Herto Man - WikiHQ

Herto Man is a set of human remains discovered in 1997 from the Upper Herto member of the Bouri Formation in the Afar Triangle, Ethiopia. The remains have been dated as between 154,000 and 160,000 years old. The discovery of Herto Man was especially significant at the time, falling within a long gap in the fossil record between 300 and 100 thousand years ago and representing the oldest dated Homo sapiens remains then described.

In the original description paper, these 12 (at minimum) individuals were described as falling just outside the umbrella of "anatomically modern human". Thus, Herto Man was classified into a new subspecies as "Homo sapiens idaltu" ( "elder"). It supposedly represented a transitional morph between the more archaic H. (s.?) rhodesiensis and H. s. sapiens (that is, a stage in a chronospecies). Subsequent researchers have rejected this classification. The validity of such subspecies is difficult to justify because of the vague definitions of "species" and "subspecies", especially when discussing a chronospecies, as the exact end-morphology and start-morphology of the ancestor and descendant species are inherently unresolvable.

Herto Man produced many stone tools which can fit into the vaguely defined "Transitional Acheulean", the long-lasting cultural tradition with both characteristically Acheulean (made by archaic humans) and Middle Stone Age (made by modern humans) tools. They seem to have been butchering mainly hippo, but also bovines, in a lakeside environment. The three most complete skulls (one a 6- to 7-year-old child) bear manmade cut marks and other alterations, which could be evidence of mortuary practices like excarnation.

Research history

Discovery

thumb|left|200px|Location of discovery

Fossils of Herto Man were first recovered in 1997 from the Upper Herto Member of the Bouri Formation in the Middle Awash site of the Afar Triangle, Ethiopia. The materials are: BOU-VP-16/1, a nearly complete skull missing the left skullcap; BOU-VP-16/2, skull fragments; BOU-VP-16/3, a parietal bone fragment; BOU-VP-16/4, a parietal fragment; BOU-VP-16/5, a nearly complete skull of a 6- or 7-year old; BOU-VP-16/6, a right upper molar; BOU-VP-16/7, a parietal fragment; BOU-VP-16/18, parietal fragments; BOU-VP-16/42, an upper premolar; and BOU-VP-16/43, a parietal fragment.

This region of the world is famous for yielding a series of ancient human and hominin species stretching as far back as 6 million years.

"H. s. idaltu"

In a simultaneously published paper, anthropologists Tim D. White, Berhane Asfaw, David DeGusta, Henry Gilbert, Gary D. Richards, Gen Suwa, and Francis Clark Howell described the material as just barely outside what is considered an "anatomically modern human" (AMH), beyond the range of variation for any present-day human. They instead considered the earliest "AMHs" specimens from Klasies River Caves, South Africa, or Qafzeh cave, Israel. They did this by comparing BOU-VP-16/1 with the Qafzeh 6 skull, the La Ferrassie 1 skull (a male Neanderthal, H. (s.?) neanderthalensis), the Kabwe 1 skull ("H. (s.?) rhodesiensis"), and 28 present-day male skulls. Consequently, they classified Herto Man as a new palaeosubspecies of H. sapiens as "H. s. idaltu" (with the presumed male BOU-VP-16/1 as the holotype), which represents an intermediary morph between "H. (s.?) rhodesiensis" and present-day H. s. sapiens. The name comes from the local Afar language idàltu "elder". Similarly transitional specimens (at the time, not well-dated) tentatively assigned to "late archaic H. sapiens" had been reported from Ngaloba, Tanzania; Omo, Ethiopia; Eliye Springs, Kenya; and Jebel Irhoud, Morocco.

thumb|The H. s. sapiens specimen [[Skhul and Qafzeh hominins|Skhul 5 (above) is anatomically similar to Herto Man. White et al. made note of this, but still considered Herto Man "clearly distinct". In 2014, anthropologists Robert McCarthy and Lynn Lucas considered a much larger sample than White et al.—using several specimens representing "archaic Homo", Neanderthal, "early modern H. s. sapiens", and Late Pleistocene H. s. sapiens—and arrived at the same conclusion as Lubsen and Corruccini. Citing these two studies, in 2016, Stringer, in his review of literature regarding the derivation of H. s. sapiens, said the name idaltu, "does not seem justified."

The main issue of palaeosubspecies validity lies in the vague definitions of "species" and "subspecies", especially when discussing a chronospecies (an unbroken lineage which gradually changes, making the exact end-morphology and start-morphology of the ancestor and descendant species unresolvable). The original describers in 2019 still upheld the name "H. s. idaltu" because their argument, "depended largely on discrete traits," whereas Mcarthy and Lucas, "focused only on the gross cranial metrics", but also stated debating the exact taxonomic names and labels is overall not as important as understanding trends in human evolution.

Anatomy

Like what could be considered an "anatomically modern human", the Herto skull has a high cranial vault (a raised forehead), an overall globular shape in side-view, and a flat face. The brain volume was about 1,450 cc. The skull is quite robust in having a projecting brow ridge, weakly curved parietal bones, and a strongly flexed occipital at the back of the skull. These traits are well within the range of variation of modern humans. Compared to the average present-day human skull, the Herto skull is notably long and has overall large dimensions, although the cheekbones are relatively weak.

References

External links

3D digital model of BOU-VP-16/1 by Edward Gonzalez-Tennant
Origins - Discovery of Earliest Homo Sapiens Skulls backs 'Out of Africa' Theory - Homo sapiens idaltu by Bradshaw Foundation