Australopithecus sediba: a possible human ancestor

Australopithecus sediba is a possible human ancestor discovered in South Africa in 2010. The discovery was made at Malapa, a fossil-bearing cave located about 15 km (9.3 miles) NE of the well-known South African hominid-bearing sites of Sterkfontein and Swartkrans and about 45 km (28 miles) NNW of Johannesburg  (Berger, et al., 2010). It is situated within the Cradle of Humankind World Heritage Site. The recovery effort was led by Lee Berger, a paleoanthropologist at the University of the Witwatersrand, Johannesburg. The find was made when Matthew, Lee’s 9 year old son, discovered hominin collar bone embedded in a rock (Balter, 2010).

The find comprised two extremely well-preserved partial skeletons that were initially thought be somewhere between 1.78 and 1.95 million years old (Dirks, et al., 2010), later revised to 1.977 million years (Pickering, et al., 2011). These belonged to a juvenile male (MH1) aged 12 to 13 at time of his death and an adult female (MH2) (Berger, et al., 2010). They were found together buried in alluvial sediment, deep within the Malapa cave, part of an eroded cave system. Also found were the remains of wildcats, hyenas and a number of other mammals. On the ground above the cave are a number of ‘death traps’, or long vertical shafts. The smell of damp issuing from the shaft would have attracted animals. The pair – possibly mother and son – may have fallen to their deaths while searching for water. The sediments imply that subsequent high-volume water inflow, perhaps the result of a large storm, caused a debris flow. This carried the still partially articulated bodies deeper into the cave, to deposit them along a subterranean stream (Dirks, et al., 2010).

MH1 and MH2 were assigned to a new australopithecine species, Australopithecus sediba. The word ‘sediba’ means ‘fountain’ or ‘wellspring’ in the Sotho language. The more complete cranium of the juvenile MH1 has a capacity of 420cc, probably at least 95 percent of adult size. The remains share numerous similarities with Australopithecus africanus in the cranial vault, facial skeleton, lower jawbone and teeth, but there are also significant differences in the cranial, dental and postcranial anatomy. Homo-like features include smaller molars and premolars and less pronounced cheekbones. Certain features of the pelvis are similar to those seen in Homo erectus. The lower-to-upper limb bone proportions are also similar to those of later Homo, and unlike the more apelike proportions of Homo habilis. The anatomy of its hip, knees and ankles suggest that Australopithecus sediba was a habitual biped. Overall, it was claimed that Australopithecus sediba shares more derived features with early Homo than it does with other australopithecines. However, Berger was reluctant to place the new discovery within Homo, preferring to classify it as an australopithecine (Berger, et al., 2010).

The initial announcement of Australopithecus sediba attracted extensive news coverage, but not everybody was convinced by the claims made for it. Australian anthropologist Darren Curnoe was reported (MacKnight, 2010) as claiming that Australopithecus sediba is in the wrong place at the wrong time to be a human ancestor. He noted that Homo habilis emerged in East Africa well before the time of Australopithecus sediba. However, his argument does assume that Homo habilis is indeed an early human.  This may not be the case. It is also possible that at least some of Australopithecus sediba’s humanlike features could have evolved independently, and may not necessarily imply shared ancestry (Wood & Harrison, 2011).

Nevertheless, subsequent studies do support Berger’s initial claims. They suggest that aspects of the brain, dental morphology, pelvis, hand and foot of Australopithecus sediba could be interpreted as incipient humanlike features. A virtual endocast of the brain, obtained from synchrotron scanning, revealed an australopithecine-like size and pattern of convolutions. However, the orbitofrontal region showed possible development towards a humanlike frontal lobe. Possibly some neural reorganization of the brain preceded its later size increase in early humans (Carlson, et al., 2011).

The teeth of MH1 and MH2 are a mosaic of primitive and derived traits. Cladistic analysis of 22 dental traits suggest that Australopithecus sediba was a sister species of Australopithecus africanus (i.e. the two shared a common ancestor) and that the two were further evolved in the direction of Homo than were the australopithecines from East Africa (Irish, Guatelli-Steinberg, Legge, de Ruiter, & Berger, 2013). The lower jawbone morphology reduced dentition (especially canines and premolars) confirms that Australopithecus sediba was a distinct species to Australopithecus africanus and not merely a late-surviving form of that species (de Ruiter, et al., 2013).

The upper ribcage of Australopithecus sediba exhibits an apelike funnel shape, unlike the barrel shape associated with Homo. The funnel shape, as noted above, may be an adaptation to under-branch suspensory locomotion. The barrel shape may be associated with the increased chest volume and lung function necessary for endurance walking and running. The lower thorax, however, appears less flared than that of apes and more closely approximates the morphology found in humans (Schmid, et al., 2013). The spine is long and flexible, a form that has more in common with early Homo than with other australopithecines. Curvature of the lower spine is a hallmark of walking upright (Williams, Ostrofsky, Frater, Churchill, Schmid, & Berger, 2013).

The upper limbs were still predominantly apelike, suggesting the retention of substantial climbing and suspensory abilities (Churchill, et al., 2013). The hands show a mixture of australopithecine and human features. They retained adaptations for tree-climbing, but there was also a long thumb and shorter fingers. These suggest precision gripping of the type associated with tool manufacture and use (Kivell, Kibii, Churchill, Schmid, & Berger, 2011).

The pelvis and foot presented a mosaic of apelike and humanlike characteristics. These suggested adaptations to a more efficient (albeit not entirely human) form of bipedalism, at the expense of reduced arboreal efficiency (Kibii, et al., 2011; Zipfel, DeSilva, Kidd, Carlson, Churchill, & Berger, 2011). The bipedal mechanics differed from those reconstructed for other australopithecines, suggesting that there may have been several forms of hominin bipedalism at this time. The adaptations of Australopithecus sediba may have enabled it to both walk and climb reasonably well and thus survive in a dual arboreal/terrestrial world (DeSilva, et al., 2013).

References:

Balter, M. (2010, April 9). Candidate Human Ancestor From South Africa Sparks Praise and Debate. Science, 328, 154-155.

Berger, L., de Ruiter, D., Churchill, S., Schmid, P., Carlson, K., Dirks, P., et al. (2010, April 9). Australopithecus sediba: A New Species of Homo-Like Australopith from South Africa. Science, 328, 195-204.

Carlson, K., Stout, D., Jashashvili, T., de Ruiter, D., Tafforeau, P., Carlson, K., et al. (2011, September 9). The Endocast of MH1, Australopithecus sediba. Science, 333, 1402-1407.

Churchill, S., Holliday, T., Carlson, K., Jashashvili, T., Macias, M., Mathews, S., et al. (2013, April 12). The Upper Limb of Australopithecus sediba. Science, 340.

de Ruiter, D., DeWitt, T., Carlson, K., Brophy, J., Schroeder, L., Ackermann, R., et al. (2013, April 12). Mandibular Remains Support Taxonomic Validity of Australopithecus sediba. Science, 340.

DeSilva, J., Holt, K., Churchill, S., Carlson, K., Walker, C., Zipfel, B., et al. (2013). The Lower Limb and Mechanics of Walking in Australopithecus sediba. Science, 340.

Dirks, P., Kibii, J., Kuhn, B., Steininger, C., Churchill, S., Kramers, J., et al. (2010, April 9). Geological Setting and Age of Australopithecus sediba from Southern Africa. Science, 328, 205-208.

Irish, J., Guatelli-Steinberg, D., Legge, S., de Ruiter, D., & Berger, L. (2013, April 12). Dental Morphology and the Phylogenetic “Place” of Australopithecus sediba. Science(340).

Kibii, J., Churchill, S., Schmid, P., Carlson, K., Reed, M., de Ruiter, D., et al. (2011, September 9). A Partial Pelvis of Australopithecus sediba. Science, 333, 1407-1411.

Kivell, T., Kibii, J., Churchill, S., Schmid, P., & Berger, L. (2011, September 9). Australopithecus sediba Hand Demonstrates Mosaic Evolution of Locomotor and Manipulative Abilities. Science, 333, 1411-1417.

MacKnight, H. (2010, April 8). Experts reject new human species theory. Retrieved September 12, 2012, from Independent: http://www.independent.co.uk/news/science/experts-reject-new-human-species-theory-1939512.html

Pickering, R., Dirks, P., Jinnah, Z., de Ruiter, D., Churchil, S., Herries, A., et al. (2011, September 9). Australopithecus sediba at 1.977 Ma and Implications for the Origins of the Genus Homo. Science, 333, 1421-1423.

Schmid, P., Churchill, S., Nalla, S., Weissen, E., Carlson, K., de Ruiter, D., et al. (2013). Mosaic Morphology in the Thorax of Australopithecus sediba. Science, 340.

Williams, S., Ostrofsky, K., Frater, N., Churchill, S., Schmid, P., & Berger, L. (2013, April 12). The Vertebral Column of Australopithecus sediba. Science, 340.

Wood, B., & Harrison, T. (2011, February 17). The evolutionary context of the first hominins. Nature, 470, 347-352.

Zipfel, B., DeSilva, J., Kidd, R., Carlson, K., Churchill, S., & Berger, L. (2011, September 9). The Foot and Ankle of Australopithecus sediba. Science, 333, 1417-1420.

