This document provides information on avian fauna (birds) including their: - Morphological features such as feathers, scales on legs/feet, and diapsid skull inherited from reptiles. - Evolution from dinosaurs including Archaeopteryx as the earliest known bird with both reptilian and avian traits. - Taxonomy including modern bird groups of Palaeognathae and Neognathae. - Life history traits like laying eggs, being precocial or altricial, and rapid growth to adult size within a year.

1. B Y :
THOMAS CHINNAPPAN.A ,
M.SC.APPLIED GEOLOGY,
PERIYAR UNIVERSITY,
SALEM.
AVIAN FAUNA

2. INTRODUCTION
 Known as birds
 Are endothermic vertebrates with
feathers
 The vertebrate class aves includes
the birds, an extremely distinctive
and successful clade, with an
estimated 9000 species
worldwide, including the snowy
owl pictured here.

3. INTRODUCTION
 Although descended from the dinosaurs, birds have
evolved remarkable specializations for flight:
 A unique “one-way” breathing system
 Light yet strong hollow bones,
 A skeleton in which many bones are fused or lost
 Powerful flight muscles
 Most importantly feathers.

4. MORPHOLOGICAL FEATURES
 Have retained reptilian scales on their beak, legs and
feet
 Have a single occipital condyle
 Have a diapsid skull
 Birds have feathers
 Feathers –are made up of keratin derived from the
epidermis.
 Replaced reptilian scales on all surfaces except the beak,legs
and feet
 With pigments facilitating recognition by other members of
species.

5. MORPHOLOGICAL FEATURES OF
ARCHAEOPTERYX
 Had a long reptilian tail, thecodont teeth on both
jaws, and feathers on the tail and wings
 Skull was more reptilian than avian
 Nostrils were far forward
 No beak
 Trunk vertebrate was not rigidly fused
 The sternum was not well developed
 The synsacrum was not well developed.

6. MORPHOLOGICAL FEATURES OF
ARCHAEOPTERYX

7. SYSTEMATICS OF THE AVES
 Living birds are classified in the taxon Neornithes.
 There are two subdivisions of the Neornithes,
distinguished by details of palate anatomy:
 Palaeognathae and
 Neognathae.
 The Palaeognathae includes two subgroups:
 Ratitae, which includes the ostrich, rhea, emu, and other
large, cursorial, flightless birds (as well as the kiwi, which
isn't so large);
 Tinamiformes, which includes the South America
tinamous.

8. SYSTEMATICS OF THE AVES
 All other living birds, from hawks to hummingbirds
and from plovers to penguins, are classified in the
Neognathae.
 During the Mesozoic, several extinct lineages of birds
shared the world with early Neornithes.
 The Ichthyornithiformes could fly and bore teeth in
the jaws; known forms seem to have resembled gulls
in their lifestyle, if not their structure.

9. Aves: Life History and Ecology
 As everyone knows, birds lay eggs -- specifically, they
lay very typical amniote eggs with calcified shells.
 Birds brood their eggs until hatching.
 Some bird species are naked and helpless at birth,
and must be fed by their parents; these birds are said
to be altricial.
 Many common songbirds, such as the American
robin, are altricial species.

10. Aves: Life History and Ecology
 Precocial birds, on the other hand, are born
feathered, and are able to walk and to feed on their
own shortly after hatching -- ducks and chickens are
well-known precocial birds.
 Whether precocial or altricial, birds grow rapidly,
reaching adult size within one year.

11. Evolution of avian
 Birds evolved from a group of theropod dinosaurs in
the jurassic period.
 The oldest known bird fossile is Archaeopteryx
lithographica which has a mix of “reptilian and
avian” features.
 Reptilian: long tail, teeth, long clawed fingers
 Avian: feathers, ribs with uncinate processes, avian
shoulder girdle

12. Evolution of avian

13. Evolution of avian
 Archaeopteryx (oldest
known fossil bird) jurassic
150mya
 Size: large chicken

14. Evolution of avian

16. Fossil record
 The fossil record of birds is not extensive: the light,
hollow bones of birds are not likely to survive as
fossils.
 However, a growing number of unusually well-
preserved fossil birds are contributing much to our
understanding of bird evolution.
 The oldest known fossil unambiguously identified as
a bird is still the dinosaur-like Archaeopteryx, from
the Solnhofen Limestone of the Upper Jurassic of
Germany.

17. Fossil record
 However, it was not the only bird of the time.
 Very recently, another bird of almost the same age
was discovered in northeastern China, and named
Confuciusornis
 Confuciusornis resembles Archaeopteryx in having
wing claws, but unlike Archaeopteryx and like
modern birds, Confuciusornis lacked teeth.

18.  Modern birds continued to diversify through the
Cenozoic.
 The Cenozoic bird fossil record consists largely of
isolated bones (although some nearly complete
skeletons have been recovered from certain
localities).
 Suffice it to say that by the early Oligocene, 35
million years ago, most of the bird orders that we
recognize today had appeared.

19. Cretaceous birds
Ichthyornithiformes -
 tern-like
 fish-eaters
 modern flight
adaptations (keeled
sternum, loss and fusion
of bones, etc.)

20. Tertiary birds
 Early to mid Tertiary (Paleocene into Miocene, 65-
15 mya) was time of major adaptive radiation of
birds.
 By the mid-Paleocene get first appearance of large,
heavy-bodied, flightless predators to fill bipedal
carnivore niche vacated by the disappearance of
dinosaurs.

21. Pleistocene birds
 Pleistocene was period of dramatic climate change
and glaciation.
 In general was a period of decline and extinction for
birds, but derivation of geographic races and
speciation also occurred.
 Some very large flightless birds also radiated during
this period.

22. Pleistocene birds
 Moas = New Zealand; up
to 9-10 feet tall
 Elephant Birds = from
Madagascar; largest bird
ever - up to > 1000 lbs.

23. Avian flight
 Bird in flight the most diverse
group of flyers ever to evolve are
the birds (the clade Aves).
 Birds show a marvelous diversity
not only of species but of flight
adaptations.
 Compare the hummingbird with
the albatross, and you'll get a good
picture of how differently animals
can fly.

24. Avian flight
 The earliest known bird is Archaeopteryx.
 Its form shows us that it was a true flyer, although
not as skilled as most modern birds, since its
sternum was flat, or at best only slightly keeled, and
later modifications of the wrist bones were not
present.

25. Avian flight
 Birds have flight adaptations similar to those of
pterosaurs:
 hollow but strong bones,
 keeled sterna (shown above) for flight muscle
attachment,
 short and stout humeri,
 and feathers (analogous to pterosaur wing fibers).

26. Thank you