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Click on Image to See Enlarged
Photograph
(Updated Sept. 25, 1996)
The
specimens depicted here (no enlargement available) are lower jaws of Eosimias
centennicus one of a growing number of diverse primate taxa from
Eocene deposits scattered throughout eastern and central China. These
minute specimens (little larger than a Lincoln head cent) have features
that clearly align with the higher, anthropoid rather than lower,
prosimain primates. Dated approximately 45 million years ago these and
similar Chinese fossils push higher primate origins back several million
years and out of Africa into Asia. The presense of primitive higher
primates such as Eosimias in China 45 million years ago supports
the hypothesis, as purported by Ciochon and Etler, that the split between
the three major divisions of living primates (i.e. lemurs, tarsiers and
anthropoids) occurred even earlier, perhaps in the late Paleocene or early
Eocene (see Ciochon and Etler 1994 for details).
The
lower jaw depicted here, from Lufeng, Yunnan, was initially attributed to Ramapithecus
lufengensis. Ramapithecus was considered, until the late
1970s, to be an early human ancestor based primarily on its hominid-like
dentition. At the time of its discovery this specimen was the most
complete mandible of "Ramapithecus" known. With the demise of
"Ramapithecus" in the 1980s, and its reassessment as the female
morph of a highly sexually dimorphic great ape with affinities to the
modern orang-utan, the Lufeng material was reevaluated. Since the
mid-1980s hominoid specimens from Lufeng have been classified as Lufengpithecus
lufengensis. Its phylogenetic affinities are still under debate with
various authors suggesting affinities to the orang-utan, African apes or
the last common ancestor of all living great apes, including humans.
The
face shown here, discovered at the Lufeng site in Yunnan, is one of the
most complete Miocene ape specimens known. Originally attributed to Sivapithecus
yunnanensis, considered at the time to be an ape with affinities to
the orang-utan, the specimen is now considered to be a male Lufengpithecus.
Its large, pointed canines differentiate it from the small-canined female
seen in the proceeding photo. Its characteristically broad, low face and
large interorbital distance distinguish Lufengpithecus from
similar fossil apes known from the Siwaliks of South Asia. Lufengpithecus
lived approximately 7-8 MYA and may represent a relic species that had
close ties to the fossil ape that gave rise to the modern large-bodied
hominoids (all living great apes and humans).
Discovered
in 1989 in the Yuanmou basin of Yunnan by the late Prof. Zhang Xingyong of
the Yunnan Provincial Museum, this remarkable juvenile ape skull is one of
the most complete and well-preserved hominoid fossils known. It is
comparable in its state of preservation to the famous Taung skull of Australopithecus
africanus from South Africa, although it lacks a mandible and brain
endocast seen in the latter. This and other less complete fossil ape
specimens from a number of sites in the Yuanmou basin are dated to the
Middle Pliocene, approximately 4.0-5.0 MYA, making them perhaps the
youngest pre-Pleistocene fossil ape remains known anywhere in the world.
Their age is comparable to that of the earliest hominids (direct human
ancestors) known from Ethiopia and Kenya. The affinities of the Yuanmou
material probably lie with Lufengpithecus although much more
research needs to be conducted.
This
is the palatal view of the above specimen. The first permanent molar is
fully erupted but unworn. All other teeth are deciduous. It is estimated
that the individual was between 3 - 5 years old at death. Of particular
interest is the large size of the permanent molar and the specimen's
short-face, much shorter than that of a comparatively aged juvenile
orang-utan. The double-barreled incisive foramen, seen on the mid-line of
the palate behind the incisors is also of significance. The incisive
foramen in orang-utans consists of a single, slit-like aperture. The
appearance of the incisive foramen in the Yuanmou specimen is more like
that seen in African apes and humans. The polarity of this character
(whether it is a primitive feature or a derived feature) is debatable, but
the morphology seen here suggests that the Yuanmou hominoids, and by
inference those from Lufeng as well, are not directly related to living
orang-utans.
The
mandibles (lower jaws) depicted in this and the two following
"thumbnails" represent the gigantic ape Gigantopithecus
blacki known from the Pleistocene of China and Vietnam, approximately
1.3 - 0.3 MYA. These three jaws all come from one site, a karst cave near
Liucheng, Guangxi, in southern China. Gigantopithecus was
originally thought to be an early human ancestor but is now considered by
many to be a cousin of the living orang-utan. Besides these three jaws and
a similar specimen dated to approximately 6 MYA from India, Gigantopithecus
is known only by isolated teeth from a number of localities in south and
central China. This giant ape was contemporaneous with archaic humans
throughout its range.
Gigantopithecus
probably subsisted on a diet rich in carbohydrates, possibly including a
large quantity of bamboo. Its teeth in some ways mimic those of early
hominids, particularly those of robust australopithecines, in the
molarization of the premolars and the reduction of the canines relative to
other apes. Although reliable estimates of its size are hard to make it
can be assumed that "Giganto" was the largest primate that ever
lived.
The
true affinities of Gigantopithecus are still unknown and they
will remain a mystery until diagnostic cranial remains are eventually
found. Southern China is dotted with karstic fissures, some of which have
yielded complete fossil skeletons of extinct Pleistocene mammals. There is
a chance therefore that someday more complete remains of "Giganto"
will be forthcoming. To learn more about Gigantopithecus read
"Other Origins" by R. Ciochon et al., Bantam
Books, 1990.
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