The earliest history of the Felidae in Africa is
brief yet difficult to interpret. From ca 12.5 Ma
(middle Serravallian) onwards there is a reason-
ably continuous record, including taxa such as
Machairodus that are also well known from other
continents (Sardella & Werdelin, 2007; Werdelin
& Peigné, 2010). However, before this time there
are only two published records of Felidae, both
from Arrisdrift in Namibia, dated to ca 17-17.5 Ma
(i.e. middle-upper Burdigalian) on biostratigraphy
(Pickford & Senut, 2003). Other records of early
Felidae in Africa, such as Pseudaelurus africanus
(Andrews, 1914) are currently referred to Afro-
smilus, which is now considered to belong to the
distinct family Barbourofelidae (Morales et al.,
Two species, Diamantofelis ferox and Dia-
mantofelis minor, were originally described from
Arrisdrift (Morales et al., 1998), with the latter sub-
sequently transferred to a separate genus, Namafelis
(Morales et al., 2003). These two species share a
number of traits, as indicated by their original
A new genus and species of Felidae (Mammalia) from
Rusinga Island, Kenya, with notes on early Felidae of
Un nuevo género y especie de Felidae (Mammalia) de la isla de
Rusinga, Kenia, con notas sobre los primeros Felidae de África
The lower Miocene (Burdigalian) deposits of the Hiwegi Fm., Rusinga Island, Kenya, have yielded a
single specimen of a small felid. This specimen, here identified as the holotype of a new genus and
species, is of the size of the smallest living Felidae. It shows some features of primitive, “
grade” cats, but also features of both morphology and metrics that are intermediate between this grade
and modern Felidae, suggesting a transitional taxon. This is in contrast with
from Namibia, which, though aberrant, are more clearly of “
-grade”. The Rusinga speci-
men is the most derived felid specimen of the lower Miocene.
Keywords: Africa, Kenya, Rusinga, lower Miocene, Felidae.
Los depósitos del Mioceno inferior de la formación Hiwegi, en la Isla de Rusinga (Kenia), han propor-
cionado un espécimen aislado de un pequeño félido. Esta pieza, identificada aquí como holotipo de un
nuevo género y especie, es del tamaño del félido actual más pequeño. Presenta algunos caracteres de
los félidos primitivos de “grado
”, pero también rasgos tanto métricos como morfológicos
que son intermedios entre este grado y los Felidae modernos, sugiriendo que se trata de un taxón tran-
sicional. Por el contrario,
de Namibia, aunque de morfología aberrante, son
más claramente del “grado
”. El espécimen de Rusinga es el félido más derivado del Mio-
Palabras clave: África, Kenia, Rusinga, Mioceno inferior, Felidae.
1Department of Palaeozoology, Swedish Museum of Natural History, Box 50007, SE-104 05 Stockholm, Sweden.
Estudios Geológicos, 67(2)
julio-diciembre 2011, 217-222
e390-11 Werdelin.qxd 30/1/12 14:18 Página 217
placement in a single genus (Morales et al., 1998).
From the perspective of functional morphology and
ecology, their most important features are those that
differentiate them from Afrosmilus [and, by impli-
cation, from the Barbourofelidae as a whole
(Morales et al., 2001)]. These features include a
rounded symphysis, non-compressed canine, and
short post-canine diastema. However, Diamantofe-
lis and Namafelis also share some features that dis-
tinguish them from contemporary Eurasian Felidae
of the genera Pseudaelurus and Styriofelis
(Werdelin et al., 2010), including a short and high
mandible, and shorter diastema. In addition, at least
N. minor has a well developed talonid on m1, with
a single, centrally positioned cusp, somewhat remi-
niscent of the m1 of the hyenid Chasmaporthetes
(Kurtén & Werdelin, 1988). The only other pre-
sumed felid with an m1 talonid of similar appear-
ance is Pratifelis kansensis (Hibbard, 1934) of the
Hemphillian of Kansas, USA (late Miocene or earli-
est Pliocene), though the latter is a much larger
species, and differs considerably in other respects
from the Namibian forms. The relationships of the
Arrisdrift species to other felids and, indeed, the
question of whether they are felids at all [and not
very aberrant barbourofelids - cf. (Werdelin et al.,
2010)], are still moot.
