The bulk of hominid skeletons uncovered in sub-Saharan East Africa has tremendously enhanced our insights into humanity's bio-evolutionary history, but in doing so, may have also created some sort of a researcher tunnel vision, wherein other places in the content are overlooked for the uncovering of other pieces of the hominid evolutionary index — where the prospect of uncovering both other "missing links" to modern humanity and "dead-enders" alike may well have been and continues to be hampered. The hominid cranium found in the Chadic area serves as such an example; it has been dubbed the "Toumai". It may well have been one of those so-called "dead-ender" hominids where ancestry to modern humanity is concerned, but the fact that it is quite old and found outside of east Africa, should serve — the present author thinks — as a wake up call to those aspirant researchers, who want to get a fuller insight into the hominid bio-evolutionary index, that they ought to pay little more attention and brush other parts of the African continent more enthusiastically, while still scavenging in east Africa for whatever hominid fossil pieces remain, for adding precision to our understanding of the hominid evolutionary history.
Toumai, the Chad Skull ~ 7 million years ago:
- Volcanic layers around the fossil were used to date it from 4.4million years ago
- Ardi's upper canine teeth are more similar to stubby human teeth than sharp chimpanzee teeth
- Tooth enamel analysis revealed they ate fruit, nuts and leaves
- Ardi's brain was positioned in a similar way to that of humans
- Pelvis and hip show the gluteal muscles were positioned so she could walk upright
"Previously, scientists believed that our common ancestor would have been very chimp-like, and that ancient hominids such as Ardi would still have much in common with them. But she was not suited like a modern- day chimp to swinging or hanging from trees or walking on her knuckles.This suggests that chimps and gorillas developed those characteristics after the split with humans - challenging the idea that they are merely an 'unevolved' version of us.
Ardi's feet were rigid enough to allow her to walk upright some of the time, but she still had a grasping big toe for use in climbing trees.And she had long arms but short palms and fingers which were flexible, allowing her to support her body weight on her palms.
Her upper canine teeth are more like the stubby teeth of modern people than the long, sharp ones of chimps. An analysis of her tooth enamel suggests she ate fruit, nuts and leaves.
Scientists believe she was a female because her skull is relatively small and lightly built. Her teeth were also smaller than other members of the same family that were found later." - Courtesy of dailymail.co.uk
A. afarensis footprints ~ 3.5-3.7 million years ago:
…Two of the most familiar species are Australopithecus afarensis (of which the Ethiopian specimen named "Lucy" is the prime example) and A. africanus, of which the classic examples are from South Africa. It is not clear whether one species preceded the other, whether they coexisted, or which – if either – was the direct ancestor of the first humans. It has generally been assumed that A. afarensis is probably the older species, but the new discovery may challenge that…
…The Geomagnetism Laboratory at the University of Liverpool in England dated the hominid at between 3.22 and 3.58 million years old based on magnetic characteristics of the surrounding breccia, or broken rock. That date would make it marginally older than "Lucy," discovered in Ethiopia in 1974, and one of the oldest known….
Source: Washington Post
The species Australopithecus afarensis was named in 1978 to include "Lucy" and the hominid footprints discovered in Laetoli by Mary Leakey and her team.
A. afarensis is widely believed to be ancestral to the other known hominids.
The Ethiopian specimens have been dated to between 2.9 and 3.5 million years.
The footprints (mentioned above) have been dated to between 3.6 and 3.75 million years.
Bringing both these sets of specimens into a single species was controversial at the time, and is still questioned by some specialists.
Homo Habilis ~ 1.9 - 1.6:
...Once the new fossil was included in the quantitative analysis, there was no clear division between African versus Asian in the one million year old crania, White said….
…"Now we have this cranium from Africa that is not distinguished at the species level from the Asian forms," White said.
Source: Courtesy University of California, Berkeley, Media Relations
KNM-ER 1466 Left Side of Cranial Vault:Thick and rather robust features could also place this specimen with H. erectus or even as a robust H. sapiens - courtesy of msu.edu.
KNM-ER 3733 Cranium ~ dated to 1.8 million years - courtesy of msu.edu :
The "Homo Erectus-like" Dmanis skulls ~ from 1.75 million years ago:
Scientists have long been thought that the first hominid out-of-Africa migrants were Homo Erectus, a species with large brains and a stature approaching human dimensions. The species was widely assumed to have stepped out in the world once they evolved their greater intelligence and longer legs and invented more advanced stone tools.
But the skulls were associated with more than 1,000 crudely chipped cobbles, simple choppers and scrapers, not the more finely shaped and versatile tools that would be introduced by H. erectus more than 100,000 years later. That undercut the accepted evolutionary explanation for the migrations.
"The possibility of variations within a species should never be excluded," Dr. Smith said. "There's a tendency now for everybody to see three bumps on a fossil instead of two and immediately declare that to be another species."
But it takes more than two or even three specimens to reach firm conclusions about the range of variations within a species. Still, Georgia is a good place to start. The three specimens found there represent the largest collection of individuals from any single site older than around 800,000 years.
"We badly want to know what the functional abilities of the first out-of-Africa migrants were," said Dr. Wood of George Washington University. "What could that animal do that animals that preceded it couldn't? What was the role of culture in this migration? Maybe other animals were leaving and the hominids simply followed."
All scholars of human prehistory eagerly await the next finds from Dmanisi, and in Chad. Perhaps they will help untangle some of the bushy branches of the human family tree to reveal the true ancestry of Homo sapiens.
