Inspired by his recent visit to the exhibition Bug Lab, resident geologist Hamish Campbell recounts finding New Zealand’s first pre-Pleistocene fossil bug.
A momentous occasion
In October 1981 a cheque arrived in the post for the princely sum of £5, drawn on a BNZ bank account owned by Sir Charles Fleming.
My father Doug Campbell (palaeontologist at Otago University in Dunedin from 1959-2001) was the recipient of the cheque as he was the most senior member of the fossil hunting party.
Following instructions, and armed with scissors, he gathered all four of us together… and ceremonially cut the cheque into four pieces.
Regardless of its worth this was a momentous occasion as it signified closure on an outstanding scientific challenge laid down by Sir Charles some 25 years prior.
At last, our generous award had been claimed: it was for the discovery of New Zealand’s first pre-Pleistocene fossil insect.
Pre-Pleistocene
In those days, pre-Pleistocene meant older than 1.8 million years; it now means older than 2.6 million.
The age of the ‘base’ of the Pleistocene Epoch, a major division of the Cenozoic Period of geological time, has been substantially revised in recent years.
The expedition
The date was Saturday 6 June 1981 and, inspired by my colleague Ian Raine (palaeontologist, GNS Science), a group of four of us went on a one-day excursion from Dunedin to Oamaru.
The group included my father, Jonathan Aitchison (a budding palaeontology student at Otago University, now a professor of geology at the University of Queensland in Brisbane), Ian Raine, and myself. I was 27-years-old and had been employed as a palaeontologist with the New Zealand Geological Survey (now GNS Science) for 2.5 years.
Our quest was to explore well-exposed fossil-bearing ‘paper shales’ (finely laminated quartzose siltstone and mudstone) within Papakaio Formation in the Livingstone area, inland from Oamaru.
We were hunting fossil plants and pollen in an effort to try and determine the age of these rather enigmatic rocks.
The original sediments accumulated as silts and muds in a fresh-water pond or small lake within a braided river system during Early to Middle Eocene time about 50 million years ago.
Striking gold
‘Take a look at this!’ I remember the moment clearly and passed the specimen around, from one sceptic to another.
What I had found was a blob of discolouration on a freshly exposed bit of fossil lake bed, but interestingly there was a hint of fine structure and subtle shapes within it.
‘I think I have found a fossil caterpillar!
‘If this is for real, perhaps the rest of the food chain is preserved in these rocks. Look out for birds and fish…’
Needless to say, no further fossils of interest were found that day and to my knowledge none have been found since.
When last visited, the locality was virtually inaccessible due to gorse and black-berry.
It is an area of rather neglected, unsightly and difficult land made grotesque and ugly by sluicing activities of early gold-crazed miners with big water hoses.
The fossil bug
My father had the sense to show this ‘fossil caterpillar’ to Tony Harris, well-known entomologist at the Otago Museum and a long-standing science communicator with the Otago Daily Times.
Tony did his magic and declared that the fossil was indeed a fossil bug, but not a caterpillar.
It was the final instar of a march fly larva, and he formally named it Dilophus campbelli in 1983 after my father.
Where’s the fossil now?
The fossil resides under high security in the Type Specimen Collection held at the Geology Department, Otago University.
Type fossils are the scientific name-bearers of formally described species of fossil animal and plant, so named because they are ‘typical’ of the species they represent.
Sir Charles Fleming was a palaeontologist with the New Zealand Geological Survey, but is most famous for his services to conservation.
When he retired in 1977, he left a huge scientific legacy including this quirky challenge and reward. Little did he realise that my father was just as quirky!
Whereas this fossil is deemed New Zealand’s ‘first pre-Pleistocene fossil insect’, it should be noted that standard laboratory processing of rock samples for fossil pollen routinely produces macerated fragmental fossil insect remains, but nothing that can be identified.
References/sources:
Harris, A.C. 1983: An Eocene larval insect fossil (Diptera: Bibionidae) from North Otago, New Zealand. Journal of the Royal Society of New Zealand 13 (3): 93-102.
Aitchison, J.C., Campbell, H.J., Campbell, J.D., Raine, J.I. 1983: Appendix: Geological setting of the Livingstone fossil insect. Journal of the Royal Society of New Zealand 13 (3): 103-105.