In this communication I report on a third felid
specimen from the Burdigalian of Africa. This
specimen, from Rusinga Island in Lake Victoria,
eastern Africa, is clearly a felid and very distinct
from Diamantofelis and Namafelis. Despite having
been recovered in 1949 (according to the field
number), this specimen has only been mentioned in
the paleontological literature once (Werdelin &
Peigné, 2010) - erroneously as coming from Song-
hor - and then only as Felidae indet. It was not dis-
cussed in either of the two previous works on
lower Miocene carnivores from eastern Africa
(Savage, 1965, Schmidt-Kittler, 1987). The speci-
men shows a number of interesting traits and opens
up new possibilities regarding the early evolution
of Felidae in general and Felinae (the extant cats)
Material and methods
The felid specimen from Rusinga consists of a small por-
tion of a right mandibular ramus incorporating complete p4-
m1, housed in the Paleontology Department, National Muse-
ums of Kenya, Nairobi. Comparative material of Pseudaelu-
rus sp. has been studied by me at various times in various
museums, and more recently from the published literature.
The majority of measurements of Pseudaelurus spp. were
kindly provided by Dr. Stéphane Peigné, Paris and Dr.
Manuel J. Salesa, Madrid. Measurements of extant felids as
well as of the Rusinga specimen were taken by me with digi-
tal calipers to the nearest 1/100 mm and rounded to the near-
est 1/10 mm. The measurements used are Lp4, Lm1: greatest
mesiodistal length of tooth; Wp4, Wm1: greatest buccolingual
width of tooth; Ltm1: greatest length of trigonid of tooth.
Standard anatomical terminology has been used throughout.
Institutional abbreviations are: KNM: Kenya National Muse-
ums. I am using marine stage names to simplify stratigraphic
terminology and comparisons.
Order Carnivora Bowdich, 1821
Suborder Feliformia Kretzoi, 1945
Family Felidae Fischer von Waldheim 1817
Genus Asilifelis gen. nov.
Type species: Asilifelis coteae gen. et sp. nov.
Diagnosis and description: As for species, below.
Differential diagnosis: Differs from Proailurus in absence of
m2, taller paraconid more equal to protoconid on m1, metaconid
lost. Differs from Styriofelis in p4 with less prominent mesial
accessory cusp, m1 with better developed paraconid (more equal
to protoconid in size), metaconid completely lost (sometimes
present in Styriofelis), and talonid much more reduced. Differs
from Diamantofelis in much less prominent p4 mesial accessory
cusp, much more reduced m1 talonid. Differs from Namafelis in
(apparently) taller main cusp of p4, much more reduced m1
talonid. Differs from all of these in much smaller size.
Etymology: From Swahili asili, origin, ancestor.
Occurrence: R106, Rusinga Island, Kenya; Hiwegi Fm., Fos-
sil Bed Mb. The dating of the Hiwegi Fm. is currently in revi-
sion, but is now considered to be between 18-20 Ma, i.e. lower
– middle Burdigalian (Peppe et al., 2011).
Species Asilifelis coteae sp. nov. (Fig. 1A-C)
Diagnosis: Felidae of very small size, matching the smallest
extant members of the family; p4 short, with accessory cusp
development intermediate between ‘Pseudaelurus-grade’ and
‘Felis-grade’ Felidae; m1 with paraconid size relative to proto-
conid as in extant Felidae: metaconid absent; talonid reduced to
almost the degree seen in extant Felidae.
Holotype: KNM RU 18349, fragment of right mandibular
ramus with complete p4-m1 (Fig. 1A-C).
Etymology: For Susanne Cote, who opened my eyes to the
wonders of the lower Miocene faunas of eastern Africa.
