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------------------------------------------------------------------------Below is a free term papers summary of the paper "------------------------------------------------------------------------." If you sign up, you can be reading the rest of this term papers in under two minutes. Registered users should login to view this term paper.
------------------------------------------------------------------------ As promised, here are the derived characters with which Gauthier (in his 1986 paper) unites Archaeopteryx with modern birds, outside of all other theropods (with Gauthier's original clarifiers in parens) [and with my editorial comments in brackets]: Premaxillae elongate, narrow, and more pointed anteriorly, with longer nasal processes [similar condition in bullatosaurs, and in the nondinosaurian Megalancosaurus, but unique to Archie and later birds in Maniraptora]. Maxillary process of premaxilla reduced so that maxilla participates broadly in external naris (also in troodontids). Enlarged brain/basicranium (temporal musculature fails to extend origin onto frontal bones [to a certain degree in bullatosaurs and therizinosauroids, and perhaps in some of the newer, "brainier" dromaeosaurids]. Double-condyled quadrate displaced from distal position on opisthotic to more anteromedial position in contact with prootic (Currie, pers. comm. and Walker, pers. comm., disagree with Whetstone's interpretation of the quadrate: Currie notes the anterior displacement of the quadrate in troodontids [maybe Nino can comment on the condition in Pelecanimimus], and Walker does not consider the quadrate to be double-condyled in Archaeopteryx). Maxillary and dentary teeth reduced in size and number (or lost), with unserrated crowns and enlarged roots that completely enclose replacement teeth within them [many of the smallest theropod teeth are unserrated, which may be a developmental constraint. The pinched roots of bird teeth are similar to those of troodontids, basal ornithomimosaurs, and (in at least a couple of cases) dromaeosaurids]. Robust furcula for hypertrophied flight musculature [true to a certain extent, although oviraptorids and (perhaps) some dromaeosaurids have substantial furculae as well, and even the new Morrison ?allosaurid seems to have a primitive furcula!]. Scapula with more or less prominent acromion process for ligamentous connection to clavicle. Lenght/bredth ratio of scapula at midlength exceeds nine (not in penguins) and scapula tapers distally. Acrocoracoid tuberosity larger than in other coelurosaurs. Coracoid enlaged and inflected posteromedially more so than in other coelurosaurs. Very long forelimb and hands (e.g., in Archaeopteryx forelimb is 120-140% of hindlimb length, and more than twice as long as distance between glenoid and acetabulum), with ... This is not the end of the termpaper! Register below to see the complete version of this term paper.
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