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Early tetrapods probably had a three-chambered heart, as do modern amphibians and lepidosaurian and chelonian reptiles, in which oxygenated blood from the lungs and de-oxygenated blood from the respiring tissues enters by separate atria, and is directed via a spiral valve to the appropriate vessel — aorta for oxygenated blood and pulmonary ...
Primitive tetrapods were particularly devastated, while stem-reptiles fared better, being ecologically adapted to the drier conditions that followed. Primitive tetrapods, like modern amphibians, need to return to water to lay eggs; in contrast, amniotes, like modern reptiles – whose eggs possess a shell that allows them to be laid on land ...
As a very basal (primitive) tetrapod, it falls under the traditional class Amphibia in Linnaean taxonomy. Pederpes is an important fossil because it comes from the period known as Romer's gap and provides biologists with rare information about the development of tetrapods in a time when terrestrial life was rare.
Suborder Charadrii (plover-like waders). Family Charadriidae (plovers and lapwings); Family Haematopodidae (oystercatchers); Family Ibidorhynchidae (ibisbill); Family Recurvirostridae (avocets and stilts)
Amniotes are distinguished from the other living tetrapod clade — the non-amniote lissamphibians (frogs/toads, salamanders/newts and caecilians) — by the development of three extraembryonic membranes (amnion for embryonic protection, chorion for gas exchange, and allantois for metabolic waste disposal or storage), thicker and keratinized ...
Circular dendrogram of feeding behaviours A mosquito drinking blood (hematophagy) from a human (note the droplet of plasma being expelled as a waste) A rosy boa eating a mouse whole A red kangaroo eating grass The robberfly is an insectivore, shown here having grabbed a leaf beetle An American robin eating a worm Hummingbirds primarily drink nectar A krill filter feeding A Myrmicaria brunnea ...
Advent and Christmas come with many different traditions, including those of the culinary variety. Here's a look at three different food customs from around the world.
Diadectidae is an extinct family of early tetrapods that lived in what is now North America and Europe during the Late Carboniferous and Early Permian, and in Asia during the Late Permian. They were the first herbivorous tetrapods, and also the first fully terrestrial animals to attain large sizes. Footprints indicate that diadectids walked ...