Description: The specimen includes a small portion of the
ramus from just mesial to p4 to the mesial end of the ramus’
ascent towards the coronoid process, with a small portion of the
masseteric fossa preserved. The latter extends to just distal to
the m1 talonid. Neither mental foramina nor any portion of the
symphysis are preserved.
218 L. Werdelin
Estudios Geológicos, 67(2), 217-222, julio-diciembre 2011. ISSN: 0367-0449. doi:10.3989/egeol.40480.185
e390-11 Werdelin.qxd 30/1/12 14:18 Página 218
Both p4 and m1 are essentially complete, lacking only
minute fragments chipped off the major cusps. They are some-
what imbricated, so that the distolingual end of the p4 overlaps
the mesiobuccal end of the m1. There is a slight crack along the
base of the m1 protoconid on the buccal side.
The p4 is slender, with a prominent mesial accessory cusp
and cingulum. The main cusp is tall. Its relative height is
greater than that of most extant Felidae and considerably
greater than that of other lower Miocene Felidae. It approaches
Felis nigripes in this respect, though the p4 of the latter is rela-
tively taller still. Distally, the accessory cusp is prominent but
relatively low. The tooth is then terminated by a short cingulum
that extends around the distal end of the tooth.
The m1 is much longer than the p4. Both paraconid and pro-
toconid are strongly developed, with the latter slightly taller
than the former. The preparacristid is nearly vertical, as is the
postprotocristid. The metaconid is entirely absent and the
talonid is short and very low. The distal end of the tooth has a
short cingulum and minute cingulum cusp. This cingulum
extends along the lingual side of the tooth to the distal end of
Measurements (in mm): Lp4: 5.5; Wp4: 2.4; Lm1: 7.4; Wm1:
2.8; Ltm1: 6.7.
Morphologic and metric comparisons
The first thing to note about RU 18349 is that it
is strikingly modern in appearance compared to
contemporary Felidae. Given the very small size
of the specimen, we can limit our comparisons to
only a few taxa: living species of the genus Felis,
especially those with African distributions: F. sil-
vestris lybica, F. chaus, F. margarita, and F.
nigripes; the smallest species of “Pseudaelurus-
grade”, Styriofelis turnauensis, and the recently
described S. vallesiensis (Salesa et al., in press);
and finally the only other African Felidae of
‘Pseudaelurus-grade’ - Diamantofelis ferox and
Namafelis minor (Morales et al., 2003, Morales et
al., 1998). To place the latter metrically, compar-
isons with larger pseudaelurines such as P. quadri-
dentatus and S. lorteti were also made.
To simplify the following comparisons, Figs. 2A
and 3A illustrate metric relationships of extant Feli-
dae and show that the small available samples of F.
margarita and F. s. lybica do not differ from the
larger sample of F. chaus except in size. Therefore,
the two former species are removed from the com-
parisons with fossil taxa. Felis nigripes on the other
hand, does differ from F. chaus and is retained in
Compared to the fossil taxa listed above, RU
18349 has a markedly reduced m1 talonid, reflected
in the relatively short m1 seen in Figure 2B, where
RU 18349 falls with F. nigripes and close to the
extension of the regression line for F. chaus. It
should also be noted that all but one of the speci-
mens of S. vallesiensis fall within the 95% confi-
dence ellipse for F. chaus. This suggests that the
former species may be transitional in some respects
between the ‘Pseudaelurus-grade’ and the ‘Felis-
grade’. To provide comparisons for D. ferox and N.
minor, Fig. 2C includes a sample of Pseudaelurus
quadridentatus, as well as some Styriofelis lorteti
specimens. This diagram shows that S. turnauensis
that has a somewhat aberrant regression of m1
length and width, and that D. ferox is very close to
P. quadridentatus in the metrics of this tooth, while
N. minor lies close to the regressions of both S. tur-
nauensis and S. vallesiensis.
