Lucy Gets a Date with Big Man
Another specimen of Australopithecus afarensis has been announced from Ethiopia. This one supposedly preceded Lucy by 400,000 years, and according to its discoverers, belonged to a group of primates that shows they “were almost as proficient as we are walking on two legs, and that the elongation of our legs came earlier in our evolution than previously thought.” The discovery by Yohannes Haile-Selassie’s team, was published in PNAS.1 It was immediately announced in the press by National Geographic, Science Daily and PhysOrg.
True to tradition, the discoverers had to give the specimen a catchy name for the press. In the local Afar tribal language, it’s Kadanuumuu, but in English, it’s Big Man. That’s because the male had substantially larger stature than Lucy – 5 feet instead of her 3 feet. The researchers claim this specimen is 3.6 million years old (compared to Lucy’s 3.2 million). Ardipithecus ramidus (Ardi), found in the same general area, is said to be 4.4 million years old.
The main claims about Big Man is that it shows upright posture more than Ardi, based on pelvic positions and limb proportions. Only a scapula, a few ribs, parts of the neck and one shoulder, parts of the pelvis, one arm and one leg were found – no skull fragments.
Only National Geographic offered a dissenting opinion. Its writeup included the observations of Zeresenay Alemseged, an anthropologist at the California Academy of Sciences in San Francisco. He doubts that it belongs to A. afarensis, and says that without skull fragments and teeth, it is hard to make a positive identification. He also thinks Lucy and another baby specimen claimed to be 3.3 million years old show evidence of living in the trees.
In the paper, the team admitted that fitting the new find into an evolutionary sequence requires a bit of punctuated equilibrium. Here’s what the last paragraph said:
The total biomechanical pattern of Au. afarensis involves a host of specialized postcranial characters, all of which are fully consistent with data reported here for KSD-VP-1/1,2 those previously available for Au. afarensis, and the Laetoli footprints (58, 60), which at 3.66 Ma are just slightly older than KSD-VP-1/1 (61). Equally important are similarities between the Au. afarensis pelvis and the recently described H. erectus specimen from Busidima (BSN49/P27a�d) (11). These similarities are particularly striking, especially in light of the time separating them (at least 2.2 million years). Such constancy of morphotype suggests that highly derived terrestrial bipedality enjoyed a long period of stasis punctuated only occasionally by additional modifications to the postcranium of apparently decreasing selective significance (e.g., length of pedal intermediate phalanges, lower limb length).
It should be noted that the Laetoli footprints, dated earlier than this specimen, are identical to modern human footprints (03/22/2010). Haile-Selassie seems to be claiming that bipedality evolved in a few hundred thousand years, then remained essentially unchanged except for minor details for almost four million years.
1. Haile-Selassie et al, “An early Australopithecus afarensis postcranium from Woranso-Mille, Ethiopia,” Proceedings of the National Academy of Sciences, Published online before print June 21, 2010, doi: 10.1073/pnas.1004527107.
2. This is the designation for the new fossil.
This is the lightning flash before the thunder. The news media all light up on cue, but then the long peals of thunder hit when the other teams get angry at the Ethiopian team for trying to put the spotlight on their Big Boy, making him the new star on the Human Evolution Walk of Shame (06/10/2010). Just you wait. This is not the History Channel, you know; it’s the Follywood Squares.