Biology:Physornis

From HandWiki

Physornis is an extinct genus of giant flightless predatory birds of the family Phorusrhacidae or "terror birds", most closely related to Paraphysornis, that lived in Argentina. The type species is P. fortis. It lived during the Middle to Late Oligocene (Deseadan). Few fossils are known, but the available material suggests that Physornis was one of the largest phorusrhacids.[1]

History and taxonomy

Fossils assigned to Physornis were first discovered in the "Pyrotherium beds" near the Deseado River,[2] eastern Santa Cruz Province, Argentina by crews working for Argentine paleontologist Florentino Ameghino.[3][1] These rock layers derive from the Oligocene-aged Deseado Formation, which corresponds to the Deseadan SALMA (South American Land Mammal Ages; a series of fauna-based geological ages), making it among the oldest known confirmed phorusrhacids. Only a single fossil, a fragment of the mandibular symphysis (the area where the mandibulae (lower jaws) meet) and attached portion of the right mandible, was found.[1][2] In 1895, Ameghino scientifically described the specimen and assigned it to a new genus and species of phorusrhacid bird, which he dubbed Physornis fortis.[3] The generic name is a combination of the Greek roots φύσια (physero) meaning "bellows" and ὄρνις (ornis) meaning "bird".[4] This specimen was kept in Ameghino's personal collection until 1895 or 1896, when Ameghino sold it and several other Argentine bird fossils to the Natural History Museum, London.[5] There, the specimen was deposited under catalog number BMNH-A583. The type specimen of Physornis fortis is very fragmentary and besides the type symphysis has virtually no other characteristics. As a result, Physornis' validity has historically come into question.[1][6][7]

During the late 19th and early 20th centuries, American institutions and museums began conducting their own expeditions to Neogene strata in Argentina.[8][9][10] In 1911, Amherst College mounted an expedition to Deseado Formation deposits in Chubut Province, Argentina. This venture, led by American paleontologist Frederic Brewster Loomis, unearthed a large, isolated right femur (thighbone) in Puesto Almendra that he assigned to Physornis in 1914. He did this based on its large size and similarity to Phorusrhacos', a phorusrhacid known from the Miocene. Loomis (1914) also noted the fragmentary nature of the holotype, stating it may be synonymous with Phorusrhacos, but opted to keep the two distinct.[10][1] In 1922, the Field Museum launched the Marshall Field Expeditions to fossiliferous outcrops, including Deseadan ones, in Argentina and Bolivia. This included to Cabeza Blanca, Chubut Province, where American paleontologist George F. Sternberg discovered an associated specimen including a mandibular symphysis, a quadratojugal (cheekbone) fragment, atlas (the first cervical vertebra), vertebra fragments, and pedal phalanges (which was deposited at the Field Museum under specimen number FM-P13340)[11] and a mandible fragment, femur, tibiotarsus, and tarsometatarsus (FM-P13619).[12] These specimens were assigned to Physornis by Alvarenga and Höfling (2003).[1] Another fossil, a single In 1941, American ornithologist Bryan Patterson stated that, after an in person examination, Physornis' holotype was likely not avian. Instead, he speculated that it could be a shard from the iliac crest of the giant mammals Parastrapotherium or Pyrotherium. He provisionally considered it a nomen dubium.[2][6] In contrast, studies like by American paleontologist Pierce Brodkorb (1967) argued that it was actually valid, though did not go into extensive detail. Upon reexamination, a 2003 article by Brazilian paleontologists Herculano Alvarenga and Elizabeth Höfling found that it was valid, although extremely fragmentary. They stated it was a close relative of the other phorusrhacids Paraphysornis and Brontornis,[1] though the latter is now classified as a galliform.[13][14]

Synonyms and other species

  • In 1898, Ameghino dubbed another phorusrhacid genus and species, Aucornis eurhynchus, on the basis of an incomplete mandibular symphysis, the proximal (towards body) end of a tarsometatarsus, and three pedal phalanges (toe bones) that had been found in "Cretaceous" Patagonian strata in Santa Cruz Province.[1][15] However, these fossils come from the Oligocene-aged Deseado Formation instead. Due to similarities in their symphysis morphology, Brodkorb (1967) and several other studies have considered it a synonym of P. fortis. The associated nature of these remains allowed for the identification of several postcranial elements of Physornis, including another tarsometatarsus.[1][2]
  • In 1899, Ameghino described another phorusrhacid from the "Cretaceous" of Patagonia, Aucornis solidus, on the proximal end of a pedal phalanx from the third toe. It too comes from the Deseado Formation. Although Brodkorb (1967) considered it a synonym of P. fortis,[2] Alvarenga and Höfling (2003) opted to consider it a species inquirenda because it could be a synonym of Andrewsornis as well.[1]
  • In 1982, Alvarenga named a new species of Physornis, Physornis brasiliensis, based on a 75% complete skeleton from the Upper Oligocene-Lower Miocene layers of São Paulo, Brazil.[16] In 1993, Alvarenga came to the conclusion that it was actually its own genus, which he named Paraphysornis.[17]

