Tuesday 13 May 2014

Digging apart: why is archaeology a humanity and palaeontology a science?

Although my Twitter account only follows scientists and scientific organisations, every day sees the arrival of a fair few archaeology tweets, even by science-orientated sites such as Science News. As someone who has been an amateur practitioner of both archaeology and palaeontology I thought I'd like to get to grips with why they are categorised so differently. After all, the names themselves don't really help: the word 'archaeology' means "the study of everything ancient." whilst the common definition of 'palaeontology' is pretty much "the study of ancient life". I've even known people with close friends or relatives in one or the other discipline to confuse them: whilst viewing my fossil cabinet, a visitor once told me that her cousin was an archaeologist studying Maori village sites!

Even historically, both fields share many common factors. Not only were they founded by enthusiasts and amateurs, but to this day non-professionals continue to make fundamental contributions. In converse, amateurs can cause serious deficiencies in the data record by lack of rigour or deliberately putting financial gain ahead of the preservation of new information. This can be caused by a variety of methods, from crude or overly hasty preparation of fossils, to metal detectorists and site robbers who sell their finds to private collectors without recording the context, or even the material itself.

It is not immediately obvious where the dividing line between the two disciplines lies when it comes to prehistoric human remains. In the 1990s, archaeologist Mark Roberts led a team that excavated the half a million year old Boxgrove site in southern England. Finds included fragmentary remains of Homo heidelbergensis, thus crossing over to what might traditionally be deemed the territory of palaeontologists. In 2001 the multi-phase Ancient Human Occupation of Britain project started, with deliberate collaboration between both sectors, proof that their skills could overlap and reinforce each other.

By and large, neither palaeontology nor archaeology utilises repeatable laboratory experiments and therefore neither can be classified as a ‘hard’ science. Even palaeontology relies to a large extent on historical contingency, both for remains to be fossilised in the first place and then for them to be discovered and recorded using the relevant methodology. As British palaeontologist Richard Fortey has said "Physics has laboratories; systematic biology has collections." Talking of which, re-examination of old evidence in both disciplines can lead to new discoveries: how often do we see headlines pointing to a fundamental discovery...made in a museum archive?

Although archaeologist were not previously known for conducting experiments,  the New Archaeology/Processual archaeology that arose in the 1960s included an emphasis on testing hypotheses, one result of which is that archaeology now uses experiments to interpret site data. This includes attempts to recreate artefacts, structures, boats, or even food recipes, based on finds from one or more sites. It may not be laboratory conditions, but it is still a method of analysis that can reinforce or disprove an idea in a close equivalent of the scientific hypothesis.

Attempts to improve the quality of data gleaned from the archaeological record have led to the utilisation of an enormous variety of scientific techniques collectively labelled archaeometry. These include microwear analysis, artefact conservation, numerous physical and chemical dating methods such as the well-known radio carbon dating and dendrochronology; geophysical remote sensing techniques involving radar, magnetometry and resistivity; and DNA analysis, pathology and osteo-archaeology.

Teeth of a sand tiger shark
(possibly Odontaspis winkleri)
I found in a wood in Surrey, UK

But there are some major differences between archaeology and palaeontology as well. Although both appear to involve excavation, this is only somewhat true. Not only does archaeology include standing structures such as buildings or ancient monuments, but a project can be restricted to non-invasive techniques such as the geophysical methods mentioned above; excavating a site is the last resort to glean information unobtainable by any other way, especially important if the site is due to be destroyed by development. In contrast, fossils are no use to science by remaining buried. Having said that, I often fossils by sifting through pebbles rather than concerted digging. I have occasionally split rocks or dug through soft sand, but a lot of the time fossils can be found scattered on the surface or prised out of exposed chalk via finger nails. The best way to spot even large finds is to have them already partially exposed through weathering, whilst some archaeology cannot be directly seen from the site but only identified via aerial photography or geophysics.

Archaeological sites can prove extremely complex due to what is known as context: for example, digging a hole is a context, back filling it is another, and any finds contained therein are yet more. Repeated occupation of a site is likely to cause great difficulty in unravelling the sequence, especially if building material has been robbed out. This is substantially different to palaeontology, where even folded stratigraphy caused by geophysical phenomena can be relatively easily understood.

