[This is a chapter from Cremo's follow-up book "The Forbidden Archeologist", which is an anthology of the author's articles. I found this one to be particularly mind-blowing. I've read the original "Forbidden Archeology" book, and though I reccommend it, I don't think it is nesscesary to have read it to understand this article as Cremo gives a brief run down of it's thesis.]

[Bold emphasis added by me for those who just want to the main points]

Who’s Anatomically Modern?

In my book Forbidden Archeology, I often made use of the phrase “anatomically modern human” to describe skeletal remains. In terms of skulls, that meant features such as a large brain case, no brow ridges, a high forehead, and a prominent chin. In terms of the rest of the skeleton, it meant gracile features—bones that appear longer and thinner than the bones of earlier human ancestors.

According to most archeologists and anthropologists today, “anatomically modern” humans, defined as above, came into existence between 100,000 and 150,000 years ago. In Forbidden Archeology, I showed there is fossil evidence that such anatomically modern humans existed more than 100,000 to 150,000 years ago. For example, early in the twentieth century, an Argentine scientist named Florentino Ameghino reported the discovery of an “anatomically modern” human skull at Buenos Aires (Forbidden Archeology, pp. 413–418). It was found in a formation over 1 million years old. In other parts of the world, skeletal remains of other humanlike creatures were found, with skulls with more robust features such as prominent brow ridges. So in discussing these cases in Forbidden Archeology I would say that there is evidence that “anatomically modern” humans coexisted with various kinds of apemen, with more robust features, like Homo erectus or the Neanderthals. 

However, in recent years, I have begun to change my understanding of what it means to be an “anatomically modern human.”

Studies have shown that among living humans we can find a great deal of variation in the morphology of skeletons, especially in terms of the skull’s size and shape. For example, in 1995, physical anthropologist Marta Mirazon Lahr did a study of recent Indian skulls from the Patagonia and Tierra del Fuego regions of South America (Yearbook of Physical Anthropology, vol. 38, pp. 163–198). Lahr found that almost all the skulls displayed brow ridges rather than smooth foreheads. The brow ridges took different forms. Some skulls had arched brow ridges over each eye but not joined above the nose. Others skulls had arched brow ridges, joined over the nose. Yet other skulls had a solid horizontal bar of bone that went straight across the forehead, over the nose and the orbits of the eyes. This is called a supraorbital torus. Lahr found that 57 percent of the Fuegian-Patagonian skulls had very pronounced arched brow ridges joined at the nose, and 8 percent had a torus! All of the skulls in the collection had some kind of brow ridge, making the collection similar to collections of human skulls from certain groups of people living in North Africa and Australia (at present and during the recent past).

Pronounced curved brow ridges and barlike supraorbital tori are generally considered typical of Australopithecus, Homo habilis, Homo erectus, and Neanderthals. So if scientists find skulls with these features, they generally classify them as something other than anatomically modern human, especially if they are found in geological formations considered too old for modern humans.

Another feature of apemen is sagittal keeling. This feature is visible as a ridge running along the midline of the top of the skull, from the back of the skull to the front of the skull. But this feature is also found in living human populations, such as Eskimos, the Ainu of Japan, and Fuegians. Lahr and others point out that the human skull remains somewhat soft until early adulthood. They say that some of the “primitive” features of the skull like sagittal keeling may be the result of cultural practices that involve using the jaws for clamping, as in leather working, for example. Anthropologist Richard G. Klein says in his book The Human Career (1989, pp. 281–282), “Biomechanically, the forces exerted by persistent, habitual, nonmasticatory use of the front teeth could ac- count in whole or in part for such well-known Neanderthal features as the long face, the well-developed supraorbital torus, and even the long, low shape of the cranium.” Another feature considered “modern” is a well-developed chin. Many fossil mandibles (lower jaws) of apemen are chinless.

But we see that many living people do not have well-developed chins. Fossil mandibles of humans considered “modern” in terms of age (i.e. less than 100,000 years old) also show a wide variety of chin development. In their book Race and Human Evolution (1997, p. 332), physical anthropologists Milford Wolpoff and Rachel Caspari (1997, p. 332, figure ) show photos of a fossil human mandible, from the Klassies site in South Africa, with a well-developed chin. It is considered “modern.” But they also show a mandible from the Dar es Soltane 2 site in Morocco, which is about 35,000 years old. It is considered early modern African. But there is no chin development, although a chin is normally considered a modern feature. In short, both are modern, but one has a chin and another does not. So there is a considerable amount of variation in “modern” skeletal samples.

