Anuran surveys in south-western Nigeria

2009·3.1 MB·English

by  Onadeko, A B

Anuran surveys in south-western Nigeria
SALAMANDRA 45 1 1-14 Rheinbach, 20 February 2009 ISSN 0036-3375
Anuran surveys in south-western Nigeria
Abiodun B. Onadeko & Mark-Oliver Rödel
Abstract. We report on the results of amphibian surveys in three south-western Nigerian states: Lagos,
Ogun and Oyo. In total, we recorded between 35 and 38 species. The number of species per state ranged
from 22 to 29. Most species were typical farmbush or savanna frogs. Although the overall species richness
was comparatively low and only a few species were forest specialists, we observed a surprising number of
frogs that could not unambiguously be assigned to described species. This was especially true of the gene-
ra Leptopelis and Phrynobatrachus. Whereas some of these taxa (Leptopelis cf. macrotis, Phrynobatrachus
cf. liberiensis) seem to indicate closer relationships between south-western Nigeria and the Upper Guinea
forests, other findings (the eastern variation of Phlyctimantis boulengeri, Nectophryne afra) indicate the
opposite geographic relation. The position of the study sites between the diversity hotspots of Upper and
Lower Guinea would suggest high anuran diversity. We failed to record such a high diversity, but possibly
found species from both areas and probably undescribed taxa (Phrynobatrachus sp., Leptopelis sp.). We
believe that the high amount of degraded and converted natural forests may have already resulted in an
impoverished anuran fauna. Remarkable and even new species may have survived in some of the small
remaining forests. Intensive surveys and sustainable conservation of the remaining forests of south-wes-
tern Nigeria is therefore highly recommended.
Key words. Amphibia, distribution, diversity, biology, forest, new records, savanna.
Introduction of West and Central African species alike. So
far, about 03 amphibian species, 0 anurans
With 30-40 million people, Nigeria is the and two caecilians, have been recorded from
most densely populated African country. within Nigeria’s borders (IUCN et al. 2006).
The high human population with the result- This is astonishingly few, compared to the ap-
ing pressure on natural habitats, as well as the proximate 200 species of neighbouring Cam-
country’s position of being the twelfth largest eroon (LeBreton 999, Frétey & Blanc
producer of oil, has resulted in a remarkably 2000, IUCN et al. 2006, J.-L. Amiet pers.
high proportion of degraded and converted comm.). However, it is questionable whether
land (www.en.wikipedia.org/wiki/Nigeria; Cameroon is really that much richer in am-
latest accessed 4 May 2007). In contrast, Ni- phibian diversity or if simply Nigeria is less
geria also comprises a great variety of ecosys- well explored.
tems, ranging from mangrove swamps and Many contributions to the knowledge
rainforests along the coast, various types of of the country’s amphibian fauna date back
savanna further north, to finally the Jos-Pla- to the sixties of last century (Schiøtz 963,
teau in Central Nigeria and the south-eastern 966, 967, Walker 966, 967, 968, 969) or
region towards Cameroon offering moun- even earlier (Sanderson 936, Romer 953).
tainous habitats. From a biogeographic point Due to long lasting political unrest, with the
of view, Nigeria is situated between West and exception of a few papers (Akintola 976,
Central Africa, and hence between the bio- Reid 987, Böhme & Nikolaus 989, Reid et
diversity hotspots of the Upper and Lower al. 990) not much has been published on Ni-
Guinea forest regions (Bakarr et al. 2004). gerian amphibians for the last decades. With-
Consequently, Nigeria might be expected to in the last five years several papers on Nige-
harbour high biological diversity composed rian amphibians have appeared again, mainly
© 2009 Deutsche Gesellschaft für Herpetologie und Terrarienkunde e.V. (DGHT)
http://www.salamandra-journal.com 1
Abiodun B. Onadeko & Mark-Oliver Rödel
Fig. 1. Geographic positions of the study sites in south-western Nigeria (compare Appendix 1).
