Pelagornis

Source: Wikipedia, the free encyclopedia.
This article is about the Neogene fossil bird. For the Cretaceous genus formerly described as Pelagornis by Seeley, see Enaliornis.

Pelagornis
Temporal range:
Ma
Reconstruction of a P. miocaenus skeleton at the
NMNH
.
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Clade: incertae sedis
Order: †Odontopterygiformes
Family: †Pelagornithidae
Genus: †Pelagornis
Lartet, 1857
Type species
†Pelagornis miocaenus
Lartet, 1857
Species

†P. miocaenus Lartet, 1857
†P. mauretanicus Mourer-Chauviré & Geraads, 2008
†P. chilensis Mayr & Rubilar, 2010
†P. sandersi Ksepka, 2014
and see text

Synonyms

see text

Pelagornis is a widespread

Odontopterygiformes to account for this uncertainty.[1]

Taxonomy

Four

suborder (Sulae) or united with other pseudotooth birds in a suborder Odontopterygia.[3]

While P. miocaenus was the first pseudotooth bird species to be described scientifically, its

MN17) deposits at Ahl al Oughlam (Morocco).[4]

Restored skull of P. sandersi

Additional

USNM 244174 (a tarsometatarsus fragment) was found near Charleston, South Carolina and assigned to P. miocaenus, and the slightly smaller left tarsometatarsal middle trochlea USNM 476044 might also belong here. A broken but fairly complete sternum probably of this genus, specimen LHNB (CCCP)-1, is known from the Serravallian-Tortonian boundary (Middle to Late Miocene) near Costa da Caparica in Portugal
. Contemporary are certain specimens
Early Pliocene.[7]

It is not clear whether the

North Canterbury, New Zealand) seems to differ little from either O. orri or P. miocaenus. The Pisco Formation specimens – which may be from the same species as the Bahía Inglesa ones, or from its direct descendant – on the other hand seem to be well distinct from Osteodontornis. It must be remembered, however, that the Isthmus of Panama had not been formed yet during the Miocene.[9]

Pelagornis sandersi was described in July 2014, whose fossil remains date from 25 million years ago, during the Chattian age of the Oligocene.[10][11] The only known fossil of P. sandersi was first uncovered in 1983 at Charleston International Airport, South Carolina, discovered by James Malcom, while working construction building a new terminal there. At the time the bird lived, 25 million years ago, global temperatures were higher, and the area where it was discovered was an ocean.[12][13] After excavation, the fossil of P. sandersi was catalogued and put in storage at the Charleston Museum, where it remained until it was rediscovered by paleontologist Dan Ksepka in 2010.[14][15] The bird is named after Albert Sanders, the former curator of natural history at the Charleston Museum, who led the excavation of P. sandersi.[16] It currently sits at the Charleston Museum, where it was identified as a new species by Ksepka in 2014.[11]

Synonyms and relationships

P. chilensis skeleton seen from below

A humerus from the

Palaeochenoides mioceanus was also hypothesized to include P. longirostris, and would need to be compared with Pelagornis to see whether it does not belong here too.[17]

Skull of P. mauretanicus

There has been little dedicated study of the relationships of Pelagornis, for while quite a lot of remains are known from the present genus, those of most other pseudotooth birds are few and far between and direct comparisons are further hampered by the damaged state of most remains. The large

articular facet for the furcula consists of a flat section at the very tip of the sternal keel and a similar one set immediately above it at an outward angle, and the spina externa is shaped like an Old French shield in cross-section. The slightly smaller LHNB (CCCP)-1 has a less sharply protruding sternal keel, the articular facet for the furcula consists of a large knob at the forward margin, and the spina externa is narrow in cross-section. While these differences are quite conspicuous, the two fossils are clearly of closely related huge dynamically soaring seabirds, and considering the 30 million years or so that separate Gigantornis and LHNB (CCCP)-1, the Paleogene taxon may be very close to the Miocene bird's ancestor nonwithstanding their differences.[18]

In any case, the

symplesiomorphy that is not informative regarding their relationships to each other and with Pelagornis. Rather, it is likely that the huge pseudotooth birds form a clade, and in this case, Pseudodontornithidae like Cyphornithidae and Dasornithidae is correctly placed in the synonymy of Pelagornithidae even if several families were accepted in the Odontopterygiformes.[20]

Description

Size and wingspan

wandering albatross
(Diomeda exulans)

The sole specimen of P. sandersi has a

Argentavis magnificens. The skeletal wingspan (excluding feathers) of P. sandersi is estimated at 5.2 m (17 ft) while that of A. magnificens is estimated at 4 m (13 ft).[16][22]

The fossil specimens show that P. miocaenus was one of the largest pseudotooth birds, hardly smaller in size than Osteodontornis or the older Dasornis. Its head must have been about 40 cm (16 in) long in life, and its wingspan was probably more than 5 m (16 ft), perhaps closer to 6 metres (20 ft).

Skull

Skull diagram and pseudoteeth of P. mauretanicus

Like all members of the

eye sockets
were extremely large and well-developed in Pelagornis.

