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Range-extension of black-fronted
duiker (Cephalophus nigrifrons Gray
1871, Artiodactyla Bovidae): first
records from Nigeria
C. B. Powell a & P. Grubb b
a Biodiversity Unit , Institute of Pollution Studies, Rivers State
University of Science and Technology , Port Harcourt , Nigeria
b 35 Downhills Park Road, London , N17 6PE , UK
Published online: 30 Jul 2012.
To cite this article: C. B. Powell & P. Grubb (2002) Range-extension of black-fronted duiker
(Cephalophus nigrifrons Gray 1871, Artiodactyla Bovidae): first records from Nigeria, Tropical
Zoology, 15:1, 89-95, DOI: 10.1080/03946975.2002.10531167
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Tropical Zoology 15: 89-95, 2002
Range-extension of black-fronted duiker
(Cephalophus nigrifrons Gray 1871,
Artiodactyla Bovidae): first records from Nigeria
1,2
3
C.B. POWELL
and P. GRUBB
1 Biodiversity Unit, Institute of Pollution Studies, Rivers State University of Science
and Technology, Port Harcourt, Nigeria
3 35 Downhills Park Road, London N17 6PE, UK
Received 10 March 2001, accepted 21 May 2002
The black-fronted duiker (Cephalophus nigrifrons) was previously known
only from Central Africa. A geographically isolated population has now been
found in a small area of the Niger Delta, 500 km from its previously known dis-
tribution. It is locally common in the marsh forest zone but has become extinct
in some districts. The Nigerian population is indistinguishable from the nomi-
nate subspecies C. n. nigrifrons. Its discovery adds to the list of endemic taxa
and isolated populations of otherwise widespread species restricted to southern
Nigeria. This faunal element may have survived adverse environmental perturba-
tions in a refuge focused on the Niger Delta during the high-latitude glaciations.
KEY WORDS: black-fronted duiker, Cephalophus nigrifrons, Niger Delta, Nigeria,
zoogeography.
Introduction
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New distribution records of the black-fronted duiker
Specimens examined
Biogeography
Acknowledgements
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References
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INTRODUCTION
The black-fronted duiker (Cephalophus nigrifrons Gray 1871) differs from
other medium-sized forest duikers in its long limbs and elongated hooves, associat-
ed with a preference for swampy habitats. It is widely distributed in the Congo
2 Deceased, 24th June 1998.

90
C.B. Powell and P. Grubb
Basin and extends into montane swampy habitats in eastern Congo (Kinshasa),
Uganda, Rwanda, Burundi and Kenya, while in the west it is known from Angola,
Congo (Brazzaville), Gabon, Central African Republic and Cameroon (EAST 1990),
where the Sanaga River was thought to be the north-western limit to its range
(ANSELL 1972). The distribution map (Fig. 1) is based on the literature and museum
specimens examined in Berlin, Brussels, Chicago, Frankfurt, London, New York,
Philadelphia, Quex Park (Powell Cotton Museum, UK), Tervuren and Washington
D.C. There are specimens from many localities in Cameroon from just south of the
Sanaga, including Afinsam, Bipindi, mouth of the Lobo River, Lolodorf, Metet,
Njangong, N’Koltop, Yaounde and Yukaduma. According to DEPIERRE & VIVIEN
(1992), it also occurs in the tongue of forest lying in the basin of the Djérem River,
a right-bank tributary on the north side of the Sanaga, and there is a skull in the
collection of the American Museum of Natural History from Bafia, in this same
area. BOWDEN (1986) reported another specimen from north-west of the Sanaga
River, on the southern slopes of Mt Cameroon. He also mentioned sightings possi-
bly attributable to this species on Mount Kupe (1,900 m) and Mount Manenguba
(2,250 m). Previous intensive mammal collecting on Mt Cameroon had not noted
the species and its preferred swamp-forest habitat does not appear to be present.
BOWDEN cited no diagnostic characters by which the specimens could be identified
or any details of their habitat, and did not notice that the records, if valid, would
represent a westward range-extension. Without supporting evidence, we cannot yet
accept these records. While the black-fronted duiker seems otherwise to be absent
north-west of the lower Sanaga River in Cameroon, there have recently been
reports from the Niger Delta, 500 km to the west (POWELL 1995, 1997; EAST et al.
1999; Figs 1-2). These are based on material evidence and interviews with infor-
mants, mostly experienced hunters, during C.B. POWELL’s field trips when his col-
laborators assisted with translation. The species had never before been recorded
from Nigeria (HAPPOLD 1987).
Fig. 1. — Distribution map of black-fronted duiker in Africa. Each symbol indicates presence with-
in a half-degree square. The star indicates the Sanaga River in Cameroon.

