Transitional Fossils

Creationists on blogs are forever asking to see just one transitional fossil. While there are thousands, let's start with a common one. One which was in fact discovered during Darwin's own lifetime: Archaeopteryx lithographica

Here is a list which lists features diagnostic of both dinosaurs and modern birds showing which features Archeopteryx had from each group.


Dino-6, Archeopteryx-6, Bird-11-23

• The Sacrum (the vertebrae developed for the attachment of pelvic girdle) occupies 6 vertebra (reptilian) 

Dino-Absent, Archeopteryx-Present, Bird-Absent

• Premaxilla and maxilla are not horn-covered (reptilian) 
• Trunk region vertebra are free (reptilian)

Dino-Absent, Archeopteryx-Present, Bird-Present

• Opposable hallux (Avian Feature)

Dino-Present, Archeopteryx-Present, Bird-Absent

• Cerebral hemispheres elongate, slender and cerebellum is situated behind the mid-brain and doesn't overlap it from behind or press down on it (reptilian) 
• Neck attaches to skull from the rear as in dinosaurs not from below as in modern birds (reptilian)
• Center of cervical vertebrae have simple concave articular facets (reptilian)
• Long bony tail with many free vertebrae up to tip (reptilian)
• Premaxilla and maxilla bones bear teeth (reptilian)
• Ribs slender, without joints or uncinate processes and do not articulate with the sternum (reptilian)
• Pelvic girdle and femur joint is archosaurian rather than avian (except for the backward pointing pubis as mentioned above) (reptilian)
• Metacarpals (hand) free (except 3rd metacarpal), wrist hand joint flexible (reptilian)
• Deltoid ridge of the humerus faces anteriorly as do the radial and ulnar condyles (reptilian)
• Claws on 3 unfused digits (reptilian)
• The fibula is equal in length to the tibia in the leg (reptilian)
• Metatarsals (foot bones) free (reptilian)
• Gastralia present (reptilian)

Dino-Present, Archeopteryx-Present, Bird-Some

• Nasal opening far forward, separated from the eye by a large preorbital fenestra (reptilian)

Dino-Some, Archeopteryx-Absent, Bird-Present

• Bones are pneumatic (reptilian)

Dino-Some, Archeopteryx-Present, Bird-Absent

• Pubic shafts with a plate-like, and slightly angled transverse cross-section (reptilian)

Dino-Some, Archeopteryx-Present, Bird-Present

• Feathers (Avian Feature) 
• Furcula formed of two clavicles fused together in the midline (Avian Feature)
• Pubis elongate and directed backward (Avian Feature)

It can be seen that Archeopteryx possesses many more characters which are present in dinosaurs and not in birds, than it does characters which are present in birds but not in dinosaurs. This is why Archeopteryx is a true transitional species, because it shares some characters which are diagnostic of one group whilst still retaining characters diagnostic of its ancestral group. Anyone who claims that Archae is 100% bird is wrong. Anyone who claims that Archae's skeleton is even predominantly bird- like is wrong. Anyone who claims Archae has a "totally birdlike" skull is wrong.

To your comment about a deer to a whale or a deer with flippers...that's just asinine! It's like the creationists that want a crock-a-duck. It shows a total lack of understanding of evolution...if you could actually find one of those it would prove evolution is wrong, not right.