Perhaps the most fundamental difference between the disciplines is that of data analysis. As anyone who has spent time on a site excavation knows, there are often as many theories as there are archaeologists. There are obviously far less fixed data points than that provided by Linnaean taxonomy and so there is a reliance on subjectivity, the keyword being 'interpretation'. Even the prior experience of the excavator with sites of a similar period/location/culture can prove crucial in gaining a correct (as far as we can ever be correct) assessment. In lieu of similarity to previously excavated sites, an archaeologist may turn to anthropology, extrapolating elements of a contemporary culture to a vanished one, such as British prehistorian Mike Parker-Pearson's comparison between the symbolic use of materials in contemporary Madagascar and Bronze Age Britain. In stark contrast, once a fossil has been identified it is unlikely for its taxonomy to be substantially revised - not that this doesn’t still occur from time to time.

As can be seen, not all science proceeds from the hypothesis-mathematical framework-laboratory experiment axis. After all, most of the accounts of string theory that I have read discuss how unlikely it can ever be subject to experiment. The British Quality Assurance Agency Benchmark Statement for Archaeology perhaps comes closest to the true status of the discipline when it lists 'scientific' as one of the four key contexts for higher level archaeological training. In addition, every edition since 2000 has stated "Where possible, thinking scientifically should be part of the armoury of every archaeologist."

So part historical science, part humanity, archaeology is an interesting combination of methodologies and practice, with more resemblances than differences to palaeontology. As the Ancient Human Occupation of Britain project shows, sometimes the practitioners can even work in (hopefully) perfect harmony. Another nail in the coffin for C.P. Snow's 'Two Cultures', perhaps?

Tuesday 1 April 2014

Dino wars: is that dinosaur Kiwi or Aussie?

It's a cheap piece of rhetoric to invoke the long-running if affectionate New Zealand-Australian rivalry, but what with the current campaign to redesign the New Zealand flag in order to differentiate it more its trans-Tasman neighbour, I thought it would be a good opportunity to discuss a science-themed story along these lines. In fact, the account bears some resemblance to the years spent arguing over Otzi, the Copper Age man found preserved in ice on the Austrian-Italian border. Although in this case, the focus of the disagreement isn't as clear-cut, since it concerns ancient remains found in both nations.

Even for a country with a population under five million, New Zealand has a seemingly minimal number of professional palaeontologists. That is, until you consider that the lack of industry application for the discipline's findings means its pretty good that there are any practitioners whatsoever. Numbers vary, but figures I have seen for the past few decades vary from less than a dozen to thirty or so professionals, most working for universities or state bodies. By comparison France, with twice the geographic area of New Zealand, has around one hundred professionals.

It isn't just the current financial crisis that has caused problems for would-be kiwi fossil hunters: funding has been steadily decreasing for the past half century and the emphasis shifted towards environmental research. This latter focuses on exploring the (very) long term changes that have affected not just the landmass as it is today but the largely submerged (90% or so) continent of Zealandia. This is of course extremely timely but it does enhance the idea that without much in the way of obvious practical returns, New Zealand palaeontology could dwindle to almost nothing. As it is, the country doesn't have a specialist palaeontological journal or even a dedicated palaeontological society.

The funding issue is claimed to be responsible for the loss of basic knowledge within the discipline, leading to problems such as taxonomic confusion and a backlog for formal descriptions, perhaps numbering some thousands of species, that are new to science. Of course New Zealand's distance from other nations doesn't help either, since the internet has frequently to be relied upon in lieu of direct representation at international conferences and the like. Therefore perhaps it's not surprising that there are only a couple of professional palaeontologists (part-time, at that) working on Mesozoic flora and fauna, including that much-loved clade, dinosaurs.

Luckily, this lack of professional numbers is partially redressed by dedicated amateurs, some of whom have played a pivotal role in dinosaur discoveries. The most famous is the late Joan Wiffen, who discovered New Zealand's first dinosaur fossils in 1974 after experts had proclaimed it unlikely any would be found (on the basis of the geological history of the current above sea-level land masses). I'm all for amateur fossicking and Joan Wiffen's four decades of dedication is an example to us all.

