Dinosaur Evolution: A Journey from Tetrapod to Bird

Xenotaris

Okay before I get in to direct Dinosaur evolution I must first weave the tale of how these guys came along, okay lets start with the Fish that crawled out of the water otherwise it would be a drag explaining the evolution of fish.

Okay along time ago back around the Devonian time, a group of Lobe-fin fishes gradually evolved lungs and slowly crawled out of the water on to land to possibly escape from hungry predators.

These fish became the first Tetrapods or Amphibians, millions of years later and millions of generations later prototreptile amniotes then evolve from Reptiliomorph amphibians during the Carboniferous peroid, officially around the Pennsylvanian Epoch but it is possible they could of appear in the Mississippian epoch.

Animotes later diverged in to two clades: Synapsids (Mammal-like Reptiles and later Mammals) and Sauropsida (Classic Reptiles).

Now since we are going in to later dinosaur evolution we can mark out the Synapsids from the discussion since that would be a topic for a later time.

Sauropsida is then divided into Parareptilia (at the side of reptiles) and Eureptilia (True Reptiles)

Eureptilia later gives rise to several lizard-like early reptiles and then the clade Romeriida evolves which will give rise to Diapsid reptiles (Modern Reptiles and their extinct relatives)

Diapsid Reptiles would evolve in to several primitive forms before two notable clades would eventually win out so to speak. Lepidosauromorphs (Snakes, lizards, Tuatara, and their extinct relatives like mosasurus) and Archosauromorphs (Ruing Reptiles). Pantestudines in my opinion belongs with Archosauromorph due to DNA and Fossil record backing. This ends the Permian peroid.

Archosauromorphs, now where getting closer. After several basal clades we finally get Archosauriformes. Most Archosauriformes roughly resembled crocodiles if more lightly armored to barely armored but lets flash forward to the clade of Archosauria; seeing as the other Archosauriformes are no long relevant to this topic. Which happens mostly in the Early Triassic.

Archosauria can be divided in to two super clades: Avemetatarsalia/Ornithodira and Pseudosuchia (Crocodilans and their extinct relatives like the Rauisuchians)

Avemetatarsalia also known as Ornithodira or Pan-Aves is the clade that holds the Pterosauromorphs and the Dinosauromorphs.

Dinosauromorphs clade contains all Dinosaur clades including modern birds and their extinct relatives. Dinosauromorphs that were closer related to true Dinosaurs were Dinosauriformes while Non-dinosaurian dinosaurmorphs belong to Lagerpetids.

Dinosauriformes housed several dinosaur-like forerunners but the most developed group besides the dinosaurs themselves were the Silesaurids. These creatures appeared roughly in the Middle Triassic.

And now we finally arrived to the clade Dinosauria which itself is broken up in to two major clades: Ornithischia (Bird-hip Dinosaurs) and Saurischia (Lizard-hip Dinosaurs) both arrived in the Late Triassic.

Ornithischia can be splitted up in to three primary clades: Ornithopods (basically beaked bipeds and duckbills), Thyreophora (Plated and armored dinosaurs with attack tails), and Marginocephalia (Head Armored Dinosaurs)

Saurischia is simply divided in to two clades: Sauropodomorphs (Long Necked herbivores) and Theropods (Bipedal Carnivores, later some beaked long necked bipedal herbivores, and birds)

The earliest members of Saurischia were fairly theropod-like but we do know the earliest members of each clade. Eoraptor long suspected to be a primitive theropod or even a basal Saurischia is now thought to be a primitive sauropodomorph along with the similar Guaibasaurids while Eodromaeus snags the spot of the Eoraptors previous position as an early theropod along side the slightly more advanced Herrerasaurids.

Xenotaris

Several Theropod groups arose in the later epochs of the Triassic like Coelophysis, Liliensternus, Zupaysaurus, and Dilophosaurids (whose famous members Dilophosaurus and Crylophosaurus appear in the early Jurassic but were very much a triassic Theropod)

In the early Jurassic another clade of theropod evolved from primitive Triassic theropods possibly sharing a common ancestors with the aforementioned early Dilophosaurids. the Averostra which are divided in to Ceratosaurs and the Tetanurae.

Tetanurae eventually lead to two more larger clades: Megalosauroidea (Megalosaurids, Spinosaurids, and Monolophosaurus) and Avetheropoda.

Avetheropoda is divided in to: Carnosauria (Allosaurids, Carcharodontosaurids, and Neovenatorids) and last but not least Coelurosauria.