New insights into differences in brain organization between Neanderthals and anatomically modern humans

A new study (Pearce, Stringer & Dunbar, 2013) has suggested that there were significant differences in the neurological organisation of Neanderthals and modern humans, reflecting physiological differences between the two species. Neanderthals, as has long been known, were larger and more robust than modern humans. Consequently, it is hypothesised, they required proportionately more 'brain power' to carry out body maintenance 'housekeeping' tasks and control functions. It is additionally proposed that Neanderthals had larger eyes than modern humans. They lived at high latitudes, where they experienced lower light levels than people living in the tropics.

Using orbit size as a proxy for eye size, Pearce, Stringer & Dunbar (2013) considered the remains of 21 Neanderthals and 38 modern humans dating from between 27 to 200 thousand years ago. Cranial volumes were adjusted to compensate for the greater Neanderthal body mass. A number of steps were taken to estimate the size of the Neanderthal visual cortex. It was suggested that Neanderthal brains comprised a significantly larger proportion of neural tissue associated with 'housekeeping' and visual function compared with the brains of contemporary modern humans.

Accordingly, less 'brain power' would have been available for social interactions, and it suggested the Neanderthal maximum social group size was smaller than the 'Dunbar Number' of 150 associated with modern humans. The area covered by extended Neanderthal communities would have been smaller than those of modern humans. Their ability to trade for exotic resources and artefacts would have been reduced, as would their capacity to gain access to distant foraging areas potentially unaffected by local shortages. Furthermore, their ability to acquire and conserve innovations may have been limited in comparison to modern humans.

A physical response to high latitude conditions based upon robustness and visual acuity was initially very effective. However, the modern human response of enhanced sociability eventually proved a better bet in the climatic instability of Eurasia during the last ice age.

Link to the Pearce, Stringer & Dunbar paper

Reference:
Pearce,E., Stringer, C., & Dunbar R. (2013) New insights into differences in brain organization between Neanderthals and anatomically modern humans, Proc. Royal Soc. B. 280

Higher levels of Neanderthal ancestry in East Asians than in Europeans

A new study published in the journal Genetics (Wall et al, 2013) has concluded that East Asians have a higher level of Neanderthal DNA than do Europeans. The result implies that there was more than one episode of interbreeding between modern humans and Neanderthals.  After the ancestors of modern Europeans and East Asians separated, the latter population continued to interbreed with Neanderthals.

Given that the Neanderthals are thought to have been a predominantly Western Eurasian species, this result is unexpected. On the other hand, it does support recent work (Wood et al, 2013) suggesting that Neanderthals died out in Europe before the arrival there of modern humans.

It is becoming clear that the history of interbreeding between modern humans and Neanderthals was rather more complex than was originally thought.

The paper is available open access - see this link on the Genetics website

References:
Wall, J., Yang, M., Jay, F., Kim, S., Durand, E., Stevison, L., Gignoux, C., Woerner, A., Hammer, M., and Slatkin, M. (2013) Higher levels of Neanderthal ancestry in East Asians than in Europeans, Genetics, Early Online

Wood, R., Barroso-Ruíz, C., Caparrós, M., Jordá Pardo, J., Galván Santos, B., & Higham, T. (2013). Radiocarbon dating casts doubt on the late chronology of the Middle to Upper Palaeolithic transition in southern Iberia. PNAS (Early Edition)

To Mars in a nutshell

‘O God, I could be bounded in a nutshell and count myself a king of infinite space…’

Hamlet was not alluding to space travel, but he might as well have been. An audacious proposal announced by American millionaire Dennis Tito calls for a man and woman to make a 501-day round trip to Mars in a spacecraft half the size of a camper van. There will be no landing – the spacecraft will simply make a fly-by, skimming past the Red Planet at a minimum altitude of 100 miles. The crew are likely to be a middle-aged married couple.

Dennis Tito first made the headlines in 2001, when over the objections of NASA he paid for a seat on the Russian Soyuz TM-32 mission to the International Space Station. He was subsequently described as the first ‘space tourist’, a rather unfortunate label in my view. Tito, now 72, shares the frustration of all space enthusiasts at the complete lack of progress with the manned exploration of space since Project Apollo. It is now four decades since Cernan and Schmitt blasted off from the surface of the Moon. Nobody has been back; no manned spacecraft has left Earth orbit since.

There have been innumerable proposals for an expedition to Mars, but none have got off the ground even metaphorically. It is of course much harder to mount an expedition to Mars than it is to the Moon. The most obvious problem is that Mars is very much further away than the Moon. The Apollo missions typically lasted under ten days; the duration of Tito’s mission will be fifty times longer. The next problem is that Mars, though small in comparison to Earth, is still much larger than the Moon. Furthermore, unlike the Moon, it has a significant atmosphere. To land on Mars and take off again, you need a craft that is not only built for re-entry, but is also able to escape the higher Martian gravity on take-off. This means a craft that is considerably larger and more complex than the Apollo lunar module. The fuel requirements for the mission are immense. Assuming an Apollo-type lander-orbiter configuration, you need sufficient fuel for 1) the spacecraft to launch and leave Earth orbit, 2) achieve Martian orbit, 3) the lander to land and take-off, 4) the orbiter to leave Martian orbit, 5) make any required mid-course alterations.

The crucial difference between a manned expedition and the innumerable unmanned landers and rovers sent to Mars since the 1970s is that the latter don’t have to return to Earth. To date, no unmanned sample return mission to Mars has ever been attempted, and even attempts to return samples from its moons have failed. To get round the problem, some have suggested a one-way trip to Mars. Unlike the Moon, there are sufficient raw materials on Mars to allow colonists to keep themselves alive indefinitely. 

The Tito proposal involves a fly-by rather than a one-way trip. There’s no landing, but the crew don’t have to spend the rest of their lives on Mars. The spacecraft will be launched on a so-called free return trajectory, which will return it to Earth without the expenditure of fuel. Very little fuel will be needed after leaving Earth orbit. The result is a far simpler mission profile, though this term is relative. Unlike the International Space Station, which is periodically resupplied from Earth, the spacecraft will need to carry oxygen and supplies for the whole of the 501 day round trip. Even items such as toilet paper will amount to 28kg (62 lb.) in the supplies manifest. A major complication is that the spacecraft will be travelling at 51,000 km per hour (32,000 mph) when it returns to Earth. No manned spacecraft has ever attempted re-entry at such speed. It is likely that the spacecraft will have to slow down by aerobraking in the Earth’s outer atmosphere. The technique has been used for twenty years to slow unmanned space probes, but has never been attempted with a manned craft.

Another factor is radiation from the Sun and from interstellar space. A vehicle in Low Earth Orbit, such as the International Space Station or a shuttle, is largely protected by the Earth’s magnetic field. On a short-duration mission beyond Earth orbit – such as Apollo – the dosage is not large enough to be a problem. The possible effects of exposure on a long-duration mission include sterility and an elevated risk of developing cancer in later life. That is the reason for selecting a middle-aged crew. It is further assumed that a married couple could better endure the psychological stresses of long-term confinement.

There is also the risk of a coronal mass ejection from the Sun – a massive burst of radiation occurring during a solar flare. The proposed mission will take place during a period of low solar activity, but the risk isn’t entirely absent. The radiation could seriously harm or even kill the crew. Unfortunately, there is very little that can be done with present-day technology to shield a spacecraft against radiation. Finally, there is the stark reality that if something goes wrong with the spacecraft or if there is a medical emergency on-board, there will be absolutely nothing that can be done to abort the mission.

No concrete proposals yet exist for the mission. A possible configuration would involve a Dragon spacecraft from the private US space company Space X. The Dragon is a re-usable capsule-type craft that has already carried out an unmanned resupply mission to the International Space Station. The Dragon would be coupled to an inflatable habitat module of the type under development by Bigelow Aerospace, another private US space company. The mission would be launched with a Space X Falcon heavy-lift launch vehicle. First launch of the Falcon Heavy is expected either late this year or early next year.

The next launch window for the 501-day flight occurs in January 2018. After that, Mars will not be in the right position again until 2031. This gives Tito 5 years to get his mission off the ground. At the glacial speeds which NASA has operated since Apollo, this might not seem possible. However, it should be remembered that little over eight years passed from Alan Shepard’s sub-orbital spaceflight in 1961 to the late Neil Armstrong’s ‘giant leap for mankind’. The entire history of powered flight from Kittyhawk to the Sea of Tranquillity took place within the lifetime of many, including my grandparents.

The cost of the mission has been estimated at between $1 to 2 billion (£660 – 1200 million). This might sound like a lot of money, but it is actually less than Russian oligarch Roman Abramovich is alleged to have spent on Chelsea FC over the last decade. In space terms, it’s peanuts. In terms of actual Mars science, the value of the mission will be far less than can be achieved with unmanned orbiters and rovers. The scientific value of the mission will be in terms of what can be learned about the physiological and psychological effects of long-term spaceflight beyond Earth orbit.

The real worth of the mission, however, will be in its inspirational rather than scientific value. Nobody much under the age of 50 can remember the Moon landings. The current President of the United States was a few days short of his eighth birthday when Armstrong and Aldrin landed on the Moon; UK Prime Minister David Cameron was a 2 ½ year-old toddler. I think we’ve been waiting long enough for mankind’s next giant leap.

