Thecodontosaurus antiquus In the autumn of 1834,
surgeon Henry Riley (1797–1848) and the
curator of the
Bristol Institution,
Samuel Stutchbury, began to excavate "saurian remains" at the quarry of
Durdham Down, at
Clifton, presently a part of
Bristol, which is part of the
Magnesian Conglomerate. In 1834 and 1835, they briefly reported on the finds. They provided their initial description in 1836, naming a new genus:
Thecodontosaurus. The name is derived from Greek θήκή, '
, "socket", and οδους, ', "tooth", a reference to the fact that the roots of the teeth were not fused with the jaw bone, as in present lizards, but positioned in separate tooth sockets.
Thecodontosaurus was the fifth dinosaur named, after
Megalosaurus,
Iguanodon,
Streptospondylus and
Hylaeosaurus, though Riley and Stutchbury were not aware of this, the very concept of
Dinosauria only being created in 1842. In 1843, in his catalogue of British fossils,
John Morris provided a complete
species name:
Thecodontosaurus antiquus. The
specific epithet,
"antiquus", means "ancient" in
Latin. The original
type specimen or
holotype of
Thecodontosaurus, BCM 1, a lower jaw, fell victim to heavy
World War II bombings. Many remains of this dinosaur and other material related to it were destroyed in November 1940 during the
Bristol Blitz. However, most bones were salvaged: today 184 fossil bones are part of the collection of the
Bristol City Museum and Art Gallery. Later, more remains were found near
Bristol at
Tytherington. Currently about 245 fragmentary specimens are known, representing numerous individuals. In 1985,
Peter Galton designated another lower jaw, a right dentary, as the
neotype, BCM 2. The remains were found in a
breccia pocket resting on Carboniferous Limestone, probably the eroded remnants of a Triassic cave. There is no definitive evidence for the age of the deposits from which the original material came, but the geomorphological context of
Thecodontosaurus remains from Tytherington indicates that they are of late
Carnian age and in 1908
Friedrich von Huene named a
Thecodontosaurus cylindrodon. Though still defended by Michael Cooper in 1981, the hypothesis that such creatures existed has now been totally discredited. On one occasion, material of
Thecodontosaurus was, by mistake, described as a separate genus. In 1891,
Harry Govier Seeley named
Agrosaurus macgillivrayi, assuming the remains had been collected in 1844 by the crew of
HMS Fly on the northeast coast of
Australia. It was long considered the first dinosaur found in Australia, but in 1999 it was discovered that the bones probably belonged to a lot sent by Riley and Stutchbury to the
British Museum of Natural History and then mislabelled. In 1906, von Huene had already noted the close resemblance and renamed the species
Thecodontosaurus macgillivrayi. It is thus a
junior synonym of
Thecodontosaurus antiquus. Presently, the only valid species is thus
T. antiquus.
Misassigned species •
Thecodontosaurus latespinatus von Huene, 1907-08 =
Tanystropheus •
Thecodontosaurus primus von Huene, 1907-1908 = indeterminate archosauromorph, previously and questionably referred to
Protanystropheus •
Thecodontosaurus elizae Sauvage, 1907 •
Thecodontosaurus gibbidens Cope, 1878 =
Galtonia •
Thecodontosaurus skirtopodus (Seeley, 1894) =
Hortalotarsus •
Thecodontosaurus polyzelus (Hitchcock, 1865) von Huene, 1906 •
Thecodontosaurus hermannianus von Huene, 1908 •
Thecodontosaurus diagnosticus Fraas, 1912 =
Efraasia •
Thecodontosaurus minor Haughton, 1918 •
Thecodontosaurus dubius Haughton, 1924 •
Thecodontosaurus browni (Seeley, 1895) von Huene, 1932 •
Thecodontosaurus alophos Haughton, 1932 =
Nyasasaurus Thecodontosaurus caducus was named by
Adam Yates in 2003 for a juvenile specimen found in
Wales; in 2007 this was made the separate genus
Pantydraco. However, Ballell, Rayfield & Benton (2020) considered
Pantydraco caducus to be a taxon of uncertain validity, and considered it possible that it might represent a juvenile of
Thecodontosaurus antiquus. ==Description==