Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 September 2020 | 12(10): 16900–16903
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
doi: https://doi.org/10.11609/jott.5876.12.13.16900-16903
#5876 | Received 18 March 2020 | Final
received 15 August 2020 | Finally accepted 04 September 2020
Range extension and first
confirmed record of the Flightless Anomalure Zenkerella
insignis (Matschie, 1898) (Mammalia: Rodentia: Anomaluridae) in Nigeria
Dolapo Oluwafemi Adejumo
1, Taiye Adeniyi Adeyanju
2 & Temidayo
Esther Adeyanju 3
1,2,3 Department of Wildlife and
Ecotourism Management, Ornithology and Wildlife Conservation, University of
Ibadan, Nigeria.
1 oadejumo225@stu.ui.edu.ng (corresponding author), 2 at.adeyanju@mail1.ui.edu.ng,
3 temidayoadeyanju@gmail.com,
Editor: Giovanni Amori,
CNR-Research Institute on Terrestrial Ecosystems, Rome, Italy. Date
of publication: 26 September 2020 (online & print)
Citation: Adejumo, D.O., T.A. Adeyanju
& T.E. Adeyanju (2020). Range extension and first
confirmed record of the Flightless Anomalure Zenkerella
insignis (Matschie, 1898) (Mammalia: Rodentia: Anomaluridae) in Nigeria. Journal of Threatened Taxa 12(13): 16900–16903. https://doi.org/10.11609/jott.5876.12.13.16900-16903
Copyright: © Adejumo et al. 2020. Creative Commons Attribution
4.0 International License. JoTT allows unrestricted use, reproduction, and
distribution of this article in any medium by providing adequate credit to the
author(s) and the source of publication.
Funding: Rufford Small Grants [No. 78ca1b-1].
Competing interests: The authors
declare no competing interests.
Acknowledgements: We appreciate the Rufford Small Grants for funding the field survey of Bats
of Omo Biosphere Reserve (OBR) during which these
observations were made. We appreciate Chief Gbade Adejumo for his logistical support, field assistants
“Daniel and Baba Soldier” for their stimulating companionship during the survey
(real names withheld), the Forest Research Institute of Nigeria (represented by
Mr Clifford Omonu) and the Ogun State Forest Project
at OBR for their collaborative support which made our stay in Omo Reserve possible. Finally, we appreciate all the
communities of Omo Biosphere Reserve for their
accommodative support and the University of Ibadan for releasing ATA.
The Cameroon Scaly-tail Zenkerella insignis (Matschie,
1898) is one of the least studied of African mammals. It has so rarely been encountered that
virtually nothing has been published about its behaviour, feeding habits, and
time budgets (Heritage et al. 2016). The
species was previously classified in the genus Zenkerella
under the family Anomaluridae along with Idiurus and Anomalurus
(Kingdon, 2013), though Marivaux et al. (2017) adds a
fourth genus Anomalurops. The new study by Fabre et al. (2018),
however, puts the genus Zenkerella under a new
completely different well-circumscribed family called Zenkerellidae
based on new phylogenetic results. This
puts Anomaluridae and Zenkerellidae
as two separate families under the Suborder Anomaluromorpha,
which are endemic to the thick rainforest habitats of western and central
Africa (Kingdon 2013) and peculiar among mammals for
the two rows of pointed scales on the ventral side of their tufted tail, which
helps them to climb in the forest canopy (Marivaux et al. 2017; Fabre et al.
2018).
Cameroon Scaly-tail Zenkerella insignis stands out from the rest
of the suborder. It is presently the
only known species in the family Zenkerellellidae and
it lacks patagia, the membranes possessed by the genera in Anomaluridae
which enable them to glide, similar to gliding squirrels (Kingdon
2013; Heritage et al. 2016; Marivaux et al. 2017). Kingdon (2013)
suggests the absence of patagia could be an adaptive feature for the species,
enabling it to adapt to very thick vegetation.