Black-fronted duiker new for Nigeria
NEW DISTRIBUTION RECORDS OF THE BLACK-FRONTED DUIKER
91
Businessman and conservationist A.P. LEVENTIS wrote as follows to C.B. POW-
ELL (15th September 1994): “In the early 1970s, I observed a duiker for sale on the
roadside between Ologbo and Sapele in Edo State [more likely, in Delta State]. On
close examination, the coloration and hoof formation suggested this could only
have been a black-fronted duiker (despite the significant range extension implied)”.
This is locality # 1 on the map (Fig. 2). A queried record of the red-flanked duiker,
C. rufilatus Gray 1846, in the southern part of the Odomu Forest Reserve (ANADU &
OATES 1982) may also refer to this species.
Material evidence that the black-fronted duiker occurs in Nigeria (horns and
hair tuft) was first obtained by L. Werre from G.E. Pabai of Azama in August 1994.
Thereafter full skins were supplied by Pabai (two specimens from Azama, localities
# 6 and # 7) and A. Koru (one specimen from Gbanraun, locality # 8).
LEVENTIS’ record in the western Delta is supported by results of interviews
made in 1996 at Oghara in the neighbourhood of Sapele (ca 5°55’N 5°42’E, locality
# 2). The informants knew the species as an inhabitant of swamp riverside, present
but scarce around Obromudu though probably absent near Oghareki, and had a
Fig. 2. — Distribution map of black-fronted duiker in Nigeria. Open circles (symbols 1-5, 9-14) rep-
resent reports from informants; closed symbols (6-8) indicate localities from which specimens have
been obtained. Stippled areas represent selected regions where the species is not believed to occur.

92
C.B. Powell and P. Grubb
name for it in the Urhobo language. It is also reported from Upomami (locality #
3). Interviews made in November 1996 reveal that the species occurs in the vicinity
of Tebidaba town (ca 4°35’N 5°58’E; Olugboagbene on maps, locality # 9) on the
left (east) bank of the Tebidaba River, Southern Ijaw Local Government Area,
Bayelsa State. Interviewees record it also from Diebu (ca 4°38’N 6°10’E, locality #
10), Bayelsa State. S. Angadigha, who has proved to be a very reliable field observ-
er, saw many tracks in the Egbema-Angalabiri area in August 1997 (locality # 5).
His brother reported that tracks could still be seen in 1997 at their father’s camp in
the eastern end of the freshwater forest block north of the creek linking the Brass
and St Nicholas estuaries (locality # 13), opposite Otokolopiri camp. It is known on
the coastal barrier islands eastward to the New Calabar River. Several informants
reported it from Ramos-Dodo barrier island (locality # 4), including 80 year-old
retired travelling hunter chief B. Dazide of Forcados, who knew it mostly from
Aghoro (5o08’N 5o27’E); there are also several records from lower Nikrogha Creek,
for example from 70 year-old B. Tuduo at Ekogbene (5°09’N 5°34’E). Hunters at
Andoni and Ukubie knew “ogodo”, an Ijaw name for the species, also called “bure”
or “bura”, and used to hunt it at Abissa (4°24’N 6°46’E, locality # 14), on the barri-
er island between the San Bartholomeo and Sombreiro Estuaries (coastline at
6°50’E), Rivers State.
The easternmost record concerns reports of the species from the lower Imo
River swamps, near the confluence of the Imo and Otamiri Rivers. L Nwenke, an
old hunter at Akwa-Etche, Rivers State (west of Imo river, about 24 km west-south-
west of Aba, ca 5°02’N 7°10’E, locality # 15) identified a skin as “okisi-omacha” and
distinguished it from “okisi”, Cephalophus ogilbyi (Waterhouse 1838), which as he
correctly stated has thicker horns. Okisi-omacha lived in wet places, he said, and
had last been killed in the area in 1959.
There are other reports of local extinction. Hunter and teacher K. Okatubo
remembered it to have been present at Okoroba, Bayelsa State (locality # 10), in his
youth. A 60 year-old hunter friend of Simon Angadigha had never seen the species
at Agudama-Ogbia but knew it was present there before he started hunting. Sunday
Angadigha, who often hunted in the next river to the east (Eminiama-Obama-
Akakumama stretch and tidal freshwaters), had never seen it there, nor at Etiema
still farther east.
Further negative evidence indicated the distribution limits of the black-front-
ed duiker in Nigeria. It is absent from two islands flanking the mouth of the Forca-
dos River (coastline at 5°20’N) and has not been found by hunters operating on the
Bonny and Andoni barrier islands (coastline at 7°10’-35’E), who knew of it from
elsewhere. It was also unknown to hunters in the northern flood-forest zone of the
Delta from Yenagoa northward, where the soil is dry during the dry season but
under water during the Niger flood.
The black-fronted duiker appears to be locally common in the marsh forest zone
of the Delta, from where it probably extends or extended eastwards and westwards
where swampy habitats are available over an area some 150 km in maximum extent.
SPECIMENS EXAMINED
Specimens obtained from Nigeria have been compared with material from Cameroon
in the Natural History Museum, London (BM):

