Struthiomimus
by Cael H.
Struthiomimus is a dinosaur much like an ostrich. Struthiomimus is a very bird-like dinosaur, but there are several things that point to Struthiomimus going down convergent evolution with birds. Convergent evolution is when two animals were tempered by the same climate, and evolved many similar adaptations. Struthiomimus is moderately related to birds. It is a theropod, and it is a coelurosaur (an adaptation of longer arms). The Struthiomimus also has a toothless beak, which makes it seem as if Struthiomimus is more closely related to birds than deinonychus. However, it doesn't have the semilunate carpal (a bone in the wrist allowing better grasping, and eventually flying) unique to the maniraptors (including birds, archaeopteryx, and deinonychus).
Struthiomimus is twice the height of a full grown man and lived in forests. It is agile, and its ankle has virtually turned into a backwards knee, giving it the advantage of both a frontward facing knee and a backwards facing knee. Struthiomimus most likely had proto feathers. An interesting fact about Struthiomimus is that paleontologists have never found footprints of Struthiomimus running, only walking. This means that it is unknown how fast Struthiomimus could run. Although, from the bones, scientists speculate that it could run eighty miles an hour. Struthiomimus is an omnivore. It ate just about anything it could find, and using its hand and feet claws, it hunted other dinosaurs, the then larger insects, and leaves off of branches.
Struthiomimus' ancestor is the first vertebrate, which means that the animal had a backbone and a skull. The first vertebrate's descendants then evolved to be gnathostomes, which means they had a jaw. Their descendants evolved to be tetrapods, which means they had four limbs. Their descendants evolved to be amniotes, which means they could lay watertight eggs. The amniotes' descendants then evolved to be sauropsids, which means they have two holes in their palate. The sauropsids then evolved into dinosaurs, which means that they have a hole in the hip bone, allowing them to walk upright. The dinosaur then evolved to be a saurischian, which means the dinosaur has a frontward facing pubis bone, a grasping hand, asymmetrical fingers, and a long, mobile neck. The saurischian dinosaurs then evolved to be theropods: three toed, hollow boned saurischians.
According to our cladogram, Struthiomimus is most closely related to the deinonychus, archaeopteryx, and seagull. The most advanced trait shown on our cladogram they share is being theropods. The greatest difference between them is a bone in the wrist called semilunate carpal. It allows better grasping motion for earlier maniraptors, and is the key for flight in later maniraptors, including seagulls. To find out what animal is most closely related to Struthiomimus, I found the node that represented the most advanced trait of Struthiomimus, and any animals on the pathway going the other way from the same node, are the animals most closely related to Struthiomimus. To figure out what the most advanced common trait between Struthiomimus and the animals most closely related to it, I just used Struthiomimus's most advanced trait (the node below Struthiomimus, closest to Struthiomimus, on the path to Struthiomimus) shown on the cladogram. To know what the most important difference between Struthiomimus and its closest relatives, I simply followed the path that the most closely related to Struthiomimus animals were on, and the node that showed up first was the largest difference.
Last updated April 7, 2007.