Coelurosauria is divided in to several groups: Primitive Coelurosauria and Tyrannoraptora.

Tyrannoraptora is then divided in to Tyrannosauroids, Compsognathids, Maniraptoriformes, and basal/primitive Tyrannoraptorans.

Maniraptoriformes are then divided in to Ornithomimosauria, Maniraptora, and basal Maniraptoriformes like Fukuivenator.

Maniraptora is divided in to Alvarezsauria, Therizinosauria, Pennaraptora, and basal Maniraptorans.

Pennaraptora is then divided in to Oviraptorosauria, Paraves, and basal Pennaraptorans.

Paraves is then divided in to Scansoriopterygids, Eumaniraptora, and basal Paraves.

we are almost at the end, Eumaniraptora can be divided in to Dromaeosaurids (like Utahraptor, Veloicraptor, and Microraptors) and Averaptora which is divided in to Troodontids and Avialae (True Birds: Both basal and modern)

Darth Shiro

Thanks for making my suggestion Xenotaris!

Darth Shiro

We should gather all of the Dinosaur experts here.

Xenotaris

Avialae is then divided into Euavialae (True winged Birds) and basal Avialae.

Euavialae eventually leads to the clade Avebrevicauda (Short tailed Birds) which then leads to Pygostylia which divides in to Omnivoropterygids, Confuciusornithiformes, Ornithothoraces, and other basal Pygostylia.

Ornithothoraces are then divided up in to Enantiornithes and Euornithes.

Euornithes later evolves in to the clade Ornithuromorpha, which later down the evolutionary road leads to Ornithurae which is divided between basal Ornithurae and the more advanced Neornithes (Modern Birds) which is divided into two clades: Palaeognathae and Neognathae.

Neognathae is further divided:

Galloanserae 

^

[Galliformes (pheasants, turkeys, peacocks, and fowls=chickens), 

Anseriformes (Ducks, Swans, Geese)]

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Neoaves 

^

[Phoenicopteriformes (Flamingos and their relatives), 

Podicipediformes (Grebe and their relatives), 

Columbiformes (Pigeons and doves), 

Mesitornithiformes (Mesite), 

Pteroclidiformes (Sandgrouse), 

Apodiformes (Swifts, Tree Swifts, and Humming Birds), 

Caprimulgiformes (Oilbirds, Nightjars, Frogmouths, potoos, and Nighthawks), 

Cuculiformes (Cuckoo), 

Otidiformes (Bustards, including floricans and korhaans), 

Musophagiformes (Turaco), 

Opisthocomiformes ( Hoatzin), 

Gruiformes (Cranes, Crakes, and Rails), 

Charadriiformes (Waders, Gulls, and Auks), 

Gaviiformes (loons or divers and their closest extinct relatives), 

Procellariiformes (Petrels), 

Sphenisciformes (Penguins), 

Ciconiiformes (Storks), 

Suliformes (Frigatebird, Gannet, Booby, Cormorant, Shag, and darters), 

Pelecaniformes (Pelicans), 

Eurypygiformes (Kagus and Sunbitten), 

Phaethontiformes (Tropicbird), 

Accipitriformes (Bird of Prey: Hawks, Eagles, Harriers, Osprey, Buzzards, Old World Vultures, Kites, and Secretarybirds), 

Strigiformes (Owls), 

Coliiformes (Mousebird), 

Leptosomiformes (Cuckoo roller), 

Trogoniformes (Trogons and Quetzals), 

Bucerotiformes (Hornbills, Hoopoe and Wood hoopoes), 

Coraciiformes (Kingfishers, the Bee-eaters, the Rollers, the Motmots, and the Todies), 

Piciformes (Woodpeckers and close relatives), 

Cariamiformes (Seriema), 

Falconiformes (Falcons and Caracaras), 

Psittaciformes (Parrots), 

Passeriformes (Sunbird, Crovids, Jays, Sparrows, Weavers)

Xenotaris

sorry for the long list was jotting out all the bird groups, LOL

Darth Shiro

Lol ok!

Darth Shiro

Also Eagles are related to which dinosaurs?

Xenotaris

read the evolution chart I made. 

Darth Shiro

Ok.

Xenotaris

All Birds belong in Paraves which they share with Troodons and Dromaeosaurids like Velociraptor, Utahraptor, and Microraptors

Darth Shiro

Thanks.