Source: Courtesy Science vol. 288, pages 1019-1025. May 12, 2000, by L. Gabunia et al.
KNM-ER 3883 Partial Cranium ~ dated to between 1.4 - 1.6 million years:
Found by Richard Leakey at Koobi Fora, Kenya
The Koobi Fora Kenyan specimens ~ 1.51 and 1.56 million years:
KNM WT 15000 Partial Skeleton ~ dated to between 1.51 - 1.56 million years:
KNM-ER 730 Skull Fragments:
KNM-ER 731 Mandible Fragment
KNM-ER 819 Mandible Fragment
Although placed in the general classification of Homo, is also a candidate for boisei. Because of its greater robusticity, it is placed into ergaster instead of habilis
KNM-ER 820 Juvenile Mandible:
Dentition compared closely to the Erectus specimen from Zhoukoudian. This specimen is placed by many under the H. Erectus classification
KNM-ER 992 Mandible ~ dated to 1.5 million years:
OH 13 Fragmented Skull ~ dated to 1.5 million years:
By Louis Leakey in 1963 at Olduvai
SK 847 Partial Cranium ~ dated to 1.5 million years:
Found at Swartkrans - South Africa in 1969 by Ronald Clarke
Several recent studies suggest that Taung is younger than once thought - possibly little more than 1 million years BP.
...Dart was certain it was an extinct hominid, although very few of his colleagues in the profession agreed. Dart called his new find various things, but finally settled forAustralopithecus Africanus, the first of the "gracile" australopithecines, hominids with aslender or graceful physique…
…The australopithecines are usually separated into two morphological types on the basis of their body build: gracile forms (Australopithecus afarensis and A. africanus) and robust forms (A. robustus, A. boisei and A. aethiopicus).
KNM-ER 1466 Left Side of Cranial Vault:
Thick and rather robust features could also place this specimen with H. erectus or even as a robust H. sapiens
KNM-ER 1593: Skull Fragments
KNM-ER 1648: Parietal Fragment
KNM-ER 1808 Adult Skull Fragments
KNM-ER 1811 Mandibular Fragments
KNM-ER 1812 Mandible Fragments
KNM-ER 1821 Right Parietal Fragment
KNM-ER 2592 Left Parietal Fragments
KNM-ER 2595 Right Parietal Fragment
KNM-ER 2598 Occipital Fragment
OH 9 Partial Cranium ~ dated to 1.2 million years:
The hominid cranium -- found in two pieces and believed to be between 500,000 and 250,000 years old -- "comes from a very significant period and is very close to the appearance of the anatomically modern human," said Sileshi Semaw, director of the Gona Paleoanthropological Research Project in Ethiopia.
Source: Courtesy UC Berkeley, Science Review.
In the words of Jennifer Viegas, for Discovery news, going back to the point about avoiding bio-anthropological "tunnel vision",....
Recommended reading:
Recent Developments in Paleoanthropology
Chronological Bits - Crania
Last updated on April 25th, 2013.
At 6-7 million years, the newly found Sahelanthropus from Chad, is the oldest known member of the human line of the ape-human family tree. - Courtesy archaeology.org, by the Archaeological Institute of America, 2002
Briefing on the Toumai
Dr. Daniel E. Lieberman, a biological anthropologist at Harvard, called the African specimen "one of the greatest paleontological discoveries of the past 100 years."
The skull was uncovered in the desert of Chad by a French-led team under the direction of Dr. Michel Brunet of the University of Poitiers. Struck by the skull's unusual mix of apelike and evolved hominid features, the discoverers assigned it to an entirely new genus and species — Sahelanthropus tchadensis. It is more commonly calledToumai, meaning "hope of life" in the local language.
...Dr. Brunet's group said the fossils — a cranium, two lower jaw fragments and several teeth — promised "to illuminate the earliest chapter in human evolutionary history…
…About a million years older than any previously recognized hominid, Toumai lived close to the time that molecular biologists think was the earliest period in which the human lineage diverged from the chimpanzee branch.
The next oldest hominid appears to be the 6-million-year-old Orrorin tugenensis, found two years ago in Kenya but not yet fully accepted by many scientists. After it is Ardipithecus ramidus, which probably lived 4.4 million to 5.8 million years ago in Ethiopia.
"A lot of interesting things were happening earlier than we previously knew," said Dr. Eric Delson, a paleontologist at the City University of New York and the American Museum of Natural History.
The most puzzling aspect of the new skull is that it seems to belong to two widely separated evolutionary periods. Its size indicates that Toumai had a brain comparable to that of a modern chimp, about 320 to 380 cubic centimeters. Yet the face is short and relatively flat, compared with the protruding faces of chimps and other early hominids. Indeed, it is more humanlike than the "Lucy" species, Australopithecus afarensis, which lived more than 3.2 million years ago.
"A hominid of this age," Dr. Wood wrote in Nature, "should certainly not have the face of a hominid less than one-third of its geological age."
Scientists suggest several possible explanations:
— Toumai could somehow be an ancestor of modern humans, or of gorillas or chimps.
— It could be a common ancestor of humans and chimps, before the divergence.
— "But why restrict yourself to thinking this fossil has to belong to a lineage that leads to something modern?" Dr. Wood asked. "It's perfectly possible this belongs to a branch that's neither chimp nor human, but has become extinct."
