EARLY HOMOS
comparison of hominin mandibles
Members of the genus homo have larger brains and a smaller, ape-like faces. What distinguished them from their predecessors was is ability to make stone tools. “Homo erectus” was the first species to expand into Asia and Europe. “Homo” is Latin for "human." [Sources: Homo erectus, National Geographic, May, 1997; Homo erectus, Rick Gore, National Geographic, July 1997]
Claims to the oldest “Homo” fossils include a 2.4-million-year- old mandible from Uraha, Malawi, a 2.4-million-year-old skull fragment from Lake Baringo, Kenya and a 2.3-million-year-old upper jawbone from Hadar, Ethiopia. For the most part though the period between two million and three million years ago there is little data and few fossils.
A fossilized mandible reported in 2015 may be the earliest-known member of the genus Homo. Archaeology magazine reported: It dates to around 2.8 million years ago, or 500,000 years earlier than the next oldest known examples. This period in human evolution — the transition from Australopithecus to Homo — is still not well understood. The bone and teeth have traits that appear to bridge the earlier (rounded chin) and later (slimmer molars) species. It may be a key finding for understanding the origins of our genus. See Below [Source: Samir S. Patel, Archaeology magazine, July-August 2015]
“Homo” species had longer bodies than the short and stocky “Australopithecus “ species. Since about 1.8 years hominins have been within the size range of modern humans. Male and females size differences characteristic of Australopithecus species decreased. The brain volume of Australopithecus species ranged between 400 and 500 cubic centimeters while the brain volume of early “ Homo” species was between 600 and 750 cubic centimeters.
Websites and Resources on Hominins and Human Origins: Smithsonian Human Origins Program humanorigins.si.edu ; Institute of Human Origins iho.asu.edu ; Becoming Human University of Arizona site becominghuman.org ; Hall of Human Origins American Museum of Natural History amnh.org/exhibitions ; The Bradshaw Foundation bradshawfoundation.com ; Britannica Human Evolution britannica.com ; Human Evolution handprint.com ; University of California Museum of Anthropology ucmp.berkeley.edu; John Hawks' Anthropology Weblog johnhawks.net/ ; New Scientist: Human Evolution newscientist.com/article-topic/human-evolution
See Separate Article: EARLY HOMOS: DEVELOPMENT, TOOLS, COMPLEXITY factsanddetails.com
Homo habilis
“Homo habilis”, meaning "handy man," was dramatically different from his predecessors. Homo habilis appeared around the same time as the first stone tools. Some scientists suggest the transformation from Australopithecus to Homo habilis was brought about by climatic changes.
Geologic Age 1.4 million to 2.5 million years. Very few “H. habalis” remains have been found, but scientists speculate he survived about a half a million years. He lived at same time as Australopithecus boisei. Linkage to Modern Man: Seen as direct ancestor. Not clear what Australopithecus species he evolved from.
Discovery Sites: Eastern and southern Africa. Discovered at Olduvai Gorge, Tanzania in 1959 by Mary Leakey and found near Lake Turkana at Koobi Fara, Kenya by B. Ngeneo and the Sterkfontein and Swartkrans in South Africa. Leakeys. The Lake Turkana remains are housed at National Museum of Kenya in Nairobi.
Size: Small compared to modern humans. males: 1.32 meters (4 feet 4 inches); females: 1.17 meters (3 feet 10 inches), 32 kilograms (71 pounds). Skull Features: Primitive face, back teeth narrower. Larger brain and smaller human-like jaws and teeth than those found on Australopithecus species. Body Features: More similar to modern man.
Homo rudolfensis and Homo ergaster
homo ergaster Nariokotome Boy “Homo rudolfensis” , is a hominin species that lived between 2.5 million and 1.9 million years ago. Little is know about this hominin which sprung up about a half million years before “Homo habilis” died out. Many scientists regard “Homo rudolfensis” as a member of the “ Homo habilis” species. If not it is the earliest known homo species. Skull Features: Long, broad face with flatter browridges and a larger, rounder braincase that “Homo habilis” . Discovery Sites: Eastern Africa. Omo, Ethiopia; Koobi Fora at Lake Turkana, Kenya; Uraha, Lake Malawi.