dealing with the Cross River region and the ger, Chad and Cameroon. The Federal Re-
area of the oil rich Niger Delta, including the public comprises 36 states and the Federal
respective environmental problems (Eniang Capital Territory. We investigated the anuran
& Luiselli 2002, Lea et al. 2003, 2005, Aka- fauna of three south-western states: Lagos,
ni et al. 2004). Ogun and Oyo. Lagos, also comprising the
However, still little is known about the sys- homonymous commercial capital, is situat-
tematics, distribution and especially biology ed between 6.4-6.7°N and 2.7-4.6°E. Ogun
of Nigerian amphibians. Remarkable excep- extends between 6.3-7.8°N and 2.7 4.6°E;
tions are the contributions on frog parasites and Oyo extends between 7.-9.2°N and 2.7-
by Aisien et al. (e.g. 200, 2004). Nigeria has 4.56°E. Nigeria is characterised by a South-
lost the large majority of its rainforests and North gradient of precipitation. This is mir-
most of its natural savanna habitats (UICN rored by a gradient of vegetation zones, nat-
996). We know that already minor alteration urally from tropical humid evergreen forests
of natural forest ecosystems in West Africa in the South, gradually transforming into dry
may result in drastically altered amphibian savannas in the North.
assemblages, including the loss of many for- Along the south-western Nigerian coast
est specialists (Ernst & Rödel 2005, Ernst there is a belt of mangrove swamps which
et al. 2006). Hence, an increased effort to as- naturally do not harbour any amphibians.
sess herpetofaunistically unknown parts of However, some species can be recorded just
Nigeria seems extremely pressing. The pri- a few metres from the brackish waters, where
mary aim of this paper is to present the am- this habitat is replaced by freshwater swamps.
phibian results gained throughout several Such areas were located at Ikorodu, Badore,
surveys undertaken by one of us (ABO) in Badagry and parts of Epe (all Lagos state).
the south-western part of Nigeria. North of these swamps, a forest belt does
naturally occur. These forests can be divided
into rainforest and mixed deciduous or dry
Study areas forest. Unfortunately, these forests have been
heavily degraded, fragmented and convert-
Nigeria covers an area of 923,768 km² and is ed by many anthropogenic activities, main-
bordered by the Atlantic Ocean, Benin, Ni- ly cultivation for agriculture. The remaining
2
Anuran surveys in south-western Nigeria
40 350 40 350
35 300 35 300
30 30
250 250
temperature (°C)122505 112050000precipitation (mm) temperature (°C)122505 121500000precipitation (mm)
10 10
5 50 5 50
0 0 0 0
a Jan Feb Mar Apr MayJun Jul Aug Sep Oct Nov Dec b Jan Feb Mar Apr MayJun Jul Aug Sep Oct Nov Dec
40 450 40 300
35 400 35
250
30 350 30
temperature (°C)122505 122350500000precipitation (mm) temperature (°C)122505 121500000precipitation (mm)
10 100 10
50
5 50 5
0 0 0 0
c Jan Feb Mar Apr MayJun Jul Aug Sep Oct Nov Dec d Jan Feb Mar Apr MayJun Jul Aug Sep Oct Nov Dec
Fig. 2. Monthly rainfall (black triangles) and monthly average maximum (open squares) and minimum
(open circles) temperatures in a) Ijebu-Ode (data from 2003), b) Ikeja (2003), c) Ibadan (2003) and d)
Ilorin (2002).
forests hence mostly comprise secondary or Climatologically, the three states are charac-
tertiary vegetation, characterised by dense terised by a rainy season from April to Oc-
undergrowths and an open or broken cano- tober and a dry season from November to
py. Farmland, secondary and tertiary forests March. The climate of four south-western Ni-
were encountered at Ikorodu, Ogijo, Ishara, gerian towns is summarized in Fig. 2.
Ijebu Oru, Ikenne, Onidundun and Fiditi.
