(Updated Sept. 21, 2001)
The specimens depicted here 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.