“Homo ergaster “ is a hominin species that lived between 1.8 million and 1.4 million years ago. Many scientists regard “Homo ergaster “ as a member of the “Homo erectus “ species. Skull Features: smaller jaws and a more projecting nose than earlier Homos. Body Features: Arm and leg proportions more similar to modern man. Discovery Site: Koobi Fora at Lake Turkana, Kenya.
"Turkana Boy" is a nearly complete skeleton and skull from a 12-year-old boy that lived 1.54 million years ago and was discovered in 1984 near the shores of Lake Turkana not far from Nariokotome, Kenya. Some scientists think he is “Homo erectus”. Others regard him as distinctive enough to be regarded as a separate species — “homo ergaster”. Turkana Boy was about 5-foot, 3-inches tall when he died and probably would have reached a height of about six feet if he reached maturity. Turkana boy is the most complete skeleton of a hominin more than a million years old.
See 1.7-Million-Year-Old Hominin Fossils in Georgia
Homo Erectus
“Homo erectus” had a considerably larger brain than “Homo habilis”, its predecessor. It fashioned more advanced tools (double-edged, teardrop-shaped "hand axes" and "cleavers" ) and controlled fire (based on the discovery of charcoal with erectus fossils). Better foraging and hunting skills, allowed it to exploit its environment better than “Homo habilis” Nickname: Peking Man, Java Man. “Homo erectus” lived for 1.3 million years and spread from Africa to Europe and Asia. Paleontologist Alan Walker told National Geographic, “Homo erectus “ "was the velociraptor of its day. If you could look one in the eyes, you wouldn't want to. It might appear to be human, but you wouldn't connect. You'd be prey."
Geologic Age 2 million years to 100,000 years ago. Homo erectus “ lived at the same time as “Homo habilis “ and “Homo rudolfensis” and later at the same time as Neanderthals and modern humans, but not necessarily in the same places. Linkage to Modern Man: Regarded as a direct ancestor of modern man, May have had primitive language skills. Discovery Sites: Africa and Asia. Homo erectus“ fossils have been found in eastern Africa, southern Africa, Georgia, Algeria, Morocco, China and Java.
See Separate Article: HOMO ERECTUS: factsanddetails.com
Three Homo Species Living at Same Time: Homo Erectus, Homo Habalis and Homo Rudolfensis?
Java Man skull Seth Borenstein of Associated Press wrote: “The Leakey scientific team contends that other fossils of old hominins - not those cited in their new study - don't seem to match either erectus or 1470. They argue that the other fossils seem to have smaller heads and not just because they are female. For that reason, the Leakeys believe there were three living Homo species between 1.8 million and two million years ago. They would be Homo erectus, the 1470 species, and a third branch. "Anyway you cut it there are three species," study co-author Susan Anton, an anthropologist at New York University. "One of them is named erectus and that ultimately in our opinion is going to lead to us." [Source: Seth Borenstein, Associated Press, August 8 2012]
Both of the species that Meave Leakey said existed back then went extinct more than a million years ago in evolutionary dead-ends. "Human evolution is clearly not the straight line that it once was," Spoor said. The three different species could have been living at the same time at the same place, but probably didn't interact much, he said. Still, he said, East Africa nearly 2 million years ago "was quite a crowded place"
“And making matters somewhat more confusing, the Leakeys and Spoor refused to give names to the two non-erectus species or attach them to some of the other Homo species names that are in scientific literature but still disputed. That's because of confusion about what species belongs where, Anton said. Two likely possibilities are Homo rudolfensis -which is where 1470 and its kin seem to belong - and Homo habilis, where the other non-erectus belong, Anton said. The team said the new fossils mean scientists can reclassify those categorized as non-erectus species and confirm the earlier but disputed Leakey claim.
“But Tim White, a prominent evolutionary biologist at the University of California Berkeley, is not buying this new species idea, nor is Milford Wolpoff, a longtime professor of anthropology at the University of Michigan. They said the Leakeys are making too big a jump from too little evidence. White said it's similar to someone looking at the jaw of a female gymnast in the Olympics, the jaw of a male shot-putter, ignoring the faces in the crowd and deciding the shot-putter and gymnast have to be a different species. Eric Delson, a paleoanthropology professor at Lehman College in New York, said he buys the Leakeys' study, but added: "There's no question that it's not definite." He said it won't convince doubters until fossils of both sexes of both non- erectus species are found. "It's a messy time period," Delson said.
