Smok wawelski

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This article is about the extinct reptile. For the mythological creature, see Wawel Dragon.

Smok wawelski
Temporal range:
Ma
↓
Reconstructed skeleton, University of Warsaw
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauromorpha
Clade: Archosauriformes
Clade: Archosauria (?)
Genus: †Smok
Niedźwiedzki et al., 2012
Species:
†S. wawelski
Binomial name
†Smok wawelski
Niedźwiedzki et al., 2012

Smok (meaning "dragon" in

theropod dinosaur (part of the bird/dinosaurian lineage of archosaurs).[1]

Description

Skeletal restoration showing known remains.

At an estimated 5 to 6 metres (16 to 20 ft) in length, Smok was the largest carnivorous archosaur in central Europe in the time it was alive. It was larger than any other known

theropod dinosaur or pseudosuchian living in central Europe during either the Late Triassic or Early Jurassic. The skull is 50 to 60 centimetres (20 to 24 in) long.[1]

Several features indicate that Smok is an

quadratojugal bones at the back of the skull, a hole in front of the eye socket called the antorbital fenestra, maxillae bones in the upper jaw that connect along their palatal processes, and a rounded projection on the upper part of the femur bone.[1]

The

derived (advanced) features. The most prominent of these is a funnel-shaped structure on the bottom of the braincase, formed by a very wide, rounded basisphenoid bone. A deep notch called the basisphenoid recess cuts into the back of this funnel. Above the funnel is a very thin area of the braincase that is formed by deep depressions on the basisphenoids.[1]

Cranial elements in several views

Smok has several features that are shared with both dinosaurs and crocodile-line archosaurs, making classification difficult. Similarities with theropods include a groove, or antitrochanter, on the ilium bone of the hip that is part of the acetabulum (a depression where the head of the femur attaches to the hip). Smok and theropods also have an anterior trochanter on the femur. Some large theropods share with Smok the deep depressions of the basisphenoids in the braincase. Similarities with rauisuchians include a triangular antorbital fenestra and a connection between the ectopterygoid and jugal bones of the skull that is split into two projections. The hip of Smok has a ridge on the lateral surface of the ilium above the acetabulum. This ridge is a defining characteristic of rauisuchians, forming a buttress over the femur and giving these animals a pillar-erect stance.[1]

Other features of Smok seem to exclude it from these groups of archosaurs. The

archosauromorphs, including the presence of a postfrontal bone on the skull and a closed acetabulum in the hip.[1]

Discovery and naming

Braincase

Smok was found in a locality near Lisowice village that is latest

Tyrannosaurus rex.[3] Bones from other parts of the body were found in 2009 and 2010. Five tracks made by a three-toed archosaur – presumably a theropod dinosaur – were found in rocks that were 1 metre (3.3 ft) above the layer where Smok was found. The footprints may belong to Smok, but the lack of foot bones in the skeleton make this association uncertain.[1]

Isolated teeth.

Smok is known from the

Wawel Hill, the namesake of the type species S. wawelski.[1]

Paleoecology

Smok was the largest predator in its environment. Other large predatory archosaurs included the dinosaur

dicynodonts.[1]

Paleobiology

Comparison of two Smok reconstructions by Szymon Górnicki

Examination of coprolites attributed to Smok by Martin Qvarnström et al., indicate that this archosaur was able to crush bone. Based on examination of the bone fragments within the coprolites, Smok's ability to retain food within its digestive system varied considerably based on prey availability and food type. The variable mixture of bones, some belonging to fish, others to dicynodonts, and to temnospondyls indicates Smok was a generalized predator. Teeth from this archosaur were also uncovered from these trace fossils, indicating it may have swallowed its own broken teeth during feeding. The heavy amounts of bone in the diet indicate that salt and marrow from the bones of herbivores and other prey items was an important component in the archosaur's diet; an important behavior often linked with modern mammalian predators but seldom studied in ancient archosaurian reptiles. The findings were published in the journal Scientific Reports in 2019.[4]

References

  1. ^
    doi:10.4202/app.2010.0045
    .
  2. doi:10.4202/app.2008.0415
    .
  3. ^ Sulej, T.; Niedźwiedzki, G. (2009). "Dawn of the Dinosaurs: The discovery of large reptile fossils in Silesia" (PDF). Academia. 2 (22): 34–35.
  4. PMID 30700743
    .
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