Langobardisaurus, Pteromimus and Amotosaurus

Langobardisaurus pandolfii (Renesto 1994a) Norian, Late Triassic ~ 210mya, ~15 cm in length was derived from Macrocnemus and was a sister to Tanytrachelos and Tanystropheus.

Distinct from Macrocnemus, the skull of Langobardisaurus was shorter and dominated by a huge orbit. The upper temporal bar bisected the orbit and the posterior cranium was depressed. The procumbent premaxillary teeth were transformed into a narrow rake-like configuration. The posterior teeth were broader and multi-cusped, as in the smaller Tanystropheus.

The cervical series was longer and more gracile, but still composed of eight vertebrae. Eleven caudals bore transverse processes. The tail tip is unknown, but rapid dimunition suggests a short caudal series.

The scapula and coracoid were relatively smaller. The scapula was strap-like. The manus was relatively smaller with shorter digits.

The ilium was elongated both anteriorly and posteriorly. The ischium was narrow proximally. The pedal digits were shorter. Digits II-IV were the same length. Pedal 5.1 was greatly elongated and extended nearly to the distal end of metacarpal IV. Pedal 5.4 extended as far as p3.4.

With a cropping muzzle, grinding, slicing teeth, a high coronoid and the ability to rise on their hind legs and reach high places with their long necks, it appears possible that the langobardisaurs were the only plant-eating macrocnemids. Occasional biepdal locomotion appears possible (Renesto, Dalla Vecchia & Peters 2002).

Langobardisaurus tonelloi was similar overall, but distinct in several traits. The orbit was not so large. The premaxillary dentition was smaller. The posteriormost teeth had elongated cutting/grinding surfaces. The coronoid process was larger than in any sister taxon (latter two not exposed in L. pandolfii).

Only four anterior caudals bore elongated transverse processes. The tail diminished rapidly after the sixteenth caudal.

The scapula did not have a strap-like appearance. The forelimbs were longer. Metacarpal I was aligned with II-IV.

The hind limbs were longer. No pedal digit tips were aligned and digit III was the longest.

The pectoral girdle of Langobardisaurus tonelloi with several elements re-identified in color overlays. The original clavicle is now rib #9. The original coracoid is now the broad clavicle. The original scapula is now the coracoid. The original rib #10 (on the right) is now the strap-like scapula. Rib #10 (on the left) and the sternum were identified correctly. See below for a reconstruction and comparison.

Langobardisaurus pectoral girdle evolution

Three pectoral girdles demonstrating the evolution of the elements from the plesiomorphic basal lizard, Huehuecuetzpalli through Langobardisaurus tonelloi to the basal fenestrasaur, Cosesaurus.

Pteromimus longicollis (Atanassov 2002) was originally considered a pterosaur and Scleromochlus relative. Unfortunately langobardisaurs were not included in the cladistic analysis. Here Pteromimus nests with langobardisaurs, with similar traits overall, especially in the cervical vertebrae. Pteromimus was probably more primitive based on the plesiomorphic premaxillary teeth.

Amotosaurus rotfeldensis SMNS 50830 (Wild 1980, Fraser and Rieppel 2006) was originally considered a juvenile Tanystropheus antiquus, but Fraser and Rieppel (2006) determined that only eight cervicals were present, a shagreen of denticles covered the vomers, palatines and pterygoids, the second sacral rib was bifurcate, the tarsus was well-ossified and three distal tarsals were present. Due to the ossified tarsus they considered the small specimen an adult. Unfortunately Fraser and Rieppel (2006) reported that Langobardisaurus had 12 rather than 8 cervicals and so missed an important shared trait. Here Amotosaurus nests with Langobardisaurus and they share a longer mt 4 compared to mt 3. The scapula is much enlarged. The ventral pubis and ischium are in contact with one another, as in Cosesaurus. The mandible is ventrally concave. The posterior teeth are difficult to see, but there seems to be little indication of anything but simple compressed cone shapes present. Pedal 5.1 was relatively shorter.

Amotosaurus is featured in

Atanassov M 2001. Two new archosauromorphs from the Late Triassic of Texas. - Journal of Vertebrate Paleontology Abstracts 21(3): 30A.

Atanassov M 2002. Two new archosauromorphs from the Late Triassic of Texas. Dissertation. online abstract

Fraser NC and Rieppel O 2006. A new protorosaur (Diapsida) from the upper Bundsandstein of the Black Forest, Germany. Journal of Vertebrate Paleontology 26(4):866-871.

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 and Dalla Vecchia FM 2007. A revision of Langobardisaurus rossii Bizzarini and Muscio, 1995 from the Late Triassic of Friuli (Italy)*. Rivista di Paleontologia e Stratigrafia 113(2): 191-201. online pdf

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.

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

Lepidosauria

Rhynchocephalia

Squamates

Tritosauria