…A few scientists sound cautionary notes. Dr. Delson questioned whether the Toumai face was complete enough to justify interpretations of more highly evolved characteristics. One critic argued that the skull belonged to a gorilla, but that is disputed by scientists who have examined it.
Just as important perhaps is the fact that the Chad skull was found off the beaten path of hominid research.
Until now, nearly every early hominid fossil has come from eastern Africa, mainly Ethiopia, Kenya and Tanzania, or from southern Africa. Finding something very old and different in central Africa should expand the hunt.
"In hindsight, we should have expected this," Dr. Lieberman said. "Africa is big and we weren't looking at all of Africa. This fossil is a wake-up call. It reminds us that we're missing large portions of the fossil record."
Source: Courtesy The New York Times, by John Noble Wilford, August 6, 2002
Australopithecus ramidus (a.k.a. Ardipithecus ramidus) ~ 4.4 million years ago:
Australopithecus ramidus is the most recent addition to the human evolutionary tree; see [ Boyd & Silk 1997 ] , pp 359-361.
In 1994, fossils were found by Tim White and his associates [ White et al. 1994 ] in the Middle Awash region of Ethiopia. They subsequently named A. ramidus, a new hominid species, though it has recently been changed to Ardipithecus ramidus.
The collection of 17 fossils includes dental, cranial and postcranial material. It is dated to around 4.4 million years ago, making it the remains of the oldest known hominid.
The features include small canines ( like humans ) and thin tooth enamel ( an african ape characteristic ).
They were found near Hadar where A. afarensis was found. Preliminary palaeogeographical reconstruction suggests that the habitat was woodland.
Australopithecus ramidus is the most recent addition to the human evolutionary tree; see [ Boyd & Silk 1997 ] , pp 359-361.
In 1994, fossils were found by Tim White and his associates [ White et al. 1994 ] in the Middle Awash region of Ethiopia. They subsequently named A. ramidus, a new hominid species, though it has recently been changed to Ardipithecus ramidus.
The collection of 17 fossils includes dental, cranial and postcranial material. It is dated to around 4.4 million years ago, making it the remains of the oldest known hominid.
The features include small canines ( like humans ) and thin tooth enamel ( an african ape characteristic ).
They were found near Hadar where A. afarensis was found. Preliminary palaeogeographical reconstruction suggests that the habitat was woodland.
Source: Courtesy whurle-hk
Update - Other notes on Ardipithecus ramidus, personified by a specimen nicknamed "Ardi":
Update - Other notes on Ardipithecus ramidus, personified by a specimen nicknamed "Ardi":
- Volcanic layers around the fossil were used to date it from 4.4million years ago
- Ardi's upper canine teeth are more similar to stubby human teeth than sharp chimpanzee teeth
- Tooth enamel analysis revealed they ate fruit, nuts and leaves
- Ardi's brain was positioned in a similar way to that of humans
- Pelvis and hip show the gluteal muscles were positioned so she could walk upright
"Previously, scientists believed that our common ancestor would have been very chimp-like, and that ancient hominids such as Ardi would still have much in common with them. But she was not suited like a modern- day chimp to swinging or hanging from trees or walking on her knuckles.This suggests that chimps and gorillas developed those characteristics after the split with humans - challenging the idea that they are merely an 'unevolved' version of us.
Ardi's feet were rigid enough to allow her to walk upright some of the time, but she still had a grasping big toe for use in climbing trees.And she had long arms but short palms and fingers which were flexible, allowing her to support her body weight on her palms.
Her upper canine teeth are more like the stubby teeth of modern people than the long, sharp ones of chimps. An analysis of her tooth enamel suggests she ate fruit, nuts and leaves.
Scientists believe she was a female because her skull is relatively small and lightly built. Her teeth were also smaller than other members of the same family that were found later." - Courtesy of dailymail.co.uk
A. afarensis footprints ~ 3.5-3.7 million years ago:
These A. afarensis footprints embedded now in volcanic rock, were made 3.5-3.7 million years ago at Laetoli in Tanzania.
They were discovered by Mary Leakey and her colleagues in 1978/79, and provide incontrovertible evidence of early hominid bipedalism.
They were discovered by Mary Leakey and her colleagues in 1978/79, and provide incontrovertible evidence of early hominid bipedalism.
Source: Courtesy whurle-hk
"Little Foot" — South African Sterkfontein Australopithecus-like specimen ~ between 3.22 and 3.58 million years old:
— The skeleton of the South African Sterkfontein Australopithecus-like specimen has been dated at between 3.22 and 3.58 million years old by the Geomagnetism Laboratory at the University of Liverpool. Previously the oldest complete hominid skeleton was a 1.5 million-year-old Homo erectus discovered in Kenya.
The analysis of "Little Foot" has already yielded some valuable insights into the hominid's ability to walk upright. An examination of its bone structure revealed the creature was adapted for clutching onto tree branches. Philip Tobias, one of Clarke's colleagues, said that the hominid had "arboreal habits coupled with terrestrial habits". His statement has created considerable controversy, as most anthropologists previously believed that hominids were completely ground dwelling 3.5 million years ago.
The current knowledge of Australopithecus has been obtained from a number of incomplete skeletons and bone fragments. Until now the oldest most complete Australopithecus was the 3.2 million-year-old fossil, known as "Lucy," which Donald Johanson discovered in 1974 in the Hadar valley of Ethiopia.
