DIK-1-1 is a nearly complete juvenile Australopithecus afarensis skeleton, from the site of Dikika in Ethiopia (Alemseged et al. 2006). The spectacular skeleton is approximately 3.3 million years old. Such a rare find is great news for paleoanthropologists, since its completeness provides much-needed information about growth and development, juvenile morphology, and even bones that rarely or almost never preserve well from hominins, including a scapula (part of the shoulder) and hyoid bone (sits in the middle of the throat, unwilling to be friends with any other bones). All in all, it’s a very interesting specimen, whose feet show that it was adapted for bipedalism. But its “gorilla-like” scapula may indicate some degree of climbing behavior. The find made the cover of Nature, and here’s part of Figure 1 from the paper:
Now compare this to Jen, a gelfling from the 1982 Jim Henson film The Dark Crystal.
Creepy. But the resemblance is dead-on, just look at the prognathic faces of DIK-1-1, above, and Jen here.
So what do we learn? Most probably A. afarensis is ancestral to the gelflings, as well as later, more well-known hominins like A. africanus, robustus, boisei, and our genus, Homo. I suppose the gelflings were an evolutionary ‘side-branch.’ And since DIK-1-1 is a juvenile while this gelfling is an adult, we have documented here a case of paedomorphosis, an evolutionary phenomenon in which the adults of the descendant taxon appear more similar to the juveniles of their ancestors (for a real-life example of this, see the axolotl).
Also, Alemseged et al. posit that the gorilla-like morphology of the Dikika scapula may reflect climbing behavior. Well, if we remember The Dark Crystal, we’ll recall that Jen climbed Aughra‘s model solar system with gusto when the bad guys came and messed the place up. So the functional interpretation of the fossil shoulder is corroborated with behavioral data from the animatronic puppet. Oh, also I think the gelflings lived in a wooded, perhaps even forest environment. Such environments likely characterized the habitats of earlier hominins, but isotopic and relative abundances of different kinds of other fossil animals suggest that Dikika may have been a bit more open (Wynn et al. 2006).
Alemseged Z, Spoor F, Kimbel WH, Bobe R, Geraads D, Reed D, & Wynn JG (2006). A juvenile early hominin skeleton from Dikika, Ethiopia. Nature, 443 (7109), 296-301 PMID: 16988704
Wynn J, Alemseged Z, Bobe R, Geraads D, Reed D, and Roman D. 2006. Geological and paleontological context of a Pliocene juvenile hominin at Dikika, Ethiopia. Nature 443: 332-336.
*Edited 08 Nov 2015