AT SENEKAL, a little town in the rocky, rolling farmland of Orange Free
State in South Africa, there is a churchyard surrounded by a wall made from
huge chunks of fossilised tree. Nearby a stone tree lies on its side,
displaying growth rings, bark and the tracks of wood-boring insects. It is
more than 220 million years old, and yet few locals would spare it a
glance.
Fossilised plants and animals are so abundant here that monstrous skulls
and limb bones are used to adorn rockeries and prop up garden tables. Few
understand the significance of these intriguing lumps of rock. And even fewer
of those travelling to and from Cape Town, beetling across the boundless and
often desolate landscape of the Orange Free State and semidesert Karoo,
realise that they are passing through what an awe-struck American
palaeontologist once described as one of the greatest natural wonders of the
world. The rocks and soils of the Karoo contain the most complete and
uninterrupted fossil record of life on Earth from about 260 million years ago
to 180 million years ago, from the Permian through to the Jurassic Period.
Captured in minute detail in the Karoo fossils is the story of how the reptile
line divided and evolved, into modern reptiles on the one hand, into mammals
on the other.
Indeed, it was a fossil found in the Karoo in 1838 鈥� the skull of a mammal-
like reptile with two large tusk-like teeth in its upper jaw 鈥� that first
convinced the scientific establishment that mammals had evolved from reptiles,
not directly from amphibians. Since then, thousands of fossilised mammal-like
reptiles, or therapsids, have been unearthed from the Karoo. The remarkable
thing is that 90 per cent of them have been collected by one man.
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鈥淢y colleagues here tell me I鈥檝e walked the equivalent of three times round
the globe, but I don鈥檛 believe them,鈥� says James Kitching, a tall, spare man
with a deep voice roughened by years of smoking. 鈥淚鈥檇 say it was only about
once round the world.鈥� He doesn鈥檛 quibble, however, with the calculation that
he has spent a total of at least 13 of the past 50 years living under canvas
in some of Africa鈥檚 most remote and rugged terrain, hunting for fossils. Nor
does he, or indeed anyone else, quibble about the significance of the fossils
that he has found.
The Karoo rocks hold the secret to the ancestry of all modern reptiles and
mammals. Apart from sorting out the taxonomy of the fossils, Kitching has been
preoccupied with biostratigraphy 鈥� the classification of rock layers according
to their fossil content. This gives a clearer picture of the age of the rocks
than can be gleaned from their geological characteristics alone and is used to
correlate findings in different locations. A 鈥渂iozone鈥� is a rock layer which
has been named after the most plentiful fossil found there. Its limits are set
by the first and last appearances of this dominant creature. Kitching鈥檚 work
on the distribution of the fossil fauna through the sedimentary layers has
helped to prove that South Africa was once yoked to Antarctica as part of the
supercontinent, Gondwanaland.
鈥淜itching鈥檚 is the first good documentation of the biostratigraphy of South
Africa,鈥� says Bruce Rubidge, who in 1990 took over from Kitching as director
of the Bernard Price Institute of Palaeontology in Johannesburg. 鈥淧revious to
that people had less evidence for their theories. They鈥檇 say they thought this
or that was the situation and the tendency. Kitching was the first person who
did the job properly.鈥� James Hopson, a professor of palaeontology at the
University of Chicago, whose main interest is mammal-like reptiles, says:
鈥淐ertainly, he鈥檚 the grand old man of Karoo palaeontology.鈥�
The Russian connection
Only now, however, are the full implications of Kitching鈥檚 research being
realised. The academic isolation of South Africa during the apartheid years
meant that he could not get a visa to visit other parts of the world such as
China, India, Russia and Australia, which have similar fossils from the same
period. Dicynodonts, theracephalians and dinocephalians, for example, are
families that occur in the Karoo as well as in Europe, Russia and China. With
the emergence from isolation of the latter two countries as well as South
Africa, researchers can at last begin to piece together the transcontinental
story of evolution by comparing specimens from different countries.
Last year, Michael Shishkin from the Palaeontological Institute in Moscow
spent months at the Bernard Price Institute comparing amphibian fossils from
the Karoo with his own Russian specimens and trying to correlate the time
periods in which they lived. Focusing on two amphibian forms, Kestrosaurus and
Parotosaurus, Shishkin discovered a new link between Russian and South African
fossils. Until then, the Karoo species Parotosuchus africanus had been
considered the same as the Parotosaurs from Russia. But Shishkin found that P.
africanus was a more advanced form, probably from the middle Triassic period,
and is in the process of renaming it. Shishkin also realised that South
Africa鈥檚 Kestrosaurs, dating from the early Triassic, are the same as the
Russian Parotosaurs.
Last year Rubidge visited China, where specimens of dinocephalians, mammal-
like reptiles previously known only from the Karoo and Russia, had recently
been unearthed. The opportunities for international collaboration now that
apartheid is dead are very exciting, he says. However, the future role of the
Bernard Price Institute is uncertain as the South African government focuses
its resources on alleviating poverty. Rubidge hopes the new international
links will attract foreign funds. 鈥淭here鈥檚 so much to discover and gaps in the
story to fill in,鈥� he says. 鈥淭he Karoo covers about two-thirds of South
Africa鈥檚 surface and there are only about six palaeontologists working in it.
Every time we go out we find more stuff.鈥�
Underpinning all these efforts is Kitching鈥檚 own work, namely his zones and
fossil classifications. On an office wall at the Bernard Price Institute 鈥�
where he still puts in an eight-hour day five years after his 鈥渞etirement鈥� 鈥�
is a huge map of the Karoo studded with over 900 coloured pins. Each one marks
a locality from which he has taken fossils, the colour representing the
sedimentary layer, or biozone, in which each was found. Some 900 localities
are marked.
Size of a lion
It is clear from all these fossils that the therapsids were a very diverse
group. The dinocephalians were giant, lumbering creatures that included flesh-
eating species and plant eaters. The mostly herbivorous dicynodonts ranged
from 20 centimetres in length, to over 2 metres, while the mostly carnivorous
gorgonopsians were about the size of a large lion. 鈥淗ow fast-moving these
creatures were; whether they were warm-blooded, had hair, laid eggs or gave
birth to young 鈥� these are the kinds of things we鈥檙e now working on,鈥� says
Rubidge.
鈥淜itching has an eye for finding fossils like nobody I鈥檝e ever met,鈥� says
Hopson, who has been into the field with him. 鈥淗e鈥檚 absolutely amazing at
being able to spot a fossil from the least promising bit of rock. The volume
of what he鈥檚 collected is unrivalled, and it鈥檚 extraordinarily important
尘补迟别谤颈补濒.鈥�
When he retired in 1990, Kitching was not only director of the Bernard
Price Institute but professor of palaeontology at the University of the
Witwatersrand 鈥� not bad for someone who left school without any academic
qualifications. But then Kitching was steeped in the fossils of the Karoo from
early childhood.
Born in 1922 and raised in the tiny Karoo village of Nieu Bethesda,
Kitching was introduced to fossil hunting by his father, a foreman of a road
gang. As his teams cut through the ground to lay their roads, Kitching senior
not only supervised their efforts but collected fossils for Robert Broom, a
maverick Scottish palaeontologist.
Broom had settled into a medical practice in the Karoo, recognising it as a
rich pasture for pursuing his overriding passion: the evolution of mammals.
Southern Africa was once under the polar icecap, and so the oldest sediments
of the Karoo were deposited by glaciers. The vast empty centre of South Africa
which is now the Karoo was then a wide basin surrounded by mountains. As the
continent drifted away from the pole and warmer climes set in, it became a
land of rivers, pools and marshes where plants and animals flourished.
Conditions were ideal for fossilisation, Rubidge explains, and 鈥渢hat鈥檚 why we
have this remarkable record鈥�. For tens of millions of years, sediment was
deposited by the rivers, which flooded periodically and changed course
regularly, and there was minimal erosion in the sheltered basin.
Kitching was still a child when his father began showing him fossils on
riverbeds. He loved reading the papers that Broom sent the family describing
the fossils. At the age of eight he had his first specimen named after him,
Youngopsis kitchingi. 鈥淚t was a little lizard-like form from the upper Permian
beds, which are represented very well in the Bethesda district,鈥� he says.
When the Second World War broke out, Kitching and his father joined prime
minister Jan Smuts鈥檚 army and left to fight in North Africa and Italy. With
his best fossil hunters gone, Broom became desperate about the Karoo: he
imagined that if nothing was done to preserve them, priceless pieces of the
jigsaw of evolution would disappear under farmers鈥� ploughs, or be broken and
scattered by wind and rain. Following an impassioned public lecture on the
subject at the University of Witwatersrand he was approached by Bernard Price,
a rich businessman and patron of the sciences, who offered to put up
拢1000 a year if Broom could find a fossil collector. 鈥淚 was in northern
Italy when Wits informed me they had a job for me after the war,鈥� recalls
Kitching.
For the next four decades, Kitching spent four or five months a year in the
field, leaving camp by 7 am every day and often finding himself miles away
when darkness fell.
Students who accompanied him into the field remember a very efficient
setup. 鈥淜itch likes fresh food on his camps, says Elizabeth Latimer, a
doctoral student who is studying Karoo amphibians from the Permian period and
their distribution in the sedimentary layers. 鈥淗e buys carrots with green tops
and plants them back in the ground. In the middle of the brown Karoo you see
this beautiful little patch of green, and you eat fresh vegetables with your
dinner.鈥� And his penchant for fresh meat means that he knows what all the
little Karoo animals taste like.
Kitching鈥檚 thesis on the distribution of Karoo vertebrates remains the
accepted framework within which younger generations of palaeontologists still
work. In it, he divides the Beaufort Group 鈥� a geological 鈥渟equence鈥� from 280
million years ago to 230 million years ago 鈥� into five distinct biozones on
the basis of his fossil finds (see
Diagram).FIG-mg20153801.GIF
Pressure and distortion
He has also spent years sorting out the taxonomy of the fossils, many of
which were first named by Broom, who was renowned for assigning new genus and
species names to practically every new fossil he discovered. In the early
days, people did not take into account the immense pressure fossils are
subjected to underground and the distortions they suffer as a result, explains
Kitching. Today, with so many more specimens collected and after the
refinement of analytical techniques, it is easier to distinguish the different
genera and species.
In 1970, Kitching was invited to join the US research programme in
Antarctica. No one else had been able to find much fossil fauna there. But
Kitching did. 鈥淚t was so amazing to find the same animals I knew here in South
Africa,鈥� he says. Until then, many plants from Permo-Triassic times that were
common in the Karoo had also been found in Antarctica. But of the animals,
only a facial fragment of these therapsid Lystrosaurus (so common in the Karoo
we don鈥檛 even collect it any more鈥�) had been discovered. In five months
Kitching found about 90 good specimens of a whole variety of forms also known
in South Africa, and he finally confounded those who still doubted that the
two continents had ever belonged to the same supercontinent of Gondwanaland.
鈥淭here were still very many critics of the continental drift theory at the
time,鈥� he says. 鈥淏ut with the combined evidence of the geology and
palaeontology the critical case just collapsed.鈥�
Kitching flew from Antarctica to the US with 700 kilograms of rocks for
delivery to the Museum of Northern Arizona for further study. A mountain in
Antarctica was named Kitching Ridge in his honour.
His travelling days are over now, and even his expeditions into the field
are rare. He is content to let younger palaeontologists take over where he
left off, and spends his time at the Institute marking and refereeing papers
and sharing his knowledge with the students and fellow-scientists who seek him
out in his spartan office under the stairs.
鈥淲e鈥檙e looking to refine Kitching鈥檚 biozonation of the Karoo even further,鈥�
explains Rubidge, whose own proposal for a revision of the classification of
the Beaufort Group into eight biozones 鈥� rather than Kitching鈥檚 six 鈥� is about
to be published. In 1993, he and a colleague, John Nyaphuli of the National
Museum in Bloemfontein, discovered three therapsids new to South Africa and
older 鈥渂y between three and five million years鈥� than any other terrestrial
reptiles so far found in the southern hemisphere. Christened Australosyodon,
Tapinocaninus and Patranomodon, they are very similar to three of the oldest
therapsids from Russia. On the strength of these discoveries Rubidge has
suggested a new and separate biozone, the Eodicynodon, at the very bottom of
the Beaufort Group below Kitching鈥檚 Tapinocephalus zone.
A mystery Kitching had been unable to clear up was exactly where one of the
dicynodonts in the zone, Kannemeyeria, became extinct. Hancox was trying to
solve this when, in 1994, he unearthed bits of the skull and jaw of a new,
tuskless dicynodont therapsid, which he estimates lived about 240 million
years ago. He believes Kannemeyeria may have evolved into this new form. It
has a more advanced skull roof and upper and lower jaw than Kannemeyeria. He
is busy describing the creature, which he suggests should be part of the fauna
of the uppermost subdivision of the Cynognathus zone.
Meanwhile, desk-bound in Johannesburg, Kitching is pining for the Karoo.
鈥淚鈥檓 dying to go back,鈥� he says wistfully. 鈥淣ot to sit and die 鈥� I could work
on papers there and I鈥檇 have the veld around me. There are places in the Karoo
I last saw in 1948 and I鈥檓 praying I鈥檒l see them again one day.鈥