What are sauropods and theropods?

Two distinctly different groups are traditionally included in the saurischians—the Sauropodomorpha (herbivorous sauropods and prosauropods) and the Theropoda (carnivorous dinosaurs). These groups are placed together on the basis of a suite of features that they share uniquely.

How are sauropods and prosauropods similar?

Sauropods generally grew to very large sizes, had long necks and tails, were quadrupedal, and became the largest animals to ever walk the Earth. The “prosauropods”, which preceded the sauropods, were smaller and were often able to walk on two legs.

Are sauropods bipedal?

Sauropods evolved from some sort of prosauropods (more properly ‘basal sauropodomorphs’) in the Late Triassic. Prosauropods, like all basal dinosaurs, originally walked on their hind legs only (bipedal), and the origin of sauropods thus entailed the transition from a bipedal gait to a quadrupedal gait.

How many toes did sauropods have?

They had tiny heads, massive bodies, and most had long tails. Their hind legs were thick, straight, and powerful, ending in club-like feet with five toes, though only the inner three (or in some cases four) bore claws.

Which of the following are defining characteristics of sauropods?

Sauropods had very long necks, long tails, small heads (relative to the rest of their body), and four thick, pillar-like legs. They are notable for the enormous sizes attained by some species, and the group includes the largest animals to have ever lived on land.

Where would you find the Gastralia in a dinosaur?

ventral abdominal wall
Gastralia are dermal ossifications situated in the ventral abdominal wall. Gastralia may be plesiomorphic for tetrapods, but are only retained in extant Crocodylia and Sphenodon, and possibly as part of the chelonian plastron.

What are some of the similarities and differences between Ornithischians and Saurischians?

Saurischians and ornithischians are the two groups of dinosaur, defined in terms of pelvic structure. Saurischians, whose name means “lizard-hipped,” had a pelvic structure more similar to that of modern lizards, while the ornithischians (“bird-hipped”) had a pelvic structure more like modern birds.

What did sauropods look like?

Sauropods shared a body plan consisting of: a small head on an extremely long neck; a long, massive body housing an enormous gut; thick pillarlike legs to support the torso; and a very long, tapering, often whiplike tail.

Why do sauropods have small heads?

Tiny head, long neck Thus free from this constraint, sauropods were able to evolve relatively small heads that required far less energy to carry and to move around, thus allowing necks to elongate and feeding envelopes – the amount of food (“browse”) that an animal can reach without having to walk – to increase.

What are the characteristics of Sauropodomorpha?

Sauropodomorpha are distinguished by leaf-shaped tooth crowns, a small head, and a neck that is at least as long as the trunk of the body and longer than the limbs. Most generalized of the Sauropodomorpha were the so-called prosauropods.

Are prosauropods the ancestors of the giant sauropods?

Footprints generally attributed to prosauropods appear to substantiate both forms of locomotion. Prosauropods have long been seen as including the first direct ancestors of the giant sauropods, probably among the melanorosaurids.

What are the different types of sauropods?

Sauropod skulls were of several main types, including the high, boxy Camarasaurus type (often incorrectly associated with Apatosaurus); the shoe-shaped Brachiosaurus type, with its large, delicately arched nasal bones; and the low, narrow, streamlined, almost horselike Diplodocus type.

What is the taxonomic classification of the theropods?

They are generally classed as a group of saurischian dinosaurs, though a 2017 paper has put them in a proposed clade Ornithoscelida, along with the Ornithischia. Theropods were ancestrally carnivorous, although a number of theropod groups evolved to become herbivores, omnivores, piscivores, and insectivores.