Stomatorhinus microps

Boulenger 1898

OsteoglossiformesNo suborderMormyridae




Lower Congo River: freshwater


Syntypes: BMNH 1898.11.12.7-9, 3 specimens.


Boma and Matadi, Lower Congo River and region of the cataracts

More details needed


Deep and fast rheophilic conditions (Stiassny and Alter 2021).

Many more details from various sources


Sullivan et al. (2000) examined four species of Stomatorhinus (three unnamed plus S. walkeri) and all four grouped together as a monophyletic assemblage.

Lavou et al. (2012) found a sister relationship between Stomatorhinus cf. ater and Paramormyrops gabonensis and, what they call Paramormyrops sp. 'type 2' (magnostipes complex).

Sonet et al. (2018) found a sister relatioship between Stomatorhinus walkeri and Ivindomyrus sp. short Kouilou, and also a sister realtionship between this pair and Ivindomyrus sp. elongate Kouilou.


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, Stiassny and Alter 2021). In particular there are at least twelve 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


Chiloglanis undescribed species "Kinsuka"


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

[VU D2:3.1:2010]

Moelants, T. 2010. Stomatorhinus microps. The IUCN Red List of Threatened Species 2010: e.T181707A7710386. Downloaded on 28 October 2021.

Museum Holdings

Natural History Museum London

Field Museum of Natural History

Museum of Comparative Zoology, Harvard

CAS Ichthyology

[From GBIF, more to add]

Internet Resources


Genbank has 40 sequences for the genus (to be added)

