In this article we will discuss about the classification of Aves.
Aves # Subclass Archaeornithes:
1. Includes all fossil birds from Jurassic, having toothed jaws, scaly limbs, long tail with tail feathers arranged in two parallel rows.
2. Pygostyle absent, free caudal vertebrate, free metacarpals.
3. Fore limbs with three digits ending in claws.
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4. Ribs without uncinate process.
Examples. Archeopteryx, Archaeornis.
Aves # Subclass Neornithes:
1. Jaws toothless except in few extinct forms.
2. Short tail, tail feathers arranged in a semicircle.
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3. A few terminal caudal vertebrae fuse to form a pygostyle.
4. Metacarpals fused.
5. Digits of fore limbs rarely with claws.
6. Ribs with uncinate process.
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7. Sternum well developed and mostly keeled.
This subclass is divided into four superorder’s
Superorder Odontognathae:
1. Toothed birds, without pygostyle.
Marine and extinct forms from North American Cretaceous strata.
Order Hesperomithiformes.
Examples. Hesperornis, Baptornis and Enaliornis.
Order Ichthyornithiformes.
Examples. Ichthyornis and Apatornis.
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Superorder Paleognathae or Ratitae:
1. Flightless, running large-sized birds with raft-like keel less sternum.
2. Wings are reduced, vestigeal or absent.
3. Pygostyle small or undeveloped, coracoid and scapula comparatively small.
4. The rectrices are absent or irregularly arranged but without hooked barbules.
Order Struthiorniformes:
1. Sternum keelless, pygostyle absent, long neck and sparsely feathered body.
2. Each hind limb with two toes.
3. Feather devoid of aftershaft.
Example. Struthio (Ostrich).
Order Casuariformes:
1. Neck and body thickly feathered; feathers with aftershaft.
2. Keelless sternum, hind limb with three toes.
Examples. Casuaris (Cassowary), Dromaeus (Emu).
Order Apterygiformes:
1. Short, keelless sternum; vestigeal wing.
2. Hind limbs with four toes.
3. Feather bristle-like, without aftershaft.
4. Bill long with nostrils at the tip.
Example. Apteryx (Kiwi).
Order Rheiformes:
1. Keelless sternum relatively large nonfunctional wings.
2. Hind limbs with three clawed digits.
3. Feathers sparsely scattered and without aftershaft.
Example. Rhea (American ostrich).
Order Dinornithiformes:
1. Unkeeled, short sternum.
2. Hind limbs large and massive with three or four toes.
3. Feather with large aftershaft.
Example. Dinornis (gigantic Moas).
Order Aepyornithiformes:
Extinct birds Aepyornis (Elephant bird) of Madagascar.
Order Tinamifornies:
1. Keeled sternum.
2. Wings well developed, possess power of flight, but great runners.
3. Pygostyle reduced.
Examples. Crypturellus (Variegated Tinamons), Eudromea (Crested Tinamons).
Superorder Impennae:
1. Flightless birds adapted to aquatic life, from Eocene to recent.
2. Forelimbs modified into flippers and feet are webbed.
Example. Aptenodytes, Eudypte’s (Penguins).
Superorder Neognathae or Carinatae:
1. Modern, widely distributed flying birds with well-developed wings, keeled sternum and toothless beak.
2. Feathers with barbs, barbules and hooklets.
3. Pygostyle present.
Order Anseriformes – Examples. Cygnus (Swans), Anas (Ducks).
Order Apodiformes – Examples. Chaetura (Swifts), Archilochus (Humming birds).
Order Gaviifornies – Example. Gavia (Divers).
Order Procellariiformes – Examples. Diomedea (Albatrosses), Daption (Cape pigeon).
Order Pelecaniformes – Examples. Pelecanus (Pelicans), Suta (Booby).
Order Ciconiiformes – Examples. Ciconia (Storks), Egretta (Egrets).
Order Falconiformes – Examples. Aquila (Eagles), Mileres (Kites).
Order Galliformes – Examples. Gallus (Fowls), Acryllium (Guinea fowls).
Order Gruiformes – Examples. Otis (Bustards), Psophia (Trumpeters).
Order Diatrymiformes – Examples. Diatryma.
Order Podicoptiformes – Examples. Podilymbus (Pied-billed grebe), Centropelara (Short-winged grabes).
Order Charadriiformes – Examples. Rostratula (Snipes), Calidris (Sandpipers).
Order Columbiformes – Examples. Columba (Pigeons), Streptopelia (Doves).
Order Psittaciformes – Examples. Kakatoe (Cocktoos), Psittacus (Parrots).
Order Cuculiformes – Examples. Cuculus (Cuckoos), EiMynamys (Koels).
Order Strigiformes – Examples. Strix (Wood owls), Bubo (Eagle owls).
Order Caprimulgiformes – Examples. Podargus (Frog mouths), Nyetibius (Potoos).
Order Coliiformes – Example. Colius (Mouse birds).
Order Trogoniformes – Examples. Trogon (Coppery-tailed trogons), Calures.
Order Coraciformes – Examples. Alcedo (Kingfishers), Merops (Bee eaters).
Order Piciformes – Examples. Picus (Wood peckers), Notharcus (Puff birds).
Order Passeriformes – Examples. Corvus (Crows), Pycnonotus (Bulbuls).