2.8-Million-Year-Old Fossil Found in Ethiopia: the First Human?
In 2015, scientists said they had unearthed the jawbone of what they claimed was one of the very first humans. The 2.8 million-year-old hominin is 400,000 years older than what had been previously described as the oldest “Homo.” The discovery also hinted that climate change might have played a part in transition from living the trees to walking upright. Prof Brian Villmoare of the University of Nevada in Las Vegas told the BBC that the discovery may be linked with “Lucy,” the iconic 3.2 million-year-old hominin found in the same area in 1974. Could Australopithecus afarensis (Lucy's species) have evolved into the first primitive humans? "That's what we are arguing," said Prof Villmoare. But the fossil record between the time period of Lucy and the emergence of Homo erectus — a “Homo” species,, with a relatively large brain and humanlike body proportions, that lived two million years ago — is thin.[Source: Pallab Ghosh, BBC News, March 4, 2015 |::|]
Homo Rudolfensis endocast
Pallab Ghosh wrote for BBC News: “The 2.8 million-year-old lower jawbone was found in the Ledi-Geraru research area, Afar Regional State, by Ethiopian student Chalachew Seyoum. He told BBC News that he was "stunned" when he saw the fossil. "The moment I found it, I realised that it was important, as this is the time period represented by few (human) fossils in Eastern Africa." |::|
“The fossil is of the left side of the lower jaw, along with five teeth. The back molar teeth are smaller than those of other hominins living in the area and are one of the features that distinguish humans from more primitive ancestors, according to Professor William Kimbel, director of Arizona State University's Institute of Human Origins. "Previously, the oldest fossil attributed to the genus Homo was an upper jaw from Hadar, Ethiopia, dated to 2.35 million years ago," he told BBC News. "So this new discovery pushes the human line back by 400,000 years or so, very close to its likely (pre-human) ancestor. Its mix of primitive and advanced features makes the Ledi jaw a good transitional form between (Lucy) and later humans." |::|
“A computer reconstruction of a skull belonging to the species Homo habilis, which has been published in Nature journal, indicates that it may well have been the evolutionary descendant of the species announced today. The researcher involved, Prof Fred Spoor of University College London told BBC News that, taken together, the new findings had lifted a veil on a key period in the evolution of our species. "By discovering a new fossil and re-analysing an old one we have truly contributed to our knowledge of our own evolutionary period, stretching over a million years that had been shrouded in mystery," he said.” |::|
Significance of 2.8-Million-Year-Old “Human” Fossil Found in Ethiopia
Pallab Ghosh wrote for BBC News: “The dating of the jawbone might help answer one of the key questions in human evolution. What caused some apes to climb down from the trees and make their homes on the ground. A separate study in Science hints that a change in climate might have been a factor. An analysis of the fossilised plant and animal life in the area suggests that what had once been lush forest had become dry grassland.As the trees made way for vast plains, apes found a way of exploiting the new environmental niche, developing bigger brains and becoming less reliant on having big jaws and teeth by using tools. [Source: Pallab Ghosh, BBC News, March 4, 2015 |::|]
Prof Chris Stringer of the Natural History Museum in London described the discovery as a "big story". He says the new species clearly does show the earliest step toward human characteristics, but suggests that half a jawbone is not enough to tell just how human it was and does not provide enough evidence to suggest that it was this line that led to us. He notes that the emergence of human-like characteristics was not unique to Ethiopia. The jawbone was found close to the area where Lucy was discovered. "The human-like features shown by Australopithecus sediba in South Africa at around 1.95 million years ago are likely to have developed independently of the processes which produced (humans) in East Africa, showing that parallel origins are a distinct possibility," Prof Stringer explained. |::|
“This would suggest several different species of humans co-existing in Africa around two million years ago with only one of them surviving and eventually evolving into our species, Homo sapiens. It is as if nature was experimenting with different versions of the same evolutionary configuration until one succeeded. Prof Stringer added: "These new studies leave us with an even more complex picture of early humans than we thought, and they challenge us to consider the very definition of what it is to be human. Are we defined by our small teeth and jaws, our large brain, our long legs, tool-making, or some combination of these traits?"”
