Dromornithidae
Dromornithids | |
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Dromornis stirtoni
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Clade: | Pangalloanserae |
Superorder: | Galloanserae |
Family: | †Dromornithidae Fürbringer, 1888 |
Genera | |
Dromornithidae, known as mihirungs (after
Classification
The scientific name Dromornithidae derives from the
What the nearest relatives of this group are is a controversial issue. For many years it was thought that dromornithids were related toBelow is the general consensus of the phylogeny under the hypothesis that they are members of Anserimorphae.[11][12][13][14][15]
Odontoanserae |
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A 2017 paper concerning the evolution and phylogeny of the giant fowl by Worthy and colleagues have found phylogenetic support in finding the mihirungs to be the sister taxon to
Anserimorphae
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A 2021 study conversely found their internal cranial anatomy more similar to that of galliforms than to anseriforms.[16]
A 2022 study concerning their proteins found them to be sister group to the common group of galliforms and anseriforms.[17]
Two year later, Mclnerney, Blokland and
Anseriformes |
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Species
The number of taxa in the Dromornithidae family was recognised as eight species in four genera by 2021,
The classification of these species has been based upon distinguishing characters of the femur, all type specimens are femurs. The cranial remains occur less frequently, with three assignable to a species level.[3]
The placement of these dromornithid species may be summarised as:
Dromornithidae (8 species in 4 genera)[16]
- Barawertornis tedfordi
- Ilbandornis P. Rich, 1979
- Ilbandornis lawsoni
- Ilbandornis woodburnei
- Genyornis newtoni Stirling& A. H. C. Zietz, 1896
Discovery
The most recent species, Genyornis newtoni, was certainly known to Aboriginal Australians during the Late Pleistocene. Cave paintings thought to depict this bird are known, as are carved footprints larger than those considered to represent emus. At Cuddie Springs, Genyornis bones have been excavated in association with human artifacts. The issue of how much of an impact humans had on dromornithids and other large animals of the time is unresolved and much debated. Many scientists believe that human settlement and hunting were largely responsible for the extinction of dromornithids, as well as many other species of the Australian megafauna.
The first Europeans to encounter the bones of dromornithids may have been
Extensive collections of any dromornithid fossils were first made at Lake Callabonna, South Australia.
In 1892,
Other sites of importance were
The best represented bones of dromornithids are
Bones are not the only remains of dromornithids that have been found:
- The polished stones that the birds kept in their gizzards (muscular stomachs) occur at a number of sites. These stones, called gastroliths, played an important role in their digestion by breaking up coarse food or matter that was swallowed in large chunks.
- Series of footprints, called
- Impressions of the inside of the skull cavity (endocranial castsor endocasts) have been found. Endocasts are formed when sediments fill the empty skull, after which the skull is destroyed. These fossils give a fairly accurate picture of dromornithid brains.
Description
This section needs additional citations for verification. (May 2024) |
Dromornithids looked superficially like very large
Locomotion
Because of their enormous size, dromornithids have been considered to have been slow, lumbering creatures. Their legs are not long and slender like those of emus or ostriches, which are specialised for running. However, biomechanical analysis of the attachments and presumed sizes of the muscles suggest that dromornithids might have been able to run much faster than originally thought, making up for their less than ideal form with brute strength.[citation needed]
Sexual dimorphism
Rich deposits of
Endocast studies
A 2021 study found that dromornithids had an internal cranial anatomy similar to that of galliforms.[25]
Diet
It has been generally thought that the dromornithids were plant eaters, a belief currently considered common scientific consensus.[26] This belief is based on:
- the lack of a hook at the end of the bill
- the lack of talons on the toes
- the association of gizzard stones (caveat: gastroliths are also found in the stomachs of some carnivores, such as modern crocodiles)
- the large number of individuals occurring together, suggesting flocking behaviour
Functional interpretations by researchers Warren Handley and Trevor Worthy suggests that dromornithids were specialised herbivores that likely possessed well-developed stereoscopic depth perception, were diurnal and fed on soft browse such as new growth, soft leaves, and fruit. Musculature for operation of the bill is “surprisingly limited", suggesting that these birds were not capable of a particularly forceful bite. There is no temporal fossa on the side of the cranium for insertion of mandibular musculature. The culmen in Dromornis, while large, has a lightly constructed osseous core that was only partially covered in rhamphotheca, was highly vascularised and likely highly innervated, a combination of features conferring relatively weak biting ability. This suggests that dromornithids were likely not consuming coarse browse requiring strong bite forces.[16]
It has been suggested that, despite the indications of herbivory in some dromornithids, Bullockornis may have been a carnivore or possibly a scavenger. However, most authorities now consider it to be a herbivore.[26] The recently-extinct thylacine may have been a potential predator.
A study on the skull of Genyornis suggests they might have feed on aquatic plants.[27]
Distribution
Records of these birds are known only from Australia. Most of the records of dromornithids come from the eastern half of the continent, although fossil evidence has also been discovered in Tasmania and Western Australia. At some Northern Territory sites they are very common, sometimes comprising 60-70% of the fossil material.
The earliest bones identified were found in
Extinction
The reasons for the extinction of this entire family along with the rest of the Australian megafauna by the end of the Pleistocene are still debated. It is hypothesized that the arrival of the first humans in Australia (around 48-60 thousand years ago) and their hunting and landscape-changing use of fire may have contributed to the disappearance of the megafauna. However, drought conditions during peak
See also
- Fossil birds
- Later Quaternary prehistoric birds
Notes
- ^ Murray, P. F. & Megirian, D. (1998)
- ^ PMID 27027304.