The discovery of "Lucy" caused a scientific sensation as it possessed human characteristics such as the ability to walk upright and use tools but had the brain size of a chimpanzee. Until then scientists had dismissed the conjecture made by Karl Marx's collaborator Fredrick Engels last century that upright stature, freeing the hands for tool making, was the crucial first step in human evolution--not brain size. - by Frank Gaglioti, WSWS.org, 1998.
— A nearly complete skeleton of one of the oldest apelike ancestors of humans – a creature who apparently swung in trees but also walked upright – has been discovered encased in a 3.5-million-year-old rock formation inside a South African cave, scientists here announced today…
…There are numerous skulls, parts of limbs, sets of vertebrae and ribs, and a few pelvises – but no specimens in which skull and skeleton are clearly from the same individual. As a result, fundamental questions about Australopithecus have remained unanswered, including the size of the brain in relation to the size of the body, its likely diet, its mode of locomotion and anatomical particulars…
…There are numerous skulls, parts of limbs, sets of vertebrae and ribs, and a few pelvises – but no specimens in which skull and skeleton are clearly from the same individual. As a result, fundamental questions about Australopithecus have remained unanswered, including the size of the brain in relation to the size of the body, its likely diet, its mode of locomotion and anatomical particulars…
…Two of the most familiar species are Australopithecus afarensis (of which the Ethiopian specimen named "Lucy" is the prime example) and A. africanus, of which the classic examples are from South Africa. It is not clear whether one species preceded the other, whether they coexisted, or which – if either – was the direct ancestor of the first humans. It has generally been assumed that A. afarensis is probably the older species, but the new discovery may challenge that…
…The Geomagnetism Laboratory at the University of Liverpool in England dated the hominid at between 3.22 and 3.58 million years old based on magnetic characteristics of the surrounding breccia, or broken rock. That date would make it marginally older than "Lucy," discovered in Ethiopia in 1974, and one of the oldest known….
Source: Washington Post
A. afarensis ( Lucy ) ~ 2.9 to 3.5 million years:
These remains ( Lucy - AL288 ) were found in the Hadar region of Ethiopia.
Lucy is one of the most important of all fossil hominid finds, with 40 percent of the skeleton recovered; [Boyd & Silk 1997] , pp 342-359.
These remains ( Lucy - AL288 ) were found in the Hadar region of Ethiopia.
Lucy is one of the most important of all fossil hominid finds, with 40 percent of the skeleton recovered; [Boyd & Silk 1997] , pp 342-359.
The species Australopithecus afarensis was named in 1978 to include "Lucy" and the hominid footprints discovered in Laetoli by Mary Leakey and her team.
A. afarensis is widely believed to be ancestral to the other known hominids.
The Ethiopian specimens have been dated to between 2.9 and 3.5 million years.
The footprints (mentioned above) have been dated to between 3.6 and 3.75 million years.
Bringing both these sets of specimens into a single species was controversial at the time, and is still questioned by some specialists.
Source: Courtesy whurle-hk
"Selam" — Australopithecus afarensis ~ 3.3 million-year-old:
Discovered by Zeresenay Almeseged in 2000 at Dikika in Ethiopia (Alemeseged et al. 2006). This is a well-preserved 3.3 million year old partial skeleton of an approximately 3 year old Australopithecus afarensis child. The fossil consists of an almost complete skull, hyoid bone, limb fragments, rib fragments, collar bones ( clavicles) and shoulder blades (scapulae), and some vertebrae. It is the most complete juvenile hominid skeleton known until Neanderthal times.
The bipedal features of other A. afarensis fossils are mostly found in this fossil, confirming that afarensis was bipedal...The features of Selam's upper body tend to be apelike: the shoulder blade closely resembles that of a gorilla, the finger bones are curved as in chimpanzees, and the semicircular canals are more like those of chimps than humans. All these lines of evidence suggest that A. afarensis was partly arboreal.
The name 'Selam' means 'peace' in the local Ethiopian language. Because it belongs to the same species as Lucy, the fossil has also been nicknamed 'Lucy's child', although it is actually about 100,000 years older than Lucy.
References courtesy talkorigins.org: Alemseged Z., Spoor F., Kimbel W.H., Bobe R., Geraards D., Reed D. et al. (2006): A juvenile early hominin skeleton from Dikika, Ethiopia. Nature, 443:296-301.Wood, B. (2006): Palaeoanthropology: a precious little bundle. Nature, 443:296-301. (the Dikika skeleton)
A. africanus Sts 5 skull ~ 2.6 million-year-old:
The female cranium Sts 5 from Sterkfontein in South Africa, found in 1936 by a vertebrate palaeontologist named Robert Broom.
This skull belonged to an adult female, and was better preserved than the Taung child.
This specimen has been variously named, including "Plesianthropus" for a while, from which has come the nickname "Mrs Ples" - pronounced "Please".
Nowadays most palaeoanthropologists assign it to Australopithecus africanus [ Boyd & Silk 1997 ] , pp 362-365.
This skull belonged to an adult female, and was better preserved than the Taung child.
This specimen has been variously named, including "Plesianthropus" for a while, from which has come the nickname "Mrs Ples" - pronounced "Please".
Nowadays most palaeoanthropologists assign it to Australopithecus africanus [ Boyd & Silk 1997 ] , pp 362-365.
Source: Courtesy whurle-hk
A. sediba remains, two fossils - MH1 (11 to 12 year old male) and MH2 (adult female) ~ between 1.78 and 1.977 million years old:
The teeth of this species -- called Australopithecus sediba -- indicate that it is also a close relative to the previously identified Australopithecus africanus. Both of these species are clearly more closely related to humans than other australopiths from east Africa, according to the new research.
