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Not to be confused with Struthio asiaticus.

Struthio anderssoni, also known as the East Asian ostrich, is a large extinct species of ostrich that lived in the Pleistocene and Holocene in China, Mongolia and Russia[2]. It was much larger than extant ostriches, with estimated mass of 250–270 kg (550–600 lb).[3]

Taxonomy

In 2023, based on a re-examination of cast of a femur, Éric Buffetaut suggested that this species be moved to the genus Pachystruthio, noting that the main differences are in size and not morphology between the femur of Pachystruthio and that of S. anderssoni.[3]

Mikhailov and Zelenkov suggested this species is a larger bodied form of extant ostriches.[4] Buffetaut disagreed with this hypothesis, noting the significantly larger size and differing morphological features, including the minimum shaft width/total length ratio of the femur.[3]

Comparison of femora of Struthio camelus (A), S/P. anderssoni (B), and Pachystruthio dmanisensis (C)

Description

Buffetaut and Angst conclude that Struthio anderssoni was significantly larger than the modern ostrich, with both eggs and skeletal remains indicating this.[5]

Femur

The femur of one specimen from Upper Cave at Zhoukoudian measures 355 mm in length (within the estimated range of 304 – 371 mm for the species) and 69 mm in minimum shaft width. A 187 mm minimum shaft circumference on a cast from this species gives a mass estimate of 258 kg (569 lb).[3] Another partial femur has a minimum shaft circumference of 190 mm, which gives it a mass estimate of 269 kg (593 lb).[6]

Eggs

In 1933, three nearly complete eggs were measured to be 17.5–19.3 cm (6.9–7.6 in) in length and 14.4–15.5 cm (5.7–6.1 in) in width.[7] Slightly differing size ranges from Lowe (1931) were calculated in a 2025 article to correspond to 1.89–2.8 kg (4.2–6.2 lb) in mass.[8] Buffetaut and Angst had earlier calculated a marginally smaller egg mass, being 1.7–2.6 kg (3.7–5.7 lb).[6] Despite their larger size, the eggs are not significantly thicker than those of modern ostriches, being 2.1 – 2.3 mm in shell thickness.[8] A mass estimate based on the eggs results in 176–350 kg (388–772 lb), with a mean of 263 kg (580 lb).[6]

Paleobiology and extinction

The large body and egg size of S. anderssoni may be an adaptation for a cold climate, in which this species was more cold tolerant than African ostriches (although this is not the sole explanation, due to the existence of large ostriches in warmer climates[6]), but both being well suited for arid environments. They may have had similar internal physiology to African ostriches, due to similarity in egg morphology.[9]

The youngest dates obtained by mass spectrometry analysis of eggshell fragments reveal that the species survived until at least 8.9 ka BP.[9]

See Also

References

  1. ^ Lowe, Percy Roycroft (1931). “Struthious remains from northern China and Mongolia; with descriptions of Struthio wimani, S. anderssoni and S. mongolicus Spp. Nov”. Palaeontologia Sinica, Series C. 6: 1–47.
  2. ^ Boev, Zlatozar; Spassov, Nikolaï (September 2009). “First record of ostriches (Aves, Struthioniformes, Struthionidae) from the late Miocene of Bulgaria with taxonomic and zoogeographic discussion”. Geodiversitas. 31 (3): 493–507. doi:10.5252/g2009n3a1. ISSN 1280-9659.
  3. ^ a b c d Buffetaut, Eric (13 February 2023). “The Missing Late Pleistocene Ostrich Femur from Zhoukoudian (China): New Information Provided by a Rediscovered Old Cast”. Diversity. 15 (2): 265. Bibcode:2023Diver..15..265B. doi:10.3390/d15020265.
  4. ^ Mikhailov, Konstantin E.; Zelenkov, Nikita (September 2020). “The late Cenozoic history of the ostriches (Aves: Struthionidae), as revealed by fossil eggshell and bone remains”. Earth-Science Reviews. 208 103270. doi:10.1016/j.earscirev.2020.103270.
  5. ^ Buffetaut, Eric; Angst, Delphine (2021-01-26). “A Giant Ostrich from the Lower Pleistocene Nihewan Formation of North China, with a Review of the Fossil Ostriches of China”. Diversity. 13 (2): 47. Bibcode:2021Diver..13…47B. doi:10.3390/d13020047. ISSN 1424-2818.
  6. ^ a b c d Buffetaut, Eric; Angst, Delphine (2017). “How Large was the Giant Ostrich of China?”. EVOLUÇÃO – Revista de Geistória e Pré-História. 2 (1): 6–8. Retrieved 9 January 2023.
  7. ^ Young, C. C. (March 1933). “On the New Finds of Fossil Eggs of Struthio Anderssoni Lowe in North China with Remarks on the Egg Remains Found in Shansi, Shensi and in Choukoutien§”. Bulletin of the Geological Society of China. 12 (1–2): 145–152. doi:10.1111/j.1755-6724.1933.mp12001013.x. ISSN 1673-274X.
  8. ^ a b Sánchez-Marco, Antonio; Amiot, Romain; Angst, Delphine; Bailon, Salvador; Betancort, Juan Francisco; Buffetaut, Eric; García-Castellano, Emma; Guillén-Vargas, Lourdes; Lazzerini, Nicolas; Lécuyer, Christophe; Lomoschitz, Alejandro; López-Jurado, Luis Felipe; Luján, Àngel H.; Perera-Betancort, María Antonia; Salesa, Manuel J. (2025-08-27). “Unraveling the Strange Case of the First Canarian Land Fauna (Lower Pliocene)”. Fossil Studies. 3 (3): Supplementary table 1. doi:10.3390/fossils3030013. hdl:10261/399033. ISSN 2813-6284.
  9. ^ a b Janz, Lisa; Elston, Robert G.; Burr, George S. (18 May 2009). “Dating North Asian surface assemblages with ostrich eggshell: implications for palaeoecology and extirpation”. Journal of Archaeological Science. 36 (9): 1982–1989. Bibcode:2009JArSc..36.1982J. doi:10.1016/j.jas.2009.05.012.