Who is the closest living relative to the T-rex?
That's right, the chicken. In 2005, unfossilized tissue of the T-Rex was found, surprisingly still intact after 65 millions years. When scientists recovered the protein collagen from this tissue and ran it through their database, they found that the animal with the highest match was the chicken. Now, the sequence similarity between chickens and T-Rex was only 58%, so we are talking about relative similarities compared to other animals. It is hard to imagine what the two animals have in common, but this degree of similarity seems to imply that chickens and dinosaurs are more closely related than any other species on the planet.
What are the other candidates?
1) Birds
The general consensus amongst today's scientists seems to be that birds are in fact avian dinosaurs and have descended from a line of bird-like dinosaurs. Which dinosaurs? Maniraptoran dinosaurs can be identified by their wrist and forelimb structure, collar bone, sternum, and stiffened tail. They are the fleet-footed, small, feathered predators that we can identify in the picture above. Here is a list of the major similarities that we can find between birds and these dinosaurs:
2) Crocodiles
Logically, crocodiles would seem more closely related to dinosaurs than birds. They are both cold-blooded reptiles, and share the same rubbery skin, sharp teeth and claws. However, fossil and genetic evidence places crocodiles on the cladogram not after dinosaurs, but alongside them. They shared the same ancestor, the archosaur, but evolved on separate branches.
The general consensus amongst today's scientists seems to be that birds are in fact avian dinosaurs and have descended from a line of bird-like dinosaurs. Which dinosaurs? Maniraptoran dinosaurs can be identified by their wrist and forelimb structure, collar bone, sternum, and stiffened tail. They are the fleet-footed, small, feathered predators that we can identify in the picture above. Here is a list of the major similarities that we can find between birds and these dinosaurs:
- Elongated arms, forelimbs, and hands
- Large eye openings in the skull.
- Flexible wrist with a wrist bone.
- Hollow, thin-walled bones.
- 3-fingered opposable grasping hand,
- Short stiffened tail.
- S-shaped neck.
- Similar eggshell microstructure.
2) Crocodiles
Logically, crocodiles would seem more closely related to dinosaurs than birds. They are both cold-blooded reptiles, and share the same rubbery skin, sharp teeth and claws. However, fossil and genetic evidence places crocodiles on the cladogram not after dinosaurs, but alongside them. They shared the same ancestor, the archosaur, but evolved on separate branches.
Gaps in the fossil record between dinosaurs and birds have been pointed out, but no one can come up with a different hypothesis for the lineage of dinosaurs. Birds are by far the most likely candidate
Types of dinosaurs
We remember that the hierarchy of life is classified as species, genus, family, order, class, and so on. There are around 1000 plausible dinosaur genera that have been classified by scientists. Some important ones include ankylosaurs, cera-topsians, and dino-birds.