Huge fossils hacked out of a limestone quarry in the Hakataramea Valley will help University of Otago researchers provide new insights into a tantalising gap in the evolutionary record of whales and dolphins.
Two of the three fossils recently removed from the quarry were ''pretty important stuff'' in international scientific terms, Otago paleontologist Prof Ewan Fordyce said this week.
The two fossils, which included skulls, were ''scientifically very promising'' and could prove to be ''some of the most informative specimens'' found at the site in the 25 years he had been recovering fossils there.
''These are really quite major specimens.''
The large ancient baleen whale fossils had been removed ''in rapid succession'' from the quarry site in recent months.
One lump of rock weighed about half a tonne - ''it's a monster''. It was about the largest piece of rock that could be readily removed using a ramp, system of pulleys, cables, rollers and a heavy trailer pulled by a four-wheel-drive vehicle.
Ancient marine mammal fossils recovered from the Waitaki area showed it was one of the planet's ''last frontiers'' for such discoveries.
Prof Fordyce said one of the largest groups of researchers on ancient whales and dolphins anywhere in the world had been built up at the Otago geology department. Some members of this ''great group of students'' would be working on the latest finds.
Such discoveries, and associated international research publications, were helping put Dunedin, and the Waitaki area, on the world map for natural science research.
The limestone quarry had proved ''the single most important site'' for finding ancient whales and dolphins in New Zealand.
The fossils had been preserved in ancient marine limestone towards the end of the Oligocene age, about 23 million years ago, at a time when at least three-quarters of modern New Zealand was underwater.
At that stage, modern Dunedin and Oamaru, and much of the present southern South Island east coast, was covered by about 100m of water, as part of a shallow inland sea.
The fossils, preserved in muddy limestone, were about 23 million years old and were likely to shed some new light on a later three million year gap in the known baleen whale evolutionary record.
Prof Fordyce hopes the latest finds will help ''answer some outstanding questions'' about this ''significant gap in whale and dolphin history''.
One fossil also included a ''significant skeleton''. Removing the fossil required a large excavation that took four days and involved removing about 15 tonnes of surrounding rock.
This was technically ''quite a difficult extraction'' - requiring use of a compressor, pneumatic chisels, rock drills and rock saws.