Gracilisuchus —
slender, long (one) [L.
gracilis = slender; Gk.
sυchnós (via irregular derivation) = long] is an
extinct genus of tiny (30 cm long)
pseudosuchian (a group which includes the ancestors of
crocodilians) from the
Middle Triassic. It is placed in the clade
Suchia, close to the ancestry of
crocodylomorphs.
Gracilisuchus was thought to be a
dinosaur, but this hypothesis has since been rejected. Its fossils were first discovered in the 1970s. Many features in the hindlimbs of
Gracilisuchus are also found in a group of primitive crocodylomorphs called
sphenosuchians. Sphenosuchians are usually considered a
paraphyletic chain of successively primitive crocodylomorphs, but the features they share in common with
Gracilisuchus suggest Sphenosuchia and
Gracilisuchus may form a
monophyletic grouping, or valid
clade, of crocodylomorphs. A recent paper places the genus in the new family
Gracilisuchidae, along with the genera
Turfanosuchus and
Yonghesuchus near the base of the Suchia.
