Marcusenius ntemensis (Pellegrin 1927)

Onglets principaux

EOL Text

Environment:

demersal; freshwater

Licensehttp://creativecommons.org/licenses/by-nc/3.0/
Rights holder/AuthorPascualita Sa-a, FishBase
Sourcehttp://www.fishbase.org/summary/SpeciesSummary.php?id=10909

Electric Organ Discharge:

EOD is of long duration (greater than five milliseconds) and unusual waveform, which begins with a pronounced head-negative phase, followed by a long-lasting head-positive plateau which persists for two to three milliseconds. This is followed by a more typical sharp head-positive peak and a head-negative peak. Male EODs tend to be longer than female EODs. There is also evidence of geographic variation in the signal: the EODs recorded from this species in the Ntem River of southern Cameroon, northern Gabon, are longer in duration than those from the Ivindo River of Gabon.

Licensehttp://creativecommons.org/licenses/by-nc-sa/3.0/
Rights holder/AuthorSullivan, John P., Hopkins, Carl D., Africhthy
Sourcehttp://mormyrids.lifedesks.org/pages/2127

Phylogenetic Relationships:

Molecular phylogenetic studies (Sullivan et al. 2000; Lavoué et al. 2003) indicate that this species is not a close relative of other Marcusenius and rather belongs to a lineage that is sister to species of Paramormyrops, a clade very diverse in Lower Guinea, particularly Gabon. Future systematic revision will have to place this taxon within Paramormyrops, or erect a new genus for it.

Licensehttp://creativecommons.org/licenses/by-nc-sa/3.0/
Rights holder/AuthorSullivan, John P., Sullivan, John P., Africhthy
Sourcehttp://mormyrids.lifedesks.org/pages/2127

IUCN Red List Assessment:
Red List Category

VU
Vulnerable

Red List Criteria

B2ab(iii)

Version

3.1

Year Assessed

2010

Assessor/s

Moelants, T.

Reviewer/s

Brummett, R., Mbe Tawe, A.N., Dening Touokong, C., Reid, G.M., Snoeks, J. Staissny, M., Moelants, T., Mamonekene, V., Ndodet, B., Ifuta, S.N.B., Chilala, A., Monsembula, R., Ibala Zamba, A., Opoye Itoua, O., Pouomogne, V., Darwall, W. & Smith, K.

Contributor/s

Justification

The lower Ntem population is threatened by a planned deep river port and iron mine with the associated infrastructure. The populations on the Lower Ivindo drainage are threatened by iron mining. The species is known from fewer than 10 locations. The AOO is estimated less than 2,000 km.
Licensehttp://creativecommons.org/licenses/by-nc-sa/3.0/
Rights holder/AuthorInternational Union for Conservation of Nature and Natural Resources
Sourcehttp://www.iucnredlist.org/apps/redlist/details/181802

Population:

Population

No information available.

Population Trend

Unknown
Licensehttp://creativecommons.org/licenses/by-nc-sa/3.0/
Rights holder/AuthorInternational Union for Conservation of Nature and Natural Resources
Sourcehttp://www.iucnredlist.org/apps/redlist/details/181802

Threats:

Major Threats

The lower Ntem population is threatened by a planned deep river port and iron mine with the associated infrastructure. The populations on the Lower Ivindo drainage are threatened by iron mining.
Licensehttp://creativecommons.org/licenses/by-nc-sa/3.0/
Rights holder/AuthorInternational Union for Conservation of Nature and Natural Resources
Sourcehttp://www.iucnredlist.org/apps/redlist/details/181802

Vulnerable (VU) (B2ab(iii))

Licensehttp://creativecommons.org/licenses/by-nc/3.0/
Rights holder/AuthorPascualita Sa-a, FishBase
Sourcehttp://www.fishbase.org/summary/SpeciesSummary.php?id=10909

Conservation Actions:

Conservation Actions

None known.
Licensehttp://creativecommons.org/licenses/by-nc-sa/3.0/
Rights holder/AuthorInternational Union for Conservation of Nature and Natural Resources
Sourcehttp://www.iucnredlist.org/apps/redlist/details/181802

General Description:

The only Marcusenius from Lower Guinea with 12 circumpeduncular scales, fewer than 70 scales on lateral line, fewer than 22 dorsal rays, and fewer than 33 anal rays. Depth of body 21-24% SL; head elongate, reaching 24-27% SL. Head depth 66-73% of its length. Snout conical in shape and elongate, 25-33% HL. Mouth terminal, submental swelling pronounced and extending well beyond the end of the upper jaw. Teeth bicuspid, six (sometimes five) in upper jaw, eight in lower. Eye diameter 28-46% of the length of the snout. Dorsal fin with 20-21 rays, anal fin with 29-32 rays. Dorsal originates well behind the anal, typically over the 14th-16th anal ray. Caudal peduncle length 15-19% SL. Caudal peduncle depth 5.6-6.4% SL. Caudal fin small with obtusely pointed lobes. 64-66 scales in the lateral line, 12 circumpeduncular scales. Uniform dark chocolate-brown coloration overall, fins darkly pigmented.

Licensehttp://creativecommons.org/licenses/by-nc-sa/3.0/
Rights holder/AuthorSullivan, John P., Hopkins, Carl D., Africhthy
Sourcehttp://mormyrids.lifedesks.org/pages/2127

Range Description:

A Lower Guinea endemic known from the Ntem River of Southern Cameroon/Northern Gabon, and the Ivindo River of Gabon, two adjacent rivers that share several endemic species.

Licensehttp://creativecommons.org/licenses/by-nc-sa/3.0/
Rights holder/AuthorInternational Union for Conservation of Nature and Natural Resources
Sourcehttp://www.iucnredlist.org/apps/redlist/details/181802
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith