Gateway drug

By July 16, 2023Science

It has been a bit quiet on this blog for the last couple of weeks, as I have been at a palaeontological conference. It is the first I have attended since well before Covid-19 and was supposed to be held in 2020 or 2021, so we were about two or three years overdue for a get-together. It was most enjoyable seeing old and younger colleagues, young enthusiastic students and the occasional amateur. There were numerous interesting talks in the few fields in which I have some expertise. I also attended a few talks in which I have almost no knowledge, just to see what was happening. One of these was given by an amateur and dealt with his experience exploring the outcrop of a Paleocene (66-56 million years ago) rock unit in New Zealand which had long been regarded as unfossiliferous by local geologists. However, his and others’ constant examination of this unit has turned up four fossil penguin species, a tropic bird and a toothed bird. Other talks were on fossils of all sorts: molecules, pollen, dinosaurs, fish, brachiopods, trilobites, molluscs, etc., and the talks dealt with fossils from the Mesoproterozoic (1,600-1,000 million years ago) to some as young as a few thousand years old.

One of the features of this conference which astonished me was the degree to which computer tomography has impacted palaeontology. While I have seen numerous scans of this sort in recent years, the resolution has increased dramatically. X-ray tomography is used for specimens which have significant contrast between the matrix and the fossil. It is used to extraordinary effect when dealing with fossil vertebrates to examine the internal structure of the skull and, in particular, the braincase. The resolution of this technique is now down to somewhere around one nanometre (one millionth of a millimetre) so that even the skeleton of single celled organisms can be examined in great detail1.

However, as I state above, x-ray tomography depends on whatever is being examined and the surrounding matrix having significant contrast. If that contrast is not significant, then neutron imaging can be used, at the only neutron imaging facility in Australia, the poetically named DINGO at the Australian Nuclear Science and Technology Organisation. A recent study using this technique showed that the stomach contents of a fossil crocodile contained the bones of a small ornithopod dinosaur2.

One of the talks I attended on which I have some expertise was on ‘small shelly fossils’ from some drillcores in the Georgina Basin which had some startling results. ‘Small shelly fossils’ is a term used to describe a diverse bunch of fossils, consisting mostly of calcium phosphate, up to about 5 mm in diameter, the phylogenetic relationships of which are not always clear. These fossils were from the Cambrian Period (539-485 million years ago) and are extremely useful in determining the precise age of rocks in the earlier part of that period and, in being small, they can be extracted from drillcore in sufficient numbers to be useful. One of the throw-away lines the presenter used was that, for palaeontologists, dinosaurs are often the ‘gateway drug’. Rarely was a truer word spoken. The How and Why Wonder Book of Dinosaurs was what roped me in to palaeontology initially3.

 While a few of us were standing talking during one of the breaks in proceedings a pregnant woman with a three- or four-year-old girl wandered past and asked us what was going on. We explained to her that we were at a conference dealing with fossils. She immediately said to her little girl ‘these people work on dinosaurs’. While most of us did not work on dinosaurs, one of us did. The little girl asked him all sorts of questions about dinosaurs and her knowledge was considerable for one so young. Unfortunately, her mother was less knowledgeable, but interested, and seemed to get the gist of the fact that not all palaeontologists work on dinosaurs. I have lost count of the number of relatively young children whom I have met over my career who know much more about dinosaurs than their parents. The more things change the more they stay the same. I wonder how many of them went into professional palaeontology.



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