Allometric Scaling in the Earliest Fossil Bird, Archaeopteryx lithographica

Either the distal secondary or distal primary interpretation would require that the small, moulted isolated feather originated from an individual much smaller than the other known Archaeopteryx specimens, which all represent immature individuals.

“Furthermore, either interpretation would require that this small, moulted 1,2,10 feather originated from an individual much smaller than the other known Archaeopteryx specimens 2,10,20 , which all represent immature individuals 21,22 .”

All other known Archaeopteryx specimens represent immature individuals.

“which all represent immature individuals 21,22 .”

Archaeopteryx skeletal measurements fit a tight regression, as in Confuciusornis, whereas Anchiornis specimens show greater variation in proportions.

“Archaeopteryx skeletal measurements also fit a tight regression [54, 55], as observed in Confuciusornis , whereas Anchiornis specimens do not plot close to the regression line indicating greater variation in proportions [6, 56].”

All known Archaeopteryx are young individuals spanning a developmentally very limited range.

“This is not unexpected because all known Archaeopteryx are young individuals spanning a developmentally very limited range [33].”

Houck et al. and Senter and Robins argued that differences in proportions in nearly all Archaeopteryx specimens are explained by allometric developmental scaling.

“Houck et al. [33] and Senter and Robins [48] argued that differences in proportions in nearly all specimens are explained by allometric developmental scaling.”

Deep intracortical growth lines are absent in the young Archaeopteryx specimen BSPG 1999 I 50.

“Deep intracortical growth lines (lines of arrested growth and/or annuli) are absent in this young specimen [33].”

Allometric scaling and skeletal fusion analyses have inferred that none of the known Archaeopteryx specimens are somatically mature and allude to a quantitatively larger endpoint.

“allometric scaling and skeletal fusion analyses have inferred that none of the known specimens are somatically mature and allude to a quantitatively larger endpoint [33].”