Pachystruthio
| Pachystruthio Temporal range:
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|---|---|
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| Restoration of a male P. dmanisensis. | |
Scientific classification 
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| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Infraclass: | Palaeognathae |
| Order: | Struthioniformes |
| Family: | Struthionidae |
| Genus: | †Pachystruthio (Kretzoi, 1954) |
| Type species | |
| Pachystruthio pannonicus (Kretzoi, 1954)
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| Species | |
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| Synonyms | |
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Pachystruthio is a genus of extinct bird which lived in Eurasia from the Late Pliocene to the Middle Pleistocene.[1] Its fossils have been found in Hungary, Greece[2], Crimea, Georgia, and China.[3] P. dmanisensis has been estimated standing 3.5 meters (11.5 feet) tall and weighing up to 450 kg (990 lb), making it much larger than the modern ostrich and one of the largest known birds.[1][4]
Taxonomy
[edit]The genus contains three species: P. pannonicus (the type species), P. dmanisensis, and P. transcaucasicus, which were all formerly placed with the ostrich genus, Struthio. Some authors have suggested placing the large (albeit smaller than P. dmanisensis) extinct ostrich species Struthio anderssoni from the Late Pleistocene of China in the genus.[5] Although P. dmanisensis is known as the giant ostrich, its relationship to the extant ostriches of the genus Struthio is not clear.[1][6]
Description
[edit]The femur of various specimens from P. dmanisensis measure from 380 – 390 mm in length and a have minimum shaft circumference of 220 – 240 mm, notably more robust than those of extant ostriches and other species within Struthio. The latter value can be used to calculate body mass, yielding values of 382 – 472 kg depending on the specimen.[3] Other mass estimates for this species from the femur have been 453 and 462 kg, utilizing different formulas.[1] An incomplete femur from the Nihewan Formation (China) has been assigned to Pachystruthio indet. and has smaller measurements than P. dmanisensis, with a length of 340 mm and minimum shaft circumference of 199 mm, which gives it a mass estimate of 300 kg.[3]
Paleobiology
[edit]Size
[edit]Zelenkov et al has proposed that larger body mass may have been an adaptation for tougher, low-nutrition food of arid environments, noting increased body mass in Dromornithidae has been related to increased aridity of Australia. This connection is also present in Eogruidae and has been proposed for Struthio anderssoni, whose large body mass may be explained by an increase in aridity in Inner Asia during cold climatic phases.[1] This hypothesis is contested, as Buffetaut and Angst note that in China where Pachystruthio lived was not especially arid. Additionally, Struthio anderssoni, although large, was smaller than Pachystruthio despite that it apparently lived under a more arid climate, and living ostriches that are also smaller lived and used to live in arid environments.[3]
Eggs
[edit]Pachystruthio laid eggs much larger than those of the extant ostriches, with material assigned to P. pannonicus measuring an estimated 22 / 18 cm and with a mass of 4.25 kg.[7] Eggshell associated with P. pannonicus is also much thicker than those of modern ostriches (2.6 – 3.4 mm).[1] P. transcaucasicus has also been associated with very thick eggshell fragments (2.9–3.3 mm)[7]
Locomotion
[edit]Vekua noted that the robust femur of P. dmanisensis compared to those more slender of other Pleistocene ostriches such as Struthio oldawayi may indicate it was less adapted for fast running. Similarly, Zelenkov et al. proposed Pachystruthio may not be as good a runner as modern ostriches due to its mass.[3] However, it has still been proposed that P. dmanisensis was a better runner than the giant species of Aepyornithidae which possess an even more robust femur.[1]
See also
[edit]
- Struthio wimani, flightless bird fossils in China
- Struthio orlovi, flightless bird fossils in Central and Eastern Europe
References
[edit]- ^ a b c d e f g Zelenkov, N. V.; Lavrov, A. V.; Startsev, D. B.; Vislobokova, I. A.; Lopatin, A. V. (2019). "A giant early Pleistocene bird from eastern Europe: unexpected component of terrestrial faunas at the time of early Homo arrival". Journal of Vertebrate Paleontology. 39 (2) e1605521. Bibcode:2019JVPal..39E5521Z. doi:10.1080/02724634.2019.1605521. S2CID 198384367.
- ^ Kostopoulos, Dimitris S.; Konidaris, George E.; Amanatidou, Marina; Chitoglou, Krystalia; Fragkioudakis, Emmanouil; Gerakakis, Nikolaos; Giannakou, Vasiliki; Gkeme, Anastasia; Kalaitzi, Christina; Tsakalidis, Christos; Tsatsalis, Vaggelis (March 2023). "The new fossil site Krimni-3 in Mygdonia Basin and the first evidence of a giant ostrich in the Early Pleistocene of Greece". PalZ. 97 (1): 147–161. Bibcode:2023PalZ...97..147K. doi:10.1007/s12542-022-00632-8. ISSN 0031-0220. S2CID 252750662.
- ^ a b c d e Buffetaut, Eric; Angst, Delphine (2021). "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. hdl:1983/0d3c1bba-d496-47b6-a61c-e141a472612a.
- ^ "Giant bird nearly as heavy as a polar bear lorded it over Pleistocene Europe". Nature. 571 (7763): 8. July 2019. doi:10.1038/d41586-019-01996-9. ISSN 0028-0836.
- ^ Buffetaut, Eric (2023-02-13). "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. ISSN 1424-2818.
- ^ McRae, Mike (27 June 2019). "Giant 11-Foot Bird Discovered in Europe Would Have Weighed Almost Half a Tonne". ScienceAlert. Retrieved 2019-06-27.
- ^ 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. ISSN 2813-6284.
- Burchak-Abramovich, N.; Vekua, A. (1990). "The fossil ostrich Struthio dmanisensis sp. n., from the Lower Pleistocene of Georgia" (PDF). Acta Zoologica Cracoviensia. 33 (7): 121–132.
- Hitchcock, Don (2010). "The Dmanisi Site". Retrieved 16 February 2011.
- Zicha, Ondrej (1999). "Struthio orlovi". Biological Library. Retrieved 2 February 2010.
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