Waterloo Farm lagerstätte

Witpoort Formation black shales within the Eastern Cape often exhibit cyclical changes in composition, which likely reflect (potentially seasonal) fluctuations in water salinity. Water stratification within the estuarine lake frequently led to anoxic bottom waters, resulting in episodes of exceptional preservation.[2]

Witpoort Formation sediments were deeply buried due to continued basinal subsidence through the Carboniferous, and were subsequently metamorphosed during the massive Permian aged Cape Fold Belt orogenesis.[3] Hundreds of millions of years of erosion and uplift brought the Waterloo Farm shales back up to near surface, they were exposed in 1985, in new road cuttings south of Makhanda/Grahamstown, during construction of a bypass road.

Waterloo Farm during the excavation in 1985.

On-site excavations were conducted in the 1990s, but the instability of the road cutting led to it being cut back in 1999 and in 2008. On both occasions large quantities of shale were rescued which provides for ongoing excavation. Decades of research has revealed the most important Late Devonian fossil site from what was the southern portion of Gondwana -a region incorporating present-day sub-saharan Africa, South America and western Antarctica.[4]

Waterloo Farm in 1988.

Waterloo Farm main fossil site in 1999 preceding roadworks.

One of the sheds of shale blocks rescued (with the help of SANRAL) from Waterloo Farm roadworks in 2008, for ongoing scientific excavation.

Because the original fine black mud was often very low in oxygen, plants and animals rapidly buried in it sometimes left behind impressions of their soft parts. This is extremely rare in the fossil record which normally only preserves bones, teeth and other hard bits. Exceptionally, what is recorded is the remains of an entire estuarine ecosystem, from delicate waterweeds and seaweeds to small clams, baby fish and the bones of larger fish. Land plants which grew nearby are also preserved, from the remains of small undergrowth species to fronds from the earliest types of trees.[5]

More than 20 species new to science have been named from Waterloo Farm, which probably represent about a third of the total number of taxa indicated by remains preserved in the shale. Taxa include the tetrapods Tutusius umlambo and Umzantsia amazana,[6] which are Africa's earliest known tetrapods and the only non-tropical Devonian tetrapods known. The first described fossils from Waterloo Farm comprise remains of sub-Saharan Africa's earliest woody trees (Archaeopteris notosaria).

Archaeopteris notosaria fronds from the Waterloo Farm lagerstätte in the Eastern Cape, South Africa. These represent the only high latitude species of Archaeopteris as yet described.

.[7] Other fossils from Waterloo Farm include the oldest known land-living animal from Gondwana (the scorpion Gondwanascorpio emzantsiensis),[8] the oldest fossil lamprey in the world (Priscomyzon riniensis)[9] and Africa's oldest coelacanth from the world's earliest known coelacanth nursery (Serenichthys kowiensis).[10]

Other species represented include several species of armour plated (placoderm) fish, spiny finned (acanthodian) fish, sharks, ray-finned (actinopterygian) fish, a range of lobe-finned fish, bivalves; seaweeds; charophyte waterweeds, and a diverse range of plants.