The smallest dinosaur was Saltopus.Saltopus elginensis is considered to be
Saltopus
Scotland's oldest dinosaur. It was discovered by chemist William Taylor, but was donated to the Natural History Museum in London. It was a very little bipedal reptile, roughly 23 inches (60 centimeters) long, discovered in Scotland. It was a late Triassic carnivore and it may have weighed in at approximately two pounds (one kilogram), and had five-fingered hands and a long head with dozens of sharp teeth. None of this can be recognized for certain, as Saltopus is known only from very poor fabric (mostly hind limb fragments).
As small as it was, its carnivorous diet must have consisted first and foremost of scavenged carcasses or insects. It has been variously recognized as a saurischian (lizard-hipped) dinosaur; a theropod (a fast-moving bipedal carnivore with clawed digits and hands on the forelimbs); and a close family member of the Herrerasaurus of the Herrerasauria infraorder, but its taxonomy is in argument because only fragmentary remains have been recovered. It may also have been a lagosuchid (a primitive reptile from which the dinosaurs arose) or an ornithosuchian (closely connected cousins of dinosaurs) instead of a true dinosaur. It has also been optional that the supposed Saltopus remains may, in fact, be incomplete remains of some already-identified animal.