The heart of this piece concerns the discovery of the ninth dinosaur species found in New Zealand and serves as an instructive example of scientists at work knee-deep in messy reality rather than the unreachable ideal. One specimen that you won't find on FRED - the 95,000+ localities' Fossil Record Electronic Database - is the young theropod (carnivorous dinosaur) discovered in 2008 in New Zealand's dinosaur heartland, the Mangahouanga Stream between Taupo and Hawke's Bay. The specimen is only about forty centimetres long and is largely intact: a fully articulated skeleton only lacking a toe and a few tail end vertebrae. After 18 months careful preparation the reptile was in a suitable condition for high-level analysis, having - due to lack of budget - only received cursory examination during the removal of the overlying matrix. Having assessed the deposition layer as mid-Cretaceous the next obvious question was presumably which species did it belong to?

The most likely candidate for a species already scientifically described is the 5-6 metre gracile carnivore Australovenator wintonensis, which is known from fragmentary remains in central Queensland. At less than half a metre long, the New Zealand find would have to be a very young individual, which was the original opinion of the preparators. But the brief analysis of a visiting British palaeontologist put this into question, for although the upper jaw is missing from the adult Australovenator specimen, enough was present to suggest that the New Zealand skull is both too deep and too robust to be the same species. In addition, the kiwi remains has forearms that appear too long when compared to Australovenator, even accounting for variation in growth between youngster and adult.

Then in late 2009 the Australian Journal of Vertebrate Paleontology published an article claiming the New Zealand specimen was just an infant Australovenator. At this point patriotism started to kick in. Even though 'Australo' only means 'south' the word is close enough to the name of the larger nation to provoke the kiwi fossil community into a counter attack. A core group of Hawke's Bay-based amateur fossil hunters nicknamed the little dinosaur 'Hillaryonyx' (named after Everest pioneer Sir Edmund, of course) and the scene was set for a brontosaurus-sized brouhaha.

Although largely powerless, the passion of the non-professional fossicking community should not be underestimated. Everything that could be done to raise funding for a full analysis of the young reptile was undertaken: web articles were written, t-shirts were printed, even lyrics for a song called 'He's ours' (to the tune of the folk song 'No Moa!') On the basis of this, questions were asked in New Zealand parliament and as a result, and a bit of a whipround by some of the universities, money was found for eight months of part-time analysis by two palaeontologists with some experience on Mesozoic vertebrates. As mentioned previously, the reduction in funding for the discipline meant that there wasn't - and still isn't - a single full-time professional scientist dedicated to the era.

Once the analysis was complete the intention was to have a monograph published by GNS Science, a government-owned research institute, prior to public exhibition of the fossil. Everything seemed to be going smoothly, until several visiting Australian palaeontologists asked to see the prepared slab. They were at first stalled, and then later denied access, even to just photographs of the bones. Several arbitrary reasons were given, but the most likely motive for this behaviour was that the kiwi scientists were still assessing the species of the dinosaur. Which, given the loss of taxonomic knowledge mentioned above, was a tricky business if restricted to just New Zealand scientists. So much so, that it took the next two and a half years before anything further was heard.

The latest New Zealand dinosaur fossil

It's not known who was allowed to examine the fossil during this time but by late 2013 rumours surfaced that the dinosaur had been finally identified as a species new to science. A badly scanned interim report was leaked, containing several figures of the prepared fossil, included the photograph above. More significantly, the report listed eleven points of fundamental anatomical disparity with Australovenator, which have since proved enough to convince the majority of naysayers. The few who are still doubtful are all, needless to mention - but I will anyway - Australian. Until the beginning of this year it seemed the specimen would remain in limbo, but someone, somewhere, perhaps a leading university figure or government official, has pulled their finger out and New Zealand's latest endemic dinosaur species may soon be appearing in the records of the International Commission on Zoological Nomenclature (ICZN).

So not exactly an ideal way to pursue science by any stretch of the imagination. But the story is proof that cuts in funding can cause all sorts of problems for science in the long-term, even if the matter appears trivial to the layman.

Oh, and as for the official name for the creature: Stultusaurus aprillis. How appropriate!