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Category Archives: human evolution

Echoes from the past (August-28-2013)

Oh, yeah, I admit it: I have been procrastinating a lot. Result: an extremely long “to do” list. Naturally, I can’t make up for all the past laziness, so here goes a synthesis of what would otherwise be left unattended, take your time, please. 
Middle Paleolithic:
Atapuerca holds “uninterrupted” sequence of European humans since 1.2 million years ago. Soon-to-be-published theory of continuity from H. erectus to Neanderthals in the Castilian site → Paleorama[es], EFE Futuro[es].
More Neanderthal evidence for symbolism found in Fumane cave (Veneto, Italy): polished and ochre-painted shells (pictured) → PLoS ONE (open access), El neandertal tonto ¡qué timo![es].
Upper Paleolithic:
Epigravettian burial, dated to ~14,000 BP, found in Cuges-les-Pins (Provence). The Epigravettian (and not the more widespread Magdalenian) culture of this site indicates a direct link to Italy → INRAP[fr], La Provence[fr], Los Andes[es].
Oldest modern human remain of Galicia found at Valdavara cave (Becerreá, Lugo province). The milk tooth is 17,000 years old, 7000 years older than any other such finding in the NW Iberian country → Pileta[es], IPHES[cat].
Epipaleolithic:
Thousands of engravings, dated to c. 6000 years ago, found in Coahuila (Mexico) → RTVE[es].
“World’s oldest calendar” found in Scotland → BBC.
Female burial found at Poças de São Bento (Sado basin, Portugal) → Paleorama[es].
Neolithic:
First farmers were inbred (at least in Southern Jordan) → Science Magazine.
Qatar Neolithic dig shows the peninsula was in contact with early Sumerian civilization (Eridu or Ubaid period, the first empire ever) → The Archaeology News Network.
Manure was already used by Europe’s first farmers → Science.
Chalcolithic:
Haryana (India) town is oldest large IVC settlement → Business Standard.
East China engravings show first Oriental writing (~5000 years’ old, just slightly younger aged as Sumerian cuneiform writing but much more recent than the controversial Tărtăria tablets of Bulgaria) → The Guardian, English People.
North American natives caused lead pollution in Lake Michigan (oldest recorded) → PPV paper (ER&T)University of Pittsburg.
Perdigões enclosure and collective burial was pilgrimage center. Antonio Valera (often so scholarly cryptic at his blog) loosens up when interviewed by a Portuguese publication, giving meaning to the archeology he’s working with → Super Interesante[por].
Bronze Age:
Cypriot harbor city dug: Hala Sultan Tekke, near modern Larnaka, had 25-50 Ha. and was active between the 16th and 12th centuries BCE → The Archaeology News Network.

Also from Cyprus: large settlement dug out near Nicosia (Cyprus), dated to 2000-1500 BCE → The Archaeology News Network.
Human evolution:
Modern human shoulder much more efficient than chimpanzees’ at throwing… but also than H. erectus’ → BBC.
Neanderthals did speak (of course) → Science Daily, open access paper (Frontiers in Psychology).

Note: their unfounded insistence on most unlikely H. heidelbergensis shared origins of Neanderthals and us casts some doubt on elements of their reasoning however.

Genetics:
Record ancient DNA: ~700,000 years’ old horse sequenced → Nature Communications (PPV).
Experimental archaeology:
How to carve your own stone tools and weapons out of modern materials: very interesting videos (in English) at Paleorama[es] (scroll down). 
More tomorrow (nope my “to do” list is not at all finished with this entry).
 

"Modern human behavior" is out, generic human potential is in

There is a hypothetical model in Prehistory on something vague and ethereal which has been called “Modern human behavior” (MHB). It’s not about nuclear weapons, Internet addiction nor commuting to work; it’s not either about the printing machine, the Industrial Revolution and the ideals of Human Rights; it’s not even about farming, living in cities and through sailing the seas… it’s about something extremely vague and ill-defined but which, by definition would set apart “modern humans” (H. sapiens) from “archaic humans” (other Homo species, particularly Neanderthals).
While it is almost intangible and every day more dubious, a large number of prehistorians, some as notorious as Mellars, Stringer or Bar-Yosef, strikingly influenced by religious ideas setting an arbitrarily absolutist line between “humans” (i.e. Homo sapiens) and the rest (including other humans), have insisted for decades on the validity of such notion. Now three researchers challenge the model radically:
Christopher J. H. James, Julien Riel-Salvatore & Benjamin R. Collins, Why We Need an Alternative Approach to the Study of Modern Human Behaviour. Canadian Journal of Archaeology Volume 37, Issue 1 (2013). Pay per viewLINK

