Philip L. Stein & Bruce M. Rowe
Number 5 Spring 1997
Copyright ©1997 by McGraw-Hill, Inc. All rights reserved. Printed in the United States of America. The entire contents or parts of this Update may be reproduced for use with Physical Anthropology, Sixth Edition, or Physical Anthropology: The Core, by Philip L. Stein and Bruce M. Rowe, provided each reproduction bears the copyright notice. The publisher's written permission must be obtained for other use.
See Physical Anthropology, 6th edition, Chapter 17, page
Physical Anthropology: The Core, Chapter 11, pages 260-261.
Although the genus Homo is thought to have first appeared between 3 and 2 million years ago, the absence of a good fossil record, com bined with taxonomic issues, has served to hide the story of the origins of this genus from our eyes.
In November 1994, fragments of a hominid maxilla were recovered from locality AL 666, located in the Hadar region of Ethiopia. The maxilla, identified as AL 666-1, is very complete and well preserved. Oldowan flakes and choppers are associated with the skeletal remains.
The single-crystal 40Ar/39Ar laser micro probe dating method, used on a number of samples, gives a minimum age for the hominid maxilla and the artifacts of 2.33 million B.P. Analysis of the faunal remains suggests that the hominid had occupied an open habitat, such as a savanna, as well as wooded areas and wet-lands that were located near sources of water. These environments contrast with the more closed or wooded habitats that are associated with Australopithecus africanus.
The morphology of the maxilla and the dentition clearly place the new find into the genus Homo. The maxilla exhibits a relatively wide and deep palate with a parabolic dental arcade.
The division of early representatives of the genus Homo into distinct species is problematical. Several species have been proposed: H. habilis, H. rudolfensis, early H. erectus, or H.ergaster. The characteristics of the new maxilla appear to be typical of the genus in general, but are not specific for any particular species.
Source: W. H. Kimbel et al., Late Pliocene Homo and Oldowan Tools from the Hadar Formation (Kada Hadar Member), Ethiopia, Journal of Human Evolution, 31 (1996), 549-561.
See Physical Anthropology, 6th edition, Chapter 17, page 443, and Chapter 19, pages 494-495; Physical Anthropology: The Core, Chapter 11, page 264, and Chapter 12, pages 297-299.
During the past decade one of the major areas of controversy in paleoanthropology has been that between the proponents of the Regional Continuity hypothesis and those who support the Replacement (Out of Africa) hypothesis concerning the origins of anatomically modern Homo sapiens sapiens. Of major importance in this debate is the taxonomic identification of the significant fossils and their dates. This debate has led to reanalysis of some of the data.
A series of fossils from central Java have been known to paleoanthropologists for some time. These fossils were first discovered be tween 1931 and 1933 at Ngandong, which is located on the Solo River. The excavations revealed over 25,000 vertebrate fossils, including 12 hominid calvaria and partial calvaria, and two tibiae. Additional hominid material, including two partial calvaria and pelvic fragments, were recovered between 1976 and 1980.
A recent report establishes new dates for the Ngandong material. Using a series of bovid teeth from museum collections and fresh excavations, the authors applied combined electron spin resonance (ESR) and uranium-series dating techniques to the tooth enamel. (The latter technique measures the decay of uranium to thorium in tooth enamel.) The results of the analysis provide a series of mean dates between 53,300 ± 4000 and 27,000 ± 2000 years ago. These dates are much younger than any earlier estimate.
The authors contend that the Ngandong hominids belong taxonomically to Homo erectus. If this is correct, than H. erectus survived in Southeast Asia much later than in any other part of the world. If this material is indeed H.erectus, then the regional continuity concept, where the Ngandong fossils represent intermediate steps in the evolution from H. erectus to H.sapiens, becomes difficult on a chronological basis. Rather, the authors contend that Java material represent a late remnant H. erectus population that was replaced at a very late date by migrations of H. sapiens.
All of this assumes, of course, that the Ngandong material is indeed H. erectus. While the authors make this assumption, it is not a universally accepted conclusion. The Encyclopedia of Human Evolution and Prehistory states ...there is still much debate about whether to classify the Ngandong hominids as an early form of archaic Homo sapiens or a late form of Homo erectus. The total morphological pattern includes characteristics of both.1
Source: C. C. Swisher III et al., Latest Homo erectus of Java: Potential Contemporaneity with Homo sapiens in Southeast Asia, Science, 274 (13 December 1996), 1870- 1874.1 I. Tattersall, E. Delson, and J. Van Couvering, Encyclo pedia of Human Evolution and Prehistory (New York: Garland Publishing, 1988), 383.
