Channallabes apus

(Günther 1873) Teugels 1986



Gymnallabes apus  Günther 1873


Lower Congo River: freshwater


Only a holotype has been assigned: BMNH 1873.7.28.16.


There are six species in the genus:

Channallabes alvarezi (Roman 1971), Channallabes apus (Günther 1873), Channallabes longicaudatus (Pappenheim 1911), Channallabes ogooensis Devaere, Adriaens and Verraes 2007, Channallabes sanghaensis Devaere, Adriaens and Verraes 2007Channallabes teugelsi Devaere, Adriaens and Verraes 2007.

Biological Notes

The lower Congo River, and especially the northern and southern rapids below Pool Malebo, are home to many endemic species (Roberts and Stewart 1976, Bailey 1986, Thieme et al. 2005, Mamonekene 2005, Alter et al. 2015, Alter et al. 2017, Stiassny 2016). In particular there are at least eleven species, in five Families, which exhibit the troglomorphic features of reduced eyes and pigment:


Channallabes apus (Günther 1873)

Dolichallabes microphthalmus Poll 1942

Gymnallabes nops Roberts and Stewart 1976

Platyallabes tihoni (Poll 1944) Poll 1977


Notoglanidium pallidum Roberts and Stewart 1976


Mastacembelus aviceps Roberts and Stewart 1976

Mastacembelus brichardi (Poll 1958) Vreven 2005

Mastacembelus crassus Roberts and Stewart 1976

Mastacembelus latens Roberts and Stewart 1976


Lamprologus lethops Roberts and Stewart 1976


Stomatorhinus microps Boulenger 1898

These features probably evolved because these species live at depth within the rapids and spend their whole lives in permanent darkness, analagous to life in caves. The ocular and craniofacial anatomy of several of these species have been studied (Schobert et al. 2010, 2011, 2013) but almost nothing else is known about these animals.

Conservation Status


da Costa, L. and Moelants, T. 2010. Channallabes apus . The IUCN Red List of Threatened Species 2010: e.T167976A6429084. Downloaded on 18 March 2020.

Internet Resources

Main page for the Congo Project

Elizabeth Alter's work on Congo fishes

New York Times article with good photographs

Convergent evolution in the Congo rapids

A fish with the bends

Melanie Stiassny video presentation on the Congo River fishes

Key References

Gunther, A. Journal Article 1873 New fishes from Angola
Pappenheim, P. Journal Article 1911 Zoologische Ergebnisse der Expedition des Herrn G. Tessmann nach Süd-Kamerun und Spanisch-Guinea. Fische
Roman, B. Journal Article 1971 Nuevas especies de peces de Río Muni (Guinea Ecuatorial)
Teugels, G.G. Book Section 1986 Channallabes apus
Devaere, S., Adriaens, D., Verraes, W. and Teugels, G.G. Journal Article 2001 Cranial morphology of the anguilliform clariid Channallabes (Gunther 1873) (Teleostei: Siluriformes) are adaptations related to powerful biting?
Adriaens, D., Devaere, S., Teugels, G.G., Dekegel, B. and Verraes, W Journal Article 2002 Intraspecific variation in limblessness in vertebrates: a unique example of microevolution
Huysentruyt, F., Adriaens, D., Teugels, G.G., Devaere, S., Herrel, A., Verraes, W. and Aerts, P. Journal Article 2004 Diet composition in relation to morphology in some African anguilliform clariid catfishes
De Schepper, N; Adriaens, D; Teugels, GG; et al. Journal Article 2004 Intraspecific variation in the postcranial skeleton morphology in African clariids: a case study of extreme phenotypic plasticity
Van Wassenbergh, S; Herrel, A; Adriaens, D; et al. Journal Article 2005 Terrestrial feeding in the eel catfish, Channallabes apus
Van Wassenbergh, S; Aerts, P; Adriaens, D; et al. Journal Article 2005 A dynamic model of mouth closing movements in clariid catfishes: the role of enlarged jaw adductors
Jansen, G., Devaere, S., Weekers, P.H.H. and Adriaens, D. Journal Article 2006 Phylogenetic relationships and divergence time estimate of African anguilliform catfish (Siluriformes: Clariidae) inferred from ribosomal gene and spacer sequences
Devaere, S., Adriaens, D. and Verraes, W. Journal Article 2007 Survey of the anguilliform Clariidae (Teleostei, Siluriformes) of Gabon and Republic of Congo, with description of two new species and key to the African clariid genera
Devaere, S., Adriaens, D. and Verraes, W. Journal Article 2007 Channallabes sanghaensis sp. n., a new anguilliform catfish from the Congo River basin, with some comments on other anguilliform clariids (Teleostei, Siluriformes)
Alter, S.E., Brown, B. and Stiassny, M.L.J. Journal Article 2015 Molecular phylogenetics reveals convergent evolution in lower Congo River spiny eels
Stiassny, M.L.J. and Alter, S.E. Journal Article 2015 Phylogenetics of Teleogramma, a riverine clade of African cichlid fishes, with a description of the deep-water molluskivore —Teleogramma obama — from the lower reaches of the middle Congo River.
Harrison, I.J., Brummett, R. and Stiassny, M.L.J. Book Section 2016 Congo River basin
Day, J.J., Fages, A., Brown, K.J., Vreven, E.J., Stiassny, M.L.J., Bills, R., Friel, J.P. and Ruber, L. Journal Article 2017 Multiple independent colonizations into the Congo Basin during the continental radiation of African Mastacembelus spiny eels
Stiassny, M.L.J., Monsembula Iyaba, R.J.C., Liyandja, T., Mbimbi Mayi Munene, J.J., Yoko, M., and Alter, E. Conference Paper 2018 The evolution of extreme phenotypic convergence across fish lineages in the hyper-diverse Lower Congo River
Stiassny, M.L.J. Journal Article 2019 Fishes in the lower Congo River An extreme case of species divergence and convergent evolution
Elbein, A. Web Page 2020 Earth’s deepest river conceals an evolutionary mystery
Aardema, M.L., Stiassny, M.L.J. and Alter, S.E. Journal Article 2020 Genomic analysis of the only blind Cichlid reveals extensive inactivation in eye and pigment formation genes
Stiassny, M.L. and Alter, S.E. Book Section 2021 Life in the fast lane: diversity, ecology, and speciation of cichlids in the lower Congo River