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Reptile egg fossils are the fossilized remains of eggs laid by reptiles. The fossil record of reptile eggs goes back at least as far as the Early Permian.However, since the earliest reptile eggs probably had soft shells with little preservation potential, reptilian eggs may go back significantly farther than their fossil record.
Bird and reptile eggs consist of a protective eggshell, albumen , and vitellus , contained within various thin membranes. The egg yolk is suspended in the egg white by one or two spiral bands of tissue called the chalazae (from the Greek word χάλαζα, meaning 'hailstone' or 'hard lump
Reptiles, from Nouveau Larousse Illustré, 1897–1904, notice the inclusion of amphibians (below the crocodiles). In the 13th century, the category of reptile was recognized in Europe as consisting of a miscellany of egg-laying creatures, including "snakes, various fantastic monsters, lizards, assorted amphibians, and worms", as recorded by Beauvais in his Mirror of Nature. [7]
Many ancient reptile groups are known from egg fossils including crocodilians, dinosaurs, and turtles. [3] Some ancient reptiles, like ichthyosaurs [8] and plesiosaurs [9] are known to have given live birth and are therefore not anticipated to have left behind egg fossils. Dinosaur eggs are among the most well known kind of fossil reptile eggs. [3]
Reptile eggs, bird eggs, and monotreme eggs are laid out of water and are surrounded by a protective shell, either flexible or inflexible. Eggs laid on land or in nests are usually kept within a warm and favorable temperature range while the embryo grows. When the embryo is adequately developed it hatches, i.e., breaks out of the egg's shell.
Reptiles, in the traditional sense of the term, are defined as animals that have scales or scutes, lay land-based hard-shelled eggs, and possess ectothermic metabolisms. So defined, the group is paraphyletic , excluding endothermic animals like birds that are descended from early traditionally-defined reptiles.
Fossilized Dinosaur eggs displayed at Indroda Dinosaur and Fossil Park. This timeline of egg fossils research is a chronologically ordered list of important discoveries, controversies of interpretation, taxonomic revisions, and cultural portrayals of egg fossils. Humans have encountered egg fossils for thousands of years. In Stone Age Mongolia, local peoples fashioned fossil dinosaur eggshell ...
A clutch of eggs is the group of eggs produced by birds, amphibians, or reptiles, often at a single time, particularly those laid in a nest. In birds, destruction of a clutch by predators (or removal by humans, for example the California condor breeding program) results in double-clutching. The technique is used to double the production of a ...