Early Birds

By | September 9, 2016

Birds evolved from dromaeosaur-like dinosaurs during the Jurassic Period. The first birds had skeletons like those of Microraptor (seach the article about Microraptor). Over time, as birds adapted to life in the air, they evolved huge flight muscles and lost their teeth, tails, and claws, making them more lightweight.

FAMILY FACT FILE

Key features of modern birds
■ Feathered body and wings
■ Toothless beaks
■ Tail bones fused into a stump
■ No finger claws or small finger claws
■ Deep keel bone on breast to anchor large flight muscles
■ Semicircular wrist bone to aid flapping

When
Birds first appeared in the Late Jurassic and have been in the skies ever since.

Confuciusornis (con-FEW-shus-OR-niss)

confuciusornis


When: 130–120 million years ago (Early Cretaceous)

Fossil location: China

Habitat: Woodlands of Asia

Length: 1 ft (0.3 m)

Diet: Probably seeds

Confuciusornis was the earliest toothless bird and the first known to have a beak. It also had a stumpy tail like that of modern birds, but it lacked strong flight muscles. Thousands of fossils of Confuciusornis have been found in China, and some of the adults have very long tail feathers. These may be male ornaments that were displayed to attract females during courtship.

Archaeopteryx (ar-kee-OP-ter-ix)

archaeopteryx-1

Modern birds have a toothless beak, but Archaeopteryx had jaws and teeth typical of a carnivorous dinosaur.


When: 150 million years ago (Late Jurassic)

Fossil location: Germany

Habitat: Forests and lakes of western Europe

Length: 1 ft (0.3 m)

Diet: Insects, probably reptiles

When the first complete fossil of Archaeopteryx was discovered in 1861, scientists were amazed—it looked like a cross between a dinosaur and a bird. It had a fully feathered tail and wings, yet it also had dromaeosaur-like claws on its hands, bones along its tail, and jaws with teeth instead of a beak. Archaeopteryx is the oldest known member of the bird family. It was the size a pigeon and had long flight feathers, but it lacked the powerful muscles needed for flapping flight and was probably more of a glider than a flapper.

archaeopteryx-fossil

This fossil of archaeopteryx was discovered in Germany.

 Amazingly clear impressions of feathers on the arms and tail are preserved in fine-grained limestone.

Hesperornis (hess-per-ORE-niss)

hesperornis


When: 75 million years ago (Late Cretaceous)

Fossil location: USA

Habitat: Coastal waters

Length: 6 ft (1.8 m)

Diet: Fish and squid

Hesperornis was an enormous seabird that had lost the power of flight but become an expert diver. It used its huge feet to push itself through the water as it chased squid and fish, which it caught in a toothed beak. The bones of its hands and forearms had vanished, leaving tiny “wings” that it likely used for steering in water. Like all birds, Hesperornis nested on land, but it was probably unable to walk and had to push itself along on its belly.

Vegavis (VAY-gah-viss)

vegavis


When: 65 million years ago (Late Cretaceous)

Fossil location: Antarctica

Habitat: Coast of Antarctica

Length: 2 ft (0.6 m)

Diet: Water plants Fossils of Vegavis, a relative of ducks and geese, were found in Antarctica in 1992. The discovery was important because it showed that some of today’s bird families had already evolved during the age of dinosaurs. Vegavis lived in Antarctica when its climate was much less cold than today.

Iberomesornis (I-beh-ro-may-SORE-niss)

iberomesornis-1


When: 135–120 million years ago (Early Cretaceous)

Fossil location: Spain

Habitat: Woodlands of western Europe

Length: 8 in (20 cm)

Diet: Probably insects

Iberomesornis was about the size of a finch. It had a stumpy tail and powerful chest muscles, indicating it was a good flyer, and its curved foot claws suggest it perched on trees. But it had features similar to a dinosaur, too, including large claws on its wings.

Ichthyornis (ICK-thee-OR-niss)

ichthyornis


When: 90–75 million years ago (Late Cretaceous)

Fossil location: USA

Habitat: Seashores

Length: 2 ft (0.6 m)

Diet: Fish

Ichthyornis (“fish bird”) was a seabird, similar in size and weight to a modern seagull, but its head and beak were much larger. It had a large, keeled breastbone, showing it had powerful breast muscles and was a strong flyer. However, its jaws were packed with small, curved teeth just like those of prehistoric fish-eating lizards called mosasaurs. It may even have fed like one, using its long snout and hooked teeth to snatch fish and other slippery prey from the water. Ichthyornis also had webbed feet with short claws.

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