A Mess of Archaeopteryx – WP#4

With two new studies on Archaeopteryx in the news, I thought I’d share my piece on them, by way of introducing my Archaeopteryx Mural.

Based on detailed examination of (unfortunately) photographs, I’ve managed to look at, measure, and compare each of the Archaeopteryx (“Archie”) specimens. As noted, this is based on photographs, and is thus inferior to personal examination, especially without having to peer through a glass case. This has been supplemented by extensive description, measurments (primary measurments rather than photographic comparisons were preferred, always), and comparison to other researchers conclusions. I’ve had the benefit of examining a cast of the London specimen from a wall, but it was for a short period and a long time ago; but I’ve also had the benefit of speaking to some of those who’ve examine the material personally. In the end, I made this:

The Archaeopteryx specimens, scaled left to right from largest to smallest.

While some out there have seen this, and know that I produced each one of these individually, this was done at the same time as I was evaluating, for myself, the argument that some of these specimens might represent unique species. Two further skeletal specimens are known, but not shown: The “chicken wing” or Burgermeister-Müller spcimen, and the Daiting specimen. And there’s the feather. Thus, there are ten skeletal specimens, while the feather is occasionally placed among these (as the first) to make eleven specimens.

So far, several of these specimens have formed the basis of taxonomic nomenclature: The Solnhofen specimen was named Wellnhoferia grandis by Elżanowski [1]; the Haarlem specimen was named Pterodactylus crassipes by von Meyer [2]; the Berlin specimen was named Archaeopteryx siemensii by Dames [3] but later made its own “genus” Archaeornis by Petronievics [4]; the London specimen is the holotype for Archaeopteryx lithographica [5] (although Wagner attempted to renamed it Griphosaurus problematicus due to his belief that it was not a bird [6]); the Munich specimen was named Archaeopteryx bavarica by Wellnhofer [7]; and the Eichstätt specimen was named Jurapteryx recurva by Howgate [8,9]. Of the specimens shown above, only the Maxberg has escaped taxonomic treatment apart from its referal to Archaeopteryx.

Because much has been made on the identity of which of these taxa should be recognized, these specimens have undergone extensive sampling for scaling, proportions, and morphological variation, to determine what material “deserves” to be a new species. The closest concensus so far is that all specimens belong to a single taxon, Archaeopteryx lithographica.

For the most part, Archaeopteryx has been differentiated on the basis of proportions, although some have recognized discrete morphological characters (e.g., the Solnhofen specimen has a fourth toe with only four phalanges rather than five [1]).

Much has been made on the proportions in Archaeopteryx, stemming from the impression first that all specimens seemingly form a single taxon and should therefore form a single ontogenetic trajectory. Testing this hypothesis, [10] reworked the previous studies of [1,11,12,13,14] in order to incorportate each current specimen known to date. Generally, all taxa appear to form a single clinal series, and as [10] argues, morphological variation is itself ontogenetic. [1] projected various morphological features to separate the Solnhofen specimen, as did [7] for the München specimen and [8,9] for the Eichstätt specimen. The last two specimens are the smallest, and they have been called juveniles [10,12,15], being particularly smaller than the largest specimens.

[1] Elżanowski, A. 2001. A new genus and species for the largest specimen of Archaeopteryx. Acta Palaeontologica Polonica 46(4):519-532.
[2] von Meyer, H. 1857. Beiträge zur näheren Kenntniss fossiler Reptilien [Contributions to the detailed British fossil reptiles]. Neues Jarhbuch fur Minereologie, Geologie und Paläontologie 1857:532-543.
[3] Dames, W. 1897. Über Brustbein, Schulter-und Beckengürtel der Archaeopteryx [On the sternum, shoulder and pelvic girdle of Archaeopteryx]. Sitzungberichte der Preusschen Akademie der Wissenschaften 2:818-834.
[4] Petronievics, B. vide Petronievics, B. & Woodward, A. 1917. On the pectoral girdle and pelvic arches of the British Museum Specimen of Archaeopteryx. Proceedings of the Zoological Society of London 1917.
[5] von Meyer, H. 1861. Archaeopteryx lithographica (Vogel-Feder) und Pterodactylus von Solenhofen [Archaeopteryx lithographica (feathered bird) and Pterodactylus from Solnhofen]. Neues Jahrbuch für Mineralogie, Geognosie, Geologie und Petrefakten-Kunde 1861:678-679.
[6] Wagner, A. 1861. Über ein neues, angeblich mit Vogelfedern versehenes Reptil aus dem Solnhofener lithographischen Schiefer [On a new purported reptile with avian feathers from the Solnhofen lithographic slate]. Sitzungberichte der Bayerischen Akademie der Wissenschaften, mathematisch-physikalisch Classe 146-154.
[7] Wellnhofer, P. 1993. Das siebte Exemplar von Archaeopteryx aus den Solnhofener Schichten [The seventh specimen of Archaeopteryx from the Solnhofen Beds]. Archaeopteryx 11:1-48.
[8] Howgate, M. E. 1984. The teeth of Archaeopteryx and a reinterpretation of the Eichstätt specimen. Zoological
Journal of the Linnean Society
[9] M. E. Howgate. 1985. Problems of the osteology of Archaeopteryx: is the Eichstätt specimen a distinct genus?. pp. 105-112 in M. K. Hecht, J. H. Ostrom, G. Viohl, and P. Wellnhofer (eds.), The Beginnings of Birds: Proceedings of the International Archaeopteryx Conference, Eichstätt 1984. (Freunde des Jura-Museums Eichstätt, Eichstätt.)
[10] Bennett, S. C. 2008. Ontogeny and Archaeopteryx. Journal of Vertebrate Paleontology 28(2):535-542.
[11] Houck, M. A., Gauthier, J. A. & Strauss, R. E. 1990. Allometric scaling in the earliest fossil bird, Archaeopteryx lithographica. Science 247:195–198.
[12] Senter, P. & Robins, J. H. 2003. Taxonomic status of the specimens of Archaeopteryx. Journal of Vertebrate Paleontology 23:961–965.
[13] Mayr, G., Pohl, B. & Peters, D. S. 2005. A well-presreved Archaeopteryx specimen with theropod features. Science 310:1483–1486.
[14] Mayr, G., Pohl, B., Hartman, S. & Peters, D. S. 2007. The tenth skeletal specimen of Archaeopteryx. Zoological Journal of the Linnean Society 149:97–116.
[15] Elżanowski, A. 2002. Archaeopterygidae (Upper Jurassic of Germany), pp. 129–159 in Chiappe and Witmer (eds.) Mesozoic Birds, Above the Heads of Dinosaurs. (University of California Press, Berkeley, California.)

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