Jurassic Period

Saurischian Dinosaurs

In general, what characteristics determine if a dinosaur skeleton is that of a theropod?

There are many unique skeletal characteristics paleontologists use to determine if certain dinosaur bones belong to a theropod. In general, here are a few of the characteristics:

  1. The bone in front of the eye (lacrimal) extends onto the top of the skull.

  2. The lower jaw has an extra joint.

  3. The shoulder blade (scapula) is strap-like.

  4. The upper arm bone (humerus) is less than half the length of the upper leg bone (femur).

  5. The elongated hand has lost (or has shrunken) two outer fingers.

  6. The top of the bones in the palm of the hand (metacarpals) has pits where ligaments were attached.

  7. The fingers have elongated bones between the second-to-last and last joints.

  8. Near the head of the upper leg bone (femur) is a shelf-like ridge for the attachment of muscles.


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