Langobardisaurus
| Langobardisaurus | ||||||||||||
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Langobardisaurus pandolfii ; Holotype MCSNB 2883 |
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| Temporal occurrence | ||||||||||||
| Middle to upper norium | ||||||||||||
| approx. 216 to 208.5 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Langobardisaurus | ||||||||||||
| Renesto , 1994 | ||||||||||||
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Langobardisaurus is a genus of relatively small representatives of the Tanystropheidae within the group of Archosauromorpha from the Upper Triassic (Middle to Upper Norium approx. 216 to 208.5 million years ago). The only generally recognized species of the so far monotypical genus is Langobardisaurus pandolfii from the Calcare-di-Zorzino Formation and the Dolomia-di-Forni Formation in Northern Italy, as well as the Seefeld Formation in Tyrol .
Etymology and history of research
The generic name refers to the place where the holotype was found in Lombardy , the heartland of the former Longobard Empire in combination with the ending “ -saurus ” ( Latin for “lizard”). The Artzusatz " pandolfii " honors Mario Pandolfi , taxidermist at the Museo Civico di Scienze Naturali Enrico Caffi in Bergamo for his contributions to the study of vertebrate fossils of the region. The species name can be roughly translated as "Pandolfi's Longobard Lizard".
The first description of the genus and type species was carried out in 1994 by Silvio Renesto based on the holotype MCSNB 2883, a largely articulated, partial skeleton, and a Paratypus MCSNB 4860, a nearly complete skeleton of a young animal. Both specimens come from a small quarry in the area of Cene in which rocks of the Calcare-di-Zorzino formation ("Zorzino limestone") were mined.
In 1995 and 1996 a third (MFSN 19235) and a fourth specimen (MFSN 1921) from the Dolomia-di-Forni formation in the area around Preone were initially named " Langobardisaurus rossii " (MFSN 19235) and Langobardisaurus tonelloi (MFSN 1921) ) described. From the same formation, another specimen (MFSN 26829), a partial skeleton with remnants of the hind limbs, the anterior caudal spine and parts of the pelvis, was described as belonging to the genus Langobardisaurus .
In 2007 Renesto and Dalla Vecchia were able to prove that the specimen described as " Langobardisaurus rossii " (MFSN 19235) is by no means a protorosaur, but rather a representative of the Lepidosauromorpha . The name " Langobardisaurus rossii " became invalid in this form.
2013 was the first time a find of Langobardisaurus outside of northern Italy was known. The specimen (P 10121), a largely complete, articulated skeleton with only the distal part of the caudal spine missing, comes from the Seefeld formation in Seefeld in Tyrol and not only expanded the known range of Langobardisaurus considerably, but also gave rise to one extensive revision of the genre. Among other things, it was found that there are no anatomical features that would justify a distinction between Langobardisaurus pandolfii and Langobardisaurus tonelloi . The taxon Langobardisaurus tonelloi became obsolete as a junior synonym and the genus Langobardisaurus has since been considered monotypical with Langobardisaurus pandolfii as the only known species.
features
Langobardisaurus pandolfii was a small, probably less than 0.5 m long representative of the Tanystropheidae with a greatly elongated cervical spine. From the side, the robust skull shows an approximately triangular outline with a short snout and very large eye sockets . The skull is generally stronger, but also shorter and taller than other representatives of the Tanystropheidae.
Another striking feature of Langobardisaurus is its heterodontic dentition. The slightly beak-shaped premaxilla appears toothless, but has a series of notches on its lateral edge that simulate slender, forward-inclined, incisor- shaped teeth. The function of these notches is unclear. Possibly these are structures for ingesting food or attachment points for a horn sheath ( Rhamphotheca ), but none of the specimens known to date have shown fossil evidence. The maxilla , on the other hand, has a row of 7–8 thick, two- to three-pointed teeth and, in the rearmost area, a particularly large molar- shaped tooth. The lower jaw is also edentulous in the front area. The teeth in the back of the lower jaw correspond to those of the maxilla. The rearmost, particularly massive teeth of the upper and lower jaw seem to occlude and were probably suitable for grinding harder food. The lower jaw is robust with a high crown process ( processus coronoideus ) on the angular bone , which indicates a strong bite as the insertion for the adductor muscles .
The up to 8 cervical vertebrae are greatly elongated and 2 to 3 times longer than the first vertebrae. The cervical ribs are long and thin and run parallel to the longitudinal axis of the cervical vertebrae. The tail is more than twice as long as the trunk.
The front limbs are slender and much shorter than the long, slender rear limbs. The long bones are thin-walled and hollow.
Systematics
Langobardisaurus was classified in the first description of 1994 as Prolacertiformes " incertae sedis ", with "Prolacertiformes" in this case being synonymous with "Protorosauria".
David Dilkes put Langobardisaurus in 1998 together with Macrocnemus and Tanystropheus in the clade of the Tanystropheidae which he defined as "the last common ancestor of Macrocnemus , Tanystropheus and Langobardisaurus and all of his descendants". Later phylogenetic analyzes confirmed the Tanystropheidae as a monophyletic group within the Archosauromorpha, whereas the group of the “Protorosauria” / “Prolacertiformes” proved to be polyphyletic .
Paleecology
Langobardisaurus probably had a largely terrestrial way of life. Anatomical adaptations to an aquatic way of life are in any case not known. The long hind legs compared to the front legs and the structure of the tarsus should have enabled Langobardisaurus to run upright on the hind legs. It may also be able to stand up on its hind legs, similar to what is the case with today's frilled lizards . The jaws and teeth were well suited for processing hard or tough food. Langobardisaurus probably ate crustaceans , larger insects or small " ganoid fish ".
