Were the dinosaurs closer to birds or reptiles?

Birds are literally a type of dinosaur (there is nothing distinctive about them to set them apart - just as bats are mammals, birds are dinosaurs). And dinosaurs are reptiles. (Yes, birds are reptiles, too). Phylogenetics has changed our understanding of how animals relate to one another. read more

And dinosaurs are reptiles. (Yes, birds are reptiles, too). Phylogenetics has changed our understanding of how animals relate to one another. It’s based on species having a common ancestor, rather than on their bone structure, appearance, or physiology. Genetically, birds descended from reptiles, and therefore are reptiles. (Turtles are probably closer to crocodiles and birds than to lepidosaurs, their placement is still in debate, hence the dotted line here). read more

So a reptile is any animal descended from the original group called reptiles, and birds (as well as mammals) would be reptiles. Usually what people mean when they say birds are reptiles is that birds are more closely related to reptiles than anything else, and this is true in a way, but there are many types of reptiles. read more

Crocodilians (and pterosaurs) are/were reptiles. Their legs do not go straight down to the ground. Dinosaurs, mammals and birds are/were not reptiles. Look at their legs. Birds are certainly closer to dinosaurs than reptiles/mammals. And dinosaurs were closer to birds than reptiles/mammals. Whether bird and dinosaur categories are separated is arbitrary. read more