The study, published in the journal Science, revealed that both africanus and sediba shared about the same number of dental traits with the first undeniably human species.
"Our study provides further evidence that sediba is indeed a very close relative of early humans, but we can't definitively determine its position relative to africanus, said Debbie Guatelli-Steinberg, co-author of the study and professor of anthropology at The Ohio State University.
...
africanus scored the same. Sediba shared 13 traits with Homo erectus, an early human species, which was comparable to how africanus scored.
Sediba and africanus shared five dental traits that weren't found in earlier australopiths, further showing their close relationship. Both also share five traits with early humans -- Homo habilis/rudolfenis and Homo erectus -- which weren't shared with earlier ancestors, demonstrating the close relationship between these two australopiths and the first humans.
...
"All of the research so far shows that sediba had a mosaic of primitive traits and newer traits that suggest it was a bridge between earlier australopiths and the first humans," she said.
Guatelli-Steinberg said their dental analysis showed that both africanus and sediba are more closely related to humans than the famous "Lucy" skeleton fossil found in East Africa in 1974. This fossil represented a species, Australopithecus afarensis, that was at one time was thought to be the closest relative of humans.
Lucy is estimated to have lived 3.2 million years ago. Sediba lived 1.977 million years ago, while africanus lived between 3.03 and 2.04 million years ago.
"Our research on teeth can't definitively settle if either sediba or africanus is more closely related to humans than the other species," Guatelli-Steinberg said. "But our findings do suggest that both are closely related to each other and are more closely related to humans than afarensis.
"We need to find more sediba remains to help fill in the missing pieces of this evolutionary puzzle." - Courtesy of Science daily, Fossilized Teeth Provide New Insight Into Human Ancestor: Species Identified in 2010 Is One of Closest Relatives to Humans, April 11, 2013.
A. sediba remains, two fossils - MH1 (11 to 12 year old male) and MH2 (adult female) ~ between 1.78 and 1.977 million years old:
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| Click on the image for a higher resolution. |
The study, published in the journal Science, revealed that both africanus and sediba shared about the same number of dental traits with the first undeniably human species.
"Our study provides further evidence that sediba is indeed a very close relative of early humans, but we can't definitively determine its position relative to africanus, said Debbie Guatelli-Steinberg, co-author of the study and professor of anthropology at The Ohio State University.
...
africanus scored the same. Sediba shared 13 traits with Homo erectus, an early human species, which was comparable to how africanus scored.
Sediba and africanus shared five dental traits that weren't found in earlier australopiths, further showing their close relationship. Both also share five traits with early humans -- Homo habilis/rudolfenis and Homo erectus -- which weren't shared with earlier ancestors, demonstrating the close relationship between these two australopiths and the first humans.
...
"All of the research so far shows that sediba had a mosaic of primitive traits and newer traits that suggest it was a bridge between earlier australopiths and the first humans," she said.
Guatelli-Steinberg said their dental analysis showed that both africanus and sediba are more closely related to humans than the famous "Lucy" skeleton fossil found in East Africa in 1974. This fossil represented a species, Australopithecus afarensis, that was at one time was thought to be the closest relative of humans.
Lucy is estimated to have lived 3.2 million years ago. Sediba lived 1.977 million years ago, while africanus lived between 3.03 and 2.04 million years ago.
"Our research on teeth can't definitively settle if either sediba or africanus is more closely related to humans than the other species," Guatelli-Steinberg said. "But our findings do suggest that both are closely related to each other and are more closely related to humans than afarensis.
"We need to find more sediba remains to help fill in the missing pieces of this evolutionary puzzle." - Courtesy of Science daily, Fossilized Teeth Provide New Insight Into Human Ancestor: Species Identified in 2010 Is One of Closest Relatives to Humans, April 11, 2013.
Homo Habilis ~ 1.9 - 1.6:
Homo habilis broke through into science in the early 1960's with the discovery of the OH 7 (the habilis type specimen) fossil at Olduvai Gorge, Tanzania by Louis Leakey and collegues. The existence of Homo habilis is currently dated to between 1.9 and 1.6 million years
Homo ergaster ~ 1.8 million years ago:
— Anatomically, the African Homo ergaster is similar to the Eurasian Homo erectus. The differentiation comes in the higher cranial vault and lighter frame and facial structure of H. ergaster, as well as in the earlier dates with which ergaster is associated.
— Anatomically, the African Homo ergaster is similar to the Eurasian Homo erectus. The differentiation comes in the higher cranial vault and lighter frame and facial structure of H. ergaster, as well as in the earlier dates with which ergaster is associated.
— Homo Erectus ( and/or Homo Ergaster? ) in Africa ~ 1.8 million years ago:
In 1997, Gilbert found the Homo erectus calvarium, or the upper part of a skull which lacks a lower face and teeth. The skull was embedded in the sediment of the Middle Awash study area in Ethiopia, about 140 miles northeast of Addis Ababa, the capital city.
The fossil was slightly exposed, and immediately recognizable as part of a skull, Gilbert said, calling the discovery of the Homo erectus cranium-the fourth one found in Africa-"breathtaking."
…"( The cranium ) looks like Asian Homo erectus," Gilbert said. "It's well within the range of variation you'd expect to see within a single widely distributed species."
