Phylogenetic tree of vertebrates

1

Myxinoidea

2

Petromyzontia

3

chondrichthyes

4

atinopterygii

5

actinistia

6

dipnoi

7

amphibia

9

mammalia

9

testudinata

10

lepidosauria

11

crocodylia

12

ornithischia (stegosaurus, triceratops)

13

sauropodomorpha (apatosaurus)

14

theropoda (tyrannosaurus oviraptor)

15

aves

16

osteostraci (primitive jawless “fishes”)

17

placodermi (early jawed fishes)

18

labyrinthodontia (first amphibians)

19

cotylosauria (stem reptiles)

20

thecodontia (stem of ruling reptiles)

21

saurishia

22

therapsida (mammal-like reptiles)

23

sister group (closest relative. Go to first node + read all taxa above this point)

24

branch = lineage

25

node = hypothetical common ancestor