Tribute to ArthurWeasley/Nobu Tamura It seems that he has left Wikipedia but is still uploading images under a new persona... oh well.

Invertebrates

Molluscs

A phylum of invertebrates with a shell and a fleshy "foot".

Orthoceras, a nautiloid.
Asteroceras, an ammonite.

Arthropods

Opabinia, an opabinid.
Opabinia, Version 2.
Anomalocaris, an anomalocarid.
Megarachne, a sea scorpion.
Mixopterus, a sea scorpion.
Stylonurus, a sea scorpion.
Pulmonoscorpius, a scorpion.

Chordates

Animals with a notocord. All the following groups of animals are chordates, but these chordates are not classified as vertebrates, and so are classified in the wastebasket taxon Invertebrates.

Pikaia, a probable lancelet.

Fish

Acanthodians

Acanthodes.
Climatius.

Placoderms

Coccosteus.
Dunkleosteus.

Chondoricthyes

Stethacanthus.
Otodus.

Osteicthyes

Sarcopterygans

Guiyu, an early sarcopterygan.
Ceratodus, a lungfish.
Holoptychius, a porolepiform fish.
Psarolepis, an onychodontiform fish.
Grossius, an onychodontiform fish.
Onychodus, an onychodontiform fish.
Osteolepis, an osteolepidid fish.
Gogonasus, an osteolepidid fish.
Eusthenopteron, an osteolepidid fish.
Panderichthys.
Tiktaalik.

Amphibians

Temnospondyls

Lepospondyls

Reptiliomorphs

Sauropsids

Anapsids

Diapsids

Archosauromorphs

Pterosaurs

Dinosaurs

Theropods

Gorgosaurus, an advanced tyrannosaurid.
Tyrannosaurus Rex
, an advanced tyrannosaurid.

Thyreophorans

Ornithopods

Hypsilophodon, currently stuck in a confusing taxonomic situation. Currently considered to be in a group with the most advanced "hypsilophodonts".
Rhabdodon, a rhabdodontid iguantodont.
Ouranosaurus, a hadrosauroid.
Corythosaurus, a lambeosaurine hadrosaurid.
Orolotitan
, a lambeosaurine hadrosaurid.
Tsintaosaurus, a lambeosaurine hadrosaurid.