© Christopher Seddon 2013

The Mesoamerican Calendar

Mesoamerican calendrical systems have become well-known to the general public in recent years as a result of the Maya Long Count, which ended on 21 December 2012. There is no reason to suppose that the Maya expected anything untoward to occur on that day, but that did not stop the doomsday industry from working overtime. As the supposed day of reckoning approached, groups camped out by a mountain in the south of France to await rescue by flying saucer. There was much nonsense about a rogue planet called Nibiru and other supposed perils. The cinema industry cashed in on the hoo-hah with the disaster movie 2012 and the rather more thoughtful Melancholia. Neither movie paid much heed to the laws of physics. In fact, periodic end of the world ‘scares’ are nothing new, and go back at least a thousand years (Moore, 1999).

The Long Count was actually only one of three calendars in use in pre-Columbian Mesoamerica. For day-to-day reckoning, there was a solar calendar or haab cycle of 365 days, and there was a ritual calendar of 260-days known as the tzolkin or sacred almanac. All three calendars made use of the vigesimal or base-20 system of counting, rather than our familiar decimal or base-10 system. The system employed a place-value notation and a zero, long before the Hindu-Arabic system introduced these concepts. It may have come about through the practice of counting the digits on the feet as well as on the hands. Numbers were represented by combinations of ones (dots), fives (bars) and zeros (various characters) stacked vertically, with place value increasing from bottom to top (Aventi, 2001). The other number that featured prominently in Mesoamerican calendrical systems was 13, representing the number of levels of heaven in Mesoamerican cosmology (cf. the seven levels of heaven in the Jewish, Islamic and Hindu traditions).

The haab cycle comprised 18 ‘months’ of 20 days each, plus 5 intercalary days. Each date denoted by one of 20 day names paired with one of 18 month names. Like the pre-Ptolemaic Egyptian calendar, it did not take leap years into consideration, and thus did not accurately track the solar year. Days in the tzolkin were denoted by a number from 1 to 13 and one of 20 names, for a total of 260 days. The haab and tzolkin cycles were combined into the Calendar Round, which repeats every 18980 days (52 years). The 52-year cycle was a period of great significance throughout Mesoamerica. The termination was celebrated by the New Fire ceremony, in which fires everywhere were extinguished and domestic implements and statues were discarded (Aventi, 2001).

The Long Count calendar generated dates from a fixed start point that were to all intents and purposes unique (as are Gregorian dates). The basic unit of time was the tun of 360 days, which was subdivided into 18 uinals of 20 kins (days) each. The tun was multiplied by successive powers of 20 (the vigesimal equivalent of decades and centuries) named katuns and baktuns. Thus a katun is 360 x 20 = 7200 days and a baktun is 360 x 20 x 20 = 144,000 days or just over 394 years. The Maya did not invent the Long Count, but by Classic times (AD 250 – 800), only they were using it (Webster & Evans, 2005). The Maya implementation of the Long Count began on a date corresponding to 11 August 3114 BC in the Gregorian calendar. The 13th baktun from that date ended on 21 December 2012. There is some dispute as to what is supposed to follow. The usual view is that 13 baktuns (just over 5125 years) represents a creation epoch and the count returns to zero (Aventi, 2001). However, there is some evidence that the Maya intended the count to continue. There may be higher-order units beyond the baktun which scholars (in the absence of the original Maya terms) have named the piktun, kalabtun, kinchiltun and alautun.

The reason for a 260-day ritual count remains uncertain. One suggestion is that it originated at a location between 14°42' and 15 N., where the Sun crosses the zenith at 260 and 105-day intervals. A possible candidate is the Late Formative Period site of Izapa, which is located on the Pacific Coast of Mexico (Malmstrom, 1973). One objection to this interpretation is that the 260-day cycle simply repeats and does not factor in the concomitant 105-day cycle (Henderson, 1973). Another problem is that the 260-day cycle may have been in use at Monte Albán around 500 BC, considerably earlier than Izapa (Henderson, 1973; Marcus & Flannery, 2004). There are also Olmec inscriptions that suggest that the cycle might date to as early as 650 BC (Pohl, Pope, & von Nagy, 2002; Stokstad, 2002).

Other suggestions are a link to the average human gestation period of 266 days, or to various astronomical cycles. Two tzolkin (520 days) corresponds closely to three eclipse half-years (519.93 days). The eclipse half-year of 173.31 days is the period between successive eclipse seasons, i.e. a period of around 33 days when the Earth, Moon and Sun can line up to produce an eclipse. There is also a close correspondence between the tzolkin and the average of 263 days that Venus remains visible as either a morning or evening star, before it disappears into the dawn or twilight skies. Links to Mars have also been suggested. The synodic period of the Red Planet (i.e. the interval between successive close approaches to Earth) is almost exactly three tzolkin, or 780 days (Aventi, 2001).

References:
Aventi, A. (2001). Skywatchers. Austin, TX: University of Texas Press.
Henderson, J. (1973). Origin of the 260-Day Cycle in Mesoamerica. Science, 185, 542.
Malmstrom, V. (1973). Origin of the Mesoamerican 260-Day Calendar. Science, 181, 939-940.
Marcus, J., & Flannery, K. (2004). The coevolution of ritual and society: New 14C dates from ancient Mexico. PNAS, 101(52), 18257–18261.
Moore, P. (1999). Countdown!... or how nigh is the end? London: Pan.
Pohl, M., Pope, K., & von Nagy, C. (2002). Olmec Origins of Mesoamerican Writing. Science, 298, 1984-1987.
Stokstad, E. (2002). Oldest New World Writing Suggests Olmec Innovation. Science, 298, 1873-1874.
Webster, D., & Evans, S. (2005). Mesoamerican civilization. In C. Scarre, The human past (pp. 594-639). London: Thames & Hudson.

BH-1 hominin mandible from Serbia suggests Neanderthals evolved in isolation in Western Europe

BH-1 is a left fragment of a human mandible (lower jawbone), complete with all three molar teeth. It was recovered in 2005 at Mala Balanica cave, Serbia, along with a number of quartz artefacts. Originally estimated to be around 115,000 years old (Roksandic, et al., 2011), it is now believed to be at least 400,000 years old. Newly obtained ages, based on electron spin resonance combined with uranium series isotopic analysis, and infrared/post-infrared luminescence dating, yielded a minimum age of between 397,000 to 525,000 years old. This date makes BH-1 one of the oldest hominins in Europe, and the most easterly European hominin of the Middle Pleistocene (Rink, Mercier, Mihailovic, Morley, Thompson, & Roksandic, 2013).

Middle Pleistocene hominins from the period 600,000 to around 200,000 years ago are conventionally lumped together as Homo heidelbergensis (or Archaic Homo sapiens). By the end of this period, the Neanderthals had emerged from the European populations and modern Homo sapiens from the African populations. In fact, the reality of the situation is far from understood and was almost certainly far more complicated.

The problem with Homo heidelbergensis is as Archaic Homo sapiens it came to be used as a kind of ‘wastebasket category’ for anything that wasn’t Homo erectus, a Neanderthal, or a modern human (Cameron & Groves, 2004). Consequently, it tends to be defined in terms of features intermediate between Homo erectus and later humans rather than unique traits, which are a prerequisite for properly defining a species (Harvati, 2007). The situation has been referred to by anthropologist Phillip Rightmire (1998) as the ‘muddle in the middle’ and there is much debate as to whether Homo heidelbergensis is indeed a single species.

BH-1 is a potentially important piece in the jigsaw. It differs significantly from European hominins generally classified as Homo heidelbergensis. It shows a complete lack of the incipient Neanderthal traits that are present for most Western European hominins of the Middle Pleistocene. Instead, it shows primitive Homo erectus-like traits (Roksandic, et al., 2011).

This data suggests that the Neanderthals may have arisen solely in Western Europe, only later spreading to Southeast Europe and Southwest Asia. During glacial periods, Western Europe was cut off from the rest of Eurasia, and the distinctive morphology of the Neanderthals may have evolved in isolation. The process may have been driven by genetic drift impacting on small isolated proto-Neanderthal populations, rather than the effects of Darwinian natural selection (Weaver, 2009). Genetic drift refers to random changes in the relative frequency in which an allele occurs in a population. In small populations, over a number of generations, the effect can result in some alleles becoming fixed and others disappearing altogether, even if the prevailing alleles confer no particular selective advantage on their possessors. An analogy for genetic drift is seen in small isolated villages where everybody ends up with the same surname. If for example Mr and Mrs Smith are the only Smiths in the village and they have only daughters, then the surname Smith will disappear from the next generation. Over enough generations, the villagers will ‘drift’ to just one surname.

In contrast to Western Europe, the Balkan Peninsula was never isolated, and early humans there remained biologically similar to those from Southwest Asia. Accordingly, the population inhabiting the Balkan Peninsula could have retained a number of primitive non-Neanderthal traits, without precluding morphological changes associated with increased brain size and tooth reduction observed in Middle Pleistocene populations throughout Eurasia and Africa (Rink, Mercier, Mihailovic, Morley, Thompson, & Roksandic, 2013).