Key References

Gunther, A. Journal Article 1873 New fishes from Angola
Boulenger, G. A. Journal Article 1898 Matériaux pour la faune du Congo. Poissons nouveaux du Congo. Première Partie. Mormyres
Pappenheim, P. Journal Article 1911 Zoologische Ergebnisse der Expedition des Herrn G. Tessmann nach Süd-Kamerun und Spanisch-Guinea. Fische
David, L. and Poll, M. Journal Article 1937 Contribution a la faune ichthyologique de Congo Belge. Collections du Dr H. Schouteden (1924-1926) et d'autres recolteurs
Poll, M. Journal Article 1942 Notes sue l'osteologie de Dolichallabes microphalmus Poll et remarques sur l'evolution des Clariidae
Poll, M. Journal Article 1942 Description d'un genre nouveau de Clariidae originaire du Congo belge
Poll, M. Journal Article 1944 Description préliminaire d'un Clariidae nouveau observé à Léopoldville par M. L. Tihon
Poll, M. Journal Article 1945 Descriptions de Mormyridae et de Characidae nouveaux du Congo belge avec une étude du genre Stomatorhinus et des genres de Characidae nains africains
Poll, M. Journal Article 1953 Les poissons d’aquarium du Congo belge.
Poll, M. Journal Article 1956 Les poissons du Congo Belge et l’aquariophilie
Poll, M. Journal Article 1957 Redescription de Gymnallabes tihoni Poll 1944, Clariidae microphalme du Stanley Pool (Congo belge)
Poll, M. Journal Article 1958 Description d'un poisson aveugle nouveau du Congo belge, appartenant à la famille des Mastacembelidae
Poll, M. Journal Article 1959 Résultats scientifiques des missions zoologiques au Stanley Pool subsidiées par le Cemubac (Université Libre de Bruxelles) et la Musée Royal du Congo (1957-1958)
Roman, B. Journal Article 1971 Nuevas especies de peces de Río Muni (Guinea Ecuatorial)
Poll, M. Journal Article 1973 Les yeux des poissons aveugles africains et de Caecomastacembelus brichardi Poll en particulier
Roberts, T.R. and Stewart, D.J. Journal Article 1976 An ecological and systematic survey of fishes in the rapids of the lower Zaire or Congo river
Poll, M. Journal Article 1977 Les genres nouveaux Platyallabes et Platyclarias comparés au genre Gymnallabes Gthr. Synopsis nouveau des genres de Clariidae
Daget, J. Journal Article 1978 Contribution à la faune de la République Unie du Cameroun. Poissons du Dja, du Boumba et du Ngoko
Banister, K.E. and Bailey, R.G. Journal Article 1979 Fishes collected by the Zaire River expedition 1974 - 1975
Beadle, L.C. Book 1981 The inland waters of tropical Africa
Travers, R.A. Journal Article 1984 A review of the Mastacembeloidei, a suborder of synbranchiform teleost fishes. Part II: Phylogenetic analysis
Travers, R.A. Journal Article 1984 A review of the Mastacembeloidei, a suborder of synbranchiform teleost fishes. Part I: Anatomical descriptions
Teugels, G.G. Book Section 1986 Channallabes apus
Banister, K.E. Book Section 1986 Fish of the Zaire System
Bailey, R.G. Book Section 1986 The Zaire River system
Derijst, E. Journal Article 1991 Kataloog der ichthyologische publikaties en nieuwe taxa beschreven door: Dr. Max Poll
Mo, T.-P. Journal Article 1991 Anatomy and systematics of Bagridae (Teleostei) and siluroid phylogeny
Cabuy, E., Adriaens, D., Verraes, W. and Teugels, G.G. Journal Article 1999 Comparative study on the cranial morphology of Gymnallabes typus (Siluriformes: Clariidae) and their less anguilliform relatives, Clariallabes melas and Clarias gariepinus
Sullivan, J.P., Lavoué, S. and Hopkins, C.D. Journal Article 2000 Molecular systematics of the African electric fishes (Mormyroidea: Teleostei) and a model for the evolution of their electric organs
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?
Decu, V., Juberthie, C. and Tercafs, R. Book Section 2001 Republique Democratique Du Congo (ex-Zaire)
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
Lavoué, S., Sullivan, J.P. and Hopkins, C.D. Journal Article 2003 Phylogenetic utility of the first two introns of the S7 ribosomal protein gene in African electric fishes (Mormyroidea: Teleostei) and congruence with other molecular markers
Schelly, R.C. and Stiassny, M.L.J. Journal Article 2004 Revision of the Congo River Lamprologus Schilthuis, 1891 (Teleostei: Cichlidae), with descriptions of two new species
Devaere, S, Teugels, G, Adriaens, D, Huysentruyt, F. and Verraes, W. Journal Article 2004 Redescription of Dolichallabes microphthalmus (Poll, 1942) (Siluriformes: Clariidae)
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; 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
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
Van Wassenbergh, S; Herrel, A; Adriaens, D; et al. Journal Article 2005 Terrestrial feeding in the eel catfish, Channallabes apus
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)
Sullivan, J.P. and Hopkins, C.D. Journal Article 2005 A new Stomatorhinus (Osteoglossomorpha: Mormyridae) from the Ivindo River, Gabon, West Central Africa
