Efraasia has had a complicated
taxonomic history involving several genera and species. Material now known under
Efraasia first came to light after Albert Burrer,
Hofsteinmetzmeister ("Court master stonemason") at
Maulbronn, in 1902 began to exploit the
Weiße Steinbruch, a quarry near
Pfaffenhofen in
Württemberg. To reach the layer of hard white
sandstone Burrer wanted to use for his building projects a thick
overburden of softer
marl had to be removed. Many vertebrate fossils proved to be present in it. This
stratum was part of the
Stubensandstein Member of the lower
Löwenstein Formation, dating to the
Norian. From 1906 until 1914 when the quarry closed, Burrer donated the finds to
paleontologist Professor Fraas of the
königliche Stuttgarter Naturalienkabinett. A specimen of a basal sauropodomorph, SMNS 11838, was first described by
Friedrich von Huene in 1907–1908 and named as a new species of
Teratosaurus:
T. minor. At the time,
Teratosaurus was thought to be a
theropod dinosaur; it was only established as a
rauisuchian non-dinosaur in the 1980s. The
specific name referred to the fact that the specimen was smaller than
Teratosaurus suevicus. The fossils consisted of a few
vertebrae from the hip, the right hindlimb, and a
pubic bone. Elsewhere in the same publication he gave the name
Sellosaurus fraasi to a partial skeleton, SMNS 12188-12192, from slightly older rocks of the same formation, as a second species of his new genus
Sellosaurus (the genus is today considered to be a synonym of
Plateosaurus). In 1912,
Eberhard Fraas reported on two partial skeletons, SMNS 12667 and SMNS 12684 collected in 1909, which he assigned to a new species of
Thecodontosaurus:
T. diagnosticus. He would never describe them due to his failing health, and thus this name remained a
nomen nudum. Von Huene adopted the specific name years later, after Fraas' death, redescribing Fraas' specimens as
Paleosaurus (?) diagnosticus in 1932. The question mark indicates that von Huene considered the reference as provisional only. In 1959
Oskar Kuhn pointed out that the name
Paleosaurus Riley & Stutchbury 1836 was preoccupied and renamed the genus
Palaeosauriscus.
Allen Charig in 1967 was the first to use the combination
Palaeosauriscus diagnosticus for the German material. However, the new generic name was itself a junior homonym of
Palaeosauriscus fraserianus Cope 1878.
Peter Galton reassigned Fraas' specimens to the new genus
Efraasia in 1973, because
Palaeosaurus, apart from the homonymy problems, was a nondiagnostic tooth genus. The generic name was a contraction of "E. Fraas". The new species name combination thus became
Efraasia diagnostica. However, Galton and
Robert Bakker later (1985) recommended that
Efraasia be considered a
junior synonym of another
prosauropod,
Sellosaurus gracilis. In 2003,
Adam Yates published a study incorporating these and other fossils from the Late Triassic of Germany. He found that the "Sellosaurus" material fell into two clusters. One included the original
Sellosaurus gracilis, which he assigned to
Plateosaurus as
P. gracilis. The other included "Teratosaurus"
minor, "Sellosaurus"
fraasi, and "Palaeosaurus"
diagnosticus.
Efraasia was the oldest valid generic name for these fossils. The specific name could not be determined as simply, as both
Teratosaurus minor and
Sellosaurus fraasi had first appeared in von Huene's 1908 book. Because the former name had page priority, Yates chose
minor as the specific name, providing for the
type species Teratosaurus minor the new combination
Efraasia minor, which is thus the single valid species name of the
taxon. Apart from the specimens mentioned above, mostly consisting of rather complete skeletons preserved in large slabs, though not fully prepared from the rock matrix, several other fossils have been found. Together they allow for a good impression of what the animal looked like. ==Description==