University of Nebraska - Lincoln
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USGS Staff -- Published Research
US Geological Survey
1986
Age of the Earliest African Anthropoids
John G. Fleagle
State University of New York
Thomas M. Bown
United States Geological Survey
John D. Obradovich
United States Geological Survey
Elwyn L. Simons
Duke University, [email protected]
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Fleagle, John G.; Bown, Thomas M.; Obradovich, John D.; and Simons, Elwyn L., "Age of the Earliest African Anthropoids" (1986).
USGS Staff -- Published Research. Paper 210.
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Age of the Earliest African Anthropoids
vcgetated in many areas, as evidenced by
numerous fossil root casts and areas with
abundant fossil trees. There wcre areally
large, but shallow and probably cphcmeral,
nonsaline ponds; soils wcre generally damp
with probably seasonal rainfall.
The earliest fossil record of African anthropoid prunates (monkeys and apes) comes
The fossil megafloras show affinities with
from the Jebel Qatrani Formation in the Fayum depression of Egypt. Reevaluation of prescnt-day tropical Indomalaysian floras.
both geologic and faunal evidence indicates that this formation was deposited in the They suggest a "tropical forest existing in a
early part of the Oligocene Epoch, more than 31 million years ago, earlier than wet, pcrhaps monsoonal climate" (5). Like
previous estimates. The great antiquity of the fossil higher prunates from Egypt the palcoflora, thc soils indicate seasonal
accords well with their primitive morphology compared with later Old World higher wetncss with good drainage in some arcas
prunates. Thus, the anthropoid primates and hystricomorph rodents from Fayum are and swampy conditions in othcrs.
also considerably older than the earliest higher primates and rodents from South
Inasmuch as neither the sedimentary
America.
rocks nor thc mammalian fauna of the Jebel
Qatrani Formation provide precise evidencc
fossils were most comparablc to late Eocene rcgarding the age of thc formation, the best
HE EARLIEST ANTHKOPOID PKImatcs of Africa comc from cxtcnsivc and carly Oligocene taxa from Europe, but cvidencc for thc agc of this forlnation and
early Tertiary deposits in the Fayum sufficiently distinct that a more precise cor- the primatcs found therc comes from thc
depression of Egypt, approximately 100 km relation was impossible (6).
respective agcs of thc immediately overlying
southwest of Cairo. From their initial disAll the Fayum primates and most of the and underlying rocks-the Widan el Faras
covery in the bcginning of the century, the terrestrial mammals have come from thc Basalt abovc and the partly marine and
fossil primatc spccies from this area havc fluvial Jebel Qatrani Formation (Fig. l), partly fluvial Qasr el Sagha Formation beplayed a critical role in our understanding of which conformably overlies the nearshore low.
anthropoid origins and thc cvolution of marine and fluvial Qasr el Sagha Formation.
In thc Fayuln depression, the uppcr Qamonkeys, apes, and humans (1-3). More- The Jcbel Qatrani Formation is comprised trani escarpment is capped by 2 to 25 m of
over, the Fayum provides thc best record of of 340 m of variegated alluvial rocks and the Widan el Faras Basalt, a dark, denscly
Palcogenc mammals from all of Africa and is finc to coarse sandstones, conglomerates, aphanitic, iron-rich extrusive basalt that is
critical for understanding the cvolution of sandy mudstones, carbonaccous mudstoncs, exposed for ovcr 50 km. In outcrops where
many mammalian groups on that continent and limestones, all of which show evidence the basalt is thinnest, it appears to be a single
including mars~ipials, pangolins, elcphant of profound mechanical and geochemical flow; however, weathered and scorchcd
shrews, bats, insectivorans, creodonts, hyra- alteration due to ancient soil (paleosol) for- contacts within the basalt as well as lenses of
coids, elephants, anthracothcres, embritho- mation. Vertebrate fossils have bcen rccov- gravelly sand containing basaltic clasts attest
pods, and hystricomorph rodents. Knowl- ered from dozens of localities throughout to the prcsencc of at least two and probably
edge of the agc of thc Fayum deposits is the formation (Fig. 1).