There only a few pockets of primary or near
primary forest were left. Further north, this Material and methods
zone is replaced by natural and derived sa-
vanna, partly comprising a forest-savanna Our surveys were performed between July
mosaic, especially where cultivation is less 2003 and December 2004. The most intense
dominant. Examples from this zone were survey time was during the rainy season
Onidundu, Fiditi, Oolo, Ibapon Oyewale and which at the same time is the breeding pe-
Ogbomosho. The northernmost collection riod of most amphibian species. Between two
sites were situated in the moist woodland sa- and four people were engaged in surveying.
vanna zone (Guinea savanna), characterised Surveys were normally undertaken during
by tall grass with fire resistant trees. Collec- the morning and evening hours. Geographic
tion in this zone was done in areas north of positions were taken with a hand-held GPS
Ogbomosho, including Gambari and Otte- receiver (Garmin eTrex). A short habitat
Egba, an area close to Ilorin. characterisation was noted for each location
A list of all study sites including a short investigated and all anurans were registered
habitat description is given in Appendix . along with their respective habitats and loca-
3
Abiodun B. Onadeko & Mark-Oliver Rödel
Tab. 1. Amphibian species recorded in Lagos, Ogun and Oyo States and number of sites where the
respective species have been recorded (compare Appendix 1).
Taxon Lagos Ogun Oyo
Pipidae
Silurana tropicalis 7, 9, 0 3, 9,  , 2
Xenopus muelleri 4, 8, 9, 0 2, 3,  2, 6, 0
Hemisotidae
Hemisus cf. guineensis 9 , 3, 0, 
H. marmoratus 2, 3, 7
Bufonidae
Amietophrynus maculatus 2, 3, 6-0 -2 -2, 4-8, 0, 
A. regularis -4, 3, 4, 6, 8, 0 -3, 5-7, 9-2 2, 3, 5-8, 0, 
Nectophryne afra 
Dicroglossidae
Hoplobatrachus occipitalis , 5, 8- 2-5, 0,  , 2, 5, 6, 8
Ranidae
Hydrophylax albolabris 7, 9 2, 8, 0, 2
H. galamensis 2, 6 , 2, 6, 9
Aubria subsigillata 6-8 , 3, 9, 0 2, 3
Ptychadenidae
Ptychadena aequiplicata 9,  2
P. bibroni , 3, 5, 8 , 2, 4, 0,  2, 3, 5, 6
P. longirostris 8, 9 
P. mascareniensis , 0,  3, 4, 0,  2, 3
P. oxyrhynchus , 6, 0,  , , 2 2, 5
P. pumilio -6, 8,  -4, 6, , 2 2, 3, 5, 6, 8-
Phrynobatrachidae
Phrynobatrachus accraensis , 2, 6, 8, 0 4, 9,  2, 9, 0
P. francisci 7, 9 3, 7, 9 2, 9, 0
P. cf. liberiensis 7
P. plicatus 2
P. sp. 9
Arthroleptidae
Arthroleptis spp. (2-4 species) 7-9 2, 3, 8, 9, , 2 2
Leptopelis cf. macrotis 0
L. cf. occidentalis/boulengeri 6, 0
L. sp. 9
L. viridis 7-9 , 3, 5, 7, 8 3-5, 7, 9
Hyperoliidae
Afrixalus dorsalis , 4, 5, 8,  5-7, 9,  2, 5
Hyperolius concolor 3, 4, 8 6, 8, 9, , 2 2, 3
H. fusciventris 3-8,  2, 6, 8-2 2-4, 6
H. guttulatus 4, 0 6,  
H. nasutus 5
H. nitidulus 2-4, 7, 9, 
Kassina senegalensis 7, 0
Phlyctimantis boulengeri 2
4
Anuran surveys in south-western Nigeria
tions. Specimens were located opportunisti- Accounts of selected species
cally by thorough visual scanning of the par-
ticular environment and careful examination We herein refer to species of particular inter-
of suspected hiding places, e.g. under stones, est concerning rarity, distribution or taxon-
fallen wood, between leaves, among leaf lit- omy or to interesting observations on habi-
ter etc. Most of the specimens were released tat choice and/or biology. For descriptions
after determination and recording of their of the species’ general distributions and nat-
characters. Measures were taken with a cal- ural history data we refer to Schiøtz (963,
liper (± 0. mm). Voucher specimens of all 967, 999), Rödel (2000) and IUCN et al.
species were collected, anaesthetized with (2006).
chloroform and subsequently preserved in 0
% formalin. Most vouchers are deposited in Xenopus muelleri (Peters, 1844) and
the collection of the Department of Zoology, Silurana tropicalis Gray, 1864
University of Lagos. Some vouchers will later These species seem to survive the dry season
be deposited in the collection of the Museum by either migrating into streams or other per-
of Natural History, Berlin (ZMB). Nomencla- manent waters or by hiding in wet mud or
ture follows Frost et al. (2006) and Frost beneath leaves (Schiøtz 963, Rödel 2000).
