Astroblepus pholeter

Collette 1962

Astroblepus pholeter
Redrawn by Rhian Kendall from Collette (1962)



It is possible that this species was first seen by Alexander Von Humboldt (1805) and described as Pimelodus cyclopum (Nico 2001) (See below and also Romero and Paulson 2001).




Holotype: USNM 196623 female 62mm SL. Paratypes: USNM 196671 male 64mm SL, female 66mm SL, FMNH 63855 female 57mm SL.

The holotype and paratype USNM 196671 are currently on loan to AMNH as AMNH 236241 (Espinasa et al. 2018) (David Smith, Smithsonian Institution, pers. comm. 20/08/2018).


Type locality: Jumandi Cave, Archidona, Napo Province, Ecuador (0o30’S, 78o00W).

Known also from Grieta Maria Juana, 8.3 km east of Tena city, close to the community Guayusa Loma (Hoese, Addison, Toulkeridis and Toomey 2015).

Known also from Cueva Silvario and Cueva Uctu Iji Changa in the same kart area as Jumandi cave (Espinasa et al. 2018)

These caves are in the biogeographic unit Amazon and drainage basin Napo/Coca of Schaefer (2011:268-273).


Jumandi Cave consists of a vadose stream passage 800m in length with a further 400m of side passages. The stream rises from a sump, flows through the cave, falls over a waterfall 0.8m high, and resurges from the cave mouth. Water temperature is 15o‑ 20oC, pH neutral, and water medium hard. The other aquatic species to be commonly seen are a characin fish Creagrutus muleri, a prawn Machrobrachium brasiliense, and nymphs of a mayfly Euthyplocia. The last of these provide the bulk of the diet of A. pholeter (Brown 1981; Hanson 1981; Brown and Hanson 1981). Sket (1985) records the amphipod Bogidiella gammariformis.

Astroblepus pholeter coexists in Jumandi Cave with Chaetostoma undescribed species (Nathan Lujan pers. comm.) and in Grieta Maria Juana with a probably troglophilic population of Chaetostoma microps (Hoese et al. 2015).


Collette (1962:313) states that A. pholeter is very different from all other known species of Astroblepus. However, some of the differences he cites (reduced pigment and eyes and increased barbel length) are simply related to a cave‑dwelling existence (stygomorphic characters) and provide no help in elucidating the relationships of the species. In other characteristics (long filaments on dorsal and anal fins, long pelvic fins, and a barbel on the nasal flap) it superficially resembles A. longifilis. It differs from this species by possessing (at least in the type series) a distinct adipose spine and in lacking an adipose ridge between dorsal and caudal fins. The adipose spine, however, poses a question since none of the animals observed by Hanson (1981) possessed one. This difference is so far unexplained.

Chardon (1966, 1968:196‑201) studied the Weberian apparatus of many siluriform fishes. He concluded that various of the Weberian structures of A. pholeter are unique.

Espinasa et al. (2018) made a thorough study of the morphology of the species from collections and observations made in 1962 (the type series, see above), 2011, 2015 and 2018. Across this time period there was clear reduction in troglomorphic characters and a clear increase in characters exhibited by epigean Astroblepus species. They suggest that this is clear case of introgressive hybridization with epigean species of Astroblepus which have been observerd in the cave. If this continues it is likely that the hypogean species Astroblepus pholeter will eventually loose its status as a separate species.

Biological Notes

The following account is taken from Nico (2001) biography of Humboldt:

