejca, J.K., Diaz, P.H. and Sprouse. P.S. Journal Article 2021 Stygobromus bakeri, a new species of groundwater amphipod (Amphipoda, Crangonyctidae) associated with the Trinity and Edwards aquifers of central Texas, USA
Gibson, R., Hutchins, B.T., Krejca, J.K., Diaz, P.H. and Sprouse. P.S. Journal Article 2021 Corrigenda: Stygobromus bakeri, a new species of groundwater amphipod (Amphipoda, Crangonyctidae) associated with the Trinity and Edwards aquifers of central Texas, USA
Hutchins, B.T., Gibson, J.R., Diaz, P.H. and Schwartz, B.F. Journal Article 2021 Stygobiont diversity in the San Marcos Artesian Well and Edwards Aquifer groundwater ecosystem, Texas, USA.
Hendrickson, D.A. and Cohen, A.E. Web Page 2022 Fishes of Texas Project Database (Version 3.0)
Niemiller, M.L., Carter, E.T., Fenolio, D.B., Gluesenkamp, A.G. and Phillips, J.G. Book Section 2022 Subterranean colonisation and diversification of cave-dwelling salamanders
Corrington, C.A. Thesis 2022 Spatial gradients and food web structure of groundwater communities
Hendrickson, D.A., Lundberg, J., Luckenbill, K. and Arce-H, M. Conference Paper 2022 Update on taxonomic and conservation status of North American blindcats (Ictaluridae)
Hendrickson, D.A. Web Page 2022 ‎Fish of the Week!: North American Blindcats feat
Hendrickson, D.A. Web Page 2022 Blind cave catfishes
Janzen, F.H., Pérez-Rodríguez, R., Domínguez-Domínguez, O., Hendrickson, D.A., Sabaj, M.H. and Blouin-Demers, G. Journal Article 2023 Phylogenetic relationships of the North American catfishes (Ictaluridae, Siluriformes): investigating the origins and parallel evolution of the troglodytic species
Federal Register Web Page 2023 Endangered and Threatened Wildlife and Plants; Endangered species status for Toothless Blindcat and Widemouth Blindcat. A Proposed Rule by the Fish and Wildlife Service on 08/22/2023
U.S. Fish and Wildlife Service Web Page 2023 Two rare Texas cavefish proposed for Listing under Endangered Species Act. Groundwater well uptake is primary threat increasing risk of extinction
Janzen, F. Thesis 2023 Evolutionary biogeography of catfishes (Siluriformes, Actinopterygii): The influence of habitat and landscape on gene flow and genetic diversification
Perez, K.E., Guerrero, Y., Castañeda, R., Diaz, P.H., Gibson, R., Schwartz, B. and Hutchins, B.T. Journal Article 2023 Two new phreatic snails (Mollusca, Caenogastropoda, Cochliopidae) from the Edwards and Edwards-Trinity aquifers, Texas