See Physical Anthropology, 6th edition, Chapter 17, page 453; Physical Anthropology: The Core, Chapter 11, page 282.
Paleoanthropologists search for the earliest fossil evidence of the hominids; they also search for the earliest evidence of manufactured stone tools. Stone tools, dating to about 2.3 million B.P., have been found in the sedimentary beds of Omo and Lake Turkana. Between 1992 and 1994, stone tools were found in the Gona River drainage of the Awash Valley of Ethio pia, which is located close to the well known area of Hadar. The tools were found within the Hadar formation. The Hadar formation has been securely dated over the years by several radiometric dating techniques and by studies of the periodic reversal of the earth's magnetic poles. The stone tools date to between 2.6 and 2.5 million B.P., making them the oldest known archaeological finds to date.
Several sites located in the Gona region have yielded more than 3000 artifacts. These artifacts include unifacially and bifacially flaked cores, flakes and flaking debris. The tools belong to the Oldowan tradition.
These artifacts are very well-preserved and they are very well made. The degree of sophistication, although primitive when compared with later artifacts, strongly suggests that the roots of stone tool manufacture extend even further back in time. No hominid remains have been found associated with the tools. Although most paleoanthropologists would conclude that the artifacts were manufactured by an early member of the genus Homo, some would not rule out Australopithecus as the toolmakers.
Source: S. Semaw et al., 2.5-million-year-old Stone Tools from Gona, Ethiopia, Nature, 385 (23 January 1997), 333-336.
See Physical Anthropology, 6th edition, Chapter 18, pages 474-475; Physical Anthropology: The Core, Chapter 11, page 277.
No matter how one defines the role of the Neandertals in the grand scheme of evolution, without a doubt this hominid population represents a facinating chapter in this story. Some paleoanthropologists conclude that the Neander tals represent a population, perhaps a subspecies, of Homo sapiens. Therefore, they are possible ancestors to anatomically-modern Homo sapiens sapiens. However, others conclude that the Neandertals are so distinctive that they are best placed into their own unique species, Homo neandertalensis; as such they cannot be considered ancestral to modern humans.
Jeffrey Schwartz and Ian Tattersall present a detailed analysis of the nasal region of the Neandertal skull. They concluded that many of anatomical features found in this area are uniquely derived features, that is, they are autapomorphic. These features are not found in any other hominid skull; in fact, this configura tion is not found in any other primate skull. This analysis supports the idea that the Neandertals are distinct from Homo sapiens at the species level.
The authors describe several distinctive nasal features such as the presence of a rim of raised bone that projects from either side of the rim of the anterior nasal aperture just within its anterior edge, forming a secondary internal margin. This rim runs one-third to halfway up the inner nasal wall on both sides and then expands to become a wide, broad-based and bluntly poined mass that protrudes medially into the nasal cavity. This medial projection fades superiorly into a low ridge that continues to frame the nasal cavity within its external margin. 1 This configuration is found in all adult specimens in which the region is preServed. It is best seen in the Gibralter 1 skull. On the other hand, this medial projection is not seen in any non-Neandertal skull except in a less developed form in the Steinheim cranium, which is considered by some anthropologists to be ancestral to the Neandertals.
Source: J. H. Schwartz and I. Tattersall, Significance of Some Previously Unrecognized Apomorphies in the Nasal Region of Homo neandertalensis, Proceedings of the National Academic of Sciences USA, 93 (1996), 10852- 10854.1 Ibid., 10852.
See Physical Anthropology, 6th edition, Chapter 14, pages 343-354; Physical Anthropology: The Core, Chapter 8, pages 198-206.
There have been many wrong interpretations and hoaxes in the history of paleoanthropology. For example the first relatively complete Neandertal skeleton, from the site of La Chapelle- aux-Saints, became the prototype of the Neandertals. It was seen as a hunched over and bowlegged creature with bestial features. Yet this particular specimen later turned out to be the skeleton of an old man with advanced arthritis of the spine. The well-known Piltdown hoax misdirected paleoanthropologists for years. In this case, someone placed a composite of modern and ancient bones in the ground. When found early in this century, the material was interpreted as a human ancestor with a large brain that was associated with an apelike face and dentition.