The idea was that African and Asian specimens represent two divergent lineages, distinguishable from each other at the species level by morphology. If this were true, a quantitative analysis of physical characteristics in all existing specimens should have partitioned them into two distinct groups, by geography as well as morphology, White said.
The idea was that African and Asian specimens represent two divergent lineages, distinguishable from each other at the species level by morphology. If this were true, a quantitative analysis of physical characteristics in all existing specimens should have partitioned them into two distinct groups, by geography as well as morphology, White said.
…"Now we have this cranium from Africa that is not distinguished at the species level from the Asian forms," White said.
Source: Courtesy University of California, Berkeley, Media Relations
KNM-ER 1466 Left Side of Cranial Vault:Thick and rather robust features could also place this specimen with H. erectus or even as a robust H. sapiens - courtesy of msu.edu.
KNM-ER 3733 Cranium ~ dated to 1.8 million years - courtesy of msu.edu :
Revealed in 1975 by the Koobi Fora Research Project at East Turkana, Kenya
The "Homo Erectus-like" Dmanis skulls ~ from 1.75 million years ago:
(Mission Paléoanthropologique Franco-Tchadienne) The small brain size of a 1.75-million-year-old Homo erectus skull [my emphasis — should rather read: "Homo Erectus-looking"; don't know yet if they were actually Homo Erectus], found in the Republic of Georgia, is causing a reevaluation of early human dispersal from Africa. (Gouram Tsibakhashvili) - Courtesy archaeology.org, by the Archaeological Institute of America, 2002
Briefing
— Although overshadowed by the news of Toumai, the well-preserved 1.75-million-year-old skull from Georgia was also full of surprises, in this case concerning a later chapter in the hominid story. It raised questions about the identity of the first hominids to be intercontinental travelers, who set in motion the migrations that would eventually lead to human occupation of the entire planet.
The discovery, reported in the July 5 issue of the journal Science, was made at the medieval town Dmanisi, 50 miles southwest of Tbilisi, the Georgian capital. Two years ago, scientists announced finding two other skulls at the same site, but the new one appears to be intriguingly different and a challenge to prevailing views.
Scientists have long been thought that the first hominid out-of-Africa migrants were Homo Erectus, a species with large brains and a stature approaching human dimensions. The species was widely assumed to have stepped out in the world once they evolved their greater intelligence and longer legs and invented more advanced stone tools.
The first two Dmanisi skulls confirmed one part of the hypothesis. They bore a striking resemblance to the African version of H. erectus, sometimes called Homo ergaster. Their discovery was hailed as the most ancient undisputed hominid fossils outside Africa.
But the skulls were associated with more than 1,000 crudely chipped cobbles, simple choppers and scrapers, not the more finely shaped and versatile tools that would be introduced by H. erectus more than 100,000 years later. That undercut the accepted evolutionary explanation for the migrations.
The issue has become even more muddled with the discovery of the third skull by international paleontologists led by Dr. David Lordkipanidze of the Georgian State Museum in Tbilisi. It is about the same age and bears an overall resemblance to the other two skulls. But it is much smaller.
"These hominids are more primitive than we thought," Dr. Lordkipanidze said in an article in the current issue of National Geographic magazine. "We have a new puzzle."
To the discoverers, the skull has the canine teeth and face of Homo habilis, a small hominid with long apelike arms that evolved in Africa before H. erectus. And the size of its cranium suggests a substantially smaller brain than expected for H. erectus.
In their journal report, the discovery team estimated the cranial capacity of the new skull to be about 600 cubic centimeters, compared with about 780 and 650 c.c.'s for the other Dmanisis specimens. That is "near the mean" for H. habilis, they noted. Modern human braincases are about 1,400 cubic centimeters.
Dr. G. Philip Rightmire, a paleontologist at the State University of New York at Binghamton and a member of the discovery team, said that if the new skull had been found before the other two, it might have been identified as H. habilis.
Dr. Ian Tattersall, a specialist in human evolution at the natural history museum in New York City, said the specimen was "the first truly African-looking thing to come from outside Africa." More than anything else, he said, it resembles a 1.9-million-year-old Homo habilis skull from Kenya.
For the time being, however, the fossil is tentatively labeled Homo erectus, though it stretches the definition of that species. Scientists are pondering what lessons they can learn from it about the diversity of physical attributes within a single species.
Dr. Fred Smith, a paleontologist who has just become dean of arts and sciences at Loyola University in Chicago, agreed that his was a sensible approach, at least until more fossils turn up. Like other scientists, he doubted that two separate hominid species would have occupied the same habitat at roughly the same time. Marked variations within a species are not uncommon; brain size varies within living humans by about 15 percent.
"The possibility of variations within a species should never be excluded," Dr. Smith said. "There's a tendency now for everybody to see three bumps on a fossil instead of two and immediately declare that to be another species."
Some discoverers of the Dmanisi skull speculated that these hominids might be descended from ancestors like H. habilis that had already left Africa. In that case, it could be argued that H. erectus itself evolved not in Africa but elsewhere from an ex-African species. If so, the early Homo genealogy would have to be drastically revised.
But it takes more than two or even three specimens to reach firm conclusions about the range of variations within a species. Still, Georgia is a good place to start. The three specimens found there represent the largest collection of individuals from any single site older than around 800,000 years.
"We have now a very rich collection, of three skulls and three jawbones, which gives us a chance to study very properly this question" of how to classify early hominids, Dr. Lordkipanidze said, and paleontologists are busy this summer looking for more skulls at Dmanisi.