thrce separate flows ovcr much of the area of
critical for calibrating early aspccts of highcr
Thc Jebcl Qatrani Formation is a complex cxposurc. Thc flows overlie the Jebel Qaprimate evolution and for understanding the alluvial unit charactcrizcd by distinct large- trani Formation with a pronounced erosionbiogeography and evolution of many other and small-scale lateral and vertical facies al unconformity, evidenced locally by broad
manlmals (4, 5).
changcs (7).In gcneral, deposition was by scours of up to 25 m in depth. The thickThe preponderance of apparently endem- meandering streams. I,ocal, small-scale ness, and even thc prescnce of individual
ic African elements in thc Fayunl mammali- changes in lithology reflcct shifting from flows, is controlled by the topographic iran fauna, however, precludes precise faunal one local channel environment to another regularities at the top of the Jebel Qatrani
correlation bctwccn the Fayum and other and transitions from channcl to floodplain Formation. I n places where the basalt flows
palcontological localities that could placc dcposits. The Jcbel Qatrani lithotope was are absent, the Jebel Qatrani Formation is
this fauna in a worldwide chronological low and had little rclief. Thc occasional
framework. Comparison of the Fayunl occurrence of sircnians and brackish watcr
mammals with Eocenc and Oligocene mam- mollusks, sharks, and rays suggests that
G. Fleagle, Department of Anatom~cal Sciences,
mals from Eurasia showed only three com- storms, tidal incursions, or both, incrcased J.Health
Sciences Center, State IJniversity of New York,
mon gencra (Peratheriuw, Pterodon, and Ap- the salinity of the streams for scvcral kilomc- Stony Brook, hT 111 794.
M. Bown and J. 13. Obmdovich, United States
terodon) and five common families. All fau- ters inland. The flood basins of thc Jebel T.
Geological Survey, Denver, CO 80225
nal comparisons indicatcd that the Egyptian Qatrani streams werc apparently heavily E. I,. Simons, Duke University, lhrharn, NC, 27705.
T
5 DECEMBER 1986
Science, New Series, Vol. 234, No. 4781 (Dec. 5, 1986), pp. 1247-1249
This article is
IS a U.S.
U.S government
governme1nt work, and is not subject
subject to copyright in
~nthe United
Unlted States.
States
I
trani Formation corresponding to late early est undoubted higher primatcs (11) and
Oligocene (9). Evcrywhere in thc Fayum have generally been rcgardcd as broadly
dcpression, the contact of the Jcbel Qatrani ancestral to the younger fossil apcs from the
Formation with thc overlying basalt is a Miocene of Europc, East Africa, and Asia.
pronounced erosional unconformity. At Howcver, thcre has been considcrable deprcscnt there is no way to estimate the time bate concerning thc phyletic relationships of
intcnral represented by this unconformity. the various Fayum primates with regard to
Thc maximum possible age for thc Jebel the cvolutionary divergence of later lineages
Qatrani Formation is provided by relatively Icading to Old World monkeys, lesser apes,
inexact invertebrate faunal correlation of the and hominids. When the Fayurn "apes" I'roconformably i~ndcrlyingQasr el Sagha For- plinpithecus and Aqypopithecus were known
mation. The uppermost part of this forma- alrnost totally from fragmentary dental retion and its lateral facies equivalcnt, the mains, individual specics of Oligoccne
Maadi Forniation, contain an abundant "apes" seemed to mark the cvolutionary
cchinodcrm and oyster fauna of taxa that divcrgencc of lineages leading to gibbons,
have traditionally niarkcd the upperniost grcat apes, and possibly cven hominids. At
Eocene (10). Thus thc minimum agc of the the sarnc timc, the lincage leading to the
Jebel Qatrani Formation and the primatcs living Old World monkeys scemed to be
found thercin is substantially greatcr than prescnt in the sympatric and synchronous
parapithccids (2).
previous radionietric datcs had suggestcd.