(2007). We recorded Xenopus muelleri as fairly abun-
dant at Ijebu Oru (Liberian Refugee Camp),
Onidundun and Abowa. The sites at Ijebu
Results and discussion Oru and Abowa were located near a forest,
while Onidundun was a muddy patch in a
In total we recorded between 35 and 38 species rice farm. These sites all dried up during the
in the three south-western states (Table ). dry season. In a drying savanna pond at Oolo
Within the genus Arthroleptis, we most prob- we collected some X. muelleri from the mud.
ably recorded between two and four species. We discovered further X. muelleri in holes,
However, because of the lack of acoustic and about half a metre depth, around the drying
genetic data, and the morphological similar- up pond.
ity of species in this genus, a more precise fig- Most of the registered S. tropicalis were
ure and exact species names cannot be given found at Onidundun in a pool not far from a
(cf. Rödel & Bangoura 2004). We therefore large stream, close to a forest. However, oth-
conservatively count all Arthroleptis records er specimens were collected near Ogbomoso
as belonging to one species. In Lagos state in a savanna region. We dug them up on the
we recorded 22 species (62.9 %), in Ogun banks of dried up ponds at Onidundun.
state we registered 29 species (82.9 %) and
in Oyo state we encountered 25 species (7.4 Hemisus marmoratus (Peters, 1854) and
%). Without considering the Arthroleptis spe- Hemisus guineensis Cope, 1865
cies, we analysed to what extent the anuran These predominantly fossorial frogs were
fauna in the three states was either dominat- collected at various sites, mostly by digging
ed by forest or savanna species. As expected soil on farmland. Most likely two species are
the northernmost state Oyo had the highest involved, namely the savanna dwelling Hemi-
proportion of savanna species, i.e. 9 out of sus marmoratus and the forest species H.
24 (79.2 %). In Ogun state, about half each of guineensis. However, both apparently com-
the 28 species were forest (46.4 %) and savan- prise complexes of species and despite the re-
na (53.4 %) specialists, respectively. In Lagos vision of the genus by Laurent (972) even
state, one third, i.e. 7 of all 22 (3.6 %) species, the distinction between the two names is not
preferred forest habitats, while the remaining well understood. Specimens collected from
5 were savanna species. Ijede and Abowa were larger (snout-urostyle-
5
Abiodun B. Onadeko & Mark-Oliver Rödel
length – SUL - males: 4.0-4.9 cm, females:
4.5-5.4 cm) than those collected from Fiditi
and Ibapon Oyewale (males: 2.2-4.0 cm, fe-
males: 3.6-4.2 cm). We tentatively assign the
larger Hemisus to H. guineensis, the small-
er ones to H. marmoratus (compare Rödel
& Ernst 2003). The H. guineensis localities
were in forest or former forest.
Nectophryne afra Buchholz & Peters in
Peters, 1875
So far the westernmost known locality of this
small Central African toad was in the Niger
Delta, West of the River Niger (Bouleng-
Fig. 3. The tree toad Nectophryne afra from Ogun
er 93, Perret 966, Schiøtz 966). Our
State.
records from a secondary forest with sparse
undergrowth close to the Oru River at Ijebu are consumed locally directly by villagers or
Oru is hence an expansion of the known dis- smoked and sold on local markets (A.O. and
tributional range. This toad is known to breed M.-O.R. unpubl. data).
in water-filled tree holes (Scheel 970). We
observed it a few metres above ground climb- Ptychadena aequiplicata (Werner, 1898)
ing on plants. The SUL was .9 cm. The toad We recorded Ptychadena aequiplicata mostly
had a greenish brown back with three trans- from secondary and primary forests that had
verse yellow lines, additional yellow spots little undergrowth (cf. Rödel et al. 2002).
could be observed on the flanks (Fig. 3). The During the rainy season puddles accumulat-
yellow pattern was also present on the hind ed in these parts of the forest. They were col-
legs. The webbing between the thumb and lected at Ijebu Oru and Ijede. Schiøtz (963)
the first finger was yellow, the remaining part collected this species from Yemoji and Gilli-
being orange-brown. The toad only moved gilli but did no report it from south-western
slowly in a very clumsy way. Nigeria.
