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 did not perch in trees. Four bird lineages survived the extinction event that wiped out the other dinosaurs. One surviving lineage led to today’s ostriches and their close relatives (Paleognatha, or “old jaws”). The other lineage, the Neognatha or “new jaws”, survived in three separate lines, one leading to ducks and fowl, another to sea gulls and their relatives, and the third to “earth birds” (Telluraves). Telluraves predominate today, and they mostly perch and nest in trees. Telluraves split into Afroaves (or “African birds”) and Australaves (or “southern birds”), represented in Clades by a bald eagle and an American robin, respectively. The common ancestor of all eagles and robins was evidently a carnivorous bird that perched on tree branches. “Old-jaw” birds and “new-jaw” birds together form the clade Aves, or birds. If one includes the many birdlike dinosaurs that didn’t survive the last extinction event, this larger clade is called Avialae (“bird wings”). Archaeopteryx are in the clade Avialae, but they are a separate branch from Aves.

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 complete metamorphosis (larva, pupa, and imago or adult). They first evolved around 300 million years ago, and they have since evolved into flies, fleas, beetles, ants, wasps, and moths. Around a 100 million years ago, moths co-evolved with flowering plants as their pollinators. One sort of wasp also co-evolved with flowering plants as a pollinator; we call them bees. The praying mantis represents Exopterygota (“outer winged”), a quite successful clade of insects whose young resemble the adult form. The young develop through multiple stages called instars (“forms”), and their wings develop on the outsides of their bodies, not within a pupa shell, as with Endopterygota. This clade, which preceded Endopterygota, includes cockroaches, termites, grasshoppers, lice, and more. The bee and mantis together represent Neoptera (“new wings”), the clade comprising all insects that can fold their wings back over their abdomens. The most successful neopterans are those that have evolved eusocial lifestyles with non-reproducing workers, such as bees, ants, and termites. The dragonfly represents the few species within Pterygota that are not neopterans. Dragonflies begin life as water breathing predators, and they develop toward the adult form one molt at a time until they finally climb out of the water, converting to adults that breathe air and fly. Nearly all insects are winged insects, although silverfish and some other forms are not. Fleas are winged insects (pterygotes) even though their ancestors lost their wings over 100 million years ago.

When I first chose three winged insects, the second was a butterfly because butterflies are highly recognizable. The bee and the butterfly, however, are both endopterygotes, so there was no insect to represent the important clade of cockroaches and grasshoppers. My plan was to swap in a cockroach for the butterfly because the cockroach has an ancient form perhaps similar to the earliest exopterygotes. A prominent backer, however, requested a praying mantis, and the mantis is a fine representative of Exopterygota. Karen drew the mantis face on to bring out all its character, but we might yet switch it to back view, like the others.

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 ago). Orb-weaver spiders and their relatives compose most of Earth’s spiders. They have fangs that point toward each other like pincers, and their ability to capture winged insects in their webs has helped them spread across the globe. Tarantulas and their relatives have fangs that point down, which makes for a weaker “bite”. These spiders create silk but don’t weave webs. Also descended from trigonotarbids are the spider-like amblypygids, whose front legs have evolved into long feelers. These feelers are similar to the antennae that pancrustaceans have, including insects, but obviously they evolved separately. Many types of animals have evolved new uses for their front legs other than walking. What other animals can you think of that have limbs that used to be legs but that aren’t any more?

When I first chose animals for the “land arthropod” card, they were a spider, a scorpion, and a tick—all land animals. Then I learned that the most recent common ancestor of these three groups lived in the water. The lines that led to today’s land-loving spiders and scorpions evolved air-breathing independently. I switched from the arachnid clade to the tetrapulmonate clade because in Clades it’s the most recent common ancestor that determines a card’s environment (water, land, or air).

US preorders are now available from the game’s future publisher, Atlas Games, for both Clades and Clades: Prehistoric. Preorder here.

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 attached to the mother’s swimming legs. Many other clades are successful because of adaptations that help them take better care of their offspring, mammals included. While lobsters live in crevices or burrows on the sea floor, crabs often live in shallower waters. Many sorts of crabs have evolved some degree of air-breathing, allowing them to take advantage of air’s higher oxygen content suisse acheter cialis. Woodlice still breathe through gills like their water-breathing ancestors, but their gills are adapted for life on land. A woodlouse’s gills stop working if they dry out, and that’s also true for your lungs. Like other crustaceans, malacostracans eat with side-by-side mandibles, quite different from arachnids’ fangs. Other crustaceans tend to be tiny, such as copepods, which often resemble shrimp but are smaller than a grain of rice. Another successful branch of the crustacean clade is the insects. They were originally classified as a sister group to crustaceans when in fact they’re a daughter. The clade of all crustaceans and insects is Pancrustacea (“all shelled ones”).

In the Clades game, the mammals of the land are represented by suprapimates, also known as Euarchontoglires. A squirrel represents rodents, a rabbit represents lagomorphs, and a child represents primates. Like most sorts of mammals, these animals diversified soon after the non-bird dinosaurs went extinct 66 million years ago. Rodents and lagomorphs are together in a clade called Glires, which is distinguished by front teeth that keep growing and growing. This adaptation allows these animals to chew through seed shells and wood without wearing out their teeth. More than any other order of mammals, rodents have diversified into many species, including unusual types such as flying squirrels, beavers, porcupines, capybaras, and naked mole rats. The sister clade to Glires is Euarchonta, which includes three tree-dwelling clades: tree shrews, colugos, and primates. Some primates live exclusively in the trees, while others climb trees to avoid predators. Two million years ago, however, our lineage lost its apelike shoulders, suggesting a shift away from tree-climbing to a life fully on the ground. Those Homo erectus ancestors gave rise to several species of human that spread out across the continents, including our species, which appeared in Africa 200 thousand years ago. We are the most successful large animal on Earth, at least for now.

Preorder Clades and Clades: Prehistoric

The mammals of the water are whippomorphs, represented by a blue whale, a dolphin, and a hippopotamus. The term “whippomorph” means “whale-hippo shape”, and it proves that scientists have a sense of humor. As with many sorts of modern mammal, the earliest whippomorphs appeared shortly after the non-bird dinosaurs were wiped out 66 million years ago. These ancestors were apparently large, semiaquatic mammals. The clade soon split into two clades, one clade including today’s hippos, and the other including today’s whales and dolphins. The whale-dolphin clade is Cetacea, meaning “whales”. Blue whales and other baleen whales have no teeth, and instead they have baleen bristles that filter plankton as a food source. Dolphins are technically toothed whales, like sperm whales are. They prey on fish, like the earliest whales probably did. Air-breathing gives toothed whales an advantage over their water-breathing prey because air has much more oxygen in it than water does.

In Clades, the sauropsids of the earth are squamates, comprising all lizards and snakes. “Squamate” means scaly, and their scales distinguish them from turtles, birds, and crocodiles. These other sauropsids have scutes, which are made of bone and horn, but they don’t have scales. The earliest modern lizards lived almost 200 million years ago and resembled geckos. That was about 50 million years after the earliest dinosaurs appeared. The common ancestor of all lizards and snakes could unhinge its jaw to swallow large prey, as can today’s squamates, especially snakes. In Clades, the three squamates are a gecko, a snake, and a chameleon. Scientists propose that snakes and chameleons are together in a “venom clade” called Toxicofera. This clade also includes iguanas, gila monsters, and related lizards.