Week 5: Genera Australopithecus and Paranthropus MORE OUTSTANDING PHOTOS FROM CSU OHIO: Photo ofAustralopithecus afarensis ( AL 288 - 1A/1B "Lucy")Closeup: Knee Joint (CSU Ohio Photos)
Photo ofAustralopithecus afarensis (AL-400-1A) 3.0 MYA Closeup: Teeth and Jaw
Photo ofAustralopithecus afarensis (AL 333 - 105) 3.3 - 3.0 MYA Closeup: Hand
Photo ofAustralopithecus afarensis (AL 288 - 1AP "Lucy") 3.3 - 3.0 MYA Original & Reconstructed Femur
Photo ofAustralopithecus africanus (STS-5)3.0-2.5 MYA
Photo of Australopithecus africanus (KNM-ER-1813)1.4-1.3 MYA
Photo ofAustralopithecus africanus (OH-24)2.1-1.7 MYA
Photo of Paranthropus boisei (KNM-ER-406)1.5 MYA
PLIOCENE HOMINIDS Ardipithecus ramidus: 4.4 MYA, East African Rift Valley (Aramis, Ethiopia). Found by Tim White from the Berkeley Institute for Human Origins in 1994. "Ardipithecus" means "ground ape"; "Ramidus" means root: the implication is that A. ramidus may be the root species which gave rise to all of the later hominids. Arms seem not to be those of a knuckle walker, and the base of the cranium suggests erect posture although it is not yet clear whether A. ramidus was bipedal. Still retains thin enamel. Cranium still very small and chimp-like.Australopithecus anamensis: 4.2 - 3.9 MYA, East African Rift Valley (Lake Turkana). Found by Maeve Leakey in 1995. Anamensis means "lake" in a local Turkana language. Twenty-one specimens. Confirmed bipedalism. Specimens show a blending of primitive (large, ape-like canines) and advanced features (bipedalism and thick enamel). Cranium still very small and chimp-like.
Australopithecus afarensis: 4 - 2.5 MYA, East African Rift Valley and North Central Africa (Hadar, Ethiopia; Bahr el Ghazal, Chad; others). In 1975, a Berkeley team including Donald Johanson & M. Taieb found remains of a very complete hominid specimen near the Awash River in Hadar, Ethiopia ("Lucy"). Name comes from the Afar region of Ethiopia where the "Lucy" specimen was found. Dentition more similar to humans than to ancestral Miocene apes (reduced canines, more parabolic jaw shape), but still retains a slight diastema. Dentition most likely reflects an omnivorous diet without specialization in any one type of food resource. Cranium still very small and chimp-like. Postcranial remains indicate that A. afarensis was a habitual biped, but also retained upper body characteristics of brachiators - may have been practicing both forms of locomotion. Highly sexually dimorphic species.
An example of one of the Australopithecines:
LUCY - photo (may be slow to load the first time)
Discovered by Donald Johanson in 1974 at Hadar in Ethiopia (Johanson and Edey, 1981; Johanson and Taieb, 1976). Estimated age is about 3.2 million years. Lucy was an adult female of about 25 years. About 40% of her skeleton was found, and her pelvis, femur (the upper leg bone) and tibia show her to have been bipedal. She was about 107 cm (3'6") tall (small for her species) and about 28 kg (62 lbs) in weight. What Lucy's missing skull might have looked like. Click here
Click here to take the LUCY TEST
Click here for Everything you ever wanted to know about Lucy. (from the Institute for Human Origins)An example of one of the Paranthropines:
NUTCRACKER MAN--P.BOISEI - photo
Discovered by Mary Leakey in 1959 at Olduvai Gorge in Tanzania (Leakey, 1959). Estimated age is 1.8 million years. It is an almost complete cranium, with a brain size is about 530 cc. This was the first specimen of this species. Louis Leakey briefly considered this a human ancestor, but the claim was dropped when Homo habilis was found soon afterwards.
The Taung Child (A. africanus). Raymond Dart started the whole thing off with THIS baby!