Features such as prominent brow ridges, sagittal keeling, and the absence of a developed chin are found in many of the skulls of the apemen that modern scientists call Homo erectus. One of the most well-known populations of Homo erectus was found at Zhoukoudian near Beijing in the 1920s and 1930s. The first reports on these Beijing Man fossils came from Davidson Black, who gave the species its official name Sinanthropus pekinensis. In the 1940s, some scientists wanted to include Sinanthropus in the species Homo erectus (which today is the general practice). Franz Weidenreich, one of the scientists involved in the discovery and description of Beijing Man, objected to calling Beijing Man Homo erectus. He did not like the name Sinanthropus either. He actually preferred to call the Chinese fossils Homo sapiens erectus pekinensis, thus making Beijing Man a variety of Homo sapiens. “Otherwise it would appear as a proper ‘species’ different from ‘Homo sapiens’ which remains doubtful to say the least,” said Weidenreich in 1943, in his report “The skull of Sinanthropus pekinensis” (p. 246).

Weidenreich went on to propose that all varieties of fossil human ancestors known at that time should be included in the species Homo sapiens. This would have included the Java apemen (Pithecanthropus erectus, now classified as Homo erectus), Beijing Man (Sinanthropus pekinesis, now also classified as Homo erectus), and the Neanderthals, as well as varieties of early Homo species like Homo heidelbergensis. Weidenreich did not consider Australopithecus to be a human ancestor.

Weidenreich’s view that all apemen from Homo erectus up to the Neanderthals should be considered part of the same species as modern humans (Homo sapiens) is shared by some modern anthropologists such as Wolpoff and Caspari.

They say (1997, p. 345):

“[It is] impossible to arrive at a definition [of modernity] that simultaneously includes the variation of all living people and excludes all members of archaic groups. . . . Any definition of moderns, therefore, must include many ancients and make it seem as though for long periods of time archaic and modern people were coexisting not just on the same continent or in the same region, but in many cases within the same family.”

Of course, I have been saying for a long time that anatomically modern humans have coexisted with other species such as Homo erectus and Neanderthals. Here’s the difference—now I am prepared to say that we should also consider many of these Neanderthals and Homo erectus individuals to also belong to the “modern” human species.

Physical anthropologist Erik Trinkaus said in a paper published in Natural History (vol. 87, no. 10, p. 58):

“Detailed comparison of Neanderthal skeletal remains with those of modern humans have shown that there is nothing in Neanderthal anatomy that conclusively indicates locomotor, manipulative, intellectual, or linguistic abilities inferior to those of modern humans.”

After examining skulls of Homo erectus, Richard Leakey concluded in a paper published in the book Human Origins, edited by J. R. Durant (1989, p. 57):

“I am increasingly of the view that all of the [skeletal] material currently referred to as Homo erectus should be placed within the species sapiens [which would] project Homo sapiens as a species that can be traced from the present back to a little over two million years.”

The idea that a single species can accommodate populations with greatly different physical appearances may seem strange. But actually it is a fairly common thing. Dogs, for example, all belong to the same species, Canis familiaris. But the dog species includes Great Danes, English bulldogs, chihuahuas, and many more varieties. If millions of years from now, paleontologists who were not aware of the actual history of dog breeding were to find skeletons of the many kinds of dogs, they would be most unlikely to conclude that skeletons of dachshunds and Great Danes should be placed in the same species. But they do belong to the same species.

Today, humans with skulls with no brow ridges, with no sagittal crests, and with developed chins coexist with humans with skulls with heavy brow ridges, with sagittal crests, and with no chins. They all belong to the same species. When we look into the past, we also see skulls with no brow ridges, with no sagittal crests, and with developed chins from the same time periods as skulls with heavy brow ridges, sagittal crests, and no chins. So unless we want to say that modern humans with these different features belong to separate species, we should conclude that ancient skulls with these different features also all belong to the same species, Homo sapiens.