130,000 year old Neanderthal eagle talon necklace predates H. sapiens influence

Does evidence from Krapina, Croatia refutes ‘bow wave’ theory?

The popular view of the Neanderthals as dimwits has been in trouble for years, as evidence for Neanderthal symbolic behaviour has continued to accumulate. Up until now, however, it is not been possible to unequivocally rule out the influence of modern humans, who reached Europe around 46,000 years ago. The Châtelperronian culture for example, long put forward as evidence of Neanderthal behavioural modernity, has now been shown not to have begun until after the arrival of modern humans. It is assumed that the Neanderthals simply borrowed the trappings of modernity from their new neighbours.

In other regions such as Spain and Italy, the evidence for Neanderthal behavioural modernity has been attributed to what Sir Paul Mellars has described as a ‘bow wave effect’, i.e. long-distance interactions between Neanderthals and modern humans occurring several millennia before the latter become visible in the archaeological record.

This view is now seriously challenged by a new study of eight white-tailed eagle talons that were found at the Neanderthal site of Krapina, Croatia over a century ago. Researchers found 21 cut marks on the talons, and there were areas of high polish consistent with ‘use wear’ as the talons rubbed against each other. The implication is that they were mounted in a necklace or bracelet – clear evidence of symbolic behaviour. Furthermore, it was concluded that the talons come from at least three eagles, suggesting that considerable effort had gone into obtaining them. The white-tailed eagle is fairly rare and it is an aggressive apex predator, far from easy to catch or trap.

Associated faunal remains suggested that Krapina dates to the warm Eemian interglacial period. A direct date of 130,000 years old was obtained in 1995 – which means that it predates any possible influence from modern humans by more than 80,000 years.

References:

1.      Radovčić, D., Sršen, A., Radovčić, J. & Frayer, D., 2015. Evidence for Neandertal Jewelry: Modified White-Tailed Eagle Claws at Krapina. PLoS One, 11 March.

Dmanisi reconsidered

Implications of LD 50-1 jawbone and Spoor H. habilis study for ‘variable single species’ theory

In October 2013, Lordkipanidze and his colleagues reported the discovery of an adult skull from Dmanisi, Georgia. The fifth skull to be discovered at the site, it was complete and undeformed; it is the only known fully-preserved adult hominin skull from the early Pleistocene. They also put forward the radical suggestion that the various species often proposed for early African Homo (Homo habilis, Homo rudolfensis, Homo ergaster and Homo erectus) were all actually variants of the same species, and that early Homo was a single lineage which evolved over time without differentiating into multiple species. This conclusion is based on a claim that shape variation between the five Dmanisi skulls is roughly the same as that seen among the various early Homo skulls from East Africa, even though the former represents a single species and the latter are generally thought to represent several (Lordkipanidze, et al., 2013).

This suggestion must now be reconsidered in the light of last week’s announcement that the LD 50-1 partial lower jawbone places the origins of Homo at least 2.8 million years ago (Villmoare, et al., 2015); and Spoor and colleagues’ (2015) reappraisal of the OH 7 Homo habilis type specimen. The latter report that:

1.       The cranial capacity of OH 7 is estimated at between 729 and 824 cc, which is substantially larger than 500 to 700 cc typically cited and within the range of early Homo erectus;

2.       OH 7 is more primitive than the 2.33-million-year-old AL 666-1 upper jawbone provisionally assigned to Homo habilis, despite being 500,000 years younger.

Spoor and colleagues suggest that AL 666-1 cannot be placed within either Homo habilis or Homo rudolfensis. They do not investigate its true affinities further but suggest that their data is consistent with it belonging to Homo erectus. That it is more derived than Homo habilis implies that the origins of the latter must be sought even further back in time than 2.33 million years ago. The reporting that LD 50-1 is transitional between Australopithecus and Homo places the origin of the latter at around 2.8 million years ago. Putting the two reports together, the implication is that Homo was already diverse lineage by 2.33 million years ago, and that early human types were distinguished by facial morphology rather than by brain size.

Lordkipanidze and his colleagues noted that the morphological diversity within the five skulls recovered at Dmanisi is greater than that recorded for specimens recovered in Africa and assigned to different species. On the basis that the Dmanisi hominins all belong to the same species, they suggest that the morphological diversity in African fossil record of Homo 1.8 million years ago is better interpreted as demes of a single evolving lineage of Homo erectus rather than multiple species.

Given that Homo habilis, Homo rudolfensis and Homo erectus might all have emerged by 2.33 million years ago, an ancestor/descendant relationship between these species seems unlikely. It could be argued that the deme interpretation is more parsimonious than the traditional multiple species view.