Hoplobatrachus occipitalis (Günther, 1858) Ptychadena bibroni (Hallowell, 1845)
Adults and juveniles of this frog were collect- This species was often collected together with
ed at most locations though in different hab- Ptychadena oxyrhynchus and P. pumilio. We
itats. This habitat separation has also been once observed a male P. bibroni in amplexus
observed elsewhere (Rödel 2000) and most with a female P. pumilio, but are not aware
likely is due to avoidance of intraspecific pre- if egg deposition had taken place or not. We
dation. Adult Hoplobatrachus are known to dug out a few P. bibroni together with X. mu-
prey on almost anything smaller than them- elleri at a dried up pond at Oolo. This sup-
selves (Rödel 2000), but usually arthropods ports Barbault (972) who stated that these
predominate in the prey (Inger & Marx 96, frogs spent the dry season in the mud of dry
Lescure 97). We observed an adult H. oc- ponds.
cipitalis swallowing a Ptychadena sp. Another
adult H. occipitalis (SUL 9.8 cm) tried to de- Ptychadena longirostris (Peters, 1870)
vour a Bufo sp. (SUL 5.6 cm), but eventually We collected this species at two locations
failed most likely due to the massive produc- only and observed it at another one. Pty-
tion of white toxic secretions by the toad. In chadena longirostris inhabited both tempo-
Nigeria and other West African countries H. rary and permanent ponds in secondary for-
occipitalis, but also many Ptychadena spp., ests. Some were found in puddles on forest
6
Anuran surveys in south-western Nigeria
roads. Ptychadena longirostris is usually con-
sidered a rainforest dweller where it often re-
produces in puddles on forest roads (Rödel
& Branch 2002). However, Schiøtz (963)
wrote that P. longirostris also invades dry for-
ests in Nigeria.
Phrynobatrachus cf. liberiensis Barbour &
Loveridge, 1927
This species is believed to be endemic to the
Upper Guinean forest bloc, where it inhabits
primary and secondary forests close to small
creeks and swamps (Guibé & Lamotte 963,
Rödel & Branch 2002, Rödel 2003). Its
occurrence in Nigeria hence seems unlike-
ly. Nevertheless, we collected a specimen in
a secondary forest in Lagos State that mor-
phologically exactly fits the Upper Guinean
populations. However, as long as genetic and
Fig. 4. A subadult Leptopelis cf. macrotis.
acoustic comparisons are lacking, affiliation
of our voucher to P. liberiensis should be tak-
en as tentative.
Phrynobatrachus plicatus (Günther, 1858)
This species has a southern West African dis-
tribution from Liberia into Nigeria, where it
predominantly inhabits open, swampy rain-
forests (Guibé & Lamotte 963, Rödel et al.
2005a, Leaché et al. 2006, Hillers & Rödel
2007, Segniagbeto et al. 2007). East of the
Cross River, Nigeria, it is replaced by the
similar Phrynobatrachus auritus (Lamotte
& Xavier 966). We recorded the species in a Fig. 5. Leptopelis cf. occidentalis/boulengeri.
secondary forest near Ogijo.
One larger transverse bar was also present on
Phrynobatrachus sp. the lower arms. The venter was white without
We collected a few specimens of an unknown any pattern or with small black spots, espe-
small Phrynobatrachus (SUL ca. .9-2.0 cm) cially in the pectoral region and the corner of
during a light rain from a secondary forest the mouth. The toe tips were slightly enlarged
not far from Ijebu-Ode along the Ijebu-Ode- but did not form a disc. The webbing on the
Ibadan road (Ogun State). All specimens had feet was well developed. The webbing formu-
a dark, almost black, head and eyelids. The la (sensu Rödel & Ernst 2002) was:  (0), 2
back was orange-red and the extremities were (0.5-0), 3 (), 4 (2), 5 ().
