There are three subgroups in Diplodocoidae: Diplodocids, Rebbachisaurids, and Dicraesaurids.
As evidenced both by Diplodocus from WWD and Apatosaurus from Ballad of Big Al, diplodocoids were realtively low-slung animals, with long necks and tails stretched vertically, rather than horizontally, as in other sauropods. Their heads were long, slender and light weight, allowing Diplodocus and others to stretch and stick their necks and heads far into forests, while the rest of the bulky body stayed outside the trees.
Also, diplodocoids had long and whip-like tails that they used against such predators as Allosaurus - strikes from such tails could knock the attacker prone, stun it, or even kill. Also, unlike the Macronarians, Diplodocus and its relatives could stand up on their hind legs, either to reach a particularly tall tree, to knock it down with their weight, or to squash a predator.Finally, the vertebrae over hips in the females of this taxon fused as they matured, in order to endure the weight of a male during a mating.
Diplodocoids also have neural spines sticking out of the vertebrae, and depending on the genus, theses spines may form quills, small sails or humps.
in Walking with seriesEdit
Diplodocus was the main character of this episode. Time of the Titans depicted the life of a female Diplodocus from her birth to sexual maturity. She survived Ornitholestes attacks, a wild fire and Allosaurus attacks. She also mated and probably became a mother when the episode ended.
This WWD special featured Apatosaurus in the background. It also showed Big Al and other allosaurs successfully attacking and bringing down a sick Diplodocus on a salt plain.