Introduction

For the next 365 days, I will post a dead bird lizard (colloquially known as "dinosaurs") every day. These will not be in any particular order and do not represent every known genus or species. Megalosaurus will be the first, however, since it was the first to be scientifically described.

Some things to remember: Late Triassic (237 million years ago - 201 million years ago) / Early Jurassic (201 million years ago - 174 million years ago) / Middle Jurassic (174 million years ago - 161 million years ago) / Late Jurassic (161 million years ago - 143 million years ago) / Early Cretaceous (143 million years ago - 100 million years ago) / Late Cretaceous (100 million years ago - 66 million years ago)

• "Basal" = primitive animal or trait in comparison to derived animals or traits. More similar to shared ancestors.
• "Derived" = advanced animal or trait in comparison to basal animals or traits. More removed from shared ancestors.
• "Theropod" = bipedal and mostly, though not always, carnivorous dead bird lizards. Live bird non-lizards of today belong to this group.
• "Sauropod" = quadrupedal, long-necked herbivorous dead bird lizards.
• "Ornithopod" = ancestrally bipedal, later both quadrupedal and bipedal herbivorous dead bird lizards. "duck-billed" hadrosaurs belong to them.
• "Thyreophoran" = quadrupedal, heavily armored dead bird lizards (ankylosaurs and stegosaurs).
• "Ceratopsian" = originally bipedal, later mostly quadrupedal, large-headed and horned dead bird lizards (Triceratops and kin).

Despite calling them "dead bird lizards", dead bird lizards aren't true lizards. True lizards belong to the order Squamata, which they share with snakes. Dinosaurs belong to a group called the Archosauria, which they share with modern crocodiles. The pigeon who shit on my head when I was a child is closer phylogenetically to crocodiles than crocodiles are to my pet iguana Devin and I tried to exhume after its death.