The sediments of the Calcare di Zorzino Formation, the Dolomia di Forni Formation and the Seefeld Formation were each deposited in small, deep sea basins within the carbonate platform along the coasts of the western Paleotethys . Anoxic conditions prevailed at the bottom of these basins , which offered ideal conditions for fossil conservation. In addition to the inhabitants of the sea itself, carcasses of land animals and plants from the adjacent, island-like land masses that were flooded in were also preserved in fossil form in these sediments. The vegetation cover of these islands consisted mainly of conifers such as representatives of the Cheirolepidiaceae , Elatocladus or Voltzia , but also included cycads and club moss plants and suggests a hot, arid climate.
Langobardisaurus shared this habitat with pterosaurs such as Austriadactylus (Seefeld Formation, Dolomia di Forni Formation), Preondactylus (Dolomia di Forni Formation), Carniadactylus (Dolomia di Forni Formation, Calcare di Zorzino Formation), Peteinosaurus (Calcare di Zorzino Formation ) and Eudimorphodon (Seefeld Formation, Calcare di Zorzino Formation), the Drepanosauriden Megalancosaurus (Dolomia di Forni Formation) and Vallesaurus (Calcare di Zorzino Formation), the Rhynchocephaliden Diphydontosaurus (Calcare di Zorzino Formation), the Aetosaurian Formation Aetosaurus (Calcare di Zorzino Formation ) and at least one representative of the Lepidosauromorpha (Dolomia di Forni Formation), the very specimen that was originally described as " Langobardisaurus rossii ".
Individual evidence
- ^ A b c S. Renesto: A new Prolacertiform Reptile from the Late Triassic of Northern Italy. In: Rivista Italiana di Paleontologia e Stratigrafia , Vol. 100, No. 2, pp. 285-306, 1994. (digitized version )
- ↑ a b c d e f g F. Saller, S. Renesto & FM Dalla Vecchia: First record of Langobardisaurus (Diapsida, Protorosauria) from the Norian (Late Triassic) of Austria, and a revision of the genus. In: New Yearbook of Geology and Paleontology - Treatises , Vol. 268, No. 1, pp. 83–95, 2013. (digitized version)
- ↑ F. & G. Bizarrini Muscio: Un nuovo rettile (Reptilia, Prolacertiformes) dal Norico di Preone (Udine, NE Italia). Nota preliminare. In: Gortania , Vol. 16, pp. 67-76, 1995.
- ^ G. Muscio: Preliminary note on a specimen of Prolacertiformes (Reptilia) from the Norian (Late Triassic) of Preone (Udine, North Eastern Italy). In: Gortania , Vol. 18, 33-40, 1996.
- ^ A b S. Renesto, FM Dalla Vecchia & D. Peters: Morphological evidence for bipedalism in the Late Triassic prolacertiform reptile Langobardisaurus. In: M. Gudo, M. Gutmann & J. Scholz (Eds.): Concepts of functional engineering and constructional morphology: biomechanical approaches on fossil and recent organisms. - Senckenbergiana lethaea , Vol. 82, No. 1, pp. 95-106, 2002. (Abstract)
- ^ A b F. M. Dalla Vecchia: The tetrapod fossil record from the Norian-Rhaetian of Friuli (northeastern Italy). In: J. Harris, S. Lucas, JA Spielmann, MG Lockley, ARC Milner & JI Kirkland (Eds.): The Triassic-Jurassic Terrestrial Transition. - Bulletins of the New Mexico Museum of Natural History and Science , Vol. 37, pp. 432–444, 2006. (digitized version )
- ^ S. Renesto & FM Dalla Vecchia: A revision of Langobardisaurus rossii Bizarrini and Muscio 1995 from the Late Triassic of Friuli (Italy). In: Rivista Italiana di Paleontologia e Stratigrafia , Vol. 113, No. 2, pp. 191–201, 2007. (digitized version )
- ↑ a b c d e S. Renesto: A Reappraisal of the Diversity and Biogeographic Significance of the Norian (Late Triassic) Reptiles from the Calcare di Zorzino. In: J. Harris, S. Lucas, JA Spielmann, MG Lockley, ARC Milner & JI Kirkland (Eds.): The Triassic-Jurassic Terrestrial Transition. - Bulletins of the New Mexico Museum of Natural History and Science , Vol. 37, pp. 445–456, 2006. (digitized version )
- ↑ D. Dilkes: The Early Triassic rhynchosaur Mesosuchus browni and the interrelationships of basal archosauromorph reptiles. In: Philosophical Transactions of The Royal Society B - Biological Sciences , Vol. 353, pp. 501-541, 1998. (digitized version )
- ↑ MD Ezcurra: The phylogenetic relationships of basal archosauromorphs, with an emphasis on the systematics of proterosuchian archosauriforms. In: PeerJ , 4: e1778, 2016. doi : 10.7717 / peerj.1778
- ↑ E. Kustatscher, Ch.Daxer & K. Krainer: Plant fossils from the Norian Seefeld Formation (Late Triassic) of the Northern Calcareous Alps (Tyrol, Austria) and their environmental / palaeoclimatic consequences. In: New Yearbook of Geology and Paleontology - Treatises , Vol. 283, No. 3, pp. 347–363, 2017 (abstract)