The prehistoric arthropods of the land are Myriapoda (“countless feet”): a gigantic millipede, Arthropleura; a millipede relative, a pauropod; and a predatory centipede. Myriapods were the first land animals. They breathed air in and out through spiracles, which are holes … Continue reading →

The extinct arthropods of the water are chelicerates: a eurypterid, Hughmilleria; a Stylonurid eurypterid; and an early horseshoe crab, Lunataspis. Eurypterids walked on legs and swam with paddles. They also had chelicerae (“claw horns”), which were claws by their mouths that helped them … Continue reading →

The sauropsids of the water are a Plesiosaurus, a Pliosaurus, and an Odontochelys, an early turtle relative. Early in the Mesozoic Era, several sorts of lizard-like sauropsids swam and hunted in the water. While some lines of sauropsids led to … Continue reading →

The arthropods of the air are flying insects, a cockroach, Aphthoroblattina; a butterfly, Prodryas; and a dragonfly relative, Meganeura. Over 300 million years ago, insects appeared that could lay their eggs on land they could fold their wings behind them, … Continue reading →

In Clades: Prehistoric, the sauropsids of the land are dinosaurs, specifically a feathered Utahraptor (a theropod), an Apatosaurus (a sauropod), and a Stegosaurus (an ornithischian). The earliest dinosaur precursors were two-legged relatives of crocodiles, as were the first theropods, sauropods, … Continue reading →

In Clades, sauropsids of the air are represented by birds. Today’s birds all descend from a species of flying theropod dinosaur that lived before the Cretaceous-Tertiary extinction event of 70 million years ago. Unlike today’s common birds, these early birds … Continue reading →

The arthropods of the air are the clade Pterygota (“winged”), known as “winged insects” and represented here by a bee, a praying mantis, and a dragonfly. The bee represents Endopterygota (“inner winged”), the massively successful clade of insects that undergo … Continue reading →

In the Clades game, the arthropods of the land are represented by tetrapulmonates (“four-lungs”), specifically an orb-weaver spider, a tarantula, and an amblypygid. Tetrapulmonates evolved from one line of trigonotarbids, the first arachnids adapted to air-breathing (about 400 million years … Continue reading →

The arthropods of the water are a crab, a lobster, and a woodlouse, together representing the most recognizable branch of crustaceans, the malacostracans. Lobsters and their relatives are distinct from other crustaceans in that mothers incubate their eggs, which are … Continue reading →