Archaeopteryx lithographica (replica)

See in 3D

The Archaeopteryx shown above is a cast made directly from an early mold of the famous Berlin specimen, which was discovered near Solnhofen by Ernst Haberlein in the late 19th century. This it is the most complete and well-preserved Archaeopteryx specimen, with vivid detail in the talons and individual feathers.

With its long tail, teeth in its mouth, and fingers on its wings, Archaeopteryx differs substantially from modern birds, but it appears to have been capable of active flight (Chatterjee & Templin, 2003; Voeten et al., 2018). Its brain resembled that of modern birds, and it had asymmetrical flight feathers on its wings (Alonso et al., 2004). Therefore, Archaeopteryx does not appear to be an intermediate between a flightless and flying animal. McClain et al. (2023) provide an interesting discussion from a creationist perspective on the assumptions and challenges this fossil presents for its classification within a particular animal group.

The discovery of Archaeopteryx – then interpreted as a “missing link” between dinosaurs and birds – caused much excitement. Charles Darwin noted, “Considering that birds are the most isolated group in the animal kingdom, what a splendid case is this Solenhofen [sic] bird-creature [Archaeopteryx] with its long tail and fingers to its wings!” (Darwin, 1903). However, Darwin himself had earlier asked, “Why then is not every geological formation and every stratum full of such intermediate links?” (Darwin, 1859).

The relative abundance of Mesozoic fossil birds reveals Archaeopteryx to be part of a larger pattern of abrupt appearance without obvious ancestral species. Even if Archaeopteryx is accepted as a potential missing link, Darwin’s theory predicted abundant intermediates, not just a few putative ones. Darwin attributed the lack of intermediate fossils to “imperfection of the geological record,” but when it comes to birds and other flying creatures (e.g., pterosaurs), they display remarkably developed adaptations for flight from their lowermost appearance in the geologic record.

Currently, 13 specimens of Archaeopteryx have been found (Rauhut et al., 2018; Boorstein, 2024), all from the Solnhofen Limestone. Despite some anatomical variability, most of them have consistently been attributed to the same genus (Rauhut et al., 2018). Their stratigraphic distribution spans the lower Tithonian Stage of the Upper Jurassic, occurring across the various subzones of the Hybonoticeras hybonotum ammonite Biozone (Schweigert, 2007; Rauhut et al., 2018). In standard chronology, this stratigraphic interval represents about 1 million years (Hesselbo et al., 2020), making Archaeopteryx an example of relative stasis rather than the rapid turnover expected if major anatomical novelties had arisen through a sequence of gradual morphological intermediates.

References:

Alonso, P.D., Milner, A.C., Ketcham, R.A., Cookson, M.J. and Rowe, T.B., 2004. The avian nature of the brain and inner ear of Archaeopteryx. Nature, 430(7000), pp. 666-669. doi:10.1038/nature02706.

Boorstein, A., 2024. Chicago Museum unveils the ‘most important fossil ever discovered’: The Feathered Dinosaur Archaeopteryx. Smithsonian. Available at: https://www.smithsonianmag.com/smart-news/chicago-museum-unveils-the-most-important-fossil-ever-discovered-the-feathered-dinosaur-archaeopteryx-180984312. (Accessed: December 2024).

Chatterjee, S. and Templin, R.J., 2003. The flight of Archaeopteryx. Naturwissenschaften, 90, pp. 27-32. doi:10.1007/s00114-002-0385-0.

Darwin, C., 1859. On the Origin of Species by Means of Natural Selection, Or, The Preservation of Favored Races in the Struggle for Life. London: John Murray, Albemarle Street. p. 280. Print.

Darwin, C. 1903. More Letters of Charles Darwin. Vol. 1. London: Murray. p. 234. Print.

Hesselbo, S.P., Ogg, J.G., Ruhl, M., Hinnov, L.A. and Huang, C.J., 2020. The Jurassic Period. In Felix M. Gradstein, James G. Ogg, Mark D. Schmitz, Gabi M. Ogg (Eds.). Geologic Time Scale, Elsevier. pp. 955-1021. doi:10.1016/B978-0-12-824360-2.00026-7.

McLain, M., Ross, M., Petrone, M., Lay, N. and Speights, M., 2023. Response to “The Debate over Classification of Archaeopteryx as a Bird”. Answers Research Journal, 16 pp. 577–593. Available at: https://assets.answersresearchjournal.org/doc/v16/response-debate-classification-archaeopteryx-bird.pdf

Rauhut, O.W., Foth, C. and Tischlinger, H., 2018. The oldest Archaeopteryx (Theropoda: Avialiae): a new specimen from the Kimmeridgian/Tithonian boundary of Schamhaupten, Bavaria. PeerJ, 6, p.e4191. doi:10.7717/peerj.4191.

Schweigert, G., 2007. Ammonite biostratigraphy as a tool for dating Upper Jurassic lithographic limestones from South Germany: first results and open questions. Neues Jahrbuch für Geologie und Paläontologie. Abhandlungen, 245(1), p. 117. doi:10.1127/0077-7749/2007/0245-0117.

Voeten, D.F., Cubo, J., De Margerie, E., Röper, M., Beyrand, V., Bureš, S., Tafforeau, P. and Sanchez, S., 2018. Wing bone geometry reveals active flight in Archaeopteryx. Nature communications, 9(1), p. 923. doi:10.1038/s41467-018-03296-8.