Rink et al (2013) New Radiometric Ages for the BH-1 Hominin from Balanica (Serbia): Implications for Understanding the Role of the Balkans in Middle Pleistocene Human Evolution may be downloaded from the open-access PLoS One website.

References:
Cameron, D., & Groves, C. (2004). Bones, Stones and Molecules: “Out of Africa” and Human Origins. Elsevier Academic Press.

Harvati, K. (2007). 100 years of Homo heidelbergensis - life and times of a controversial taxon. Mitteilungen der Gesellschaft für Urgeschichte, 16, 85-94.

Rightmire, P. (1998). Human Evolution in the Middle Pleistocene: The Role of Homo heidelbergensis. Evolutionary Anthropology, 6(6), 218-227.

Rink, W., Mercier, N., Mihailovic, D., Morley, M., Thompson, J., & Roksandic, M. (2013). New Radiometric Ages for the BH-1 Hominin from Balanica (Serbia): Implications for Understanding the Role of the Balkans in Middle Pleistocene Human Evolution. PLoS One, 8(2).

Roksandic, M., Mihailovic, D., Mercier, N., Dimitrijevic, V., Morley, M., Rakocevic, Z., et al. (2011). A human mandible (BH-1) from the Pleistocene deposits of Mala Balanica cave (Sicevo Gorge, Nis, Serbia). Journal of Human Evolution, 61(2), 186-196.

Weaver, T. (2009). The meaning of Neandertal skeletal morphology. PNAS, 106(38), 16028–16033.

Ice Age art: arrival of the modern mind

Astonishingly lifelike, the 21,000 year old mammoth-ivory bison sculpture (below) is unquestionably the work of a talented artist. Excavated at Zaraysk in Russia in 2002, it is one of 130 portable art objects from the European Upper Palaeolithic featured in Ice Age art: arrival of the modern mind, which opens at the British Museum on 7 February. These have been set alongside a small selection of works by Henry Moore, Henri Matisse, Piet Mondrian and other 20th Century artists. Exhibition curator Dr Jill Cook was unfortunately unable to include Genesis by Sir Jacob Epstein and works from the currently-closed Musée Picasso in Paris.

However, the modern art is not included for comparison but to emphasise that this exhibition is first and foremost about art rather than archaeology. Art is not merely a product of what we glibly term ‘civilisation’, it is a fundamental part of the modern human condition. We see the earliest evidence for its expression in South Africa over 70,000 years ago, but the earliest-known figurative art appears around 40,000 years ago in Europe. Modern humans entered Europe 46,000 years ago, and over the next 5000 years they dispersed across the continent. Although the last Ice Age had yet to reach its full extent, conditions were very different to those in the African homeland they had left tens of millennia earlier. Nevertheless, the richness of the art they produced over the next 35,000 years clearly demonstrates that there was far more to their lives than a grim battle for survival.

One of the earliest-known examples of what is unequivocally figurative art, the Löwenmensch (Lion-man) of Hohlenstein-Stadel (below) is a therianthropic (part human, part animal) figurine of a human figure with a lion’s head. It is 30 cm (11.8in) high and is carved from mammoth ivory. Hohlenstein-Stadel is an Aurignacian cave site in the Lone Valley of the Swabian Jura Mountains of south-western Germany. The Löwenmensch was discovered by archaeologists Otto Völzing and Robert Weitzel in 1939 in numerous fragments, but with the outbreak of World War II, it was forgotten for thirty years. Reconstruction of the figurine was begun in 1969 by Joachim Hahn, but was not completed until 1988. The Löwenmensch is over 36,000 years old. It may represent a shaman partially transformed into a lion, or a mythical being or a supernatural spirit. In 2003, a similar but much smaller figurine was discovered at Hohle Fels Cave in the Ach Valley, only a short distance from Lone Valley. The implication is that the people of the Ach and Lone Valleys were members of the same cultural group, and shared beliefs and practices connected with therianthropic images of felines and humans.

Among the most iconic objects of Ice Age Europe are the so-called 'Venus' figurines that have found at many Upper Palaeolithic sites. Most date to the Gravettian period from 28,000 to 22,000 years ago, though some are from the preceding Aurignacian. Typically lozenge-shaped, these figurines are characterised by exaggerated sexual characteristics, with very large breasts, accentuated hips, thighs and buttocks, and large, explicit vulvas. Other anatomical details tend to be neglected; especially arms and feet, and the heads generally lack facial detail. The contrast with the classical portrayal of Venus could not be greater. The figurines are carved from materials including mammoth ivory, serpentine, steatite or limestone and are often coloured with ochre. The Black Venus of Dolni Věstonice (below) was made from fired clay, and is among the earliest known ceramics.

The 'Venus' figurines are often interpreted as fertility figures, mother goddesses etc, but their real function is unknown. One novel suggestion, by anthropologists Leroy McDermott and Catherine Hodge McCoid, is that they may be self-portrayals of pregnant women. They note likenesses between a photograph of a “Venus” figurine viewed from above and one of a pregnant woman standing with her feet together, viewed from her own perspective looking down on her breasts and abdomen.

After visiting the newly-discovered Lascaux Caves in 1940, Pablo Picasso is said to have remarked “We have invented nothing” in reference to the cave’s 17,000 year old polychrome rock art. The story may be apocryphal, but the British Museum has offered the public a unique opportunity to judge for themselves.

Ice Age Art: Arrival of the Modern Mind is at the British Museum from 7 Feb until 26 May, 2013

Doubts cast about late survival of Neanderthals in southern Iberia

A new study has cast doubt on the widely-accepted view that Neanderthals persisted in refugia in the south of Iberian Peninsula for several millennia after their extinction elsewhere in Europe.  If this conclusion is correct, it could mean that the Neanderthals were already extinct by the time modern humans reached Europe.

The latest dates for Neanderthal remains and the associated Mousterian industry are generally taken to occur south of the Ebro River in northern Spain. North of the Ebro, the Mousterian ends shortly before the start of the Proto Aurignacian. The latter industry first appears 42,000 years ago, and is associated with modern humans. However, south of the Ebro, the Mousterian is generally believed to persist until around 36,000 years ago.

Wood et al (2013) report in the journal PNAS the use of a technique known as ultra-filtration to remove modern contaminants from fossil bone collagens prior to radiocarbon dating. Without this process, it is claimed that the contaminants make samples appear younger than they actually are. For example, a carbon contamination of just 1 percent will make a 50k radiocarbon years before present sample appear to be just 37k radiocarbon yr. BP.

A total of 215 Neanderthal bones from 11 supposedly-late Neanderthal sites were screened for collagen. Unfortunately, only 27 bones were found to contain enough collagen for radiocarbon dating using the ultra-filtration technique. These were from just two sites, Jarama VI and Cueva del Boquet Zafarraya. The results suggested that the Neanderthal remains from the two sites were at least 46,000 years old in calibrated radiocarbon years.

This is around 12,000 years earlier than the results reported by Finlayson et al (2006) for the Neanderthal occupation of Gorham Cave, Gibraltar. These suggest that Neanderthals persisted until 28k radiocarbon yr. BP and possibly as recently as 24k radiocarbon yr. BP, albeit the latter date is less well supported. Note that these dates are uncalibrated; the calendar dates will be earlier, but no earlier than around 32,000 years ago. In a follow-up report, Finlayson et al (2008) dismiss any possibility of modern carbon contamination affecting their results.

We should therefore keep an open mind about the implications of this report, but it does highlight the considerable scope for error with radiocarbon dating.

Contrary to what is being widely reported in the media, there is certainly no truth in the suggestion that these results disprove the view that modern humans interbred with Neanderthals. The latter conclusion is based upon genetic data and it suggests that the interbreeding occurred long before modern humans reached Europe (Green, et al., 2010). However, an earlier than believed extinction date for European Neanderthals would explain the lack genetic evidence for any subsequent interbreeding in Europe.

References:
Finlayson, C., Fa, D., Espejo, F., Carrion, J., Finlayson, G., Pacheco, F., et al. (2008). Gorham’s Cave, Gibraltar - The persistence of a Neanderthal population. Quaternary International, 181, 74-71.

Finlayson, C., Pacheco, F., Rodrıguez-Vidal, J., Fa, D., Lopez, J., Perez, A., et al. (2006). Late survival of Neanderthals at the southernmost extreme of Europe. Nature, 443, 850-853.

Green, R., Krause, J., Briggs, A., Maricic, T., Stenzel, U., Kircher, M., et al. (2010). A Draft Sequence of the Neandertal Genome. Science, 328, 710-722.

Wood, R., Barroso-Ruíz, C., Caparrós, M., Jordá Pardo, J., Galván Santos, B., & Higham, T. (2013). Radiocarbon dating casts doubt on the late chronology of the Middle to Upper Palaeolithic transition in southern Iberia. PNAS (Early Edition).

Humans from the beginning

This blog has been largely defunct for nearly four years while I have been writing my book Humans: from the beginning which is now nearing completion. I have now resumed blogging on my new site, www.humanprehistory.com and may also be followed on Twitter @prehistory and @neandertalwatch.

When time permits, I hope to use this blog for posting photographs and for writing about non-prehistory related topics.

Nature Magazine: the battle continues

Latest on my battle with Nature Magazine and their ridiculous restriction on accessing content from 1997 and earlier.