That's her fossilized brain on the leftAustralopithecus africanus
Australopithecus africanus: 3.5 - 2.5 MYA, South Africa (Taung, Sterkfontein and others). First Australopithecine to be identified (Raymond Dart's Taung child, 1924). Name means "southern ape of Africa." Dentition much more similar to humans than to ancestral Miocene apes (canines reduced, more parabolic jaw shape, no diastema). Dentition most likely reflects an omnivorous diet without specialization in any one type of food resource. Cranium still very small and chimp-like. Postcranial remains indicate that A. africanus was a habitual biped, but also retained upper body characteristics of brachiators - may have been practicing both forms of locomotion. A. africanus is similar to afarensis, and was also bipedal, but body size was slightly greater. Brain size may also have been slightly larger, ranging between 420 and 500 cc. This is a little larger than chimp brains (despite a similar body size), but still not advanced in the areas necessary for speech. The back teeth were a little bigger than in afarensis. Although the teeth and jaws of africanus are much larger than those of humans, they are far more similar to human teeth than to those of apes (Johanson and Edey, 1981). The shape of the jaw is now fully parabolic, like that of humans, and the size of the canine teeth is further reduced compared to afarensis. Australopithecus afarensis and africanus are known as gracile australopithecines, because of their relatively lighter build, especially in the skull and teeth. (Gracile means "slender", and in paleoanthropology is used as an antonym to "robust".) Despite this, they were still more robust than modern humans.
Paranthropus boisei & P. robustus. Note the sagittal crest like Worf on Star Trek--able to chew and chew and chew . . .
Paranthropus boisei (was Australopithecus boisei)
Paranthropus boisei: 2.4 - 1.3 MYA, East African Rift Valley (Olduvai Gorge and other sites). Discovered by Louis & Mary Leakey in 1959. Originally named "Zinjanthropus." Cranial features suited for heavy chewing and a diet of hard foods (sagittal crest, flaring zygomatic arches, huge jaw, large molars for grinding). Cranium still very small and chimp-like. Considered the most "robust" of the three robust species. It was similar to robustus, but the face and cheek teeth were even more massive, some molars being up to 2 cm across. The brain size is very similar to robustus, about 530 cc. A few experts consider boisei and robustus to be variants of the same species. Paranthropus aethiopicus, robustus and boisei are known as robust paranthropines, because their skulls in particular are more heavily built.Paranthropus robustus
Paranthropus robustus: 2 - 1 MYA, South Africa. Discovered by Robert Broom in 1938. Name means "robust near-man." Cranial features suited for heavy chewing and a diet of hard foods (sagittal crest, flaring zygomatic arches, huge jaw, large molars for grinding). Cranium still very small and chimp-like.P. robustus had a body similar to that of africanus, but a larger and more robust skull and teeth. It existed between 2 and 1.5 million years ago. The massive face is flat or dished, with no forehead and large brow ridges. It has relatively small front teeth, but massive grinding teeth in a large lower jaw. Most specimens have sagittal crests. Its diet would have been mostly coarse, tough food that needed a lot of chewing. The average brain size is about 530 cc. Bones excavated with robustus skeletons indicate that they may have been used as digging tools.Paranthropus aethiopicus: 2.6 - 2.3 MYA, East African Rift Valley (Lake Turkana, others). "Parathropus" means "near man." The first specimen ("Black Skull) was discovered by Richard Leakey in 1985. Cranial features suited for heavy chewing and a diet of hard foods (sagittal crest, flaring zygomatic arches, huge jaw, large, flat molars for grinding). Features seem to be mid-way between A. afarensis and the other robust types (P. boisei and P. robustus). Cranium still very small and chimp-like.