Xenotaris

I will later discuss more on individual Theropod linages, my personal favorite are the Dromaeosaurids, Tyrannosauroids, and the Dilophosaurids

Darth Shiro

Nice i will follow your lists and i will ask GG to feature it! You know we could work together on discussions! PM me if you want to. Also what's your favourite Dinosaur? Mine is Spinosaurus.

Xenotaris

Well I love all Dinosaurs but my favorite is Dilophosaurus and it turned out to be the cornerstone of theropod evolution.

Xenotaris

Its the dinosaur I've been using in most of my posts.

Darth Shiro

Yup! I sent a PM to GG asking him to feature this btw.

GG

Still have not admitted that chickens and T.rex are the closest in DNA though.

Darth Shiro

.........rlly

Xenotaris

Why? My Evolution chart is based on fossil evidence. A Chicken is a bird there for it would be a relative to Dromaoesaurus "ie Utahraptor and Velociraptor" and Troodons. Tyrannosauruses broke away early in Bird evolution to the point they had little to no direct relations to Birds. Also if Chciekns and T. rexes were identical then a chicken would look exactly like a tyrannosaurus if there DNA were similar. Your DNA is your biological blue print, Chickens might have T. rex proteins but they are still closer related to Raptors I'm sorry dromaeosaurs than a darn Tyrannosauroid!

Xenotaris

Not to mention dromaoesaurids ie Utahraptors and Velociraptors had more bird features than any tyrannosauroid aside from feathers but it seems that most dinosaurs were covered in some sort of feather covering except the Dromaosaurids, Troodontids, and Birds have flight feathers and had powered flight/glide.

I Meme Everything

Well yes, dromaeosaurids are the closest to birds.

Sci-Fi King25

Thanks for sharing this with us. :) I like all the details about how dinosaurs evolved.

Xenotaris

Your welcome, Dinosaurs are my passion.

GG

^We can all agree on dinosaurs being our passion.

Alright man, hey I'm just stating what paleontologists and news websites have reported. It is indeed your view against the rest of the World. Although your view makes a good deal of sense. Based on the blood vessel they found of the Tyrant King--chicken shares the most similarities to T.rex, closer than any other bird. Therefore, it is its closest living relative.

Xenotaris

Actually I found some sights that said that Chickens  and their relatives are just more basal theropod like not exactly being part T. rex

Darth Shiro

So they may be part raptor too?

Xenotaris

Chickens being a member of the modern bird clade/group shares a close common ancestor (its closests relative) to Dromaosaurids (Raptors) and Troodons. The Chicken does not share a common ancestor with Tyrannosaurids, it does share a distant common ancestor with Tyrannosauroids but so do all Coelurosaurians.

Xenotaris

Now I would like to move on to Tyrannosaurus evolution. The early basal Tyrannosauroids belong to a subclade called Proceratosaurids it was called this back when scientists used to think they were primitive ceratosauruses. Now Proceratosaurids have been reclassified as early Tyrannnosauroids rather than basal Ceratosaurids. Tyrannosauroids are a clade of animals that include basal Tyrannosauroids like Dilong and Guanlong, as well as the advanced Tyrannosauroids, the ever popular Tyrannosaurids with Tyrannosaurus rex as its crowning member.

Now early Tyrannosauroids like Dilong and Guanlong may have been somewhat raptor-like but only because they are both Coelurosaurians and they occupied a similar niche to larger dromaeosaurids but unlike the later dromaoesaurids, these basal tyrannosauroids lacked flight feathers as they were only covered in protofeathers and unlike the latter dromaoesaurids they couldn't glide or had power flight; a trait that defines paravians such as Dromaoesaurids, Troodontids, and Avians but not the Tyrannosauroids.

Other basal Tyrannosauroids include Juratyrant, Proceratosaurus, Sinotyrannus, and Yutyrannus. Later we start seeing more advanced Tyrannsauroids such as Eotyrannus, Raptorex, Bagaraatan, Alectrosaurus, Appalachiosaurus, and Alioramus before proper Tyrannosaurids make an appearance.
Now we are on to the Tyrannosaurids, we have the basal Gorgosaurus and Albertosaurus and the more advanced Tyrannosaurians such as Daspletosaurus, Teratophoneus, Bistahieversor, Lythronax, Tarbosaurus, Zhuchengtyrannus, and finally Tyrannosaurus.

Darth Shiro

Interesting! I love this post we should gather Dinosaur fans here.

Xenotaris

Indeed