Dear Sir

I have been a subscriber to Nature magazine for a number of years. As a science author in the field of human evolution and prehistory, I make extensive use of your online content – in fact it is my principle reason for subscribing to Nature and indeed to other science journals. I therefore find it somewhat vexing to be presented with a paywall if I try to access content from 1997 or earlier. Your website provides the singularly unhelpful explanation that such content is “not available” to personal subscribers, without a word of justification for this policy.

Since I flatly refuse to pay US$ 32 to download such articles, I am forced to obtain them at the British Library. I work from my home in North London and having to travel to and from St Pancras for these articles is a very annoying waste of my time. US$ 32 is far more than any other periodicals charge, even to non-subscribers (and by the way, the currency used in the UK is sterling, not US dollars).

Nor can I make any headway with your support staff regarding an explanation for a policy that strikes me as petty and frankly iniquitous. After nearly three months of repeated chasing and mounting frustration on my part, the best you have been able to come up with is that it is “a business decision supported by the board”, which you must surely accept is a wholly-inadequate explanation. In fact it is obvious that nobody within your organization either knows or cares what the explanation is. 1997 is the year Nature went online and I understand that the earlier content was only placed online more recently. Probably somebody at the time felt it would be a good idea to restrict access to it and because nobody complained the policy has remained in place, the reasoning behind it (if any) long since forgotten.

How much extra revenue is Nature making from this policy? My guess is, not a penny. Or cent. I don’t know, but my guess is that the vast majority of users of the online content are in academia and are not personal subscribers. The few personal subscribers that do use the online content probably obtain the restricted material from a library, as indeed do I. I cannot imagine any subscriber paying to access the restricted content. So all this restriction is accomplishing is to waste peoples’ time. In fact in my case I am seriously considering not renewing my subscription next month on the basis that if I have to go to the British Library anyway, I might as well read the magazine while I am there.

Charging subscribers for this content should be scrapped with immediate effect.

Yours sincerely,
C.P. Seddon

Modern Humans in Arabia 125,000 years ago?

Stone tools have been recovered from a site in the United Arab Emirates. The tools are reported to be 125,000 years old and it is claimed by British archaeologist Simon Armitage in the journal Science that they were made by modern humans. This date is 40,000 to 60,000 years before modern humans are generally thought to have reached the Arabian Peninsula.

The tools were found at a rock shelter on Jebel Faya, a 350m (1,200ft) mountain equidistant from the Gulf of Oman and the Persian Gulf and lying due south of the Straits of Hormuz. The rock shelter itself is 180m (600ft) above sea level. It contains archaeological layers dating from the Iron and Bronze Ages all the way back to the Palaeolithic. Artefacts from the latter have been found in three layers, the oldest of which, Layer C, has been dated by optical stimulated luminescence methods to the Eemian Interglacial, 125,000 years ago. The artefacts were manufactured using a number of different reduction strategies including Levallois, volumetric blade, and simple parallel methods. The tools include small handaxes, foliates, end scrapers, side scrapers, and denticulates. It has been suggested that they have more in common with contemporary artefacts from North and Northeast Africa than with those known from other Arabian sites. Since the African artefacts were made by modern humans, it is proposed that the Eemian Jebel Faya artefacts were too.

The Eemian Interglacial was warm period between the last and penultimate ice ages during which “humid corridors” opened up in the Sahara Desert. Modern humans reached the Levant, probably via the “humid corridors”, but they are not generally thought to have reached further into Asia. The general view is at that time, the Levant was effectively a north-eastern extension of Africa. After conditions worsened 91,000 years ago, modern humans disappeared from the Levant, which was subsequently re-occupied by Neanderthals.

Armitage believes that humans crossed the Bab Al Mandab Strait at the southern end of the Red Sea at the onset of the Eemian, when sea-levels were fairly low and it could readily be crossed. Once in Arabia, the colonists benefitted from reduced competition for resources and exploit both the coast and interior for food. Groups occupied the southern coast and pushed inland, taking advantage of the warm wet conditions. Armitage suggests that it is these rather than technological innovation that provided the stimulus for the expansion. The more recent Palaeolithic artefacts suggests that the colony survived the harsher conditions that set in at the end of the Eemian, although it was probably cut off from groups living further south.

It cannot be ruled out that the tools were of Neanderthal origin, although co-author Anthony Marks rejects this view and in an article in Science claimed that Neanderthals did not use this combination of tools. Archaeologist Michael Petraglia noted that the site was out of the Neanderthal habitat range. But archaeologist Sir Paul Mellars was quoted as being “totally unpersuaded”. He does not believe that there is any evidence that the tools were made by modern humans and does not see the tool style as African.

I will personally admit to being sceptical and think it is far more likely that these tools were made by Neanderthals. Petraglia’s comments notwithstanding, it was reported last year that modern humans interbred with Neanderthals soon after leaving Africa. Assuming they left via the Bab Al-Mandab Strait, as is widely believed, they must have encountered Neanderthals in Arabia.

Reference:
Armitage, S., Jasim, S., Marks, A., Parker, A., Usik, V., & Uerpmann, H. (2011). The Southern Route “Out of Africa”: Evidence for an Early Expansion of Modern Humans into Arabia. Science , 331, 453-456.

Loud music in pubs

As a regular pub-goer for many years I find it infuriating that all too often, my experience in a pub is ruined by music that is gradually increased in volume to a level that makes conversation all but impossible. Attempts to find a quieter spot are generally futile; loudspeakers are positioned to ensure that no place in the pub can escape the ghastly conversation-defeating THUD THUD THUD of the music, which itself is generally rubbish, utterly devoid of merit. I will generally be forced to move on and find somewhere quieter. In addition, there are many occasions where I enter a promising looking pub, only to turn round and walk straight out because of ridiculously loud music.

Please don’t misunderstand me, I have nothing against music in pubs, but its purpose should be background. I totally fail to understand how anybody can enjoy volume levels appropriate to a nightclub or trendy bar. The pubs I visit do not have a particularly young demographic and drinkers are of a wide age range, with many in their 40s to 60s. I would imagine that few, if any, feel that the music adds anything to their drinking/eating experience. Furthermore, in the past, when I have gone drinking with work colleagues, there were times when even the younger people in the gruup found the music to be objectionably loud. Finally, I would call upon the support of Sir Patrick Moore, who on the TV program “Room 101” a few years ago listed pubs that play loud music even before he got on to his well-known dislike of fox hunting.

I have heard two theories, neither of which shows publicans in a very favourable light. The first is that the bar staff do it for their own benefit, totally forgetting that it is people like me who ultimately pay their wages. The other is that it is a cynical and wholly-irresponsible ploy to boost sales on the basis that people respond to the stress the music causes by drinking more.

I can in fact refute the latter theory. At one now-embargoed pub in Highgate, I have seen the pub empty almost visibly as the volume is increased. So it is clear that in that case at least, the music is purely for the benefit of the bar staff.

We are often hearing about the decline of the British pub. In such circumstances, surely it is a massive own goal to alienate your customer base by foisting something on them that at best adds nothing and at worst unacceptably detracts from the pub experience. If all drinkers would follow my example of boycotting pubs where loud music is played, by forcing a change of policy it would in the long do the industry a huge favour.

Unfortunately the industry don't seem care very much - I have emailed the British Beer and Pub Association about the issue, but nobody could be bothered to reply.

© Christopher Seddon 2011

How Neanderthals cooked their food

But the Neanderthals were also capable of harvesting and processing plant foods. In a study published in the US journal PNAS, calculus was removed from the teeth of three Neanderthal individuals: Shanidar III from Shanidar Cave, Iraq and Spy I and Spy II from Spy Cave, Belgium. Shanidar III yielded a large number starch grains, some of which were identified as originating from the Triticeae tribe of grasses, which includes the wild relatives of wheat, barley and rye. Others were from legumes. Importantly, many of the grains had been cooked. Although less numerous than the starch grains, a number of phytoliths were also recovered. These are rigid microscopic bodies, composed of silica, that occur in many plants and serve a number of purposes, including lending the plant structural rigidity and making it distasteful to predators. The bulk of the phytoliths recovered from Shanidar III originated from date palms. Starch grains were also recovered from the two Spy Cave Neanderthals. Some were found to be from tubers, possibly of water lilies. Others were from grass seeds, possibly sorghum.

Although neither site has yielded evidence of stone artefacts specialized for use as grinding implements, or of storage features, there is clear evidence that at both sites Neanderthals were employing preparation techniques which increased the edibility and nutritional quality of plant foods, including husking and cooking of seeds. Date palms have different harvest seasons to barley and legumes, suggesting that the Shanidar Neanderthals practiced seasonal rounds of collecting and scheduled returns to harvest areas.

Anthropologists have long been interested in the timing of two major hominin dietary adaptations; the cooking of plant foods and an expansion in dietary breadth or “broad spectrum revolution”. This led to the incorporation of a diversity of plant foods such as grass and other seeds that are nutritionally rich but relatively costly to exploit. That the Neanderthals mastered both adaptations in two widely-separated climates – Mediterranean and northern oceanic – is further proof of their sophistication.

References:
Henry, A., Brooks, A., & Piperno, D. (2010). Microfossils in calculus demonstrate consumption of plants and cooked foods in Neanderthal diets (Shanidar III, Iraq; Spy I and II, Belgium). PNAS , Early Edition, 1-6.

