Wednesday, March 4, 2015

New papers on earliest Homo from our Ethiopia collaboration

We have two papers coming out in Science on our research in the Afar, Ethiopia which document early Homo (based on a high quality mandible and teeth) at 2.8 Ma--about 400kyr earlier than the last reported example (from Hadar--Kimbel, et al., 1996). Our work over numerous field seasons since 2002 was to build on the very little prior information to produce a structural and stratigraphic and temporal framework into which we could place any fossils of importance. The area is faulted (due to regional extension pulling the Horn of Africa away to the east and Arabia away to the northeast from the rest of Africa) so we have to divide it into separate fault blocks and characterize each individually and then relate them temporally both by the basic logic of geology as well as by numerical and correlative dating of numerous volcanic deposits (“tephra”). The important point is that the sedimentary sequence represents a time period previously undocumented in the region (hence the opportunity of finding and documenting this mandible).

Here is the ASU press release.

Both papers have ASU alumns as first authors:

Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia
Brian Villmoare, William H. Kimbel, Chalachew Seyoum, Christopher J. Campisano, Erin DiMaggio, John Rowan, David R. Braun, J. Ramon Arrowsmith, and Kaye E. Reed
Published online 4 March 2015 [DOI:10.1126/science.aaa1343] 
Late Pliocene fossiliferous sedimentary record and the environmental context of early Homo from Afar, Ethiopia
Erin N. DiMaggio, Christopher J. Campisano, John Rowan, Guillaume Dupont-Nivet, Alan L. Deino, Faysal Bibi, Margaret E. Lewis, Antoine Souron, Lars Werdelin, Kaye E. Reed, and J. Ramón Arrowsmith
Published online 4 March 2015 [DOI:10.1126/science.aaa1415] 

This research is very much interdisciplinary: our international team (graduate students to senior researchers) includes expertise ranging from evolution of dental anatomy to geologists (stratigraphy, dating, structures) to paleontology and ecology. This great breadth is required to produce, integrate, and interpret the complex and often subtle story of hominin evolution. We have worked to build a space and time constrained paleoenvironmental framework in which to consider the hominin. The core team spans the Arizona State University campus in the Schools of Human Evolution and Social Change/Institute of Human Origins and the School of Earth and Space Exploration.

The geological work was part of Erin DiMaggio's Ph.D. dissertation. She worked with me on her M.S. and Ph.D., finishing the latter in 2013. This work is part of a sustained collaboration with friends and colleagues from whom I have learned very much (Kaye Reed, Chris Campisano, Bill Kimbel, Brian Villmoare, and Guillaume Dupont-Nivet to name a few). We also started the work with our friend Charles Lockwood who sadly passed away several years ago. He would have been really happy about this.

Here are a few other links:

Here is an old page with maps
Here are many pictures from over the years:
Ethiopia and Afar region (2002)
Ethiopia and Afar region (2004)
Ethiopia and Afar region (2005)
Ethiopia and Afar region (2006)
Ethiopia and Afar region (May 2008)
Web-sized images for Ethiopia and Afar region (November 2008); Ethiopia and Afar region (November 2008) full size images
Web-sized images for Hadar Field School (2009); Hadar Field School full size images
Afar region 2012
Afar region 2013
Afar region 2015

This research was funded by the NSF (BCS-1157351 and BCS-1322017), the Institute of Human Origins and School of Human Evolution and Social Change at ASU, grants to E.N.D. from AAPG, SEPM, GSA, and the Philanthropic Education Organization, to G.D-N. from Marie Curie CIG and A. v. Humboldt, and to A.S. from Fyssen and HERC/UC Berkeley.