10) cyclopum Pimolodus Humboldt 1805:21-25, plate 6. Family: Astroblepidae. Eschmeyer (1998) references Burgess (1989:443) in stating that the species is valid as Astroblepus cyclopus. The original description includes a drawing of the specimen with number of rays grven next to each fin. Humboldt notes that he sketched the fish, and the sketch was then colored by M. Turpin. Eigenmann and Eigenmann (1890:349-350) discuss the species in some detail. They state: "The poor description of P. cyclopum makes an absolute identification impossible." For a period of time, this species was placed in the genus Cyclopium Swainson 1839 (now considered a synonym of Astroblepus). Eigenmann (1918) described a new variety, A. c. santanderensis, based on specimens taken from an elevation of 1,000-2,000 meters in the Rio Suarez drainage, Colombia. The taxonomic status of the subspecies is unclear. Most of Eigenmann's material currently is housed at the Field Museum of Natural History, Chicago (FMNH). Henn (1928:82) designated a lectotype: FMNH 58433 (ex CM 7430). I have not been able to uncover additional information on Eigenmann's species. According toEschmeyer (1998), the type locality of Humboldt's catfish is subterranean waters in the Andes of Quito (basin of Rio Esmeraldas), Ecuador. In contrast, Eigenmann and Eigenman (1890:349-350) indicate that Humboldt's species is found in the Andes and the Amazon, but they make no mention that its habitat is subterranean waters. I have been unable to locate the Rio Esmeraldas on my maps, but a geographical dictionary indicates the river flows west from the Andes Mountains into the Pacific ocean. According to Humboldt's original text, his description apparently was based on one or more specimens collected in a surface stream in the vicinity of several active volcanoes. In his original description, Humboldt relates that locals, including some reliable sources, told him that large numbers of fish are periodically spewed from vents as well as from the summit of area volcanoes. Named volcanoes involved in the strange phenomena included Cotopaxi, Imbabura, Cargueirazo, and Tungurahua (see rnap of Papavero 1971). Reportedly, fish were either ejected together with cold water or embedded in clay materials, all were dead but in relatively good condition. Humboldt fully accepted the stories and concluded that his new species was the same fish spewed from the volcanoes, but he does not explain how he came to this determination. He does note that the new catfish is rather uncommon in surface waters. However, based on the numbers of fish periodically spewed from volcanoes, Humboldt believed it to be abundant in subterranean waters. In describing the catfish Humboldt notes that its eyes are small, but describes the fish as being olive color with small black spots (based on its somewhat dark pigmentation pattern, Humboldt's catfish is not a highly-evolved cave form). Interestingly, modern researchers apparently have overlooked Humboldt's unusual account of this possible subterranean species. For instance, the catfish is not included in an unpubtished list (dated 1997) of cavedwelling fishes of the world that was disbibuted during a symposium on the biology and evolution of cavefishes held at the 1998 annual meeting of the American Society of Ichthyologists and Herpetologists in Guelph, Canada. Collette (1962) described as new a cave-dwelling Astroblepus, A. pholeter, based on specimens taken from a large cave in Latas, 4 km north of Archidona, Napo Province, in eastern Ecuador. The species is described as essentially unpigmented and minute-eyed. Interestingly Collette makes no reference to Humboldt's cyclopum and states that his A. pholeter is the first known cavernicolous astroblepid. The oversight suggests the need to take another look at A. pholeter to determine if it is closely allied to A. cyclopus and to dismiss the possibility of it being a junior synonym. The type locality of A. photeter is less than 100 km southeast from Quito and falls within the Napo-Amazon rivers basin.

Conservation Status


(Jimenez-Prado and Arguello 2016. Astroblepus pholeter. The IUCN Red List of Threatened Species 2016. Downloaded on 02 July 2017).The species has a restricted range and probably is affected by habitat modification produced by cropland, livestock, dams and urbanization. It therefore probably qualifies for classification in a threatened category under criterion B1b(iii). However, at present the lack of precise field data, largely concerning severity of population fragmentation and number of locations, impedes determination of the appropriate category (Endangered). It is therefore classified as Near Threatened.

Museum Holdings

As above plus: BMNH.

