Adding Compsognathus longipes to the large reptile tree

Updated 1.17.2016 with a revised figures based on higher resolution data. On this date, Compsognathus was nested with Struthiomimus.

Figure 1. Reconstruction of Compsognathus with revised face, fingers and foot.

Figure 1. Compsognathus in lateral view. Small inset at reduced scale shows complete tail. Note the variety of neural spines along the spinal column

For many decades
Compsognathus longipes
(Wagner 1859, Ostrom 1978, Late Jurassic, quarry unknown, 150 mya, 3 ft (89 cm) long, BSP AS I 563 ) was considered the smallest known dinosaur and something close to its contemporary, the first bird, Archaeopteryx, also from the Solnhofen formation.

Here with very few other theropods to nest with, Compsognathus nests in the large reptile tree (604 taxa) with the very much larger Tyrannosaurus. (updated January 17, 2016) This clade includes the feathered theropod, Sinocallioptery, at its base. Many have wondered if Compsognathus had feathers or not. With modern birds lacking body scales one wonders if subsequent scales are all derived from primordial feathers as the scales on the feet of modern birds appear to be. That would be the opposite of traditional thinking, discussed earlier here.

The number of fingers
in Compsognathus has been an issue largely resolved by Gishlick and Gauthier 2007. Here (Fgi. 2) I found four fingers, all from the left hand, except m1.2 from the right.

Figure 3. New reconstruction of Compsognathus fingers from grayscale data in Gischlick and Gauthier 2007, which has two extra phalanges not found in the online color image.

Figure 2. Revised 1.17.2016. Note the addition of m2.1 and m2.2 on the grayscale data. All phalanges except one of the unguals are from the left hand. Here not two, not three, but four fingers are recovered. 

The entire skeleton was traced
and these elements were used in a similar fashion to create the Compsognathus reconstruction (Fig. 1). Inside this specimen is the ingested lizard Bavarisaurus.

References
Gishlick AD and Gauthier JA 2007. On the manual morphology of Compsognathus longipes and its bearing on the diagnosis of the Compsognathidae. Zoological Journal of the Linnean Society 149: 569–581. 
Ostrom JH 1978.
 The osteology of Compsognathus longipes. Zitteliana 4: 73–118.
Wagner JA 1859. Über einige im lithographischen Schiefer neu aufgefundene Schildkröten und Saurier. Gelehrte Anzeigen der Bayerischen Akademie der Wissenschaften 49: 553.
wiki/Compsognathus

 

 

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