Recently, another type of misinterpretation was reported. Fraud or sampling error was not involved here; it was an error in evaluation based on an intrusion. A fossil, thought to be as old as 35,000 years, might be as recent as 300 to 200 years old. The fossil from the Ukraine, known as Starosele, was found in sediments that had accumulated over about 80,000 years.
The Starosele fossil was that of an 18- month-old infant, and it was originally thought to be a transitional form between Neandertals and anatomically modern Homo sapiens. However, this interpretation was questioned by some investigators because of the modern appearance of the infant. Now the doubters have been shown to probably be correct. Recent analysis indicates that the infant was buried in an 17th or 18th century Muslim burial ground. The grave was simply dug into old fossil-bearing sediments.
Source: A. E. Marks et al., Starles and the Starles Child: New Excavations, New Results, Current Anthropology, 38 (1997), 112-123.
See Physical Anthropology, 6th edition, Chapter 19, pages 495-496; Physical Anthropology: The Core, Chapter 12, pages 299-301.
The Jinmium rockshelter is located in the northwestern corner of the Northern Territory, Australia. Stone artifacts have been found in sediments that have been dated by thermoluminescence to more than 116,000 ± 12,000 B.P. Until recently, it was thought that Australia was first occupied by hominids only 60,000 to 50,000 years ago.
The Jinmium rockshelter was excavated beginning in 1992. An occupation of Australia at this antiquity is surprising and causes us to rethink the prehistory of anatomically modern humans in southeast Asia. The investigators are continuing work on the site and suggest that the results be "treated with caution" at the present time.
Source: Fullagar, R. L. K., D. M. Price, and L. M. Head, Early Human Occupaton of Northern Australia: Archae ology and Thermoluminescence Dating of Jinmium Rock- Shelter, Northern Territory, Antiquiy, 0 (1996), 751-773.
See Physical Anthropology, 6th editionChapter 19, pages 496-497; Physical Anthropology: The Core, Chapter 12, pages 300-301.
A topic of continuing interest is the origins of the aboriginal populations of the New World. Evidence continues to mount from geology, paleontology, and archaeology.The Bering Land Bridge
An adequate understanding of the migrations of humans from Asia into North America is an important research topic. The Chukchi Sea, located north of the Bering Straits, and the Bering Sea, located to the south, are relatively shallow and emerge above sea level when sea level falls 100 meters or more as it does during glacial periods. This forms the Bering Land Bridge between Asia and North America more than 1500 kilometers in width (from north to south).
Two questions regarding the Bering Land Bridge are of great importance: When was the land bridge available for migration between the two continents? The new study confirms a date of 11,000 B.P. for the latest connection. And what was the landscape of the Bering Land Bridge like?1
The present study is based upon a series of cores from the Bering and Chukchi Seas. Environments of the last glaciation were reconstructed using beetles, pollen, and plant fossils found in these cores. Analysis of the pollen reveals a landscape similar to that of tundra of the Arctic Alaska of today. This can be described as tussocky fields with prostrate willows, tiny (dwarf) birches that are often shorter than the sedge tussocks between which they grow, and a characteristic mass of spring flowers. 2 What does this mean? It means that the Bering Land Bridge was not a steppe, as once thought, but a tundra. Instead of a rich grassland supporting a high density of herd animals, the tundra was relatively unproductive and required the development of a specialized technology for survival, not unlike that seen in Eskimo populations in this century.Siberian/North American Archaeology
According to geologists, the Bering Land Bridge ceased to become a land link between northeastern Siberia and North America be tween about 11,000 and 10,000 B.P. The earliest firmly dated New World archaeology tradition is the Paleoindian Tradition which lasted from about 11,200 to 8500 B.P. The early Paleoindian Tradition is characterized by distinctive fluted lanceolate bifacial points.
Archaeological data from Siberia is very limited. The earliest well-documented tradition is the Upper Paleolithic Diuktai Culture dated from 35,000 to 10,000 B.P. Yet there is little resemblance between these artifacts and those of the Paleoindian Tradition.
