Final answer:
The characteristic feature of iguanodontids is a long, horse-like snout. They had distinct peg-like teeth for grinding plants and limbs adapted for bipedal locomotion, differing from equal limb length, clawed hands, or large tusks.
Step-by-step explanation:
Characteristic features of iguanodontids include a long, horse-like snout. Iguanodontids were a diverse group of herbivorous dinosaurs known for their unique physical characteristics. These creatures were distinct for their peg-like teeth suited for grinding plant material and their elongated snouts that resemble that of a horse.
They were not characterized by having clawed hands, as their hands ended in hoof-like structures with a spike-like thumb for defense. Their forelimbs and hind limbs were not of equal length; instead, they were adapted for bipedal locomotion, with the rear limbs being more robust and longer for walking or running. Additionally, iguanodontids did not possess large tusks; instead, their dentition was more specialized for an herbivorous diet.
Examining fossils and reconstructions provides us with insight into their adaptation, where their anatomy hints at efficient movement and feeding strategies. The recognition of these features is crucial for paleontologists when identifying and classifying dinosaur species from fossil remains.