The first Langobardisaurus: MCSNB 2883

The day before yesterday
we looked at the latest (fourth) specimen attributed to the genus Langobardisaurus (Renesto 1994, Late Triassic). Today let’s look at the first specimen. This is really my first serious look at it because the second and third specimens were so much easier to study, both with good skulls.

The holotype of Langobardisaurus
(Renesto 1994, MCSNB 2883) has never (to my knowledge) been reconstructed, as it is here (Fig. 1), and not with to scale comparisons to the other three specimens. Saller et al. 2013 considered all four to be conspecific. However, as I found out, and as in so many putative pterosaur genera and Archaeopteryx genera, no two are alike.

Figure 1. Four Langobardisaurus specimens compared to scale. Contra Saller et al. 2013, these four specimens do not appear to be conspecific.

Figure 1. Four Langobardisaurus specimens compared to scale. Contra Saller et al. 2013, these four specimens do not appear to be conspecific.

Larger than the others (if the scale bars are correct),
the holotype of Langobardisaurus appears to have a smaller skull, smaller fingers and longer hind limbs. Distinct from two of the specimens, the tail remains long and robust. Powerful caudofemoral muscles were attached the elongate and numerous caudal ribs (fused transverse processes). The gastralia were more numerous with less space between sets. Such gastralia help hold up the anterior skeleton when standing bipedally. This specimen (MCSNB 2883) appears to be, by convergence, like Sharovipteryx, an obligate biped.

Figure 2. Langobardisaurus holotype in situ MCSNB 2883.

Figure 2. Langobardisaurus holotype in situ MCSNB 2883. Inserts show pectoral girdle elements and pes (x2).

Almost a worst case scenario for a roadkill fossil
the pectoral + skull region of MCSNB 2883 (Fig. 3) provides an excellent opportunity to try out the Digital Graphic Segregation (DGS) method. In the original photo you can see what a mess it is and how Renesto has labeled some of the bones and teeth, but ignores others and never outlines any of the bones. Colors just make things easier to understand in cases like this and it ensures that you are studying every millimeter of this fossil. Even tiny bone corners that peek out from beneath the rubble can be color coded. The reconstruction (Fig. 1) confirms or refutes your identifications as they fit or do not fit the assembled puzzle of bones without resorting to the danger of freehand illustration.

Figure 3. The pectoral region of Langobardisaurus (MCSNB 2883) with DGS color overlays. Compare to Figure 4 for identification of pectoral elements. Anterior skull elements are also present here.

Figure 3. The pectoral region of Langobardisaurus (MCSNB 2883) with DGS color overlays. Compare to Figure 4 for identification of pectoral elements. Anterior skull elements are also present here. Premaxillae and sternum are both yellow. Scapulae are blue. Coracoids are violet. Clavicles are green. Interclavicle is tan. Ribs are red. The tiny metacarpals are still attached to the end of the ulna and radius (amber and green).

The coincidence of the interclavicle, clavicle and sternum
in Langonbardisaurus (Fig. 4) and other fenestrasaurs like Cosesaurus and Longisquama is the precursor structure to the pterosaur sternal complex, seen only in this clade within the entire Tetrapoda.

Figure 5. Langobardisaurus (MCSNB 2883) pectoral girdle in left lateral and ventral views.

Figure 4. Langobardisaurus (MCSNB 2883) pectoral girdle in left lateral and ventral views.

References
Muscio G 1997. Preliminary note on a specimen of Prolacertiformes (Reptilia) from the Norian (Late Triassic) of Preone (Udine, north-eastern Italy). Gortania – Atti del Museo Friulano di Storia Naturale 18:33-40
Renesto S 1994. A new prolacertiform reptile from the Late Triassic of Northern Italy. Rivista di Paleontologia e Stratigrafia 100(2): 285-306.
Renesto S and Dalla Vecchia FM 2000. The unusual dentition and feeding habits of the Prolacertiform reptile Langobardisaurus (Late Triassic, Northern Italy). Journal of Vertebrate Paleontology 20: 3. 622-627.
Renesto S, Dalla Vecchia FM and Peters D 2002. Morphological evidence for bipedalism in the Late Triassic Prolacertiform reptile Langobardisaurus. Senckembergiana Lethaea 82(1): 95-106.
Saller F, Renesto S, Dalla Vecchia FM 2013. First record of Langobardisaurus (Diapsida, Protorosauria) from the Norian (Late Triassic) of Austria, and a revision of the genus. Neues Jahrbuch für Geologie und Paläontologie. 268 (1): 89–95. doi:10.1127/0077-7749/2013/0319
Wild R 1980. Tanystropheus (Reptilia: Squamata) and its importance for stratigraphy. Mémoires de la Société Géologique de France, N.S. 139:201–206.

uninisubria/Langobardisaurus
wiki/Langobardisaurus

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