Description

Ameghino differentiated Physornis from Phorusrhacos and Brontornis based on its age and that the former has a more convex mandibular surface. Physornis has been referred to the Brontornithinae subfamily, the largest and most solidest shock birds, though Brontornis itself is likely not a Phorusrhacid. Physornis probably had a huge size, possibly even approaching to that of Brontornis. The Symphysis Mandibulae is remarkably short and wide and has a characteristic ventral surface in the middle section. The lateral edge of the Hypotarsus is, seen from behind, an excellent comb that clearly distinguishes the genus Paraphysornis and Brontornis.[7][1] The lateral cotyle of the tarsometatarsus is almost square when it is seen from close by.[1]

Classification

Ameghino originally classified Physornis with his taxa Phorusrhacos and Tolmodus, though in years since it has also been classified closest to Brontornis and Paraphysornis, the former possibly being a type of gastornithid or Anseriform instead.[13] The following phylogenetic tree shows the internal relationships of Phorusrhacidae under the exclusion of Brontornis as published by Degrange and colleagues in 2015, which recovers Physornis as a member of a large clade that includes Patagornis, Phorusrhacos and Andalgalornis, among others.[18]

Paleobiology

In 2025, German paleontologist Lotta Dreyer and colleagues published a study wherein they analyzed the histology and growth patterns of Physornis and Andrewsornis. Using the limb bones of FM-P13619, Dreyer and colleagues extracted thin bone samples which they studied using ground-section microscopy. This allowed them to research the growth structures, vascularization systems, and remodeling processes of the bone tissues. The femur fragment displays a stocky set of cortical bone, which features highly vascularized fibrolamellar interspersed with secondary osteons.[12]