In August 1996, Maureen L. King and Sergei B. Slobodin published a description of the Uptar site in Magadan Oblast, located in northeastern Siberia, which was first discovered in 1984.3 In addition to debitage, several bifacial tools were recovered, including four cores, seven flake tools, ten blades or blade fragments, and thirteen bifacial points. The points are lanceolate in cross section. One of these bifacial points is a fluted point.
This artifact suggests that fluting and the use of lanceolate projectile points were characteristic of northeastern Siberia. However, the point differs from the fluted points found in the Americas in many ways. Also, the dating of the site is not firm, and it is not known whether the points are earlier or later than the time the Bering Land Bridge disappeared.Genes and Language
Anthropologists agree that the first Americans came from Asia, although they debate precisely from where they came. They also agree that these early migrants walked to North America during a period of time when sea levels were low and the land that had been under water between what is modern Russia and Alaska was exposed. Two questions are more problematic: When was the first time that people entered the New World? Was there more than one early migration?
Eleven years ago an anthropological linguist, an archaeologist, and a geneticist concluded that the data from all of their disciplines indicated that there were three separate early migrations from Asia to the New World. Called the Greenberg hypothesis after linguist Joseph Greenberg, they hypothesized that three waves of migrants established three different genetic patterns which corresponded to three different language families.4
The first of the three migrant groups was the Eskimo-Aleut. This population included people who settled in Alaska, northern Canada, and Greenland. The second group was called the Na-Dene which included populations living today in parts of Alaska, northwest and north-central Canada, and in the American Southwest and northern Mexico. The last group included the ancestors of populations living today in the rest of the New World. This idea has received wide-spread popularity within anthropology, although most linguists have not been convinced. Now, a new generation of geneticists are placing doubt on the Greenberg hypothesis as well.
The Greenberg hypothesis in based, in part, upon the presence of three distinct genetic populations in the New World. New and more precise genetic tests, however, lead to the conclusion that New World populations are not as diverse as previously thought, and that differences that exist between contemporary populations could have evolved after an initial migration or perhaps two migrations. The authors of a recent study examined 574 mitochondrial DNA control region sequences from aboriginal Siberians and Native Americans.5 They conclude that a major wave of northeast ern Siberians entered the Americas between 25,000 and 20,000 years ago. This date corresponds to new archaeological data that predates the traditional 12,000 and 11,000 year-old materials.
The original migrant population arose near the Bering Land Bridge. About 11,300 years ago another wave of people moved from that area deeper into the Americas. This second wave were the ancestors of the present Eskimo and Na-Dene populations.
Although this idea corresponds well to archaeological data, the new genetic analysis is by no means considered firm. As with mitochondrial DNA studies of the origin of all modern humans (the Mitochondrial Eve hypothesis ), the use of genetic data to establish migrations and the time of those migrations remains controversial. Even among geneticists there is no consensus on the number of migrations to the New World. For instance, a Japa nese geneticist recently suggested that there were four migrations. In the meantime, Joseph Greenberg is in a holding pattern. He says that if a hypothesis is refuted it should be given up. However, he is not willing to see his hypothesis become history yet.
Part of the difficulty in reconstructing the origins of the aboriginal populations of the New World is the few fossils that are known. On July 28, 1996, a new find of a skeleton was uncovered in Kennewick, Washington, on the Columbia River. The skeleton has become known as Kennewick Man.6 Dated at around 9300 B.P., Kennewick Man is one of the oldest human fossils found in the New World.
More than 90 percent of the skeleton was recovered. A projectile point fragment was found in the pelvis; the wound had apparently healed while the person was still alive. The amount of organic material remaining in the bones will permit both radiocarbon dating and DNA analysis. Forensic analysis of the skeletal material suggests that the skeleton is that of a male approximately 69 to 70 inches tall, who died between 40 and 55 years of age. Charac teristics of the skeleton include a long, narrow skull, a projecting nose, receding cheekbones, and a square mandible. The lower bones of the arms and legs were relatively long compared to the upper bones. 7 This grouping of features are not found among Native Americans living in the area today. In fact, they suggest Caucasoid affiliations. Because of the appearance of the skeleton, archaeologists are anxious to run an analysis of the DNA remaining in the bones in order to determine more accurately the affiliation of Kennewick Man to living populations.
