There are close to 400 specimens from
A. afarensis. Even if you were just counting cranio-facial fragments, there are many. These don't all represent separate individuals, and some of these specimens are just one tooth, but there really are a lot for this species. It's an incredibly well-known fossil taxon. Every single fragment doesn't get a spread in Nat Geo or Science--that's usually reserved only for relatively complete skeletons, fragments that are remarkable for their geological age or location, or very controversial finds.
Facial reconstructions are based on composite crania formed from the fragments we have from many, many different individuals. That wouldn't be good enough to do a facial reconstruction that could differentiate between you and me, but the same techniques would be good enough to differentiate between a human and a gorilla. For
Paranthropus aethiopicus, for which we only have parts of the cranial vault, sure, reconstructions are a stretch. But even then, you can tell a lot about the architecture of a missing mandible based on what you see in the maxilla and temporal bones, since they go together, you know (and because what we see in that species looks similar to what we see in closely related species, for which we DO have mandibles)? But in any case, the cranial architecture is very well understood for this species--we know what these guys looked like osteologically. Of course, the shape of the soft-tissue parts of the nose and hair coverage is anybody's guess.
Lucy is an adult.
A. afarensis has long been known to have extreme sexual dimorphism in body size. So extreme, in fact, that there has been substantial debate about whether these specimens represent more than one species. It is more sexually dimorphic in body size than any living primate. None of the above is anything new.
The new information that Kadanuumuu contributes to understanding about
A. afarensis is in the new skeletal elements it has that no other specimen has had. It has a scapula, a clavicle, and more ribs than were previously represented. So before, we didn't know what the scapula or clavicle actually looked like, and our guess about the shape of the ribcage was based on fewer ribs. The authors for Kadanuumuu state that the shoulder girdle looks more like a modern human than we had assumed before, and that the rib cage is shaped more like a modern human and less like a chimp than we had previously thought. Previous interpretations of
A. afarensis locomotor behavior have been that, even though it was a biped, it must have retained some habitual climbing behavior because of its relatively long, curved finger and toe bones and relatively long arms. These authors conclude, based on the new shoulder morphology and the shape of the distal end of the tibia, that
A. afarensis was an obligate biped that was doing
no climbing at all. That's all that's new here--a few post-cranial elements and an interpretation of them that is at odds with previous interpretations of
A. afarensis locomotion.
Keep in mind, though, that so far--just like with
Ardipithecus (this is the same team)--only
this team has actually looked at the fossils, and they are casting a new interpretation over all the osteological features that were already well-known and have been interpreted differently for some time. So whether their interpretation of the new find will be in line with the general consensus of other paleoanthropologists once other people get to look at the specimens remains to be seen. For example, I just got an earful about how robust the scapula appears to be compared to humans, which suggests the presence of a sizeable forelimb musculature. The orientation and robusticity of the scapular spine does appear human-like, but the rest of the blade looks more like a gorilla. Another example of differences in interpretation--this team's interpretation of the degree of sexual dimorphism in
A. afarensis is that it is "similar" to that of humans. Nobody says that. Not even Outcast. Furthermore, Zerey (discoverer of Dikika baby), says he isn't completely convinced the new skeleton is
A. afarensis since there's no cranium.
My point is that I always wait until more than one group of scientists has actually seen and interpreted the fossils before I accept anyone's new and fundamentally different interpretations of old bones. Some researchers are a little more circumspect in their interpretations of the fossils they find than others are. Some won't say anything until they're reasonably sure it makes sense in light of all the data we have available. Some are not so careful.
If you're interested, the
new website at the Smithsonian is a nice one.