Morc complete fossil matcrial has
Since thcy wcre first described in the
beginning of this century, the Fayum an- brought increasing cvidcncc that thc early
thropoids havc becn recognized as thc earli- "apcs" from thc Fayu~narc extremely primitive with respect to living catarrhines ( 3 ) .
Although thcy sharc with living catarrhines
a reduced dental for~nulawith two prcnlolars, Agyptopithecus and I'ropliopithecus retain
more primitive, platyrrhinc-like featurcs in
many aspccts of cranial and postcranial anatomy and ccrtainly precede the nionkcy-ape
divergence.
C7~niparedwith the Fayum anthropoids,
the higher primates from the early Miocene
of Kenya are more advanced niorphologically and more similar to living catarrhines.
Although there is debatc regarding the prccise relationship of the I'roconsul group to
living apcs, they have all the fcatures that
characterize living catarrhines and a few
distinctly ape-like characters (12). Similarly,
R (209m),Pnr;?piiil~cu.s:'A~gyptopitiicr:~';
the early Mioccne monkeys from Napak and
Huluk clearly document the presence of cercopithccoids in East Africa between 15 a~ld
20 million years ago (13).
'I'hus, there appears to be a considerable
morphological gap between the early anthropoids of the Fayurn and the monkeys
and apes of the early Miocene of East Africa.
'I'hc former show only a few fcatures that
distinguish them from a generalized higher
primate condition, u~hcrcasthe latter document the divergence of lineages leading to
living cercopithccoids and hominoids. In
light of the revised minimum age of the
Jebcl Qatrani Formation we realize that this
morphological gap corresponds to a substantial temporal gap of more than 10 million years betwcen the two groups of fossil
anthropoids. At present, we havc virtually
no c~idenccof anthropoid evolution bctween 30 and 20 million years ago, the timc
Qasr el Sagha Formation
Fig. 1. Schematic stratigraphic section of the Jebel Qatrani E'or~ilationshowing relations with of a major adaptive radiation of catarrhincs
other formations in the Fa1~1rndepression and the ciistribution of fossil primate taxa within the and probably the phyletic divergence of
monkeys and apcs.
geological section. Capital letters designate fossil vertebrate quarqr sites.
overlain unconformably by the alluvial Kashab Formation of lower Miocenc age.
Earlier, Simons (8)reported K-As ages of
24.7 ? .4 and 27.0 & 3.0 million years for
two samples of thc Widan el Faras Basalt
collected in the area betwcen Widan cl Faras
and Tel Headnell (whcre the flow is relatively thick). It is uncertain exactly where within
the basalt these samples wcre obtained;
however, they are almost certainly from
basalts higher in the local palcotopography
than a ncw sample collected in 1981 from
70 cm above the base of the lowest flow
wcst-nv~rhwestof Widan el Faras. This sample was dated by one of us (J.1).0.) and
yieldcd an age of 31.0 t 1.0 million years
(6). Thc m7o younger ages cither werc on
rocks obtained from different flows higher
in the basalt or were determined on partially
altered samples.
Tlie age of 31 niillion years for the lowest
part of the Widan el Faras Basalt provides a
minimum age for the underlying Jebel Qa-
7
SCIENCE, VOI,. 234
Some authorities havc suggested that, bccause of their many primitive a~lthropoid
characteristics, one group of Fayum primates, the parapithccids, may be related to
the New World platyrrhincs (14). A major
line of evidence against an African origin for
platyrrhines has been the apparent diffcrcnccs in the relative age of the earliest
African and South American anthropoids.
Earlier correlations placed the carlicst platyrrhines at 35 million years ago, nearly 10
million years older than the supposed age of
the Fayum primates. However, more recent
studies of the geology of the Salla basin in
Bolivia (15) havc shown that the carlicst
platyrrhines are probably from about 25
million years ago, substantially younger
than the Fajwm anthropoids. Thus, the new
minimum age estimate of the Jebel Qatrani
Formation indicates that the Fayum primates are substa~ltiallyolder than the first
appearances of all modern anthropoid radia-
tions, a chronology that accords well with
morphological analyses that place some species at the base of the higher primatc radiation.