Modern humans interbred with Denisovans

In 2008, a distal manual phalanx of from a hominin little finger was recovered from Denisova Cave in the Altai Mountains of southern Siberia. The cave is named for a hermit called Dionisij (Denis) who is supposed to have lived there in 18th Century, but if this is true he was only the latest in a long line of inhabitants.

In April 2010, a report was published in the journal Nature (Krause, et al., 2010) suggesting that the phalanx had belonged to a hitherto-unknown human species. The small bone was dated by stratigraphic methods and found to be in the region of 30,000 to 48,000 years old. It is believed to have belonged to a child aged between 5 and 7 years old, but other than that no morphological classification could be made. However, due to the cool, dry climate, it proved to be possible to extract DNA from the bone and isolate mtDNA fragments, from which it proved possible to sequence the entire mitochondrial genome. Because we inherit our mtDNA solely from our mothers, this led to the find being dubbed X Woman, despite being from a juvenile of then unknown gender.

At the time in question, Neanderthals, identified as such by their mtDNA, were living less than 100 km (60 miles) away. The presence of an Upper Palaeolithic industry at Siberian sites such as Kara-Bom and Denisova itself has been taken as evidence for the appearance of modern humans in the Altai before 40,000 years ago. The expectation, therefore, was that the mitochondrial DNA from the bone would match that of either Neanderthals or modern humans, but neither turned out to be the case. Instead, sequencing revealed that X Woman had last shared a common ancestor with Neanderthals and modern humans about a million years ago.

X Woman clearly wasn’t a Neanderthal or a modern human, but what was she (if indeed she was a “she”)? One possibility was Homo heidelbergensis, the presumptive common ancestor of the Neanderthals and modern humans. But Homo heidelbergensis appeared no earlier than 600,000 years ago – long after X Woman’s ancestors. On the other hand, the date of one million years was too late for X Woman to be a late-surviving descendant of the first wave of Homo erectus to reach the Far East.

Towards the end of 2010, a second report was released in Nature detailing the sequencing of X Woman’s nuclear genome (Reich, et al., 2010). It turned out that “X-Woman” lacked a Y-chromosome and therefore was indeed female. Also described in the same report was an upper molar tooth. The latter appeared to be from a young adult and also yielded mtDNA, which in turn confirmed that it belonged to a different individual to phalanx. For this reason, the term “X-Woman” was dropped in favour of “Denisovan”.

According to the report, both mitochondrial and nuclear genomes suggest that the Denisovans are more closely related to Neanderthals than they are to modern humans. The nuclear data suggested that the Denisovans diverged from Neanderthals 640,000 years ago and from present-day Africans 804,000 years ago, suggesting that Densovans and Neanderthals were sister groups, sharing a more recent common ancestor than modern humans and Neanderthals. Africans were used for the comparison to avoid the confounding effects of the interbreeding thought to have occurred between archaic humans (previously thought to be Neanderthals) and the first modern humans to leave Africa. It was also found that the archaic component of the modern Eurasian genome has closer affinities to Neanderthals than to Denisovans, confirming that the interbreeding did occur with the former rather than the latter.

The divergence data obtained from the nuclear DNA is rather at odds with that obtained from the mtDNA. The report suggested two possible causes; firstly interbreeding between Denisovans and as yet unknown hominins; secondly, that the Denisovans retained an archaic mitochondrial lineage that has been lost from Neanderthals and modern humans due to the effects of genetic drift. The latter explanation is the more parsimonious, but the report concluded that the two scenarios were equally likely according to the data.

The most remarkable finding was that 4.8 percent of the nuclear genome of present-day Papuans derives from Denisovans, greater than the Neanderthal contribution of 2.5 percent and meaning that uniquely for modern humans, the Papuans are more closely-related to Denisovans than they are to Neanderthals. Overall, the data was consistent with a scenario in which modern humans, on leaving Africa, interbred with Neanderthals and then, at some subsequent point, the ancestors of present-day Papuans interbred with Denisovans, but this did not affect any other non-African populations. The implication is that Denisovans were present in Southeast Asia as well as southern Siberia. This in turn raises the possibility that the archaic humans living in the Far East as recently as 27,000 years ago (Swisher, et al., 1996), conventionally described as late Homo erectus, may in fact be Denisovans.

The Denisova tooth, which is probably a third or possibly second left upper molar, is fairly large, within the size range occupied by Homo erectus and Homo habilis and larger than that typical of Neanderthals and early modern humans. But the report failed to note that some early modern human teeth are also very large, such as those associated with the 35,000 year old lower jawbone from Peştera cu Oase in Romania I) (Trinkaus, Milota, Rodrigo, Mircea, & Moldovan, 2003; Trinkaus, et al., 2003). Size alone probably does not tell us very much. That the tooth shares no derived morphological features with Neanderthals or modern humans further indicates the distinctiveness of the Denisovans; but it also lacks any features in common with the very few third upper molars that have been recovered from other late archaic hominins in the Far East. Thus the tooth fails to support a connection between the Denisovans and known archaic human fossil remains from the Far East.

Clearly there is a very interesting story here, but until further fossil and/or genetic evidence comes to light, there is nothing more definite that can be said at this stage.

References:
Krause, J., Fu, Q., Good, J., Viola, B., Shunkov, M., Derevianko, A., et al. (2010). The complete mitochondrial DNA genome of an unknown hominin from southern Siberia. Nature , 464, 894-897.

Reich, D., Green, R., Kircher, M., Krause, J., Patterson, N., Durand, E., et al. (2010). Genetic history of an archaic hominin group from Denisova Cave in Siberia. Nature , 468, 1053-1060.

Swisher, C., Rink, W., Anton, S., Schwarcz, H., Curtis, G., Suprijo, A., et al. (1996). Latest Homo erectus of Java: Potential Contemporaneity with Homo sapiens in Southeast Asia . Science , 274, 1870 - 1874.

Trinkaus, E., Milota, S., Rodrigo, R., Mircea, G., & Moldovan, O. (2003). Early modern human cranial remains from the Pestera cu Oase, Romania. Journal of Human Evolution , 45, 245–253.

Trinkaus, E., Moldovan, O., Milota, Ş., Bîlgăr, A., Sarcina, L., Athreya, S., et al. (2003). An early modern human from Peştera cu Oase, Romania. PNAS , 100 (20), 11231–11236.

© Christopher Seddon 2010

Grim fate of Neanderthal family group, 49,000 years ago

Evidence has come to light of the grim fate of a Neanderthal family group that lived in Spain 49,000 years ago. After apparently enduring a lifetime of privation, they were killed and eaten by members of a neighbouring Neanderthal group – presumably themselves on the brink of starvation and thus driven to extremities.

In 1994, extensive human remains were found at El Sidrón, an extensive system of karstic limestone caves in the Asturias region of northern Spain. Systematic excavation commenced in 2000 and to date around 1800 hominin skeletal fragments and 400 Mousterian-type stone tools have been recovered. The latter include side scrapers, denticulate pieces, a hand axe, and several Levallois points. The human remains are thought to represent twelve Neanderthal individuals, including three adult males, three adult females, three male adolescents and two juveniles and an infant of unknown gender.

A group size of 12 individuals at El Sidron is reasonably consistent with a previous estimate of between 8 to 10 individuals per Neanderthal group, based on the size of sleeping and combustion activity areas in the long-occupied rock shelter of Abric Romaní, near Barcelona. However, because the original external deposit cannot be studied, it could not be rules out that the El Sidrón group was larger and that some original members are not represented among the remains.

The tools and remains were found in a side gallery deep within the cave complex, and was probably introduced into the cave from the surface when a violent storm caused an upper gallery or a series of fissures to collapse. Pebbles and clay were also dragged down from the surface. The whole assemblage is around 49,000 years old. Around 18 percent of the tools have been refitted, suggesting that they are all the same age and that the associated human remains represent all or part of a contemporaneous social group of Neanderthals, who died at around the same time.

The low temperature of the side gallery meant that genetic material has survived and mitochondrial DNA has been extracted from each of the individuals. It was found that all three of the adult males carried the same mitochondrial lineage, but the three adult females all carried different lineages. Mitochondrial DNA is not a part of the primary genome and is inherited solely from the maternal line. The implication, therefore, is that the males shared the same maternal lineages but the females all had different maternal lineages. This suggests that in Neanderthal groups, mature males remained within their family birth group, but females came from outside. Patrilocality, as it is known, is present in about 70 percent of modern human societies, where men remaining in the family home but women move to the home of their new husband upon marriage.

But there is a darker side to the discoveries. All the El Sidrón individuals suffered from developmental stress, or periods of growth arrest, presumably arising from malnutrition. This is indicated by deficiencies in dental enamel, present on over 50 percent of the group members’ incisors, canines and premolars and over 30 percent of their molars. Five of the members had experienced two such episodes of growth arrest and one adult had experienced four. It is clear that for this extended Neanderthal family, life was very difficult – and in the end, it seems, they met a grim fate.

Cut marks and breaks have been found on many of the bones, including lower jawbones, skulls and long bones; evidence of skinning activity and extraction of bone marrow and brains – in other words, cannibalism.

