218: PNSO Therizinosaurus Review

𝗔𝗱𝗱𝗲𝗻𝗱𝘂𝗺 𝗼𝗻 𝗣𝗹𝗮𝗻𝘁𝗶𝗴𝗿𝗮𝗱𝘆
Thanks to a few viewer comments (thank you 六小鱼, Jai'sOnFire, and others I have undoubtedly missed) I realise I should have been a lot clearer in my statement. The idea I should have conveyed was that the 𝘭𝘢𝘳𝘨𝘦/𝘭𝘢𝘳𝘨𝘦𝘴𝘵 therizinosaurids were probably plantigrade, not 𝘢𝘭𝘭 therizinosaurs as such.
As pointed out to me, there have been reports of possibly therizinosaur footprints that show a digitigrade mode of locomotion. Most specifically, Fiorillo et al 2012. In that paper the average footprints were about 21cm and they though Erlikosaurus was a possible suitor. The Sennikov 2021 paper states Macropodosaurus as being about 50cm. Therizinosaurus is clearly a lot larger and heavier than Erlikosaurus, lending possibility to Sennikov's proposal.
Incidentally Sennikov was aware of the Fiorillo hadrosaur paper, but unceremoniously dismissed their conclusion as "attributed clearly incorrectly... and should be attributed to oviraptorosaurs." The papers he cites after this statement (Gierliński, 2009, 2015; Gierliński and Lockley, 2013a) I have read briefly and noted no direct refutation of Fiorillo et al. As such I wouldn't dismiss that paper as well. My personal inclination is that smaller therizinosaurids could well be digitigrade, and the larger ones, plantigrade.
Once again thanks guys, I'll be more careful in the future!
𝗦𝘆𝗻𝗼𝗽𝘀𝗶𝘀
Coming right on the heels of that bizarre Deinocheirus, PNSO follows with another oddball - the Therizinosaurus.
Similar to the Deinocheirus in many ways, though unfortunately not as well preserved, Therizinosaurus has always been a bit of an enigma. Here, PNSO gives Therizinosaurus a beautiful paint job that is as subtly pleasing as the Deinocheirus was loud.
With due attention paid to the anatomy, and most pleasingly having all four toes weight bearing, this is the best Therizinosaurus I have in my collection, and I don’t foresee needing to get another one soon!
𝗥𝗲𝗳𝗲𝗿𝗲𝗻𝗰𝗲𝘀:
Sennikov is a must-read on this subject
Clark, J. M.; Perle, A.; Norell, M. (1994). "The skull of Erlicosaurus andrewsi, a Late Cretaceous "Segnosaur" (Theropoda, Therizinosauridae) from Mongolia". American Museum Novitates (3115): 1-39.
Sennikov, A.G. (1989) The main evolutionary patterns of the development of the locomotor apparatus of archosaurs, Paleontol. Zh., 1989, no. 4, pp
Sennikov, A.G. (2006). “Reading segnosaur tracks”, Priroda (Moscow), no. 5, pp. 58-67.
Sennikov, A. G. (2021) "The Plantigrade Segnosaurians: Sloth Dinosaurs or Bear Dinosaurs?" Paleontological Journal, vol. 55, no. 10, Dec. 2021, pp. 1158+.
Zanno, L. E. (2010). "A taxonomic and phylogenetic re-evaluation of Therizinosauria (Dinosauria: Maniraptora)". Journal of Systematic Palaeontology. 8 (4): 503-543.
#th