Updated May 23, 2016 with a new mandible. M. Mortimer pointed out correctly that I had traced two coincident mandibles as one.
The less well-known
French specimen of Compsognathus corallestris (Bidar et al. 1972b; Peyer 2006; CNJ79) is a bit larger with a different morphology (Fig. 1) than the coeval smaller Bavarian Solnhofen specimen, Compsognathus longipes (Fig. 1 right). Dr. Peyer considers these two Late Jurassic theropods conspecific and representative of ontogenic rather than phylogenetic variation.
From the Peyer abstract:
“The absence of an external mandibular fenestra, dorsally fan-shaped dorsal neural spines with hook-shaped ligament attachments, and a very short McI and a PhI-1, which is stouter than the radius distinguish compsognathids from other coelurosaurs. Anatomical and morphological characters of the Bavarian specimen of Compsognathus are nearly identical to those of the French specimen. The differences are related to ontogenetic or within-species variation or are caused by preservational factors. Therefore this study proposes that C. corallestris is a subjective junior synonym of Compsognathus longipes from Bavaria.”
You’ll note that “compsognathids” sensu Peyer are scattered throughout this large reptile tree subset of the Theropoda (Fig. 2). Sinocalliopteryx and Juravenator are widely considered compsognathids, yet both nest far from one another here.
I tested the ontogenetic hypothesis of Peyer
in the large reptile tree. Indeed, the two Compsognathus specimens do nest next to one another, but at the bases of two different clades.
The large Compsognathus specimen
nested with the oviraptorid, Khaan, Limusaurus, therizinosaurs, Sinosauropteryx and others. More derived clades include Eotyrannosaurus and other paravians such as dromareosaurids, troodontids and birds.
The new reconstruction
of the large Compsognathus skull is relatively shorter. Both the premaxilla and the dentary tip are oriented slightly down. The bones of the mandible slid apart during taphonomy. Put them back together to match the skull length and you might get a mandibular fenestra, as also seen in the smaller Compsognathus. The new skull reconstruction (Fig. 1) was created using DGS, not freehand as in the Peyer reconstruction.
Current traditional compsognathids include the following taxa
- Juravenator (some say yes, others say no)
In the large reptile tree the clade that includes Compsognathus now include the following taxa
- all ornithomimids, including Struthiomimus
Bidar AL, Demay L and Thomel G 1972b. Compsognathus corallestris,
une nouvelle espèce de dinosaurien théropode du Portlandien de Canjuers (Sud-Est de la France). Annales du Muséum d’Histoire Naturelle de Nice 1:9-40.
Ostrom JH 1978. The osteology of Compsognathus longipes. Zitteliana 4: 73–118.
Peyer K 2006. A reconsideration of Compsognathus from the upper Tithonian of Canjuers, southeastern France, Journal of Vertebrate Paleontology, 26:4, 879-896,
Wagner JA 1859. Über einige im lithographischen Schiefer neu aufgefundene Schildkröten und Saurier. Gelehrte Anzeigen der Bayerischen Akademie der Wissenschaften 49: 553.