References:
Lalueza-Foxa, C., Rosas, A., Estalrrich, A., Gigli, E., Campos, P., García-Tabernero, A., et al. (2010, December). Genetic evidence for patrilocal mating behavior among Neandertal groups. PNAS .

Rosas, A., Martınez-Maza, C., Bastira, M., Garcıa-Tabernero, A., Lalueza-Fox, C., Huguet, R., et al. (2006). Paleobiology and comparative morphology of a late Neandertal sample from El Sidron, Asturias, Spain. PNAS , 103 (51), 19266–19271.

Vallverdu, J., Vaquero, M., Caceres, I., Allue, E., Rosell, J., Saladie, P., et al. (2010). Sleeping Activity Area within the Site Structure of Archaic Human Groups Evidence from Abric Romanı Level N Combustion Activity Areas. Current Anthropology , 51 (1), 137-145.

© Christopher Seddon 2010

Whatever happened to "the customer is always right"?

If you are running a shop, it always used to be a rule that you should give the customer what they want. Not any more it seems. Increasingly, presumptuous managers are coming round the the idea that THEY know best.

Until recently, I used to have a couple of fresh-baked poppy-seed rolls or ciabattas from my local Sainsburys for lunch. Notably these two types were easily the most popular types, and often sold out. I was therefore completely mystified and a little put out when, shortly before Christmas last year, the store stopped selling poppy seed rolls and then, to compound the felony, discontinued the ciabattas a few months later. As both types remained on sale elsewhere, I assumed that this was the result of some kind of mixup, but after months of correspondance had failed to resolve the situation, I finally got to the bottom of the matter - "This is based on our policy to provide a wide and varied range of products and to offer our customers the opportunity to try something different."

Excuse me, I'll decide when and if I want to "try something different". For my part, I "tried" shopping at Waitrose instead of Sainsburys, which is "different" but probably wasn't the intended consequence of this policy. Unfortunately, Sainsburys are not the only offender. The sandwhich chain Pret a Manger is virtually synonymous with its All Day Breakfast - a bacon, sausage, egg and tomato sandwhich which is even described as "famous" on their website. Except try finding an outlet that actually sells it. If you live in Glasgow or Liverpool, you are fresh out of luck - "None of our shops in Glasgow or Liverpool sell this sandwich" I was informed, after frustrating experiences in both these places. The situation in London is little better; earlier this week I gave up in disgust after trying no fewer than four outlets.

The explanation: "This sandwich is one that Managers can choose whether to sell or not in their shops dependent on sales and customer demand." Right, once again, the manager knows best. If you are nursing a hangover in Glasgow or Liverpool - hardly an infrequent occurrence - you'll have to make do with some ghastly rabbit-food special and tell yourself it it so much better for you than the all-day breakfast you'd dragged yourself out of bed for.

© Christopher Seddon 2010

MS Queen Victoria in Istanbul

Launched in 2007, the Cunarder MS Queen Victoria and her sister ship MS Queen Elizabeth are twice the size of the Titanic and significantly larger than the original RMS Queen Mary and RMS Queen Elizabeth and the legendary French SS Normandie.



Tied up alongside the Istanbul Modern art gallery, the sheer size of the ship is apparent in this photograph.



The Victoria is a modified Vista class cruise ship. Unlike her even bigger sister RMS Queen Mary 2, she is not an ocean liner, lacking the reinforced hull and greater speed of the Mary and her predecessors. For this reason, Cunard have been criticised for designating the Victoria and the Elizabeth as "Queen" ships. But the fine lines of the ship contrast sharply with the motorised barge looks of many cruise ships.



The great ship sets sail.



A day after the Victoria's departure, her place on the quay was taken by the even larger but rather more mundane-looking MSC Magnifica.

© Christopher Seddon 2010

Feral cats of Istanbul

It is impossible to go anywhere in Istanbul without seeing cats, often congregrating in large groups.



A short distance from the Hagia Sophia, an orange tabby sits on the bonnet of a Mercedes.



Another orange tabby, sitting on the door of a large, derelict wooden house on the Asian side of the city.



© Christopher Seddon 2010

The enigmatic "Venus" figurines of Upper Palaeolithic Europe

Female carvings are known throughout the European Upper Palaeolithic and are collectively known as Venus figurines, though they predate the Roman goddess by tens of millennia. They are chiefly associated with the Gravettian period, though they are also known from the preceding Aurignacian. The earliest currently known is the 35,000 year old Hohle Fels Venus, a mammoth-ivory figurine recovered in 2008 at Fohle Fels Cave in the Swabian Jura of south-western Germany (Conard, 2009).

Typically lozenge-shaped, these figurines are characterised by exaggerated sexual characteristics, with very large breasts, accentuated hips, thighs and buttocks, and large, explicit vulvas. Other anatomical details tend to be neglected; especially arms and feet, and the heads generally lack facial detail. The contrast with the classical portrayal of Venus could not be greater. The figurines are carved from materials including mammoth ivory, serpentine, steatite or limestone and are often coloured with ochre. Others are made from fired clay, making them among the earliest known ceramics (Vandiver, Soffer, Klima, & Svoboda, 1989). Many have engraved or incised patterns, which may represent hair and clothing.

Since the first examples were discovered in the 19th Century, many have attained iconic status. These include the Venus of Willendorf, which is 11.1cm (4 3/8 in) high and carved from oolitic limestone. The statue was discovered in 1908 by archaeologist Josef Szombathy near the village of Willendorf in Austria, which is associated with the Gravettian period and now resides in the Natural History Museum Vienna.

The figurines are often interpreted as fertility figures, mother goddesses etc, but their real function is unknown. One novel suggestion, by anthropologists Leroy McDermott and Catherine Hodge McCoid, is that they may be self-portrayals of pregnant women. They note likenesses between a photograph of a “Venus” figurine viewed from above and one of a pregnant woman standing with her feet together, viewed from her own perspective looking down on her breasts and abdomen The theory has met with a certain amount of scepticism, but McDermott and McCoid argue that it provides a parsimonious explanation for the features found in representations of the female form from the Upper Palaeolithic (McDermott, 1996; McCoid & McDermott, 1996).

You couldn't make it up - but rail companies can!

In the last month, there have been two cases where rail passengers have been fined because they got off the train BEFORE the right stop.

Couple fined £114 for getting off train before their final stop - 6 September 2010

Getting off train early costs Durham professor £155 - 27 September 2010

You don't have to be Mr Spock to see that this is a totally illogical state of affairs. In fact it is barking mad and the words "you couldn't make it up" spring to mind. Unfortunately rail companies can and do, being run by people whose brains operate on wavelengths different to those used by the majority of humans since Upper Palaeolithic times.

The arguement employed by the rail companies is that "it is against the terms and conditions" to get off at an earlier stop if buying a discounted-rate ticket, contrary to something known as "common sense" (admittedly in short supply at rail companies). But it is more than contrary to common sense, I would argue that it is also contrary to law.

A train company can force a passenger to leave a train or penalise them for remaing aboard without a valid ticket. What it cannot do is when a train has made a scheduled stop to force or coerce somebody to remain aboard against their will, or penalise them for failing to remain aboard. I would argue that to do so is not only stark staring mad, it is false imprisonment, a serious offence in common law.

If so then the terms and conditions are irrelevant and unenforceble, because common law takes priority. For example, if the terms and conditions said "If you leave the train before your stop, you will be shot", it is extremely unlikely that anybody trying to implement this policy would escape a lengthy jail sentence. I strongly doubt if the argument "I was only enforcing the terms and conditions" would cut much ice in court.

False imprisonment is a less serious offence, but it is still an offence. If somebody did sucessfully argue in a court of law that preventing somebody from leaving a train early did constitute false imprisonment, then railway companies would be in trouble. Which is why I suspect they backed down in the case of Professor Evans, albeit hiding behind the face-saver of "good will". If the London couple had refused to pay, I suspect the outcome would have been the same.

If this argument is ever successfully tested in a court of law, it will hopefully force and end to this ridiculous policy and it will be a massive victory for common sense.

70th Anniversary of the discovery of the Lascaux Cave paintings

On 12 September 1940, less than three months after the fall of France, four teenage boys and a small dog named Robot made one of the greatest archaeological discoveries of the last century. The group were walking through the sloping woods above Lascaux Manor, near the town of Montignac, which lies on the Vézère River, Dordogne. They were investigating a local legend about an old tunnel, said to connect Lascaux Manor to the ruined Château de Montignac on the other side of the river. Robot was running on ahead of the boys and was attracted to a deep hole in the ground. Covered with overgrowth, it had been exposed by the falling of a tree.

Accounts vary as to what happened next. According to some versions, the little dog fell into the hole and had to be rescued; others claim the boys used their penknives to enlarge the hole, cutting away earth and removing stones; others suggest that the boys first equipped themselves with picks, shovels and lighting before returning to investigate further. Whichever version is correct, they enlarged the hole and at length they were able to slide through feet-first, one by one, along a semi-vertical shaft embedded with stalagmites, finally reaching a dark underground chamber. There, in the flickering glow of their oil-lamp, they saw prehistoric paintings of horses, cattle and herds of deer, brilliantly multicoloured in reds, blacks, browns and ochres, unseen by human eyes for at least 18,000 years.

