Chirotherium

Chirotherium Temporal range: 245–205 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Cheirotherium trace fossil, displayed in Oxford University Museum of Natural History
Trace fossil classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Archosauria
Clade:	Pseudosuchia
Ichnofamily:	†Chirotheriidae
Ichnogenus:	†Chirotherium Kaup, 1835
Type ichnospecies
†Chirotherium barthii Kaup, 1835
Ichnospecies
†Chirotherium barthii Kaup, 1835 †Chirotherium sickleri Kaup, 1835 †Chirotherium stortonense Morton, 1863 †Chirotherium vorbachi Kirchner, 1927 †Chirotherium beasleyi Peabody, 1948 †Chirotherium moquinense Peabody, 1956 †Chirotherium rex Peabody, 1948 †Chirotherium lulli Bock, 1952 †Chirotherium wondrai Heller, 1952 †Chirotherium swinnertoni (Sarjeant, 1970) †Chirotherium courelli DeMathieu, 1970 †Chirotherium atlensis Biron & Dutuit, 1981 †Chirotherium mediterraneum DeMathieu & Durand, 1991
Synonyms
Chirosaurus Kaup, 1835 Cheirotherium Sickler [de], 1836 Cheirotherion Nopcsa, 1923 Krokodilipus Nopcsa, 1923 Saurichnites Kirchner, 1927

Chirotherium, also known as Cheirotherium (‘hand-beast’), is a Triassic trace fossil consisting of five-fingered (pentadactyle) footprints and whole tracks. These look, by coincidence, remarkably like the hands of apes and bears, with the outermost toe having evolved to extend out to the side like a thumb, although probably only functioning to provide a firmer grip in mud. Chirotherium tracks were first found in 1834 in Lower Triassic sandstone (Buntsandstein) in Thuringia, Germany, dating from about 243 million years ago (mya).

The creatures who made the footprints and tracks were probably pseudosuchian archosaurs related to the ancestors of the crocodiles. They likely belonged to either prestosuchidae or rauisuchidae groups, which were both large carnivores with semi-erect gaits.