brown. On the eyelids and the forehead a few Compared to similar sized West African
larger warts were discernible. There were Phrynobatrachus these frogs differ as follows:
no warts or ridges on the back. The slightly from P. annulatus, P. calcaratus, P. taiensis
granular back was almost coloured uniform and P. villiersi by lacking an eyelid cornicle
red-brown. The hind legs bear one large dark, (cf. Perret 988); from all these species and
transverse bar on thighs and lower legs each. P. gutturosus and P. tokba by the extensive
7
Abiodun B. Onadeko & Mark-Oliver Rödel
webbing (Rödel 2000, Rödel et al. 2005b); descriptions of Leptopelis occidentalis and L.
from P. annulatus, P. ghanensis, P. taiensis boulengeri. The dorsal coloration best fitted L.
and P. villiersi by a different ventral pattern occidentalis. “Real” L. occidentalis are known
or colour (Guibé & Lamotte 963, Perret from Liberia to central Ghana and “real” L.
988, Rödel & Ernst 2002); from all other boulengeri have been recorded from the Ni-
species, except P. fraterculus (but completely ger Delta south to the Democratic Republic
different body shape, see e.g. Fig. 3 in Rödel of Congo. According to Schiøtz (999), sim-
& Bangoura 2004), by lacking discernible ilar frogs have been occasionally collected
warts or ridges on the back, i.e. in the neck in western Nigeria. Without call recordings
region. (different voice in both species) and/or ge-
We hence believe these frogs may repre- netic analyses it is currently impossible to as-
sent an undescribed species, possibly en- sign these frogs with certainty. L. occidentalis
demic to south-western Nigeria, but refrain inhabits almost exclusively primary rainfor-
from describing it before its taxonomic po- est in the Upper Guinea region. L. bouleng-
sition can be clarified by acoustic and/or ge- eri seems to choose similar habitats (Perret
netic data. 966, Amiet 986). Our frog was collected
in a rubber plantation that enclosed a small
Leptopelis viridis (Günther, 1869) swamp with tertiary vegetation.
Farmers reported that Leptopelis viridis were Another juvenile Leptopelis sp. was caught
dug up during the dry season while they were about 0 km from Ijebu Ode, sitting on a fern
tilling their lands in preparation for the com- in a secondary forest that encircled a swamp.
ing rainy season. Subterranean aestivation This small frog (SUL: . cm) had a very broad
and cocoon formation were also reported by head, much wider than the body. The dorsal
Lamotte (967), Walker (968), Barbault coloration was dark green with conspicu-
(972) and Grafe (2000). Schiøtz (967) ous white spots on the heels and the elbows,
collected this species from Iperin and four hence not fitting any described West African
miles north of the University in Ibadan. Leptopelis (Rödel 2007). Another white spot
was situated below the eyes. The hind limbs
Leptopelis cf. macrotis Schiøtz, 1967 were fully webbed. We cannot decide wheth-
This species is the largest of the West African er this is a juvenile of the above mentioned
treefrogs (Schiøtz 967, 999); however, the species or represents another, potentially un-
SUL of the sub-adult female that we collected described treefrog.
was 5.2 cm only. Our decision to tentatively
assign the frog to L. macrotis was due to its Hyperolius fusciventris burtoni
coloration (Fig. 4) and the fully webbed feet Schiøtz, 1963
(cf. Schiøtz 967, 999). So far this species Most Hyperolius fusciventris burtoni were col-
has been only recorded from rivers in pri- lected from leaves of the oil palm tree, Elais
mary forests ranging from Sierra Leone into guineensis. Abandoned farmlands near ponds
western Ghana (e.g. Rödel & Branch 2002, or streams also served as habitats. Schiøtz
Rödel et al. 2005a, Hillers & Rödel 2007). (963, 967) collected specimens from Iperin,
We collected the frog in a secondary forest Ijebu Oru, south of Oyo and 9 km north of
beside a river along the Shagamu-Benin ex- University of Ibadan.
pressway.