That the m1 of extant cats is shorter due to the
reduction of the talonid also in part explains the
relatively shorter m1 in relation to p4 seen in these
animals (Fig. 3B). This figure shows three distinct
regressions: one for extant Felis, one for S. tur-
nauensis, and an intermediate one for S. vallesien-
sis. This once again demonstrates the transitional
character of the latter taxon. Both F. nigripes and
RU 18349 fall on or near the extended line from S.
vallesiensis, with RU 18349 slightly above it. This
suggests that despite the reduced talonid and other
characters of the Rusinga specimen, it is still par-
Estudios Geológicos, 67(2), 217-222, julio-diciembre 2011. ISSN: 0367-0449. doi:10.3989/egeol.40480.185
A new genus and species of Felidae (Mammalia) from Rusinga Is., Kenya 219
Fig. 1.—The holotype specimen of
, gen. et sp.
nov., in A) buccal, B) lingual, and C) occlusal view. Photographs
©Kenya National Museums.
e390-11 Werdelin.qxd 30/1/12 14:18 Página 219
220 L. Werdelin
Estudios Geológicos, 67(2), 217-222, julio-diciembre 2011. ISSN: 0367-0449. doi:10.3989/egeol.40480.185
0.80 0.85 0.90 0.95 1.00 1.05 1.10
0.8 0.9 1.0 1.1 1.0
0.8 0.9 1.0 1.1 1.2 1.3
Fig. 2.—Bivariate diagrams of length and width of m1 of select-
ed Felidae as labeled. A) Extant Felidae, with regression line
and 95% confidence ellipse for
All species fall near
the regression line for
. For this reason,
have been eliminated from the overall com-
is retained because of its similarity in size
to the Rusinga specimen. B) Overall comparison of extant and
extinct Felidae, with regression lines and 95% confidence
(solid lines) and
lines). The regressions differ considerably in slope, and the
Rusinga specimen falls nearer the
Comparison of extant and extinct taxa incorporating some larg-
er species. Regression lines and 95% confidence ellipses are
(long dashes). Note the position of
very near the 95% confidence ellipse of
0.60 0.70 0.80 0.90 1.00 1.10
0.65 0.75 0.85 0.95 1.05 1.15
0.7 0.8 0.9 1.0 1.1 1.2 1.3
Fig. 3.—Bivariate diagrams of length of p4 and m1 of selected Feli-
dae as labeled. A) Extant Felidae, with regression line and 95%
confidence ellipse for
F. chaus. Felis silvestris
near the regression line for
and have been eliminated
from the overall comparison.
differs, and has been
retained. B) Overall comparison of extant and extinct Felidae, with
regression lines and 95% confidence ellipses for
(dashed lines), and
lines). The regressions are similar in slope but differ in location. The
Rusinga specimen falls near the
regression, as does
. C) Comparison of extant and extinct Felidae including
some larger species
Regression lines and 95% confidence ellipses
are shown for
(dotted lines), and
lines). Note the position of
95% confidence ellipse, and that the regression for the latter taxon
is very similar to that of
e390-11 Werdelin.qxd 30/1/12 14:18 Página 220
tially of ‘Pseudaelurus-grade’ and not yet a mod-
To better place Diamantofelis and Namafelis met-
rically in relation to Eurasian pseudaelurines, a third
diagram of p4 versus m1 length incorporating larger
species was made (Fig. 3C). The smaller Namafelis
minor lies comfortably within the 95% confidence
ellipse of S. turnauensis, while the relative lengths
of p4 and m1 in the larger D. ferox are within the
95% confidence ellipse of P. quadridentatus.
Apart from the features discussed above, that
leave traces in the metrics of the specimens, the
only noteworthy feature of RU 18349 lies in the rel-
atively low mesial and distal accessory cusps on p4.
In felids of ‘Pseudaelurus-grade’ these accessory
cusps are generally larger and more distinctly set
off from the main cusp. At the same time, they are
less appressed to the main cusp than in the majority
of small extant Felidae, thus again representing
something of a transitional form between the
‘Pseudaelurus-grade’ and ‘Felis-grade’ cats. Both
D. ferox and N. minor are of ‘Pseudaelurus-grade’
in this respect.