Abstract

In this paper we review recent developments in the debate over the emergence of modern human behaviour (MHB) to show that despite considerable diversity among competing models, the identification of given material traits still underpins almost all current perspectives. This approach, however, allows assumptions over the biological relationship between archaic and modern humans to permeate the definitions of MHB and, as a result, has effectively stultified archaeology’s potential contribution to the issue. We suggest that the concept of MHB as currently defined is flawed. It must either be redefined in strictly behavioural terms before reincorporation into the debate over modern human origins or, more productively, discarded all together to avoid the harsh and unrealistic dichotomy it creates between a modern and non-modern archaeological record.
They essentially argue that: that the model (of which there are several, often contradictory variants) is extremely useless and confusing, that there are “archaic humans” with many or even all traits of MHB and there are “modern humans” without many or even most of them.
They tentatively argue for a throughout revision of the model but then they seem to lean rather for the whole abandonment of the idea suggesting instead a mosaic and punctuated evolution pattern that is socio-cultural rather than merely genetic or essentialist:


(…) the rapidly accumulating evidence for a mosaic pattern of behavioural change (…) and the evidence of behavioural advances appearing and rapidly disappearing in the MSA, make the harsh dichotomy model untenable. What it does suggest is a punctuated or saltation model that led to widespread adoption of more complex behavioural patterns once the demographic circumstances were appropriate (…).

Somehow this made me recall one of my all-time favorite bands: Suicidal Tendencies and their 1990 hit “Disco’s out, murder’s in” (surely not apt for pop, techno and folk music lovers):
 

Some 7% modern humans retain ape-like fexible feet

A very curious story this one: a study performed on 398 visitors of Boston Museum of Science revealed that one of every thirteen people retain flexible characteristics in their feet, reminiscent of our ape cousins.


Most of us have very rigid feet, helpful for stability, with stiff ligaments holding the bones in the foot together. 


When primates lift their heels off the ground, however, they have a floppy foot with nothing holding their bones together. 


This is known as a midtarsal break and is similar to what the Boston team identified in some of their participants.

Source: BBC.

 
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Posted by on June 2, 2013 in human evolution

 

Neanderthals weaned their babies between 9 and 18 months of age

Or at least one of them did. 
The finding is the product of detailed analysis of milk tooth formation in one infant Neanderthal from Scladina cave (Belgium) and comparison with many monkey teeth. The researchers concluded that the barium accumulation in the teeth correlates tightly with breastfeeding and gives information on this with almost a day of precision.
This Neanderthal kid was exclusive breastfed up to the age of nine months and then had another nine months of gradual weaning, eating also other foods, as well as its mother’s milk. 
This is probably much more than the average breastfeeding in our modern societies but less than it has been documented among some hunter-gatherers like Bushmen, who may well partly breastfeed their children for up to four years, what acts as (unsafe) contraceptive. Chimpanzees seem to breastfeed their infants for some 5.3 years, while non-civilized humans (H. sapiens) have ranges of around 2.4 years instead.
Sources: Science Daily, Paleorama[es].
Ref. Christine Austin, Tanya M. Smith, Asa Bradman, Katie Hinde, Renaud
Joannes-Boyau, David Bishop, Dominic J. Hare, Philip Doble, Brenda
Eskenazi, Manish Arora. Barium distributions in teeth reveal early-life dietary transitions in primates. Nature, 2013; DOI: 10.1038/nature12169
 

Echoes from the past (May 17 2013)

Some interesting news I cannot dedicate much effort to:

Human intelligence not really linked to frontal lobe.

New research highlights that the human frontal lobe is not oversized in comparison with other animals. Instead the human intelligence seems to be distributed through all the brain, being the network what really matters → Science Daily

Ref. Robert A. Barton and
Chris Venditti. Human frontal lobes are not relatively large. PNAS, May 13, 2013 DOI: 10.1073/pnas.1215723110
 

Early hominin ear bones found together in South Africa.

The three bones, dated to c. 1.9 Ma show intermediate features between modern humans and apes → PhysOrg.