Unfortunately the skeleton is the center piece of a major legal battle between local Native American groups who are claiming the remains under the Native American Graves Protection and Repatriation Act. A group of archaeologists and physical anthropologists have filed suit suggesting that the remains do not show biological relationship to modern tribes, and that scientists should be permitted to continue with their study and analysis.
See Physical Anthropology, 6th edition, Chapter 15, pages 381-386; Physical Anthropology: The Core, Chapter 9, pages 221-222.
The discovery of several fossils in Egypt and China have contributed to the discussion of the origins of the suborder Anthropoidea. Recently, news of a new anthropoid species from Thailand has been published. The new material comes from the Late Eocene site of Krabi. The fossils consist of a fragment of the right maxilla and a fragment of the right mandible, both containing teeth. They have been placed into the new species Siamopithecus eocaenus.
Siamopithecus is estimated to have weighed between 6.5 and 7 (14 to 15½) kilograms. It was about the size of the living mantled howler monkey. The cusps on the molars are low and massive and the crests on the molars are also low. This suggests a diet primarily based on hard food.
The role played by Siamopithecus in early anthropoid evolution is open to several interpretations. It does show a number of dental simi larities to Pondaungia and Amphipithecus from the Eocene of Burma which may indicate that all three genera share a common ancestry.
The authors suggest that the anthropoids may have first evolved in Africa, and migrated into southeast Asia during the Early or Middle Eocene where they underwent an adaptive radiation giving rise to the several anthropoids now known from this region.
Source: Chaimanee, Y. et al., A New Eocene Anthro poid Primate from Thailand, Nature, 385 (January 30, 1997), 429-431.
History is characterized by the existence of families whose members have achieved eminence in some area of human endeavor, such as the Bach family in music, the Darwin family in science, and the Leakey family in paleoanthropology. The matriarch of the Leakey family died on December 9, 1996. She was 83.
Mary Leakey, along with her late husband, Louis Leakey, who died in 1972, and her son and daughter-in-law Richard and Meave Leakey, have made major contributions to our knowledge of hominid evolution in East Africa. Although her outspoken husband, Louis Leakey, received much of the credit for their East African discoveries, most of their significant finds were made by Mary. In 1948, while on an expedition to Rusinga Island in Lake Victory, Mary found skull fragments of Proconsul africanus, which at that time was thought to be a human ancestor. A decade later at Olduvai Gorge she uncovered a 1.75 million-year-old skull of Zinjanthropus boisei, now called Australopithecus boisei (OH5). At a time when most anthropologists considered hominid evolution to have occurred within the last million years, this find almost doubled the estimated time span for human evolution.
In 1978, Mary Leakey made what some feel was her most spectacular discovery. At the site of Laetoli in Tanzania, she found 3.6 million-year-old footprints impressed in what had been volcanic ash. These footprints showed that hominids, perhaps Australopithecus afarensis, were walking fully upright at a very early date. The footprints confirmed that upright walking preceded the evolution of large brains by millions of years.
Sources: F. Golden, First Lady of Fossils Mary Nicol Leakey: 1913-1996, Time (December 23, 1996), 69; B. Wood, Mary Leakey 1913-1996, Nature (2 January 1997), 28.
As scientists move forward unraveling the human genome we are moving closer to an swering the question: how many genes are there in the human genome? The human genome contains approximately 3 billion base pairs, but only about 3 percent of these base pairs are actually genes, that is, segments of DNA that code for proteins. Estimates as to the number of genes that will be found at the end of the project vary widely. Some of the estimates of the total number of genes given by researchers in the field include 60,000, 80,000 to 100,000, and 120,000 to 150,000. Only time will tell!
Source: How Many Genes Are There? Science, 769 (7 February 1997), 769.
As this Update goes to press, news of a major breakthrough in genetics has been reported in the media. A sheep named Dolly has become the first mammal cloned from an adult animal's body cell.
Dolly, who is now seven months old, was created by removing the DNA from a cell from the udder of an adult ewe. This DNA was placed into an unfertilized ovum from which the original DNA had been removed.
The implications of this feat are immense. Domestic animals with desirable traits, such as cows that produce large quantities of milk, could be cloned in large numbers. Medical applications are only beginning to be inventoried. Of course, the media is focusing on the ethical concerns of possible human cloning. We will provide further information on this development in the next Update.