References

  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 Alvarenga, Herculano M. F.; Höfling, Elizabeth (2003). "Systematic revision of the Phorusrhacidae (Aves: Ralliformes)" (in en). Papéis Avulsos de Zoologia 43 (4): 55–91. doi:10.1590/S0031-10492003000400001. ISSN 0031-1049. https://www.scielo.br/j/paz/a/4Fg4WZvd43qzy65KSpSyWLb/?lang=en. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Brodkorb, Pierce (1967-06-12). "Catalogue of Fossil Birds, Part 3 (Ralliformes, Ichthyornithiformes, Charadriiformes)" (in en). Bulletin of the Florida Museum of Natural History 11 (3): 99–220. doi:10.58782/flmnh.koax3014. ISSN 2373-9991. https://flmnhbulletin.com/index.php/flmnh/article/view/flmnh-vol11-no3. 
  3. ↑ 3.0 3.1 Ameghino, Florentino (1895). "Sur les oiseaux fossils de patagonie et le faune mammalogique des couches á Pyrotherium. Premiére contribution á la connissance de la faune mammalogique des couches á Pyrotherium.". Boletín del Instituto Geografico Argentino 15: 603–660. 
  4. ↑ Charles, Richmond (1902). "List of generic terms proposed for birds during the years 1890 to 1900, inclusive, to which are added names omitted by Waterhouse in his "Index Generum Avium"" (in en). Proceedings of the United States National Museum 24 (1241–1274): 663–730. doi:10.5479/si.00963801.1267.663. ISSN 0096-3801. http://www.biodiversitylibrary.org/page/15782588. 
  5. ↑ Buffetaut, Eric (2013). "Who discovered the Phorusrhacidae? An episode in the history of avian palaeontology". Paleornithological Research 2013. Proceedings of the 8th International Meeting of the Society of Avian Paleontology and Evolution: Wien, Naturhistorisches Museum 8: 123–134. https://verlag.nhm-wien.ac.at/buecher/2013_SAPE_Proceedings/10_Buffetaut.pdf. 
  6. ↑ 6.0 6.1 Patterson, Bryan (1941). "A new phororhacoid bird from the Deseado formation of Patagonia". Publication (Field Museum of Natural History). Geological Series 8 (8): 49–54. https://www.biodiversitylibrary.org/bibliography/3387. 
  7. ↑ 7.0 7.1 Brodkorb, P. (1967). Catalogue of fossil birds: part 3 (Ralliformes, Ichthyornithiformes, Charadriiformes). University of Florida.
  8. ↑ Fernicola, Juan Carlos; Bargo, M. Susana; Vizcaíno, Sergio Fabián; Kay, Richard (20 December 2019). "Historical background for a revision of the paleontology of the Santa Cruz Formation (Early-Middle Miocene) along the Río Santa Cruz, Patagonia, Argentina" (in en). Publicación Electrónica de la Asociación Paleontológica Argentina 19 (2). doi:10.5710/PEAPA.18.09.2019.300. ISSN 2469-0228. https://peapaleontologica.org.ar/index.php/peapa/article/view/300. 
  9. ↑ Vizcaíno, Sergio; Brinkman, Paul D.; Kay, Richard F. (2016). "Sobre los objetivos y resultados de la expedición paleontológica de Handel T. Martin (1903-04) a la Formación Santa Cruz en Patagonia austral." (in en). Revista del Museo de La Plata 1: 316–333. doi:10.24215/25456377e037. ISSN 2545-6377. https://publicaciones.fcnym.unlp.edu.ar/rmlp/article/view/143. 
  10. ↑ 10.0 10.1 Loomis, Frederic Brewster; Amherst Patagonian Expedition (8th : 1911) (1914). The Deseado Formation of Patagonia. Concord, N.H: Published under the auspices of the Trustees of Amherst College [by] Rumford Press. doi:10.5962/bhl.title.28110. https://www.biodiversitylibrary.org/bibliography/28110. 
  11. ↑ "Field Museum Geology Collections". 2026. https://collections-geology.fieldmuseum.org/catalogue/2391157. 
  12. ↑ 12.0 12.1 Dreyer, Lotta; Cooper, Christian; O'Connor, Jingmai (2026-01-19). "Osteohistology of two phorusrhacids reveals uninterrupted growth strategy" (in en). The Anatomical Record. doi:10.1002/ar.70135. ISSN 1932-8486. https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/ar.70135. 
  13. ↑ 13.0 13.1 Agnolin, Federico L. (2021-02-20). "Reappraisal on the Phylogenetic Relationships of the Enigmatic Flightless Bird (Brontornis burmeisteri) Moreno and Mercerat, 1891" (in en). Diversity 13 (2): 90. doi:10.3390/d13020090. ISSN 1424-2818. Bibcode: 2021Diver..13...90A. 
  14. ↑ Agnolin, Federico (2007). "Brontornis burmeisteri Moreno & Mercerat, un Anseriformes (Aves) gigante del Mioceno Medio de Patagonia, Argentina" (in es). Revista del Museo Argentino de Ciencias Naturales 9 (1): 15–25. ISSN 1853-0400. https://revista.macn.gob.ar/index.php/RevMus/article/view/361. 
  15. ↑ Ameghino, Florentino (1898). "Sinopsis geológico-paleontológica de la Argentina." (in es). Segundo Censo de la República Argentina 1: 112–255. https://books.google.com/books?id=LjVYAAAAYAAJ&dq=Aucornis&pg=PA694. 
  16. ↑ Alvarenga, H.M.F. (1982). "Uma gigantesca ave fóssil do cenozóico brasileiro: Physornis brasiliensissp. n." Anais da Academia Brasileira de Ciências. 54 (4): 697–712.
  17. ↑ Alvarenga, H.M.F. (1993). "Paraphysornis Novo Gênero Para Physornis brasiliensis Alvarenga, 1982 (Aves:Phorusrhacidae)". Anais da Academia Brasileira de Ciências. 65 (4): 403–406.
  18. ↑ Degrange, F.J.; Tambussi, C.P.; Taglioretti, M.L.; Dondas, A.; Scaglia, F. (2015). "A new Mesembriornithinae (Aves, Phorusrhacidae) provides new insights into the phylogeny and sensory capabilities of terror birds". Journal of Vertebrate Paleontology 35 (2). doi:10.1080/02724634.2014.912656. Bibcode: 2015JVPal..35E2656D. 

Template:Cariamiformes Wikidata ☰ Q1617702 entry



Retrieved from "https://handwiki.org/wiki/index.php?title=Biology:Physornis&oldid=4470427"