Who are Bodo and Herto? Or first of all -should we say- where are Bodo and Herto?

Bodo is a hominin fossil named after its site of discovery (in 1976): Bodo d’Ar in the Middle Awash Valley of Ethiopia. Herto is one of the earliest-know anatomically modern humans (AMH), named after the Herto Bouri Formation where it was found (in 1997) also in the middle Awash Valley.

Bodo and Herto are key fossils to understand the emergence of our species Homo sapiens. Probably the ancient populations of Bodo (archaic Homo sapiens) could have been distant relatives of the Herto modern humans populations in the same area.

Skulls of Herto and Bodo. Credit: Roberto Sáez

The Middle Awash is a key site to understand human evolution: many other early hominin specimens were found there from different species such as Ardipithecus kadabba, A. ramidus, Australopithecus afarensis, Au. garhi and Au. anamensis.

Middle Awash Valley. Source: selamta.net

Bodo

Bodo is a skull dated to 600 ka. It is one of the first archaic specimens we can consider closer to Homo sapiens, likely an ancestor of the modern human populations that appear in East Africa 200 k years ago.

It has primitive features which actually represent a transition between Homo ergaster/erectus and Homo sapiens:

• Very thick, double-arched supraorbital torus, but interrupted at the glabella.
• Broadest nasal aperture in the human fossil record.
• Projecting and broad middle face below the nasal bones.

Bodo remains were associated with several hippo skeletons and Acheulean tools. The skull has 17 cut marks made on fresh bone, suggesting that immediately after the death of this individual stone tools were used to remove the flesh from the bone.

There is some discussion around the species assigned to Bodo:

• For some paleoanthropologists it represents an African example of Homo heidelbergensis.
• For others who consider H. heidelbergensis strictly a European species, the taxon used for Bodo is Homo rhodesiensis – together with the more recent Kabwe-1 skull (c. 250 ka).
• In 2021 Roksandic & Radović propose Bodo as holotype of a new taxon Homo bodoensis, which would be an early Middle Pleistocene ancestor of the Homo sapiens lineage, with a pan-African distribution that extends into the eastern Mediterranean (Southeast Europe and the Levant). They propose other skulls included in Homo bodoensis: Kabwe 1 (Broken Hill), Ndutu, Saldanha (Elandsfontein), Ngaloba (LH 18), and potentially Salé and Ceprano (this one from Europe).

However Kabwe-1 and Bodo have also similarities with Asian Homo erectus specimens like Sangiran 17: broad zygomatics, thick supraorbital torus, long and sloping forehead, sagittal keel, broad nasal aperture.

Skulls of Bodo & Sangiran 17. Credit: Roberto Sáez

Herto

Herto is dated to c. 160 ka. It was the earliest-known modern human until 2005 when the Omo remains were dated to c. 195 ka, which made them earlier than Herto.

The Herto remains are actually three specimens, of which I will refer here to the best preserved skull BOU-VP-16/1, an adult male with very large endocranial volume 1450 cc (within the larger end of living humans). Its general morphology corresponds to Homo sapiens, although it still preserve some archaic features:

• Prominent supraorbital tori.
• Very prominent zygomatics.
• Slight projection of lower face.
• Occipital angle more acute than in modern African populations.
• Eye sockets are more separated than ours.

Finally, it is remarkable the morphological continuity that Bodo-Kabwe-Herto specimens show as we move through time. For example, the transition into a lighter supraorbital torus (but still a double arch), and the prominent zygomatics appearing more modern.

Skulls of Bodo, Kabwe and Herto. Credit: Roberto Sáez