- ^ a b Murray, P. F. & Vickers-Rich, P. (2004)
- ^ Miller, G. H. et al. (1999)
- ^ Roberts, R. G. et al. (2001)
- ^ Gerald Mayr, Paleogene Fossil Birds, 2009[page needed]
- ^ McInerney, P. L.; Blokland, J. C.; Worthy, T. H. (2024). "Skull morphology of the enigmatic Genyornis newtoni Stirling and Zeitz, 1896 (Aves, Dromornithidae), with implications for functional morphology, ecology, and evolution in the context of Galloanserae". Historical Biology: An International Journal of Paleobiology. 36 (6): 1093–1165. doi:10.1080/08912963.2024.2308212.
- Tjapwuringpeople of western Victoria that means 'giant bird'.
- ^ Fürbringer, Max (1888). Untersuchungen zur Morphologie und Systematik der Vögel, zugleich ein Beitrag zur Anatomie der Stütz- und Bewegungsorgane. Vol. 2. Amsterdam: T. van Holkema. p. 435.
- ^ PMID 29134094.
- ^ Murrary, P.F; Vickers-Rich, P. (2004). Magnificent Mihirungs: The Colossal Flightless Birds of the Australian Dreamtime. Indiana University Press.
- S2CID 9453177.
- .
- PMID 18784798.
- S2CID 13246547.
- ^ .
- PMID 35609205.
- .
- ^ a b Rich, P. (1979)
- S2CID 181496834.
- ^ Vickers-Rich, P. & Molnar, R. E. (1996)
- ^ Rich, P. & Gill, E. (1976)
- ^ Rich, P. & Green, R. H. (1974)
- ^ Sexual dimorphism in the late Miocene mihirung Dromornis stirtoni (Aves: Dromornithidae) from the Alcoota Local Fauna of central Australia, DOI:10.1080/02724634.2016.1180298, Received: 9 Jul 2015 Accepted: 20 Feb 2015 Published online: 07 Jun 2016
- .
- ^ a b Peter F. Murray,Patricia Vickers-Rich, Magnificent Mihirungs: The Colossal Flightless Birds of the Australian Dreamtime
- ^ McInerney, P. L.; Blokland, J. C.; Worthy, T. H. (2024). "Skull morphology of the enigmatic Genyornis newtoni Stirling and Zeitz, 1896 (Aves, Dromornithidae), with implications for functional morphology, ecology, and evolution in the context of Galloanserae". Historical Biology: An International Journal of Paleobiology. 36 (6): 1093–1165. doi:10.1080/08912963.2024.2308212.
- ISSN 0311-5518.
- ^ Field, J. H. & Boles, W. E. (1998)
- ^ Roberts et al. 2001
- ^ Wroe et al. 2002
References
- Field, J. H.; Boles, W. E. (1998). "Genyornis newtoni and Dromaius novaehollandiae at 30,000 b.p. in central northern New South Wales". Alcheringa. 22 (#2): 177–188. .
- Miller, G. H.; Magee, J. W.; Johnson, B. J.; Fogel, M. L.; Spooner, N. A.; McCulloch, M. T.; Ayliffe, L. K. (1999). "Pleistocene extinction of Genyornis newtoni: human impact on Australian megafauna". PMID 9880249.
- Murray, P. F.; Megirian, D. (1998). "The skull of dromornithid birds: anatomical evidence for their relationship to Anseriformes (Dromornithidae, Anseriformes)". Records of the South Australian Museum. 31: 51–97.
- Murray, Peter; Vickers-Rich, Patricia (2004). Magnificent mihirungs : the colossal flightless birds of the Australian dreamtime. Bloomington: Indiana University Press. ISBN 978-0-253-34282-9.
- Rich, P (1979). "The Dromornithidae, an extinct family of large ground birds endemic to Australia" (PDF). Bulletin of the Bureau of Mineral Resources, Geology and Geophysics. 184: 1–190.
- Rich, P.; Gill, E. (1976). "Possible dromornithid footprints from Pleistocene dune sands of southern Victoria, Australia". .
- Rich, P.; Green, R. H. (1974). "Footprints of birds at South Mt Cameron, Tasmania". doi:10.1071/mu974245.
- Roberts, R. G.; Flannery, T. F.; Ayliffe, L. A.; Yoshida, H.; Olley, J. M.; Prideaux, G. J.; Laslett, G. M.; Baynes, A.; Smith, M. A.; Jones, R.; Smith, B. L. (2001). "New ages for the last Australian megafauna: continent-wide extinction about 46,000 years ago". S2CID 45643228.
- Vickers-Rich, P.; Molnar, R. E. (1996). "The foot of a bird from the Eocene Redbank Plains Formation of Queensland, Australia". Alcheringa. 20 (1): 21–29. .
- Williams, D. L. G. (1981). "Genyornis eggshell (Dromornithidae; Aves) from the Late Pleistocene of South Australia". Alcheringa. 5 (#2): 133–140. .
- Williams, D. L. G.; Vickers-Rich, P. (1992). "Giant fossil egg fragment from the Tertiary of Australia". Contributions in Science, Natural History Museum of Los Angeles County. 36: 375–378.
Further reading
- Chinsamy, Anusuya; Handley, Warren D.; Worthy, Trevor H. (17 August 2022). "Osteohistology of Dromornis stirtoni (Aves: Dromornithidae) and the biological implications of the bone histology of the Australian mihirung birds". The Anatomical Record. 306 (7). Wiley: 1842–1863. PMID 37314297.