Despite the unhappy times, news of the discovery spread rapidly. Villagers flocked to the caves and they soon drew visitors from further afield. Among these was the Catholic priest and archaeologist Abbé Henri Breuil, who was able to attest to the great antiquity of the caves and described them as “The Sistine Chapel of Prehistory”. Another early visitor was Pablo Picasso, who on emerging from the cave, is said to have remarked in reference to modern art “We have invented nothing”.

In 1948, the site’s landowners opened the caves as a tourist attraction, and soon they were attracting a quarter of a million visitors annually. Unfortunately, by 1955 it became clear that CO2 exhaled by the large numbers of visitors was promoting the growth of algae, causing significant damage to the paintings. After a number of unsuccessful attempts to ameliorate the problem, the caves were eventually taken over by the French Ministry of Cultural Affairs and closed to the public in 1963. Only five people a day are now admitted and scholars wishing to visit the caves for research purposes face a lengthy wait for a twenty-minute slot. Ordinary visitors have to make do with Lascaux II, a facsimile of the original which opened in 1983.

The paintings are now believed to be between 18,000 to 19,000 years old – four times older than the Pyramids - and are associated with the Solutrean or early Magdalenian period. There are 915 animals depicted, mainly horses, deer, aurochs (wild cattle) and bison - animals which at that time roamed wild on the steppes of Ice Age Europe (Clottes, 2008). Despite their great antiquity, the Lascaux Caves are certainly not the oldest cave paintings known; that title is currently held by the Chauvet Caves near Vallon-Pont-d’Arc, Ardèche, which are almost twice as old. Considered to be of equal artistic merit with Lascaux, the oldest paintings at Chauvet are now thought to be 36,000 years old (Mellars, 2006), associated with the Aurignacian people and dating to a time when two species of human – Neanderthals and Homo sapiens – coexisted in Europe.

God does not exist (again)

Robin Dunbar’s explanation (Dunbar, 2006) provides what is probably the most convincing explanation of religion. It is based around theory of mind (the ability to anticipate the thoughts of others) and orders of intentionality (what X might be thinking about Y’s thoughts regarding Z).

Story-telling, science and religion all require 5th order intentionality - eg, when writing Othello, Shakespeare required five orders: he intended (1) his audience his audience to understand (2) that Iago wants (3) Othello to believe (4) that Desdemona intends (5) to run away with Cassio. Probably, though, story-telling was a spinoff – from the ability to, as we would now put it, to “do science”. High-order intentionality is crucial to understanding the natural world – science – which would have been crucial to the survival of early modern humans as the left Africa and attempted to colonize novel environments. To understand seasonal migration patterns of herd animals, the correlation between moon phases, tides and fishing, etc and to share this knowledge with others, would have required equally high orders of intentionality.

The ability to tell engaging stories round the campfire would have been a useful spinoff, good for group morale; serving the same purpose as literature – and indeed cinema and theatre today. But there was another spinoff – religion.

Theory of mind is crucial to religion. To engage in religious activities, I must believe in a parallel world inhabited by beings whose intentions can be influenced by my prayers. These beings must be able to understand what I want – requiring third-order intentionality: I believe (1) in gods that can be persuaded to understand (2) what I desire (3) and will act on my behalf. In fact, more than three orders of intentionality are required in any practical religion because religion is a social activity; a shared belief system and people must share their faith with others in a community.

In his book The God Delusion, Richard Dawkins argues that religion is a “misfiring by-product” of something else (Dawkins, 2006), though in early hunter-gatherer societies, religion would have been a powerful group bonding mechanism and not as entirely malign as Dawkins supposes. Only much later, when humans began living in far more complex societies, was religion used as a means of control by the ruling elite.

However, it is possible that it was responsible for social division as far back as the Upper Palaeolithic, manifesting itself in the cave art of that time. David Lewis-Williams has suggested that art and ritual, while contributing to social cohesion, did so by marking off groups from other groups, thus creating the potential for social tensions (Lewis-Williams, 2002); a trend which has unfortunately continued to the present day. It is probably no coincidence that some of the finest art and architecture ever produced has been religious in nature and if Lewis-Williams is right, the origins of this creativity are very ancient indeed.

Homo helmei revisited

Homo helmei is one of many human species that has failed to gain widespread recognition. Textbooks tend to either mention it only in passing, or not at all. The species was assigned to the single partial skull which was recovered in 1932 by Professor T.F. Dreyer from the depths of the hot spring at Florisbad, some 50km (30miles) from Bloemfontein, South Africa. The skull comprises the right side of the face, most of the forehead and portions of the roof and sidewalls. A single upper right wisdom tooth was also found with the skull and in 1996 two small samples of enamel from this were found to be 259,000 years old using a technique known as electron spin resonance. In 1935, Dreyer described the find as Homo helmei to mark its distinctiveness from other fossil Homo sapiens. Homo helmei is not widely accepted, largely because it is still known only from this one specimen and it is usually “lumped” into Homo heidelbergensis ("archaic Homo sapiens").

The etymology of Homo helmei is something I have yet to find listed in any textbook and it took a good deal of digging around on the internet until I eventually came across the website of the National Museum, Bloemfontein, which provided the following insight:

The town of Florisbad is named for Floris Venter, a local entrepreneur who in 1912 enlarged the pools at the spring for use as a spa. Later that year an earthquake caused a new spring to open up, revealing stone tools and fossils. During the late 1920s, zoologist Professor T.F. Dreyer and his assistant Ms. A. Lyle carried out excavations in the vicinity of the spring. These were funded by Captain R.E. Helme and produced further quantities of animal fossils. The story goes that Venter feared loss of revenue if his baths were temporarily drained and Dreyer and Ms. Lyle had to wade around in the waters and grope for bones. On one such occasion, Dreyer plunged his hand into the spring deposits underwater and – rather in the manner of Little Jack Horner – pulled out part of a human skull, with his fingers stuck between its eyes!

This was the find later described as Homo helmei - it simply means "Helme's Man" and was named for Capt. Helme, whose funding had made the discovery possible.

Did Lucy use tools

A paper published today in Nature (McPherron et al, 2010) reports the discovery of 3.4 million year old bones from Dikika in the Lower Awash Valley, Ethiopia with cut marks claimed to have been made by stone tools - some 800,000 years before the oldest-known stone tools from nearby Gona. The only hominins known from the region during this time period is Australopithecus afarensis ("Lucy").

The evidence is not overwhelming - no actual tools were recovered and the marks could be due to other causes. But if hominins were butchering carcasses 3.4 million years ago and meat was a significant part of their diet a million years before the appearance of Homo habilis, it would be a problem for the "expensive tissue" hypothesis that proposes that a switch to a meat-based diet released the constraint on brain size, allowing larger-brained hominins such as Homo habilis and Homo ergaster to appear. See this entry on Prof. Hawks ever-informative blog:

http://johnhawks.net/weblog/reviews/archaeology/lower/dikikia-cutmarks-mcpherron-2010.html

Humans in the Philippines, 67,000 years ago

Mijares et al report in the Journal of Human Evolution the discovery of a 67,000 year old human 3rd metatarsal at Callao Cave on the island of Luzon in the Philippines. The bone is gracile and could be from a small-bodied modern human, like the indigenous "Negrito" people of Island Southeast Asia; or it could be from an earlier-type human - the report stated that it was within the range of Homo habilis or Homo floresiensis.

Either possibility is intriguing - if it is modern, then it implies the migrants from Africa must have left before the 65kya date widely touted, possibly before the Toba eruption - despite the most recent genetic evidence pointing to later rather than earlier dates for the migration. If on the other hand it is pre-modern, then as with Flores we are left with the question of how did archaic humans reach an island which was never connected to the mainland? I've always felt that Homo floresiensis is a downsized version of Homo erectus, descended from a small group who reached Flores by accident after being swept out to sea by a storm or tsunami - but another possibility is that Homo floresiensis was a sea-faring species that established itself on at least two islands in ISEA.

Best to reserve judgement for now.

The Artificial Ape, by Timothy Taylor

On order from Amazon. Sounds interesting and I need to read it, if only for professional reasons. Taylor apparently cites the reduction of lactose intolerance in humans as an example of technology bringing about evolutionary change. Originally, when weaned, the ability to process milk in humans was “switched off” as it was no longer needed. In other words, nearly all adults were lactose intolerant. But with the “secondary products revolution” that followed the Neolithic adoption of agriculture, milk became a useful food source; lactose intolerance became a disadvantage and was selected against.

However, one ”pet” example of such change (I DON’T know if this is in Taylor’s book) has now been shown to be dubious - the change from large ape-like guts in the australopithecines to the smaller guts of humans came about through tool use, enabling humans to butcher carcasses and switch to a meat-based diet. Smaller, less energy-expensive guts were required for this higher quality diet, opening up the way for our large, gas-guzzling brains.

But: australopithecines (not just late ones like A. garhi) may have used tools (McPherron et al, 2010), and probably didn’t have large guts (Haile Selassi, 2010). Both discoveries are very recent, but the inclusion of meat in the australopithecine diet and implied tool use has been suspected for over a decade (Sponheimer & Lee-Thorp, 1999; Teaford & Ungar, 2000).

The trouble with writing in this field is that it is VERY easy to be out of date!