Postcranial skeleton

Pelagornis differed from

apomorphic, the latter two may indeed be very close relatives.[23]

Paleobiology

Life restoration of P. chilensis

P. sandersi had short, stumpy legs, and was probably only able to fly by hopping off cliff edges.[22] This is supported by its location being near coasts. Originally, there were controversies over whether or not P. sandersi would be able to fly. Previously, the assumed maximum wingspan of a flying bird was 17 ft (5.2 m), because it was hypothesized that above 17 ft, the power required to keep the bird in flight would surpass the power capacity of the bird's muscles. However, this calculation is based on the assumption that the bird in question stays aloft by repeatedly flapping its wings, whereas P. sandersi more likely glided on ocean air currents close to the water, which is less power-intensive than reaching high altitudes.[15][24] It has been estimated that it was able to fly at up to 60 km/h (37 mph).[22] P. sandersi's long wingspan and gliding power would have enabled it to travel long distances without landing while hunting.[13] Due to P. sandersi's size, the bird likely molted all of its flight feathers at once, similarly to a grebe, since larger feathers take longer to regrow.[13] P. sandersi is theorized to have glided and traveled similarly to a modern albatross, however, according to Dan Ksepka, its closest modern relatives are chickens and ducks.[14]

Some scientists expressed surprise at the idea that this species could fly at all, given that, at between 22 and 40 kg (48 and 88 lb), it would be considered too heavy by the predominant theory of the mechanism by which birds fly.[25] Dan Ksepka of the National Evolutionary Synthesis Center in Durham, North Carolina, who identified that the discovered fossils belonged to a new species, thinks it was able to fly in part because of its relatively small body and long wings,[26] and because it, like the albatross, spent much of its time over the ocean.[12] Ksepka is currently focused on solving how P. sandersi evolved and what caused the species to go extinct.[14]

Distribution

Fossils of Pelagornis have been found in:[27]

Eocene
Oligocene
Miocene
Pliocene
Early Pleistocene

References

  1. ^ Bourdon (2005), Mayr (2009: p. 59)
  2. ^ Olson (1985: p. 197)
  3. ^ Lanham (1947), Brodkorb (1963: p. 262–263), Olson (1985: p. 197), Mlíkovský (2002: pp. 83–84)
  4. ^ Mlíkovský (2009)
  5. MUSM 209 (a broken left humerus), MUSM 265 (a broken right humerus), MPC 1000 (a proximal
    right humerus end), and perhaps the additional remains MPC 1001 to 1006: Chávez et al. (2007)
  6. tarsometatarsi), perhaps also a distal right coracoid; all from near Bahía Inglesa
    : Walsh (2000), Walsh & Hume (2001), Chávez et al. (2007)
  7. MNHN
    : Chávez et al. (2007)
  8. cervical vertebrae
    ): Chávez et al. (2007)
  9. ^ Scarlett (1972), Olson (1985: pp. 195-199), Goedert (1989), Rasmussen (1998), Mlíkovský (2002: p. 84), Rincón R. & Stucchi (2003), Bourdon (2005), Chávez et al. (2007), Mayr et al. (2008), NEO (2008), NMNH-DP [2009]
  10. ^
    PMID 25002475
    .
  11. ^ a b Osborne, Hannah (July 7, 2014). "Pelagornis Sandersi: World's Biggest Bird Was Twice as Big as Albatross with 24 feet (7.3 m) Wingspan". International Business Times. Archived from the original on July 7, 2014. Retrieved July 7, 2014.
  12. ^ a b c Feltman, Rachel (July 7, 2014). "A newly declared species may be the largest flying bird to ever live". The Washington Post. Retrieved July 11, 2014.
  13. ^ a b c Charles Q. Choi (2014-07-07). "World's Largest Flying Bird Was Like Nothing Alive Today". livescience.com. Retrieved 2022-09-21.
  14. ^ a b c "This Ancient Bird Had the Largest Wingspan Ever". Connecticut Public. 2014-07-14. Retrieved 2022-09-21.
  15. ^ a b Hu, Jane C. (2014-07-07). "The World's Largest Flying Bird Had a Wingspan the Length of Four People Laid Head to Toe". Slate Magazine. Retrieved 2022-09-21.
  16. ^ a b Choi, Charles Q. (July 7, 2014). "World's largest flying bird was like nothing alive today". Fox News. Fox News. Archived from the original on July 8, 2014. Retrieved July 7, 2014.
  17. ^ Brodkorb (1963: pp. 245, 263), Hopson (1964), Olson (1985: p. 198), Mlíkovský (2002: pp. 80, 82-83)
  18. ^ Olson (1985: p. 196), Mayr (2009: p. 56, 58), Mayr et al. (2008)
  19. ^ As Argillornis; see Mayr (2008)
  20. ^ Olson (1985: p. 195), Mlíkovský (2002: p. 81), Bourdon (2005), Mayr (2009: p. 59)
  21. ^ Morelle, Rebecca (July 7, 2014). "Fossil of 'largest flying bird' identified". BBC News. Archived from the original on July 7, 2014. Retrieved July 8, 2014.
  22. ^ a b c Karim, Nishad (July 7, 2014). "Fossils dug up at airport may be largest flying bird ever found". The Guardian. Archived from the original on July 8, 2014. Retrieved July 7, 2014.
  23. ^ Olson (1985: p. 198), Goedert (1989), Rincón R. & Stucchi (2003), Bourdon (2005), Mayr (2008), Mayr et al. (2008)
  24. ^ "Biggest Flying Seabird Had 21-Foot Wingspan, Scientists Say". History. 2014-07-07. Archived from the original on September 21, 2022. Retrieved 2022-09-21.
  25. Wall Street Journal. Archived
    from the original on July 11, 2014. Retrieved July 7, 2014.
  26. ^ Khan, Amina (July 7, 2014). "Fossil's 21-foot wingspan shows Pelagornis was 'largest flying bird'". Los Angeles Times. Archived from the original on July 8, 2014. Retrieved July 8, 2014.
  27. ^ Pelagornis at Fossilworks.org

Bibliography

External links
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