New BioLogos Post on Hominin Taxonomic Variability in the Early to Middle Pliocene

I have a new post on hominin taxonomic variability in the early to middle Pliocene in light of the new Australopithecus deriyemeda find from Burtele that establishes that at least two very different hominin adaptations were occurring at the same time, around three to four million years ago.  There is a lengthy intro by Brad Kramer, the content editor, warning people that there are “technical terms” and that the article is a “black diamond” article, which suggests that they keep a glossary or dictionary handy.

It seems that, when I wasn't paying attention, I  turned into a cladist.  This comes from reading too many papers on Pseudosuchia and Avemetarsalia and trying to explain evolutionary theory to people.

The one thing that is missing from Brad's intro is an effort to explain how this fits into the grand Christian scheme of things, which would probably not have been appropriate in this setting, in any event, since it is a separate, but related topic.  I sometimes suffer from a slightly reductionist mindset in that I take these discoveries to be self-evident and just another part of God's creation (Brad does allude to that) without really taking the time to reflect on how this information comes across to your average Christian who likely is not familiar with it and how it might challenge their scriptural interpretations.  To this end, I probably need to make a better effort to work that in, somehow. 

BioLogos Blurb about Australopithecus deyiremeda

My blurb about the new australopithecine is included in the Saturday Science Links at the BioLogos site.  There will be a longer piece next week.

New Hominin Species Coeval with Au. afarensis

A new hominin has been announced by Haile-Selassie and colleagues.  Here is the abstract from the Nature paper¹:

Middle Pliocene hominin species diversity has been a subject of debate over the past two decades, particularly after the naming of Australopithecus bahrelghazali and Kenyanthropus platyops in addition to the well-known species Australopithecus afarensis. Further analyses continue to support the proposal that several hominin species co-existed during this time period. Here we recognize a new hominin species (Australopithecus deyiremeda sp. nov.) from 3.3–3.5-million-year-old deposits in the Woranso–Mille study area, central Afar, Ethiopia. The new species from Woranso–Mille shows that there were at least two contemporaneous hominin species living in the Afar region of Ethiopia between 3.3 and 3.5million years ago, and further confirms early hominin taxonomic diversity in eastern Africa during the Middle Pliocene epoch. The morphology of Au. deyiremeda also reinforces concerns related to dentognathic (that is, jaws and teeth) homoplasy in Plio–Pleistocene hominins, and shows that some dentognathic features traditionally associated with Paranthropus and Homo appeared in the fossil record earlier than previously thought.

The Washington Post has a write-up of the new find, which they glibly refer to as “An Ethel for Lucy.” Rachel Feltman:

Haile-Selassie and his co-authors believe the find should encourage reexamination of other possible instances of pre-Homo cohabitation.  Two other species have been proposed as living at the same time as Australopithecus afarensis -- Australopithecus bahrelghazali and Kenyanthropus platyops -- but both remain controversial, with some scientists saying they aren't different enough from A. afarensis to constitute a new species. And in a previous expedition, Haile-Selassie himself found a partial foot that he believed was from the same time period -- but not the same species -- as Lucy. Unlike the jaw reported in Nature, the foot didn't provide enough evidence to name a new species.

As noted with the Ledi jaw, there seems to be quite of a bit of morphological variability and experimentation going on at the Plio-Pleistocene boundary.   

¹Haile-Selassie, Y., Gibert, L., Melillo, S.M., Ryan, T.M., Alene, M., Deino, A., Levin, N.E., Scott, G., Saylor, B.Z. (2015) New species from Ethiopia further expands Middle Pliocene hominin diversity. Nature. 521(7553): 483-488.
http://dx.doi.org/10.1038/nature14448