Black-fronted duiker new for Nigeria
93
BM 94.464. East side of Pennington River, opposite Gbanraun (4o48’N 5o54’E, locality #
8), Nigeria.
BM 95.245. Swampy area of Azama and Kassama common land (4o53’N 5o59’E, locality
# 7), Nigeria.
BM 95.215. Sampoi-Apoi, north-west of Azama (4o55’N 5o58’E, locality # 6), Nigeria.
BM 32.6.19.8. Njangong, Cameroon.
BM 36.10.28.32, 36.10.28.33. Oballa’s village (Arteck), Batouri district, Cameroon.
BM 49.104, 49.105. Meyoss, Batouri district, Cameroon.
Within the sample of five skins from Cameroon, there is variation in the general body
colour (deep reddish-mahogany to a lighter orange-chestnut); the development of a black line
down the neck, and black streaking on the withers; the intensity of brown or black markings
on the limbs; whether the blackish fetlock marks extend up the hind-shank; and the amount
of red speckling invading the black frontal blaze. The Nigerian skins are neither as richly
coloured as the darkest Cameroon skin nor as orange as the lightest skins.
Number 94.464 is in pieces; brown of pasterns extends as a narrow line up the back of
the hind shank to the black patch on the hock and about half-way up on the front; whole of
the lower forelimb greyish brown; frontal blaze very black, so that red supraorbital streaks
are isolated from the red tone in the crest.
Number 95.245 has similar colour; neck and withers streaked black; inside of the lower
forelimb streaked blackish and yellowish; hind pasterns dark blackish brown with median
streak reaching about half way up to hock; blackish streak on hock and pastern marks not
joined; rest of hindleg paler, yellower than the body.
Number 95.315 is not so red; blackish streaking on neck and withers very diffuse and
rather faint; blackish pasterns connected to hock patch by a narrow line.
The material available for examination is indistinguishable from the very widespread
nominate race C. nigrifrons nigrifrons, which is now seen to be discontinuously distributed.
BIOGEOGRAPHY
The Niger Delta lies within a Center of Endemism that includes unique
species and subspecies of mammals, as well as some isolated populations of other-
wise widespread species (GRUBB 1990). In the late Pleistocene, tropical aridity dur-
ing high-latitude glacial maxima led to contraction of Africa’s forests (HAMILTON
1988). The fauna of the Niger Center may have survived this adversity in a refuge
from which many species were excluded. The bongo, Tragelaphus eurycerus (Ogilby
1837), and golden cat, Profelis aurata (Temminck 1827), for instance, are absent
from Nigeria but occur farther to the west and east. The mammals of the Niger
Delta were poorly known even recently (HAPPOLD 1987) but much new information
is now available (POWELL 1997). New discoveries and systematic revisions are aug-
menting the diversity of the Niger Center (CORBET 1969, GRUBB & POWELL 1999,
GRUBB et al. 2000). The fauna includes not only this geographically isolated and
localised population of the black-fronted duiker but also a subspecies of another
wetland ungulate, the pygmy hippopotamus, Hexaprotodon liberiensis heslopi (Cor-
bet 1969), possibly now extinct. Other endemic taxa include new subspecies of red
colobus monkey, Procolobus badius epieni Grubb & Powell 1999, and white-throated
guenon, Cercopithecus erythrogaster pococki Grubb, Lernould & Oates 2000, togeth-
er with Sclater’s guenon, C. sclateri Pocock 1904 (OATES et al. 1992). Widely distrib-
uted species with isolated populations restricted to the Delta include the black-bel-
lied pangolin, Phataginus tetradactyla (Linnaeus 1766), olive colobus, Procolobus
verus (Van Beneden 1838), Bates’ pygmy antelope, Neotragus batesi De Winton 1903

94
C.B. Powell and P. Grubb
(POWELL 1995), and the long-nosed mongoose, Xenogale naso (De Winton 1901)
(COLYN & VAN ROMPAEY 1994). A population of the localised crested genet, Genetta
cristata Hayman 1940, has also been found in the Delta (POWELL & VAN ROMPAEY
1998). The Delta mammal fauna is a mixture. Olive colobus and pygmy hippopota-
mus are West African species at the eastern end of their range, while the black-
fronted duiker and Bates’ pygmy antelope are Central African species at their west-
ern limits.
ACKNOWLEDGEMENTS
Peter Grubb is grateful to Derek William Yalden for useful comments on the original
manuscript.
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as the name for the Nigerian white-throated guenon. Mammalia 63: 389-392.
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