REFERENCES A N D NOTES
1. M. Schlosscr, Pnlcontol. Ceol. 0 s t . - U y .Onent. Mict~.
2, 24 (191 1).
2. E. I-. Slrnons. 1'~imateEvolution (Macmillan. Nc\v
York, 1972).
oJ'
3. J . G. Flcaglc and R. 1;.Kay, in New lnter~~rctations
Apeand Humnn Anccstv, R. I.. Clochon and R. S.
Corri~ccini,Eds. (Plenum, New York, 1983), pp.
181-210.
4. V. M ~ g l i o~ n d11. 15. S. Cookc, Eds., Evolution cf
Afi.ican Mammals (I1.1rv~rdUIIIV.Press, C:rlrnbridgc,
19; 4 '1'. M. BO\VII and E. L. Sirnons, Natum
(1,undun) 308, 447 (1984).
4 T . M. Aown et d.,
J . Hum. Evol. 11, 603 (1982).
6. J. G. Flc~glc,T. M. BO\VII,J. l>. Obr~dovich,E. I-.
Simons, in l'nmate C'i~olutzon,J. G. Else 2nd 1'. C.
Lcc, Eds. (Cambridge Univ. Prcss, Carnbridgc,
19861, p p 3-17.
7. T. M. BOUJIIalid M. J. Kraus, U.S. <;eel. Sum. 1'rc$
Pail., in press.
8. E. L. Sirnons, Sci. Am. 217, 28 (llcccmbcr 1967);
and A. E. Wood, Bull. I1cabodv iLIus. Nnt.
Hist. 28, 1 ( 1968).
4 W. A. Rcrggrcn, I). V. Kent, J. J. 1;1\~1111,
J. A. Van
Couvcr~ng,<;cd.Soc. Am. Hull. 96, 1407 (1985).
10. R. Said, Tlrc <;eoLq~~y
cfE8111t (Elscvicr, An~stcrdam,
1062).
11. 'nlc highcr primate status of the still poorly known
Burlncsc prilnatcs Amphipitl7ecus ~ n d1'0ndnun~ia
jR. L. Ciochon, 11. E. Savage, T. Tint, A. Maw,
Science 229, 756 ( 1985) 1 is unsettled.
12. P. Andrcws, in Anccsto~s:'/'he Hard Emdcnce, E .
I>CISC>II,
Ed. (L~ss,New York, 1985), pp. 14-22.
4 11. l'ilbc~~nand A. Walker, Natum (I,on&n) 2220,
657 (1968); M. 1-cake!., Folia l'~imato11.44, 1
(1085).
14. V. Sar~ch,in Old LVorldMonBeys,J. R. Napicr and 1'.
11. Napicr, Eds. (Academic Prcss, 1-ondon, 1970),
pp. 195-196; R. Hothtcttcr, Bull. Mem. Soc. Antl7~opol.Pam 4, 027 ( 1077)
15. R. J. Mac1;addcn etal.,J. <;eel. 93, 223 (1985); B. J.
M ~ c l ; ~ d d cJ.
n , Vert. Paleontol. 5, 169 (1985).
16. Wc thank the Geological Survey of Egypt for assistance and coo cration, cspcc~allyR. Issawi, R. Eissa,
B. el-Khashal, A. A. el A\vady Kandil, A. el Ghany
Ibrihim Shcll~by,and M. Askal.lny; ~ n dM. Kraus,
P. Ch~trath,I). I>ornnuig, T. Rasmusscn, P. Gingcrich, R. Kay, S. Wing, and 11. Krausc for inform^ti011 and suggcstions.~uppo~tcd
in part by ENS
8310913, BNS 8546024, and ENS 8521655, frorn
NSF alid 70869600 and 809479 f i > m thc Smith.
'
Ccntcr publi&tion 415.
14 July 1986; accepted 10 October 1086
REPORTS
1249