Homo Gautengensis
Homo Gautengensis
Homo gautengensis is a hominin species proposed by biological anthropologist Darren Curnoe in 2010 based on the analysis of a partial skull found in 1977 at Sterkfontain Cave near Johannesburg, South Africa. Some scientists had earlier classified the fossils as Homo habilis or Homo ergaster. Others said they belonged to an Australopithecus species. Curnoe has argued that Homo gautengensis is the earliest species in the genus Homo. The view is controversial to say the least. Many scientists dismiss the idea that Homo gautengensis is a unique species.
According to the Bradshaw Foundation: “Further identification of Homo gautengensis was based on partial skulls, several jaws, teeth and other bones found at various times and cave sites in South Africa’s Cradle of Humankind. The oldest specimens are those from Swartkrans between 1.9 and 1.8 million years ago. The Sterkfontain specimen is dated between 1.8 and 1.5 million years ago, and the Gondolin Cave 1.8 million years ago. The youngest specimens from Swartkrans are dated to sometime between 1.0 and 0.6 million years ago. [Source: Bradshaw Foundation \=]
“According to Curnoe, Homo gautengensis had big teeth suitable for chewing plant material, was small-brained and large-toothed, and was probably an ecological specialist, consuming more vegetable matter than Homo erectus, Homo sapiens and probably Homo habilis. It apparently produced and used stone tools and may even have made fire, as there is evidence for burnt animal bones associated with Homo gautengensis' remains. Standing just over 0.91 meters tall and weighing about 50 kg, it walked on two feet when on the ground, but probably spent considerable time in trees, perhaps feeding, sleeping and escaping predators. It probably lacked speech and language skills. \=\
“Homo gautengensis was a close relative of Homo sapiens but not necessarily a direct ancestor. It would have lived at the same time and in the same place as Australopithecus sediba, the latter being more primitive [and therefore less likely to be the ancestor of humans]. Indeed, there would have been a number of distinctive, perhaps short-lived, species of proto-humans living in both eastern and southern Africa in the period between 2 and 1 million years ago.” \=\
H Rudolfensis, H Gautengensis, H Ergaster and H Habilis All Homo Erectus?
Homo rudolfensis, Homo gautengensis, Homo ergaster and Homo habilis are regarded separate species from homo erectus but some think they may all be the same species. Those that believe they may be the same species began by comparing the 1.8-million-year-old Dmanisi remains with those of supposedly different species of human ancestor that lived in Africa at the time.
Ian Sample wrote in The Guardian: “The scientists concluded that the variation among them was no greater than that seen at Dmanisi. Rather than being separate species, the human ancestors found in Africa from the same period may simply be normal variants of H erectus. “"Everything that lived at the time of the Dmanisi was probably just Homo erectus," said Prof Zollikofer. "We are not saying that palaeoanthropologists did things wrong in Africa, but they didn't have the reference we have. Part of the community will like it, but for another part it will be shocking news." [Source: Ian Sample, The Guardian, October 17, 2013]
Homo ergaster skull replica
“David Lordkipanidze at the Georgian National Museum, who leads the Dmanisi excavations, said: "If you found the Dmanisi skulls at isolated sites in Africa, some people would give them different species names. But one population can have all this variation. We are using five or six names, but they could all be from one lineage." If the scientists are right, it would trim the base of the human evolutionary tree and spell the end for names such as H rudolfensis, H gautengensis, H ergaster and possibly H habilis. "Some palaeontologists see minor differences in fossils and give them labels, and that has resulted in the family tree accumulating a lot of branches," said White. "The Dmanisi fossils give us a new yardstick, and when you apply that yardstick to the African fossils, a lot of that extra wood in the tree is dead wood. It's arm-waving." |=|
“"I think they will be proved right that some of those early African fossils can reasonably join a variable Homo erectus species," said Chris Stringer, head of human origins at the Natural History Museum in London. "But Africa is a huge continent with a deep record of the earliest stages of human evolution, and there certainly seems to have been species-level diversity there prior to two million years ago. So I still doubt that all of the 'early Homo' fossils can reasonably be lumped into an evolving Homo erectus lineage. We need similarly complete African fossils from two to 2.5 million years ago to test that idea properly." |=|
