Gogo-Formation
The Gogo Formation is a fossil site, are included consisting of a former coral reef, in the exceptionally well-preserved fossils from the Devonian. It is located in the Australian state of Western Australia in the Kimberley region (Australia).
The former reef is located inland in the desert west of Australia. It is the main attraction of the Windjana Gorge National Park. In the up to 100 meters high cliffs spectacular fossil discoveries to be made again and again. So far about 45 species of fish have been discovered.
Parts of the Gogo Formation consist of siltstone, shale, and tuff with numerous concretions of limestone. These concretions are highly resistant to weathering, whereby the plurality of the fossil record is explained.
The sediments of the Gogo Formation originated in the Upper Devonian deposits by the anoxic sea floor. The limestone mineral masses formed on objects in shallow water, which then sank into deep, anoxic areas. By Fossilationsbedingungen in the deposit, namely the fast envelope with minerals and the slow decay in the oxygen- poor environment of the reef, many extinct fish, especially Plattenhäuter ( placoderms ) are so well preserved that the entire three-dimensional structure can be reconstructed. In many instances, the head regions, and some even soft tissues such as muscle, nerve fibers, and the olfactory system, very well reconstructed.
The reef was described in 1940 by paleontologist Curt Teichert, who discovered the first fossil fish in this region.
Gogonasus andrewsae ( German for " The muzzle of Gogo "), a 380 million year old meat -finned fishes ( Sarcopterygii ), was discovered in 1985 in the Gogo Formation. He heard how Panderichthys ( 370-360 million years) and Tiktaalik (375 million years) to a taxon that also includes the forerunner of the later land vertebrates ( tetrapods ).
The Plattenhäuter Mcnamaraspis kaprios was discovered in 1986 by Australian paleontologist John Long in the Gogo Formation and described in 1995 by him. These fish have cartilage rings in the oral region, proving that Placodermen have a close evolutionary relationship to sharks. Because of its spectacular features of about 25 cm long Mcnamaraspis was appointed Fossil Emblem of Western Australia.
In 2008, about 375 million years old copy of Placodermen Materpiscis attenboroughi was discovered in the interior of a well-preserved embryo was found with umbilical cord. At least some of Placodermen thus already showed viviparous.
In 2009 also an embryo and paired with a male specimen Klaspern and so that further features a reproduction by copulation at Placodermen were at another Plattenhäuter, the Arthrodiren Incisoscutum ritchiei, at a about 365 million year old female specimen described. Internal fertilization is therefore already emerged very early in the evolution of vertebrates.