Against this view, it has been suggested that the limb proportions of Homo habilis are more apelike (longer arms, shorter legs) than those of Homo erectus (Richmond, et al., 2002). The main problem is that in comparison to classic fossils such as ‘Lucy’ (Australopithecus afarensis) and the Turkana Boy (Homo erectus), we do not have a well-preserved example of Homo habilis. The evidence for the apelike limb proportions of Homo habilis largely rests on the two fragmentary skeletons KNM-ER 3735 and OH 62.

In the case of OH 62, the leg is represented by an upper section of the femur, the true length of which is uncertain. KNM-ER 3735 preserves even less limb detail. A re-evaluation of these specimens in comparison to fossil limb parts OH 34 and OH 35 suggests that the upper-to-lower limb ratio of OH 62 lies within the upper range of modern humans and lower range of chimpanzees; and that KNM-ER 3735 lies in the middle of the modern range, entirely outside the chimpanzee range. Based on these results, the limb proportions of Homo habilis were modern rather than apelike (Haeusler & McHenry, 2004).

Overall, these results appear to refute suggestions that Homo habilis should be reclassified as an australopithecine (Wood & Collard, 1999) and are consistent with the conclusions of Lordkipanidze and his colleagues.

References:

1.      Haeusler, M. & McHenry, H., 2004. Body proportions of Homo habilis reviewed. Journal of Human Evolution, Volume 46, pp. 433-465.

2.       Lordkipanidze, D. et al., 2013. A Complete Skull from Dmanisi, Georgia, and the Evolutionary Biology of Early Homo. Science, 18 October, Volume 342, pp. 326-331.

3.       Richmond, B., Aiello, L. & Wood, B., 2002. Early hominin limb proportions. Journal of Human Evolution, Volume 43, pp. 529-548.

4.       Spoor, F. et al., 2015. Reconstructed Homo habilis type OH 7 suggests deep-rooted species diversity in early Homo. Nature, 5 March, 7541(519), pp. 83-86.

5.       Villmoare, B. et al., 2015. Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia. Science, 5 March.

6.       Wood, B. & Collard, M., 1999. The Human Genus. Science, 2 April, Volume 284, pp. 65-71.

The LD 350-1 jawbone

Introduction:

A partial lower jawbone and a number of teeth have been recovered from a surface outcrop of fossil-bearing sedimentary rock in the Ledi-Geraru research area, in the Afar region of Ethiopia. This region has long been associated with the fossils of early hominins. The jawbone has been assigned to Homo (species indeterminate) (Villmoare, et al., 2015). The age of the jawbone is constrained by stratigraphic and palaeomagnetic considerations to between 2.80 and 2.75 million years old (DiMaggio, et al., 2015). This means that LD 350-1 is at least 400,000 years older than the earliest previously-known fossil assigned to Homo. The findings are published as two articles in the journal Science.

What was our previous understanding of human origins?

The conventional view is that the first human species was Homo habilis (‘Handy man’). Discovered in 1960 and announced as a new species four years later, it is believed to have evolved from an australopithecine ancestor though which is disputed. Possibilities include the South African Australopithecus africanus and Australopithecus afarensis from East Africa (or its probable descendant species Australopithecus garhi). The famous ‘Lucy’ belongs to Australopithecus afarensis. In comparison to a modern human, Homo habilis was small brained and its limb proportions (short legs, long arms) were still very apelike. However, the skull was less massively-built than an australopithecine; the upper and lower jawbones were within the human size range; and the feet and thumb joints were humanlike (Conroy, 1997). Homo habilis is known in the fossil record from 2.33 to 1.44 million years ago (Kimbel, et al., 1997; Spoor, et al., 2007). It is then presumed to have given rise to Homo erectus. Although still small-brained in comparison to a modern human, the limb proportions of Homo erectus are similar to those of later humans. Homo erectus first appears in the fossil record 1.8 to 1.9 million years ago (Wood, 2011).

This conventional view has a number of problems. Firstly, a second species, Homo rudolfensis is now known to have been contemporary with Homo habilis. First proposed in 1972, it was confirmed as a separate species in 2012 (Leakey, et al., 2012). How Homo rudolfensis fits into the bigger picture is far from clear: some have noted similarities to an earlier hominin, Kenyanthropus platyops (‘Flat-faced man of Kenya’) and it is possible that Homo rudolfensis belongs in Kenyanthropus rather than Homo.

Another problem is that the earliest example of Homo habilis, a 2.33 million year old upper jawbone known as AL 666-1 from Hadar, Ethiopia might in fact be something other than Homo habilis. The oldest uncontested example of Homo habilis is only 1.9 million years old (Lieberman, 2007) and given that the species also persisted well after the appearance of Homo erectus an ancestor/descendant relationship seems unlikely. Instead, it has been suggested that the two species shared a common ancestor (Spoor, et al., 2007).

