Reptiles
The group of vertebrates most closely related to birds are probably the dinosaurs.
The group of vertebrates that are most closely related to birds is reptiles.
Phylum Chordata: Subphylum Cephalochordata and Urochordata along with the subphylum Craniata
Birds.
The group of fishes most closely related to ancestral amphibians are the lobe-finned fishes, which include the coelacanths and lungfishes. These fishes share certain characteristics with amphibians, such as limbs with digits and lungs or lung-like structures, indicating a close evolutionary relationship.
none.birds are the most numerous.
fish is a type of animal. Same with birds.
The closest living relatives of dinosaurs are birds.
Bony Fishes
Dinosaurs most resemble birds and reptiles but mainly birds because birds evolved from dinosaurs.
Mammals are most familiar vertebrates .
Former Answer by some dummy: "The most diverse group is insects, which belong to the group ARTHROPODA*.*Arthropoda-Largest and most diverse animal phylum, mostly insects."This answer is completely wrong based on the question.Arthropods are invertebrates! They are the most numerous INvertebrates.The most diverse vertebrates are BONY FISH.