Homo habilis and Australopithicus africanus
SOFTWARE: Human Evolution uses 3D, photo-realistic images of fossils to teach students about ten important milestones in human evolution,from the appearance of the primates to the demise of the neanderthals. Students can rotate over 30 fossil and modern skulls, bones, and artifacts, viewing them from any angle. The text and photos illustrate the anatomical differences between the different members of the human lineage, including prosimians, monkeys, apes, and hominids. Illustrated definitions of all technical terms can be obtained simply by clicking on the word. A demo is available and can be downloaded for a couple of the skulls. Requires downloading the shockwave plugin from Macromedia if you do not have it. ------------------------------------------------------------------------ Week 5: Genera Australopithecus and Paranthropus You have learned to compare the skeletal appearance of living primates and to consider how the differences in their skeletons might relate to particular adaptations in behavior and habitat. The goal of this lab is to enable you to identify the morphological/physical differences between Australopithecus and Paranthropus, and to identify the evolutionary changes that took place in the progression from Miocene ape to these ancestors to the genus Homo. We do not have a complete cast of a Miocene ape, so for this week's lab, parts of a modern chimpanzee are used instead. You can base your observations of the Miocene ape on this modern chimpanzee skeleton, but remember that THIS IS ONLY A STAND-IN. Chimpanzees are a living species. They are NOT our ancestors. There are five stations in this exercise: Station 1: anatomically modern Homo sapiens Station 2: modern ape skull (standing in for a Miocene ape) Station 3: Australopithecus afarensis and Australopithecus africanus Station 4: Paranthropus robustus and Paranthropus boisei Station 5: pelvis bones of three species: a modern ape standing in for a Miocene ape; an australopithecine; and modern Homo sapiens The questions on the next page are designed to guide your observations at each of the stations. You may again find it helpful to refer to the skeletal diagrams on pages 2 and 3 of this manual. Comparison of pelvis, femur, and knee of chimpanzee (Pan troglodytes), Australopithecus afarensis, and Homo sapiens Observation questions for Stations 1-4: 1. Examine the teeth of each specimen. Are there prominent canines? Does the specimen have a diastema (look carefully at the difference between A. afarensis and A. africanus at Station 4)? Do you see a pattern of generalized dentition or are some teeth more prominent than others? If so, which teeth? 2. How prominent are the zygomatic arches? Very (as with the male gorilla), somewhat, or not prominent at all? 3. Is there prognathism (a protruding lower face)? To what degree? 4. What is the size of the supra-orbital torus (brow ridge)? Very large (as in the male gorilla), somewhat prominent, or not prominent at all? 5. To what degree is there post-orbital constriction? A great degree, slight, or very little? 6. Does the specimen have a vertical forehead? 7. Is there a sagittal crest? 8. What is the size of the nuchal area? 9. Examine the foramen magnum. Is it in the center of the base of the skull or is it positioned farther back? For those stations with fragmentary skulls, you will have to infer the position of the foramen magnum from the location of the rest of the skull features. Consult the lab handout as well. Observation questions for Station 5: 10. What is the shape of the pelvis? Bowl-shaped or flat? Long and narrow or short and wide? 11. What is the shape of the ilium? Is it fan-shaped, rectangular, square? 12. How long is the neck of the femur? How robust is it? Observation Notes Station 1: 1. 6. 2. 7. 3. 8. 4. 9. 5. Station 2: Station 3: 1. 1. 2. 2. 3. 3. 4. 4. 5. 5. 6. 6. 7. 7. 8. 8. 9. 9. --------------------------------------------------------------------------- Station 4: 1. 6. 2. 7. 3. 8. 4. 9. 5. --------------------------------------------------------------------------- Station 5: "Miocene Ape" Australopithecus H. sapiens 10. 11. 12. Australopithecus afarensis Australopithecus africanus Paranthropus robustus Paranthropus boisei Prosimian, Anthropoid, and Hominoid Evolution GEOLOGICAL EPOCH GROUP/GENUS/SPECIES LOCATION PALEOCENE, 65-54 mya proto-prosimians North America & Europe EOCENE, 54-37 mya prosimians North American & Europe OLIGOCENE, 37-24 mya Aegyptopithecus Fayum, Egypt MIOCENE, 24-5 mya Proconsul Dryopiths Ramapiths Africa Africa, some Europe Europe, some Africa Hominid Evolution PLIO-PLEISTOCENE, 5-1.8 mya Australopithecines develop Africa, various places "primitive": A. ramidus, ~4.4 mya E. Africa (Ethiopia, Kenya) Australopithecines: A. afarensis, 4-3 mya Lucy, Laetoli footprints A. africanus, 3-2 mya Taung child E. Africa (Ethiopia, Kenya) South Africa Paranthropines: P. aethiopicus, 2.8-2.2 mya P. robustus, 2.5-1 mya P. boisei, 2.5-1 mya E. Africa (Kenya, Ethiopia) South Africa South Africa & E. Africa Development of Homo Genus "early Homo": H. habilis, H. rudolfensis, 2.4-1.5 mya East Africa PLEISTOCENE, 1.8 mya - 10 kya H. erectus, 1.8 mya-400 kya Africa, Europe, and Asia archaic H. sapiens, 400 kya-? Africa, Europe, and Asia Neandertals (archaics in Europe), 300 kya? - 35 kya Europe, Near East H. sapiens sapiens ~200 kya to present widespread ------------------------------------------------------------------------
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