Zenkerella has been viewed as an
important example of macroevolutionary reversion in the development of locomotory adaptations because it is assumed that the
species lost its patagia and hence its ability to glide (Fabre et al.
2018). Molecular analysis, however,
proves that the species is from a lineage called Zenkerellidae,
a distinct non-gliding, and long-lived lineage.
This would mean that the lineage never developed patagia or any
adaptation that enables gliding flight, rather than having lost its
capabilities of performing gliding flight (Fabre et al. 2018; Heritage et al.
2016).
Remarkably, the first pictures of
a live specimen of Zenkerella insignis
were taken in 2015 on the Island of Bioko by Curtis Hart (Dinets
2017). Dinets
(2017) also recorded his encounter with a Zenkerella
in the lowland forest of the Dzanga-Sangha Special
Protected Area in the central African republic (Dinets
2017). From his observations, the
specimen had a preference for dense thickets and was nocturnal, observed at
22.00h, a possible reason why it was so rarely seen and observed in the wild (Dinets 2017).
We encountered the elusive and
mysterious flightless Cameroon Scaly-tailed on 17 May 2019. We were in the Queen’s Forest (core zone) of Omo Forest Reserve sitting under a short tree at 6.756N
& 4.353E from 18.00h. The
vegetation at that particular location was relatively dense and shrubby with
little undergrowth. At about 20.08h, we
heard something rustling just above where we were seated. We put on our headlights and saw the
scaly-tail on the branch directly above us.
We were instantly interested in the specimen because of its tail tuft
which stood out unlike in any other previously observed species in the forest
reserve. The tail tuft is the shape of a
spherical fan. The branch was at a
height of about 5m above the ground.
When we put on our headlights, the animal ceased moving for a few
seconds and just glared at the light source similar to what was previously
observed by Dinets (2017). Then, it started traversing the tree branch
going up and down. This could be a
display of territoriality, seen in some male and female rodents, or
investigative behavior. It could also be a protective display to
ensure it is not followed back to its young ones if it had any. This behaviour would have been easier to
understand if we could tell the sex of the specimen. Its territorial behaviour was further
confirmed when the specimen urinated directly on the branch and upon us. Observations continued for about 19 minutes
while pictures were taken.
Unlike other rodents, the
specimen showed no signs of fear, probably because it had never seen or
interacted with humans before. It seemed
simply curious, looking down from different positions on the branch to get a
better view of us.
The specimen had a dark grey body
pelage (Image 1). The tail tuft and
ankle tuft (both visible in Image 3, 7) were clearly black in colouration. It is also noticeable that the ear of the
observed specimen lacked fur and was almost bare even on the outer surface of
the ear (Image 2).
Similar to the observation by Dinets (2017), the tail of the specimen was kept straight
out from the specimen’s body and was used as a rudder. Unlike descriptions from previously curated
specimens, the observed Zenkerella had tail
hair that stood straight on end in a spiky manner rather than the bushy hair
depicted from curated specimens (Image 3, 7).
Dinets (2017) suggested that the very
conspicuous tail tuft is used for either intraspecific signaling
or to distract predators from vital parts of the body.
Another observation made was that
the specimen had two prominent maxillary incisors that were larger than the
mandibular incisors visible in Image 4 and 6 (Heritage et al. 2016). The specimen also had four and five digits on
its fore and hind feet respectively and all digits ended in decurved claws
(Image 3, 5, 6) (Heritage et al. 2016).
This is the first confirmed
record of the Cameroon Scaly-tail Zenkerella
insignis in Nigeria and the first set of clear pictures showing accurate
morphological descriptions of the species.
This find is quite remarkable because it extends the species’ range
significantly westwards across important biogeographic boundaries such as the Cameroonian
volcanic range and across the large Cross and Niger rivers. Given the distance of over 800km from the
previously described sightings, the observation could very well be a subspecies
or a new species in the Zenkerella genus.
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