Diplodocids

Diplodocids are a family of very long, whip-tailed sauropod dinosaurs that lived during the Late Jurassic period. They are part of the larger group Sauropoda and include some of the longest land animals known, notably Diplodocus and Barosaurus, as well as Apatosaurus and Brontosaurus in some classifications.

They are characterized by extremely elongated necks and tails, a relatively slim build, and skulls that were small in proportion to the body. Their teeth were peg-like and confined to the front of the jaws, suited for stripping vegetation.

Most diplodocids were quadrupedal, though their long necks could be held high or low; their low-slung, heavy hindquarters and long tails suggest a dynamic but stable gait. They were herbivores, feeding on vegetation available at low- to mid-height; the exact height of browsing varies among species, but their skulls indicate they did not chew with the robust, shearing bite of some other sauropods.

The tail was long and may have functioned as a counterbalance or, in some interpretations, as a whip-like defense, though this is debated.

Taxonomically, the family Diplodocidae is divided into subfamilies Diplodocinae (including Diplodocus and Barosaurus) and Apatosaurinae (including Apatosaurus and Brontosaurus). Fossils are primarily from the Late Jurassic Morrison Formation of western North America, with additional material from elsewhere.

Diplodocids reached lengths of about 20 to 30 meters and weights of tens of tons. Their fossils have helped establish the image of the classic long-necked sauropod of the Jurassic.