Platyallabes tihoni

(Poll 1944) Poll 1977



Gymnallabes tihoni  Poll 1944


Lower Congo River: freshwater


Original holotype: MRAC 13307

Neotype: MRAC 103307 (Derijst 1991)


Platyallabes tihoni is the only species in the genus. The original description (Poll 1944) was based on a photograph. Redescribed by Poll (1957:240) where he selected a new "holotype" which Derijst (1991:43) regards as neotype designation. It was redescribed for a second time by Devaere et al. (2004). The species was moved from its original genus (Gymnallabes) by Poll (1977).

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) Teugels 1986

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


Moelants, T. 2010. Platyallabes tihoni. The IUCN Red List of Threatened Species 2010: e.T182369A7871734. Downloaded on 20 March 2020.

Museum Holdings

MRAC 13307 (original holotype), MRAC 73-68-P-143, MRAC 138698–699, 1 25345–349, MRAC 73-22-P-3127, BMNH 1976.5.21.30–39, MCZ 50239, MCZ 88947, MCZ 50537, MCZ 50297 (Devaere et al. 2005).

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

Genbank cytochrome b (Wright and Bailey 2012)

Key References

Poll, M. Journal Article 1944 Description préliminaire d'un Clariidae nouveau observé à Léopoldville par M. L. Tihon
Poll, M. Journal Article 1957 Redescription de Gymnallabes tihoni Poll 1944, Clariidae microphalme du Stanley Pool (Congo belge)
Poll, M. Journal Article 1977 Les genres nouveaux Platyallabes et Platyclarias comparés au genre Gymnallabes Gthr. Synopsis nouveau des genres de Clariidae
Derijst, E. Journal Article 1991 Kataloog der ichthyologische publikaties en nieuwe taxa beschreven door: Dr. Max Poll
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
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
Devaere, S., Adriaens, D., Teugels, G.G., De Clerck, N.M. and Postnov, A.A. Journal Article 2005 Skeletal morphology of the holotype of Gymnallabes nops Roberts & Stewart, 1976, using micro CT-scanning
Devaere, S., D. Adriaens, G. G. Teugels and W. Verraes Journal Article 2005 Morphology and spatial constraints in a dorso-ventrally flattened skull, with a revised species description of Platyallabes tihoni (Poll, 1944)
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
Schobert, C.S., Stiassny, M.L.J., Jeffery, W.D. and Dubielzig, R.R. Journal Article 2011 Comparative ocular anatomy In troglomorphic fish: Sensory compensation for reduced vision
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