New hominin site in Hunan (China).

The sediments of Fuyan cave, in which five human teeth (Homo erectus?) were found, along with plenty of animal ones, are dated to 141,700 (±12,100) years ago. → IVPP – Chinese Academy of Sciences.

The five human teeth

Neanderthal workshop found in Poland.

In Pietrowice Wielkie (Silesia), which is at the end of a major natural corridor from the Danubian basin → PAP.

Ancient Eastern Europeans ritually killed their pets to become warriors.

In the Bronze Age site of Krasnosamarkskoe (Volga region, Russia) more than 50 ritually pieced skulls of dogs have puzzled archaeologists, who have reached the conclusion, after researching Indoeuropean accounts from India, that the animals may have been killed in adulthood rituals: the boys who were to become warriors had to kill their most beloved pet in order to be accepted as such, and did so in a precise and macabre ritual → National Geographic.

Ancient log boat found in Ireland.

In the Boyne river, which was in the past a major artery of the island. Not yet dated: it could be from prehistoric times or the 18th century. → Irish Times.

 

Ardipithecus ramidus’ skull is hominin

Ardi’s skull reconstructed
(CC by T. Michael Keesey)
I recently mentioned that Sahelanthropus tchadiensis ‘Toumaï’ was quite clearly within the hominini biological tribe, i.e. in the line leading to us and not anymore in the one leading to chimpanzees and bonobos. Now I have to echo the claim that a more recent being, Ardipithecus ramidus ‘Ardi’ also seems to have skull characteristics that place it in the hominin group. 
While the relevance of Toumaï’s grouping is much greater, because it help us to clarify the issue of Pan-Homo divergence dates, which seems to be of the order of c. 8-13 million years ago (Langergraber 2012), the case of Ardi is not without interest anyhow in the understanding of human evolution. 

By examining 79 skull bases of chimps, gorillas, modern humans and ancient hominids, Kimbel’s group identified relationships among anatomical landmarks that distinguish apes from people and hominids. The researchers estimated the total length of A. ramidus’ skull bottom and found that it fell within a range characteristic of hominids, not apes.

As in more recent members of the Australopithecus genus, such as the 3.2-million-year-old partial skeleton nicknamed Lucy, Ardipithecus ramidus displays a relatively short, humanlike skull base, Kimbel said.

A new 3-D analysis of Ardi’s previously reconstructed pelvis, also presented April 11 at the anthropology meeting, finds a mix of monkey, ape and hominid characteristics. Although not confirming a consistently upright gait, this version of Ardi’s hips doesn’t undermine her proposed hominid status, said Nicole Webb of City University of New York, who led the research.

As for Ardi’s disputed mode of travel, she probably had a two-legged gait “but didn’t use her hands much while upright,” said Caley Orr of Midwestern University in Downers Grove, Ill., who didn’t participate in the new research. 

While Ardipithecus ramidus is dated to c. 4.4 Ma BP, there is another specimen of the same genus, Ardipithecus kadabba, dated to c. 5,7 Ma.

Ref. AAPA 2013 meeting (abstracts):

  • W. Kimbel et al. Ardipithecus ramidus and the evolution of the human cranial base.
  • N. Webb et al. An analysis of the Ardipithecus ramidus pelvis reconstruction using 3D geometric morphometric techniques.
 
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Posted by on April 22, 2013 in human evolution, paleoanthropology

 

Brain shape favors ‘Toumaï’ as a human ancestor

The seven million years old Sahelanthropus tchadensis (i.e. Sahel man from Chad), nicknamed Toumaï, already had a hominin structure in its small brain:

… though Toumaï’s brain was apelike in its small size, it was apparently
homininlike in other ways. In a presentation given on April 2 at the
annual meeting of the Paleoanthropology Society, Bienvenu reported that
the endocast shows strongly posteriorly projecting occipital lobes, a
tilted brainstem, and a laterally expanded prefrontal cortex, among
other hominin brain characteristics.
Other human-like traits in Toumaï are small canines and the forward position of its foramen magnum (where the backbone connects to the skull), which suggest upright walking, which is now argued to be related to brain reorganization. 
This clearly confirms, as I have insisted so much, that the Pan-Homo divergence date is necessarily older than 7 million years, because Toumaï  was already closer to us than chimpanzees and bonobos, our closest living relatives.