Archaeopteryx lithographica (Meyer 1861) Late Jurassic ~150 mya, 30-50 cm in length, was derived from a sister to Sinocalliopteryx and preceded the rest of the birds, a few of which are shown here, plus Ichthyorinis. Discovered first as a single feather, there are now eight skeletal specimens of Archaeopteryx now known.
Much smaller than and distinct form Sinocalliopteryx, the skull of Archaeopteryx had a smaller, shorter rostrum with a posteriorly displaced naris set lower in the skull with its ventral rim aligning with the ventral antorbital fenestra. The rostrum was distinctly narrower than the back half of the skull. The teeth were smaller and more widely spaced. The mandible was more gracile.
The neural spines were shorter. The cervical ribs were reduced. The caudal vertebrae were fewer in number and the morphology of the posterior caudals appeared much further anteriorly.
The clavicles were fused to form a furcula. The coracoids were taller and locked in place, unable to slide upon the small sternum. Every forelimb element was elongated. The fingers were gracile.
The pubis was rotated further posteriorly. The ischium was rotated further ventrally. The ilium was more gracile. The femur, tibia and fibula were all more gracile. Pedal digit I was rotated to oppose the other digits for perching.
Archaeopteryx had flight feathers emanating from its forelimbs and long tail feathers emanating from its caudal joints.
The other taxa shown above are later, more derived birds, all discovered prior to the newest birds from China. |