Finally, it has been suggested that the late australopithecine species Australopithecus sediba from South Africa, which dates to around 2 million years old (Pickering, et al., 2011) is a more plausible ancestor for Homo erectus than is Homo habilis (Berger, et al., 2010).

Could LD 530-1 be an australopithecine?

The date of 2.8 million years ago puts it just after the time of Australopithecus afarensis (3.9 to 3.0 million years ago) and before the late australopithecine species Australopithecus garhi (2.5 million years ago).Given that the Australopithecus garhi is thought to descendant of Australopithecus afarensis, LD 350-1 is in the right place at the right time to be a part of that lineage. In terms of size, both the jawbone and the teeth are within the Australopithecus afarensis range, albeit towards the lower end. However, most other respects, the mandibular and dental characteristics of LD 350-1 fall outside the range for Australopithecus afarensis. The dentition is also reduced (and therefore more humanlike) in comparison to Australopithecus garhi, which would appear to bump the latter from the lineage leading to Homo. Overall, LD 350-1 appears to be transitional between Australopithecus and Homo and is likely to represent the earliest-known example of the latter.

What are the implications if LD 350-1 is indeed Homo?

Models that posit an australopithecine ancestor for Homo from the period 2.5 to 2.0 million years ago (e.g. Australopithecus garhi or Australopithecus sediba) would be ruled out. Instead, Homo diverged from Australopithecus much earlier than hitherto believed. Notably, 2.8 million years ago coincides with a shift to a more arid climate in Africa, suggesting a link between climate change and the emergence of Homo. The fossil record of Ledi-Geraru records a shift to a more open habitat of grasses or low shrubs at around this time.

Reboot for Homo habilis

In a separate study, published in the journal Nature, Fred Spoor and colleagues (Spoor, et al., 2015) carried out a reconstruction of the 1.8 million year old Homo habilis holotype specimen OH 7. The results suggest that the species was larger-brained than previously believed, within the range of Homo erectus. It was also found that the dentition of OH 7 is more primitive than the 2.33 million year old AL 666-1, suggesting that the latter cannot be Homo habilis – but implying that the origins of Homo habilis go back even further. The study did not consider the affinities of AL 666-1 any further but speculated that it could be early Homo erectus. By 2.33 million years ago, the Homo lineage was already apparently diverse, with early human species distinguished from one another more by gnathic morphology than by brain size. The reporting of the early Homo jawbone LD 350-1 dovetails neatly with this study.

What species is LD 350-1?

It is more primitive than Homo habilis but nevertheless lies within Homo. Its describers did not assign a species to it, but it is likely that it will be eventually recognised as a new species within Homo; the earliest human species yet. 

References:

1.      Berger, L. et al., 2010. Australopithecus sediba: A New Species of Homo-Like Australopith from South Africa. Science, 9 April, Volume 328, pp. 195-204.

2.       Conroy, G., 1997. Reconstructing Human Origins: A Modern Synthesis. New York, NY: W. W. Norton & Company, Inc..

3.       DiMaggio, E. et al., 2015. Late Pliocene fossiliferous sedimentary record and the environmental context of early Homo from Afar, Ethiopia. Science, 5 March.

4.       Kimbel, W., Johanson, D. & Rak, Y., 1997. Systematic Assessment of a Maxilla of Homo From Hadar, Ethiopia. American Journal of Physical Anthropology, Volume 103, pp. 235-262.

5.       Leakey, M. et al., 2012. New fossils from Koobi Fora in northern Kenya confirm taxonomic diversity in early Homo. Nature, 9 August, Volume 488, pp. 201-204.

6.       Lieberman, D., 2007. Homing in on early Homo. Nature, 20 September, Volume 449, pp. 291-292.

7.       Pickering, R. et al., 2011. Australopithecus sediba at 1.977 Ma and Implications for the Origins of the Genus Homo. Science, 9 September, Volume 333, pp. 1421-1423.

8.       Spoor, F. et al., 2015. Reconstructed Homo habilis type OH 7 suggests deep-rooted species diversity in early Homo. Nature, 5 March, 7541(519), pp. 83-86.

9.       Spoor, F. et al., 2007. Implications of new early Homo fossils from Ileret, east of Lake Turkana, Kenya. Nature, 9 August, Volume 448, pp. 688-691.

10.    Villmoare, B. et al., 2015. Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia. Science, 5 March.

11.    Wood, B., 2011. Did early Homo migrate “out of ” or “in to” Africa?. PNAS, 28 June, 108(26), p. 10375–10376.