Key References

Humboldt, F. H. A. Book Section 1805 IVe Memoire, sur une nouvelle espece de Pimelode, jetee par les volcans du Royaume de Quito
Johnson, R.D.O. Journal Article 1912 Notes on the habits of a climbing catfish (Arges marmoratus) from the Republic of Colombia
Collette, B. B. Journal Article 1962 Astroblepus pholeter, a new species of cave-dwelling catfish from eastern Ecuador
Chardon, M. Journal Article 1966 Specialisation anatomique de l'appareil de Weber d'Astroblepus pholeter, Silure cavernicole microphthalme de la Republique de l'Equateur
Chardon, M. Journal Article 1968 Anatomie comparee de l'appareil de Weber et des structures connexes chez les Siluriformes
Balazs, D. Journal Article 1972 The Jumandi Caves of Ecuador
Balazs, D. Journal Article 1974 The Jumandi Caves of Ecuador
Montoriol-Pons, J. Journal Article 1976 [A note on the Jumandi Cave (Archidona, Napo Province)]
Sket, B. Journal Article 1979 [Fauna in the Caverna de Jumandi]
Hanson, P. D. Book Section 1981 The aquatic fauna
Brown, P. and Hanson, P.D. Journal Article 1981 The Jumandi Cave of Ecuador
Brown, P Report 1981 Southampton University expedition to Ecuador 1979
Sket, B. Journal Article 1985 Bogidiella (s.l.) gammariformis sp. n. (Amphipoda) from Ecuador
Peck, S. B. Journal Article 1985 The invertebate fauna of the tropical American caves. Part 6:Jumandi Cave, Ecuador
Peck, S.B. Book Section 1994 Ecuador
Buitrago-Suarez, U.A. and Galvis, G. Journal Article 1997 Description of some accessory stuctures of the urogenital system in the neotropical Family Astrobelpidae (Pisces, Siluroidei)
Nico, L.G. Journal Article 2001 Alexander Von Humboldt (1769-1859): Contributions to knowledge of New World fishes
Romero, A. and Paulson, K.M. Journal Article 2001 Humbodt's alleged subterranean fish from Ecuador
Schaefer, S.A. and Buitrago-Suarez, U.A. Journal Article 2002 Odontode morphology and skin surface features of Andean astroblepid catfishes (Siluriformes, Astroblepidae)
Schaefer, S.A. and Arroyave, J. Journal Article 2010 Rivers as islands: determinants of the distribution of Andean astroblepid catfishes
Soares, D. Conference Paper 2010 Cavefishes as models for sensory adaptation
Schaefer, S.A., Chakrabarty, P., Geneva, A.J. and Sabaj Pérez, M.H. Journal Article 2011 Nucleotide sequence data confirm diagnosis and local endemism of variable morphospecies of Andean astroblepid catfishes (Siluriformes: Astroblepidae)
Conway, K.W., Lujan, N.K., Lundberg, J.G., Mayden, R.L. et al Journal Article 2012 Microanatomy of the paired-fin pads of ostariophysan fishes (Teleostei: Ostariophysi)
Haspel, G., Schwartz, A., Streets, A., Camacho, D.E. and Soares, D. Journal Article 2012 By the teeth of their skin, cavefish find their way
Haspel, G., Schwartz, A. and Soares, D. Journal Article 2012 Unique mechanosensory adaptation to extreme environments in cavefish
Spadella, M.A., Oliveira, C., Ortega, H., Quagio-Grassiotto, I. and Burns, J.R. Journal Article 2012 Male and female reproductive morphology in the inseminating genus Astroblepus (Ostariophysi: Siluriformes: Astroblepidae)
Crop, W.D., Pauwels, E., Hoorebeke, L.V. and Geerinckx, T. Journal Article 2013 Functional morphology of the Andean climbing catfishes (Astroblepidae, Siluriformes): alternative ways of respiration, adhesion, and locomotion using the mouth
Lujan, N.K. and Conway, K.W. Book Section 2015 Life in the fast lane: A review of rheophily in freshwater fishes
Hoese, G., Addison, A., Toulkeridis, T. and Toomey, R. Journal Article 2015 Observation of the catfish Chaetostoma microps climbing in a cave in Tena, Ecuador
Espinasa, L., Christoforides, S. and Morfessis, S.E. Journal Article 2017 Sequence analyses of the 16S rRNA of epigean and hypogean diplurans in the Jumandi Cave area, Ecuador
Robinson, J Journal Article 2017 Astroblepus pholeter: Convergent regressive evolution of the mc1r gene in cavefish species
Espinasa, L., Robinson, J. and Espinasa, M. Journal Article 2018 Mc1r gene in Astroblepus pholeter and Astyanax mexicanus: Convergent regressive evolution of pigmentation across cavefish species
Espinasa, L., Robinson, J., Soares, D., Hoese, G., Toulkeridis, T. and Toomey, R. Journal Article 2018 Troglomorphic features of Astroblepus pholeter, a cavefish from Ecuador, and possible introgressive hybridization
Espinasa, L., Hoese, G., Toulkeridis, T. and Toomey, R. Journal Article 2018 Corroboration that the Mc1rGly/Ser mutation correlates with the phenotypic expression of pigmentation in Astroblepus
Conde-Saldan, C.C., Souza Cunha, M., Albornoz-Garzo, J.G., Valiati Barreto, C.A., Ibagon, N., Villa-Navarro, F.A. and Abdala Dergam, J. Journal Article 2019 Karyotypic divergence of two co-occurring species of Andean climbing catfishes (Siluriformes: Loricarioidei: Astroblepidae)
Crawford, C.H., Randall, Z.S., Hart, P.B., Page, L.M., Chakrabarty, P., Suvarnaraksha, A. and Flammang, B.E. Journal Article 2020 Skeletal and muscular pelvic morphology of hillstream loaches (Cypriniformes: Balitoridae)