English: Restoration of the armoured dinosaur Tarchia (Ankylosauria, Ankylosauridae, Ankylosaurinae). It is an update of a drawing that I first uploaded in 2008.

• Head: The new head restoration is mostly based on PIN 3142/250, a specimen which on occasions have been attributed to Saichania, but in 2017 was designated as Tarchia teresae.^[1]
• Armour: the arrangement of osteoderms in ankylosaurids can be difficult to determine if the osteoderms are not found in place (as in the case of Ankylosaurus),^[2] In some cases, very intact ankylosaur specimens are found with some or most of their osteoderms still in place. Ankylosaurid examples of this include a specimen of Euoplocephalus (NHMUK 5161)).^[3] and a fossil specimen attributed to Tarchia, ZPAL MgD I/113 (preserving part of the osteoderm arrangement intact in the dorsal region and a fairly complete tail),^[4] which is used as a model in the current restoration (it should be noted that ZPAL MgD I/113 differ from other attributed to Tarchia and couls represent a different genus).^[5] Many ankylosaurids had osteoderms forming two bony bands rings around the neck (called the cervical half rings),^[2] including Tarchia..^[6] As images of cervical half rings from Tarchia are not available, and the current restoration is based on those of Ankylosaurus.
• Spikes: the current restoration of Tarchia have small spikes extending from the hip region down along the proximal part of the tail, similar to the skeletal restorations of Euoplocephalus by Paul (while his restoration of Pinacosaurus have larger spikes, all the way from the neck down on the base of the tail).^[7] The restoration of Tarchia with more frugal amount of spikes in Tarchia is a guess, based on that ZPAL MgD I/113 preserve a single triangular spike on its tail, indicating it possessed some spikes (Tumanova claim that Tarchia possessed "perforated large spines",^[6] but do not provide details of what they looked like).

References

1. ↑ Penkalski P. & Tumanova T. (2017). "The cranial morphology and taxonomic status of Tarchia (Dinosauria: Ankylosauridae) from the Upper Cretaceous of Mongolia". Cretaceous Research 70: p. 117-127
2. ↑ ^{a b} Arbour V.M. & Mallon J.C. (2017). "Unusual cranial and postcranial anatomy in the archetypal ankylosaur Ankylosaurus magniventris". FACETS 2(2): p. 764-794
3. ↑ Brown C.M. et.al. (2017). "An Exceptionally Preserved Three-Dimensional Armored Dinosaur Reveals Insights into Coloration and Cretaceous Predator-Prey Dynamics". Current Biology 27(16): p. 2514-2521
4. ↑ Arbour V.M., Lech-Hernes N.L., Guldberg T.E., Hurum J.H. & Currie P.J. (2013). "An ankylosaurid dinosaur from Mongolia with in situ armour and keratinous scale impressions". Acta Palaeontologica Polonica 58(1): p. 55-64
5. ↑ [1]
6. ↑ ^{a b} [2]
7. ↑ Paul G.S. Dinosaurs: A Field Guide. (London: A & C Black): p. 233-234.