Notable Fossilized Characters from People of the Lake (gone, but never forgotten):
Au. africanus was anatomically similar to Au. afarensis, with a combination of human-like and ape-like features. Compared to Au. afarensis, Au. africanus had a rounder cranium housing a larger brain and smaller teeth, but it also had some ape-like features including relatively long arms and a strongly sloping face that juts out from underneath the brain case with a pronounced jaw. Like Au. afarensis, the pelvis, femur (upper leg), and foot bones of Au. africanus indicate that it walked bipedally, but its shoulder and hand bones indicate they were also adapted for climbing.
Age: 3.3-2.1 mya
Year discovered: 1924
Australopithecus boisei/Paranthropus boisei
Like other members of the Paranthropus genus, P. boisei is characterized by a specialized skull with adaptations for heavy chewing. A strong saggital-crest on the midline of the top of the skull anchored the temporalis muscles (large chewing muscles) from the top and side of the braincase to the lower jaw, and thus moved the massive jaw up and down. The force was focused on the large cheek teeth (molars and premolars). Flaring cheekbones gave P. boisei a very wide and dish-shaped face, creating a larger opening for bigger jaw muscles to pass through and support massive cheek teeth four times the size of a modern human’s. This species had even larger cheek teeth than P. robustus, a flatter, bigger-brained skull than P. aethiopicus, and the thickest dental enamel of any known early human. Cranial capacity in this species suggests a slight rise in brain size (about 100 cc in 1 million years) independent of brain enlargement in the genus Homo.
Age: 2.3-1.2 mya
Year Discovered: 1959
Ramapithecus, a fossil primate dating from the Middle and Late Miocene epochs. For a time in the 1960s and ’70s, Ramapithecus was thought to be a distinct genus that was the first direct ancestor of modern humans before it became regarded as that of the orangutan ancestor Sivapithecus.
Age: 14-12 mya
Year Discovered: 1932
This species, one of the earliest members of the genus Homo, has a slightly larger braincase and smaller face and teeth than in Australopithecus or older hominin species. But it still retains some ape-like features, including long arms and a moderately-prognathic face. Its name, which means ‘handy man’, was given in 1964 because this species was thought to represent the first maker of stone tools.
Year Discovered: 1960
Early African Homo erectus fossils are the oldest known early humans to have possessed modern human-like body proportions with relatively elongated legs and shorter arms compared to the size of the torso. These features are considered adaptations to a life lived on the ground, indicating the loss of earlier tree-climbing adaptations, with the ability to walk and possibly run long distances. Compared with earlier fossil hominins, note the expanded braincase relative to the size of the face. The most complete fossil individual of this species is known as the ‘Turkana Boy’ – a well-preserved skeleton, dated around 1.6 million years old. Microscopic study of the teeth indicates that he grew up at a growth rate similar to that of a great ape. The appearance of Homo erectus in the fossil record is often associated with the earliest handaxes, the first major innovation in stone tool technology.
Age: 1.89 mya-143,000 ya
Year Discovered: 1891
Anatomically, modern humans can generally be characterized by the lighter build of their skeletons compared to earlier humans. Modern humans have very large brains, which vary in size from population to population and between males and females, but the average size is approximately 1300 cubic centimeters. Housing this big brain involved the reorganization of the skull into what is thought of as “modern” — a thin-walled, high vaulted skull with a flat and near vertical forehead. Modern human faces also show much less (if any) of the heavy brow ridges and prognathism of other early humans. Our jaws are also less heavily developed, with smaller teeth.
Age: 300,000 ya-Present
Year Discovered: Depends–We each discover ourselves sooner or later
Chimpanzees are great apes and one of our closest living relatives. People of the Lake, along with many others, uses the chimpanzee as a good comparison for humans due to our genetic similarity. While there are marked differences, studying these apes can help us greater understand ourselves as humans.
Year Discovered: Ambiguous
Sources: Smithsonian and Brittanica