Hyperolius concolor ibadanensis
Leptopelis cf. occidentalis/boulengeri and Schiøtz, 1967
Leptopelis sp. Hyperolius concolor ibadanensis were collect-
This is a medium sized treefrog with a SUL ed mostly in the forest region around ponds
of 4.6 cm (Fig. 5). The white spot beneath the at Onidundu, Ikenne, Ijebu Oru and on the
eye and the amount of webbing best fitted the campus of the University of Lagos. In the for-
8
Anuran surveys in south-western Nigeria
est zone they could be found throughout the geriensis (F), A. vittiger (S), A. weidholzi (S),
year in thick vegetation close to water sourc- Hyperolius sylvaticus (F) and Chiromantis
es. rufescens (F; for exact localities cf. Schiøtz
963; taxonomy adopted to current names; F
Hyperolius guttulatus Günther, 1858 = forest, FB = farmbush, S = savanna).
The majority of individuals of the extremely
variable Hyperolius guttulatus (cf. Schiøtz
967, Rödel 2000) were observed in swamps Conclusions and recommendations
with large stagnant ponds, having dense veg-
etation, especially floating Pistia sp. in sec- We recorded a surprisingly high number of
ondary forests and farmbush habitats. Ac- unexpected frog species, especially of the
cording to Schiøtz (967) a typical habitat of treefrog genera Leptopelis (L. cf. macrotis, L.
H. guttulatus comprises a large swamp with cf. boulengeri/occidentalis, L. sp.) and Necto-
open water surrounded by shrubs but not by phryne, as well as within the leaf litter genus
closed forests. We also collected a few speci- Phrynobatrachus (P. cf. liberiensis, P. plicatus,
mens from leaves of oil palm trees. P. sp.). Some of these species may be new to
science. If our tentative determinations prove
Phlyctimantis boulengeri Perret, 1986 to be correct, this would indicate a potentially
This treefrog is known from two disjunct ar- high anuran diversity comprising faunal ele-
eas: (i) coastal Cameroon (including the type ments from the Upper (e.g. Phrynobatrachus
locality) and further south plus easternmost liberiensis) and Lower Guinean (e.g. Nec-
Nigeria and (ii) forests from Sierra Leone tophryne afra) forests, as well as potentially
into western Ghana (Perret 986, Schiøtz endemic species (Phrynobatrachus sp.). The
999, Rödel et al. 2005a, A. Hillers unpubl. overall amphibian diversity of each state, so
data). No records have been reported from far being not only comparatively poor with
in-between. It therefore seemed likely that respect to more western localities (cf. Rödel
these populations belong to two distinct spe- et al. 2004), but being even below that of par-
cies. Our record represents the first record of ticular West African savanna regions (e.g.
a frog in the distributional gap. Based on its Lamotte 967, Nago et al. 2006), seems to
size (SUL: 5.5 cm) and coloration (dorsum contradict these first findings. A likely expla-
beige, hidden part of thighs with traverse nation for these contradictory results is that
yellow and black stripes) our frog resem- south-western Nigeria did indeed harbour
bles more the eastern populations (Schiøtz a very rich amphibian fauna, but due to the
999). The single specimen originated from a tremendous loss of primary habitats a huge
stagnant pond covered by Pistia sp., about 6 number of these species has already been
km north of Ibadan. This pond was bordered lost, or at least is now restricted to very iso-
by secondary forests and farmland. lated remnants of the former habitats. It there
would appear to be extremely important to
protect and maintain the remaining natural
Further anuran records from or near natural habitats, in particular the for-
south-western Nigeria ests (including small fragments) and to sur-
vey further forests for those species that so
Schiøtz (963, 966) lists a few species for far may have escaped our attention.
south-western Nigeria, which have not been
recorded by us. In particular these are: Car-
dioglossa leucomystax (F), Leptopelis spiritus-
Acknowledgements
noctis (F), Phrynobatrachus calcaratus (FB),
P. gutturosus (S-F), P. alleni (F), P. batesi (F, We thank A. Schiøtz for various comments on
determination to be verified), Afrixalus ni- the collected treefrogs, W.O. Odiete for his finan-
9
Abiodun B. Onadeko & Mark-Oliver Rödel
cial support, the staff of the Department of Zool- Boulenger, G.A. (93): On the presence of two
ogy, University of Lagos for their moral backup, closely allied species of toads of the genus Nec-
and J. Penner for compiling figure . tophryne in Cameroon. – Annals and Magazi-
ne of natural History, 8é sér., 2: VIII.
Eniang, E.A. & L. Luiselli (2002): Ikpan wetland
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10