"We badly want to know what the functional abilities of the first out-of-Africa migrants were," said Dr. Wood of George Washington University. "What could that animal do that animals that preceded it couldn't? What was the role of culture in this migration? Maybe other animals were leaving and the hominids simply followed."
All scholars of human prehistory eagerly await the next finds from Dmanisi, and in Chad. Perhaps they will help untangle some of the bushy branches of the human family tree to reveal the true ancestry of Homo sapiens.
Source: Courtesy The New York Times, by John Noble Wilford, August 6, 2002
— It may well be instructive to note the following, that is said of the Dmanisi specimen found in Republic of Georgia…
The Dmanisi specimens share more similarities with the African species Homo ergaster than they do with the Asian Homo erectus, both of which may have existed at the time when the Dmanisi individuals lived. The only characteristic shared with H. erectus and not with H. ergaster is the presence of an angular bulge or torus at the back of the cranium. Homo ergaster specimens do not have an angular torus, whereas both D2280 and D2282 do. The presence or lack of this feature, though, is not considered significant in phylogenetic analysis.
The Dmanisi specimens share more similarities with the African species Homo ergaster than they do with the Asian Homo erectus, both of which may have existed at the time when the Dmanisi individuals lived. The only characteristic shared with H. erectus and not with H. ergaster is the presence of an angular bulge or torus at the back of the cranium. Homo ergaster specimens do not have an angular torus, whereas both D2280 and D2282 do. The presence or lack of this feature, though, is not considered significant in phylogenetic analysis.
Morphological and proportional similarities that D2280 and D2282 share with H. ergaster are considered more important. These similarities have led to the classification of both cranial remains as H. ergaster.
… This classification expands the boundaries of this species, which, until these finds, appeared to be geographically confined to East Africa. H. ergaster has been challenged by many paleoanthropologists who consider it a mere variation of the species H. erectus. The Dmanisi cranial remains show that H. ergaster is more than a limited geographical variant of another species.
… This classification expands the boundaries of this species, which, until these finds, appeared to be geographically confined to East Africa. H. ergaster has been challenged by many paleoanthropologists who consider it a mere variation of the species H. erectus. The Dmanisi cranial remains show that H. ergaster is more than a limited geographical variant of another species.
Source: Courtesy Science vol. 288, pages 1019-1025. May 12, 2000, by L. Gabunia et al.
—D2280 Cranium:
Found in 1999 at Dmanisi, Georgia
—D2282 Cranium:
Found in 1999 at Dmanisi, Georgia
—D2282 Cranium:
Found in 1999 at Dmanisi, Georgia
More pics in Source: Link
The remaining tid bits are extracts courtesy of msu.edu, *unless otherwise stated:
KNM-ER 3883 Partial Cranium ~ dated to between 1.4 - 1.6 million years:
Found by Richard Leakey at Koobi Fora, Kenya
The Koobi Fora Kenyan specimens ~ 1.51 and 1.56 million years:
One of the truly more amazing finds in the history of east african paleoanthropology is the Nariokotome Boy, found by K. Kimeu, Alan Walker, and Richard Leakey at Nariokotome III, West Turkana, Kenya. This find represents a nearly full skeleton of an ergaster youth, dating to between 1.51 and 1.56 million years.
KNM WT 15000 Partial Skeleton ~ dated to between 1.51 - 1.56 million years:
The cranium was found by K. Kimeu in 1984, while the remainder was found by Alan Walker and Richard Leakey over the next three years at Nariokotome III, West Turkana, Kenya
KNM-ER 730 Skull Fragments:
By M. G. Leakey in 1970, at Koobi Fora, Kenya. Traits correlate with both Ergaster on one hand, and Erectus on the other
KNM-ER 731 Mandible Fragment
KNM-ER 819 Mandible Fragment
Although placed in the general classification of Homo, is also a candidate for boisei. Because of its greater robusticity, it is placed into ergaster instead of habilis
KNM-ER 820 Juvenile Mandible:
Dentition compared closely to the Erectus specimen from Zhoukoudian. This specimen is placed by many under the H. Erectus classification
KNM-ER 992 Mandible ~ dated to 1.5 million years:
It is the type specimen for Homo ergaster found by C. Groves and V. Mazak in 1975 at Koobi Fora, Kenya
OH 13 Fragmented Skull ~ dated to 1.5 million years:
By Louis Leakey in 1963 at Olduvai
SK 847 Partial Cranium ~ dated to 1.5 million years:
Found at Swartkrans - South Africa in 1969 by Ronald Clarke
Taung skull, Australopithecus africanus ~ 1 million years ago:
1924 - the year the first australopithecine came to light in South Africa. Professor Raymond Dart of Witwatersrand University was sorting another crate of limestone rock from a quarry near a place called Taung…
…Limestone is good fossil-bearing rock. But dynamited fragments ( often associated with quarries ) are hard to date, particularly with radiometric techniques.
This is why the Taung fossil is difficult to date. Faunal correlation ( i.e. dating a fossil by association with other fossils whose dates are known ) is one way round this, and there are others. But Taung dates are still controversial.
1924 - the year the first australopithecine came to light in South Africa. Professor Raymond Dart of Witwatersrand University was sorting another crate of limestone rock from a quarry near a place called Taung…
…Limestone is good fossil-bearing rock. But dynamited fragments ( often associated with quarries ) are hard to date, particularly with radiometric techniques.
