Rhamdia urichi

(Norman 1926) Mees 1974

Rhamdia urichi
Redrawn by Rhian Kendall from Norman (1926)


Caecorhamdia urichi  Norman 1926

Caecorhamdella urichi  (Norman 1926) Hubbs 1938 lapsus calami

Rhamdia quelen urichi  (Norman 1926) Mees 1974

Hubbs (1938:264) used the generic name Caecorhamdella for this species but this was obviously a mistake since the correct name is used three pages later. The generic name was misspelt Caecohamdia by Wolf (1934, 1938).




The description was based on a syntype series of two individuals: BMNH 1926.7.28:1‑2. This species is the type species by monotypy of the genus Caecorhamdia.


Known only from the type locality: Guacharo Cave (or Oropuche, Oropouche, or Cumaca Cave) Trinidad (10o30’N, 61o30’W).


Guacharo Cave is a vadose cave with a stream running through it. The fishes tend to be concentrated in the resurgent sump at the end of the cave. It is thought that the main body of the population is concentrated in the groundwater supplying the cave and nothing is known of this habitat (Darlington 1995).


Norman (1926) erected the genus Caecorhamdia "in order to draw attention to this interesting fish". He realised however "that this procedure is somewhat unsatisfactory, for, were the eyes developed, the [fishes] would be probably be identified with the species Rhamdia queleni [sic]". Mees (1974:160-165) examined one preserved specimen and living animals at the type locality. His observations indicated that neither generic nor specific distinctions were merited. Instead of synonymising the cave form completely with R. quelen he gave it subspecific status. In common with the cave form of Poecilia mexicana there is a suggestion that a fully evolved troglomorphic fish is undergoing intogression with an epigean form. At Guacharo Cave it is possible to observe all degrees of pigmentation and eye morphology, from pure quelen at the entrance to pure urichi at the end of the cave (observations made by Jack Price; John Endler pers. comm.; Romero 1983:82). Silfvergrip (1996) does not recognise the subspecies. If a troglomorphic, and stygobitic, fish is resident in the area of this cave it will require a separate status and name. Rhamdia urichi seems sensible. However, recent studies by Romero and co-workers (Romero and Creswell 2000, Romero and Creswell 2000, Romero et al. 2002) suggests that the troglomorphic form may have been replaced by an epigean morph. It still remains possible that the troglomorphic form exists in more remote passages, none of which have ever been entered.

Conservation Status


Museum Holdings

As above plus: BMNH 1926.7.28:3, RMNH 26733 (Mees, 1974).

Key References

Norman, J. R. Journal Article 1926 A new blind catfish from Trinidad, with a list of blind cave-fishes
Boeseman, M. Journal Article 1960 The freshwater fishes of the islands of Trinidad
Mees, G. F. Journal Article 1974 The Auchenipteridae and Pimelodidae of Surinam (Pisces, Nematognathi)
Romero, A. Journal Article 1983 Introgressive hybridisation in the Astyanax fasciatus (Pisces, Characidae) population at La Cueva Chica
Junge, P. Journal Article 1992 Egg size and larval development of epigean and cave forms of Rhamdia guatemalensis (Pimelodidae, Pisces)
Langecker, T. G. and Wilkens, H. Journal Article 1992 Comparative ultrastructural studies on the pineal organ of the Mexican catfish Rhamdia laticauda Heckel, 1858 and one of its cave-dwelling derivatives (Pimelodidae, Teleostei)
Darlington, J. P. E. C. Journal Article 1995 A review of current knowledge about the Oropouche or Cumaca Cave, Trinidad, West Indies
Silfvergrip, A. M. C. Book 1996 A systematic revision of the neotropical catfish genus Rhamdia (Teleostei, Pimelodidae)
Romero, A. and Creswell, J. Conference Proceedings 2000 Eyes wide open: the "eyeless cave fish of Trinidad, W.I. is not blind
Carvalho Gomes, L. de, Golombieski, J.I., Chippari Gomes, A.R. and Baldisserotto, R. Journal Article 2000 Biology of Rhamdia quelen (Teleostei, Pimelodidae)
Romero, A. and Creswell, J. Journal Article 2000 In search of the elusive "eyeless" cave fish of Trinidad, W.I.
Perdices, A, Bermingham, E, Montilla, A and Doadrio, I Journal Article 2002 Evolutionary history of the genus Rhamdia (Teleostei: Pimelodidae) in Central America
Romero, A., Singh, A., McKie, A., Manna, M., Baker, R., Paulson, K.M. and Creswell, J.E. Journal Article 2002 Replacement of the troglomorphic population of Rhamdia quelen (Pisces: Pimelodidae) by an epigean population of the same species in the Cumaca Cave, Trinidad, West Indies
Weber, A Thesis 2003 Taxonomie und Artstatus hohlenbewohnender und oberirdischer Welse der Gattung Rhamdia (Pimelodidae, Teleostei) in Mexiko
Angrizani, R.C. and Malabarba, L.R. Journal Article 2018 Morphology and molecular data reveal the presence of two new species under Rhamdia quelen (Quoy & Gaimard, 1824) (Siluriformes: Heptapteridae) species complex
Scaglione, M.C., Cerutti, R.D., Arfuso, F. and Piccione, G. Journal Article 2018 Light and dark rations and the photic entrainment of circadian locomotor activity patterns in the South American Silver Catfish (Rhamdia quelen, Quoy & Gaimard, 1824)
Ricci, J.M.B.,Martinez, E.R.M., Butzge, A.J., Doretto, L.B., Oliveira, M.A., Bombardelli, R.A., Bogerd, J. and Nóbrega, R.H. Journal Article 2018 Characterization of vasa homolog in a neotropical catfish, Jundiá (Rhamdia quelen): Molecular cloning and expression analysis during embryonic and larval development