“The analysis by Lordkipanidze also casts doubt on claims that a creature called Australopithecus sediba that lived in what is now South Africa around 1.9 million years ago was a direct ancestor of modern humans. The species was discovered by Lee Berger at the University of Witwatersrand. He argued that it was premature to dismiss his finding and criticised the authors for failing to compare their fossils with the remains of A sediba. "This is a fantastic and important discovery, but I don't think the evidence they have lives up to this broad claim they are making. They say this falsifies that Australopithecus sediba is the ancestor of Homo. The very simple response is, no it doesn't. What all this screams out for is more and better specimens. We need skeletons, more complete material, so we can look at them from head to toe," he added. "Any time a scientist says 'we've got this figured out' they are probably wrong. It's not the end of the story." |=|
See Separate Article: HOMO ERECTUS SUBSPECIES, RELATED SPECIES AND FAMOUS FOSSILS factsanddetails.com
Skull 1470 and Recent Fossils Finds by Meave Leaky
In 2012, Meave Leakey announced that her team had found facial bones from the time of Homo erectus that didn’t belong to Homo erectus, proving that more than one hominin lived at that time and perhaps meaning that there was more than one common ancestor for man. Leakey’s team found facial bones from one creature and jawbones from two others between 2007 and 2009 about 10 kilometers away from a an old fossil-rich site in Lake Turkana region. [Source: Seth Borenstein, Associated Press, August 8 2012]
Valerie Ross wrote in Discover: “In 1972, researchers found a partial skull in the fossil beds near Lake Turkana. Its big cranium—with room for a large brain—made clear it was a member of the genus Homo. Its unusual face, flat and long, led some scientists to believe it represented a new species, dubbed H. rudolfensis; others felt the skull could just be an odd-looking specimen of a known species, H. erectus or H. habilis, an example of natural variation in action. With the skull’s entire lower jaw missing, it was impossible to make a definitive classification. Just a few years ago, researchers found fossils of a complete and partial lower jaw and of another face, dating from 1.78 million to 1.95 million years ago. The newly discovered jaws fit well with the earlier skull, as shown above, and are different from those seen in before, confirming that the 1972 find is a new species. The other find, the fossil face, was from a juvenile, and clearly mirrored the other skull’s features and shape. [Source: Valerie Ross, Discover, August 9, 2012]
Hominin brain sizes
Seth Borenstein of Associated Press wrote: The “finding has led the researchers to conclude that man's early ancestor had plenty of human-like company from other species. These would not be Homo erectus, believed to be our direct ancestor. They would be more like very distant cousins, who when you go back even longer in time, shared an ancient common ancestor, one scientist said. But other experts in human evolution are not convinced by what they say is a leap to large conclusions based on limited evidence. It is the continuation of a long-running squabble in anthropology about the earliest members of our own genus, or class, called Homo - an increasingly messy family history. And much of it stems from a controversial discovery that the Leakeys made 40 years ago.
“In their new findings, the Leakey team says that none of their newest fossil discoveries match erectus, so they had to be from another flat-faced relatively large species with big teeth. The new specimens have "a really distinct profile" and thus they are "something very different," said Meave Leakey, describing the study published online in Nature. What these new bones did match was an old fossil that Meave and her husband Richard helped find in 1972 that was baffling. That skull, called 1470, just did not fit with Homo erectus, the Leakeys contended. They said it was too flat-faced with a non-jutting jaw. They initially said it was well more than 2.5 million years old in a dating mistake that was later seized upon by creationists as evidence against evolution because it indicated how scientists can make dating mistakes. It turned out to be two million years old.
For the past 40 years, the scientific question has been whether 1470 was a freak mutation of erectus or something new. For many years, the Leakeys have maintained that the male skull known as 1470 showed that there were more than one species of ancient hominins, but other scientists said it wasn't enough proof. The Leakeys' new discoveries are more evidence that this earlier "enigmatic face" was a separate species, said study co-author Fred Spoor of the Max Planck Institute in Germany.”
Image Sources: Wikimedia Commons
Text Sources: National Geographic, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Nature, Scientific American. Live Science, Discover magazine, Discovery News, Natural History magazine, Archaeology magazine, The New Yorker, Time, Newsweek, BBC, The Guardian, Reuters, AP, AFP and various books and other publications.
Last updated April 2024