This is why the Taung fossil is difficult to date. Faunal correlation ( i.e. dating a fossil by association with other fossils whose dates are known ) is one way round this, and there are others. But Taung dates are still controversial.
Several recent studies suggest that Taung is younger than once thought - possibly little more than 1 million years BP.
...Dart was certain it was an extinct hominid, although very few of his colleagues in the profession agreed. Dart called his new find various things, but finally settled forAustralopithecus Africanus, the first of the "gracile" australopithecines, hominids with aslender or graceful physique…
…The australopithecines are usually separated into two morphological types on the basis of their body build: gracile forms (Australopithecus afarensis and A. africanus) and robust forms (A. robustus, A. boisei and A. aethiopicus).
KNM-ER 1466 Left Side of Cranial Vault:
KNM-ER 1593: Skull Fragments
KNM-ER 1648: Parietal Fragment
KNM-ER 1808 Adult Skull Fragments
KNM-ER 1811 Mandibular Fragments
KNM-ER 1812 Mandible Fragments
KNM-ER 1821 Right Parietal Fragment
KNM-ER 2592 Left Parietal Fragments
KNM-ER 2595 Right Parietal Fragment
KNM-ER 2598 Occipital Fragment
KNM-ER 3734 Mandibular Fragments
KNM-ER 3889 Mandible Fragment
KNM-ER 3892 Frontal and Parietal:
Robusticity places it in comparison with that of Asian Erectus
Olduvai, Tanzania specimens:KNM-ER 3892 Frontal and Parietal:
Robusticity places it in comparison with that of Asian Erectus
OH 9 Partial Cranium ~ dated to 1.2 million years:
Discovered in 1960 by Louis Leakey at Olduvai, Tanzania
Already mentioned above: OH 13 Fragmented Skull ~ dated to 1.5 million years:
By Louis Leakey in 1963 at Olduvai
Already mentioned above: OH 13 Fragmented Skull ~ dated to 1.5 million years:
By Louis Leakey in 1963 at Olduvai
The Gawis cranium dated ~ 500 ky - 250 ky ago:
Missing link between the extinct Homo erectus and modern man?
Omo crania ~ 195 ky ago:
Feb 2005: Two skulls found near the Omo River in Ethiopia in 1967 by Richard Leakey and thought to be about 130,000 years old have now been dated at 195,000 years, the oldest date known for a modern human skull (McDougall et al. 2005). The Omo I skull is fully modern, while Omo II has some archaic features - Courtesy Jim Foley, talkorigins.org
Feb 2005: Two skulls found near the Omo River in Ethiopia in 1967 by Richard Leakey and thought to be about 130,000 years old have now been dated at 195,000 years, the oldest date known for a modern human skull (McDougall et al. 2005). The Omo I skull is fully modern, while Omo II has some archaic features - Courtesy Jim Foley, talkorigins.org
Herto Crania ~ 160 ky ago:
…After uncovering more fossilized fragments, the team reconstructed skull fragments and teeth from seven individuals. The three most complete fossils, however, were one adult cranium ( excluding the lower jaw ), cranial fragments from another adult, and a less-complete child’s skull.
…To determine the age of the fossils, White and his team turned to Paul Renne, of UC Berkeley’s Department of Earth and Planetary Sciences and the Berkeley Geochronology Center--a non-profit organization that dates geological events in the Earth’s history. Renne’s research group used argon-isotope dating to find the age of the Herto fossils. This process takes advantage of the radioactive decay of an isotope of potassium ( potassium-40 ) into argon ( argon-40 ). By knowing the rate of this decay and measuring the proportion of potassium-40 to argon-40, Renne and his team determined the age of volcanic ash above and below the fossils. After correlating the make-up of the Herto fossils with the volcanic ash, they dated the skulls to about 160,000 years ago, chronologically placing them between pre-Homo sapiens and modern man
…The Herto individuals are not the only early humans found in Africa, but their relative wholeness makes them the most significant. Unlike remains dating from 130,000 to 260,000 years ago found in South Africa, Tanzania and Morocco, the Ethiopian fossils are “especially well preserved and clean,” said Renne. They do not show evidence of disease or pathologies, which can sometimes misrepresent a species and mislead scientists.
The most unique quality of the crania is their combination of early and modern human features For example:
The most unique quality of the crania is their combination of early and modern human features For example:
— the wide-set eyes, anteriorly-placed teeth, and short occipital bone at the base of the skull are found in more ancient African crania.
— But the wide upper face, moderately domed forehead, and globular braincase resemble modern human fossils, like those found in Israel from about 115,000 years ago.
Source: Courtesy UC Berkeley, Science Review.
In the words of Jennifer Viegas, for Discovery news, going back to the point about avoiding bio-anthropological "tunnel vision",....
Although Omo I may be the world's "Adam" for now, it's possible that modern humans emerged even earlier at some other place in Africa.
"We only have evidence for what we have found," Fleagle said, adding that there "almost certainly were modern individuals before Omo I."
He explained that Ethiopia's geology has deposits suitable to bone preservation and discovery, which is perhaps why so many fossil hominids have been excavated there over the years.
"Paleontology is a very opportunistic science," he concluded. "When we have a record of fossils in one place, we can reconstruct what happened there, but it is impossible to say what was going on in places from which there is no fossil record." - Jennifer Viegas, Earliest Known Human Had Neanderthal Qualities, Discovery News - August 22, 2008.
Recommended reading:
Recent Developments in Paleoanthropology
Chronological Bits - Crania
Last updated on April 25th, 2013.
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