McNamara, A.M., Denizot, J.-P. and Hopkins, C.D. Journal Article 2005 Comparative anatomy of the electrosensory lateral line lobe of mormyrids: The mystery of the missing map in the genus Stomatorhinus
Vreven, E.J. Journal Article 2005 Mastacembelidae (Teleostei; Synbranchiformes) subfamily division and African generic division: an evaluation
Mamonekene, V. Book Section 2005 Ecoregion 60. Lower Congo rapids
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)
Hanssens, M., Vreven, J., E. and Snoeks, J. Conference Paper 2008 The ichthyofauna of Lower Congo and Pool Malebo
Vreven, E.J. and Stiassny, M.L.J. Journal Article 2009 Mastacembelus simbi, a new dwarf spiny eel (Synbranchiformes: Mastacembelidae) from the lower Congo River
Jackson, P.R., Oberg, K.A., Gardiner, N. and Shelton, J. Conference Paper 2009 Velocity mapping in the Lower Congo River: A first look at the unique bathymetry and hydrodynamics of Bulu Reach, West Central Africa
Schobert, C.S., Schwab, I.R., Stiassny, M.L., Schelly, R.C., Lowenstein, J.H., Zeiss, C. and Dubielzig, R.R. Conference Paper 2010 Abstract 4. Comparative ocular anatomy of four species of lower Congo River fish
Schobert, C.S., Stiassny, M.L.J. and Dubielzig, R.R. Conference Paper 2011 Abstract 12. Comparative ocular and craniofacial anatomy in nine species of lower Congo River fish
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
Kish, P.E., Bohnsack, B.L., Gallina, D., Kasprick, D.S. and Kahana, A. Journal Article 2011 The eye as an organizer of craniofacial development
Lavoue, S., Miya, M., Arnegard, M.E., Sullivan, J.P., Hopkins, C.D. and Nishida, M. Journal Article 2012 Comparable ages for the independent origins of electrogenesis in African and South American weakly electric fishes
Schobert, C.S., Stiassny, M.L.J., Schwab, I.R., Zeiss, C., Schelly, R.C. and Dubielzig, R.R. Journal Article 2013 Comparative occular anatomy in a blind African cichlid fish, Lamprologus lethops
Geerinckx, T., Vreven, E.J., Dierick, M., van Hoorebeke, L. and Adriaens, D. Journal Article 2013 Revision of Notoglanidium and related gerera (Siluriformes: Claroteidae) based on morphology and osteology
Carlson, B.A., Stevens, J.A., Sukhum, K.V. and Carlson, B.A. Journal Article 2013 Independent evolution of visual and electrosensory specializations in different lineages of Mormyrid electric fishes
Lucanus, O. Journal Article 2013 First notes on the husbandry of the blind cichlid Lamprologus lethops from the Congo River
Brawand, D. et al. Journal Article 2014 The genomic substrate for adaptive radiation in African cichlid fish
Tougas, S. and Stiassny, M.L.J. Journal Article 2014 Lamprologus markerti, a new lamprologine cichlid (Teleostei: Cichlidae) endemic to the lower Congo River in the Democratic Republic of Congo, west-central Africa
Ozouf-Costaz, C., Coutanceau, J.P., Bonillo, C., Belkadi, L., Fermon, Y., Agnese, J.F., Guidi-Rontani, C. and Paugy, D. Journal Article 2015 First insights into karyotype evolution within the family Mormyridae
Lujan, N.K. and Conway, K.W. Book Section 2015 Life in the fast lane: A review of rheophily in freshwater fishes
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
Alter, S.E., Munshi-South, J. and Stiassny, M.L.J. Journal Article 2017 Genomewide SNP data reveal cryptic phylogeographic structure and microallopatric divergence in a rapids adapted clade of cichlids from the Congo River
Mahamba Byanikiro, R., Kankonda Busanga, A., Ndjaki Nsila, J. and Micha, J.-C. Journal Article 2017 Régime alimentaire et biologie de la reproduction de Stomatorhinus corneti Boulanger, 1899 (Pisces, Mormyridae)
Schedel, F.D.B., Musilová, Z. and Schliewen, U.K. Conference Paper 2018 New divergence ages provide novel insights into the biogeographic rigin of the East African Cichlid Radiation (EAR)
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
Schedel, F.D.B., Musilova, Z. and Schliewen, U.K. Journal Article 2019 East African cichlid lineages (Teleostei: Cichlidae) might be older than their ancient host lakes: new divergence estimates for the east African cichlid radiation
Sonet, G., Snoeks, J., Nagy, Z.T., Vreven, E., Boden, G., Breman, F.C., Decru, E., Hanssens, M., Zamba, A.I., Jordaens, K., Mamonekene, V., Musschoot, T., Van Houdt, J., Van Steen, M. Journal Article 2019 DNA barcoding fishes from the Congo and the Lower Guinean provinces: Assembling a reference library for poorly inventoried fauna
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
Kurata, N.P., Hickerson, M.J., Hoffberg, S.L., Gardiner, N., Stiassny, M.L.J. and Alter, S.E. Journal Article 2022 Riverscape genomics of cichlid fishes in the lower Congo: Uncovering mechanisms of diversification in an extreme hydrological regime