The existence of a member of the Felidae as
derived as Asilifelis coteae gen. et sp. nov. in the
Burdigalian of Africa is surprising. In Eurasia and
North America, the Burdigalian is the time of diver-
sification of felids of ‘Pseudaelurus-grade, includ-
ing the genera Pseudaelurus, Styriofelis, and
Hyperailurictis (Werdelin et al., 2010). It is not
until much later, around the beginning of the Tor-
tonian (11.6 Ma) that felids of ‘Felis-grade’ appear,
with the first appearance of Pristifelis attica (Salesa
et al., in press). At the same time, since the only
felids of ‘Pseudaelurus-grade’ are the aberrant D.
ferox and N. minor (the felid status of which has
still to be determined), it is not unreasonable that
there is room for one or several small felids in the
The importance of A. coteae gen. et sp. nov. thus
is two-fold: its presence as the only member of its
family in eastern Africa until the latest middle
Miocene, and its derived nature. With regard to the
first, it may be that the plethora of small Viverridae
and Herpestidae in the lower Miocene of Africa
(Morlo et al., 2007, Savage, 1965, Schmidt-Kittler,
1987, Werdelin & Peigné, 2010) excluded Felidae
from these ecosystems. Alternatively, African Feli-
dae may primitively have favored habitats that are
poorly or not at all sampled at these early African
localities. A similar cause may explain the presence
of the ursid Hemicyon sp. at Rusinga, approximate-
ly 10 million years before the next occurrence of
Ursidae on the continent.
The derived nature of the specimen is equally
hard, if not harder, to explain. One could speculate
that competition from the many Viverridae and Her-
pestidae forced a precocious evolution of the lin-
eage into a part of hypercarnivore niche space that
Felidae did not reach elsewhere until much later.
With only one specimen available, there are not
enough data to evaluate this possibility. Nor can we
know whether this African lineage migrated out of
Africa to become the founder of the modern Felidae
radiation - a possibility that does not militate
against the reconstruction of the earliest Felidae
ancestor as coming from Asia (Johnson et al.,
2006), since this only refers to extant Felidae, not to
any possible stem lineage taxa. An origin from
African antecedents would at least explain why
fully evolved Felidae of extant grade, such as P.
attica and Machairodus, appear so abruptly in Eur-
asia near the beginning of the Tortonian. But again,
without more material, this rapidly enters the realm
of pure speculation.
Diamantofelis ferox and N. minor are clearly
‘Pseudaelurus-grade’ forms. Whether they belong
to this grade-group or are not felids at all cannot
be determined from metric analysis at this time
and is still a moot point. They match Eurasian
pseudaelurines in dental metrics, and, interesting-
ly, show a size difference typical of sympatric
Eurasian pseudaelurines. However, as pointed out
by Morales et al., (1998, 2003), they share certain
dental features with Afrosmilus and the possibility
that they are conical-toothed barbourofelids must
be entertained. At all events, they are less derived
than A. coteae gen. et sp. nov. and the relationship
between them must be distant, involving separate
migrations into Africa from Eurasia in the late
Oligocene or early Miocene.
I would first and foremost like to thank the editors of this
volume for the invitation to participate in this testimonial to the
career of Prof. Léonard Ginsburg. Drs. Jorge Morales and
Manuel J. Salesa provided valuable comments on the manu-
script. The latter kindly translated the abstract into Spanish and
provided comparative data for this study, as did Dr. Stéphane
A new genus and species of Felidae (Mammalia) from Rusinga Is., Kenya 221
e390-11 Werdelin.qxd 30/1/12 14:18 Página 221
Peigné. Thanks to the Rusinga team, and especially Drs. Kieran
McNulty and Tom Lehmann, for inviting me to study the
Rusinga carnivores. Kenya National Museums staff led by Drs.
Emma Mbua and Fredrick Kyalo Manthi permitted access to
the collections, and Mary Muungu was invaluable in tracking
down specimens and information in the collections. My work is
funded by the Swedish Research Council.
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Recibido el 29 de octubre de 2010
Aceptado el 17 de mayo de 2011
222 L. Werdelin
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