Hypselornis: Difference between revisions
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{{short description|Genus of fossil crocodilian}} |
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{{Italic title}} |
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| fossil_range = Late [[Pliocene]] |
| fossil_range = Late [[Pliocene]] |
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| image = |
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| image_caption = |
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| parent_authority = [[Richard Lydekker|Lydekker]], [[1891 in paleontology|1891]] |
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| type_species = {{Extinct}}'''''Hypselornis sivalensis''''' |
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| species = sivalensis |
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| authority = Lydekker, 1929 |
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| authority = Lydekker, 1891 |
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'''''Hypselornis''''' is |
'''''Hypselornis''''' is an [[extinct]] [[genus]] of [[fossil]] [[reptile]], most likely a [[crocodilian]], from the late [[Pliocene]] of [[India]]. Known only from a single [[toe bone]], ''Hypselornis'' was originally mistakenly identified as a [[ratite]] [[bird]] related to the living [[cassowary]] before being re-identified as belonging to a large reptile, probably a crocodilian. |
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==Discovery and |
==Discovery and naming== |
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The [[holotype]] specimen of ''Hypselornis'' (no. 39733) was found in the late [[Pliocene]] aged [[Siwalik Hills]] of northern India, and was collected by [[Proby Cautley]] who presented it to the [[Natural History Museum, London|Natural History Museum]] in [[London]]. This specimen consists of a single toe bone (phalanx), and was initially mistakenly thought to have been referred to ''[[Struthio asiaticus]]'' by [[Richard Lydekker]] in 1879. This mistake was corrected by [[palaeontologist]] [[William_Davies_(palaeontologist)|William Davies]] in 1880, who concluded that the phalanx was from the middle toe of a new species of ratite distinct from the contemporary ''Struthio asiaticus'' and ''[[Dromaius]] sivalensis'' (a purported species of [[emu]] from India also known from toe bones that themselves likely belong to an [[ungulate]] [[mammal]]).<ref name='Davies'>{{cite journal |last1=Davies |first1=W. |year=1880 |title=On some Fossil Bird-Remains from the Siwalik Hills in the British Museum |journal=[[Geological Magazine]] |volume=7 |issue=1 |pages=18–27 |doi=10.1017/S0016756800146904|bibcode=1880GeoM....7...18D |url=https://zenodo.org/record/2024847 }}</ref><ref name='Brodkorb'>{{cite journal |last1=Brodkorb |first1=P. |year=1978 |title=Catalogue of fossil birds, Part 5 (Passeriformes) |journal=Bulletin of the Florida State Museum, Biological Sciences |volume=23 |issue=3 |pages=139–228}}</ref> |
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The holotype of ''Hypselornis'' was found in the [[Siwalik Hills]] formation, dating to the Late Pliocene. It was first described in 1879 as '''''[[Dromaius]] sivalensis''''', before a slightly younger revision allocated it to its own genus.<ref>Lowe, Percy Roycroft 1929. Some remarks on Hypselornis sivalensis Lydekker. Ibis. 71: (4) 571–576. (Journal Article)</ref> |
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Lydekker would later classify the fossil as "Genus, non det." in 1884, and in 1891 he referred the fossil to its own genus and species, '''''Hypselornis sivalensis''''' (despite using the same [[Specific name (zoology)|specific name]], Lydekker named ''H. sivalensis'' as a new species independent of ''D. sivalensis'').<ref name='Lydekker'/><ref name='Lowe'>{{cite journal |last=Lowe |first=P. R. |year=1929 |title=Some remarks on ''Hypselornis sivalensis'' Lydekker. |journal=[[Ibis (journal)|Ibis]] |volume=71 |issue=4 |pages=571–576 |doi=10.1111/j.1474-919X.1929.tb08775.x}}</ref> An [[etymology]] for the name was never given by Lydekker, but one was offered by [[Ornithology|ornithologist]] [[Charles Wallace Richmond]] as deriving from the [[Ancient Greek]] "''ὑψηλός''" (lofty, towering) and "''ὄρνις''" (bird).<ref>{{cite journal |last=Richmond |first=C. W. |year=1902 |title=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," |journal=Proceedings of the United States National Museum |volume=24 |issue=1267 |pages=663–730 |doi=10.5479/si.00963801.1267.663|hdl=2027/coo.31924090189725 |hdl-access=free }}</ref> |
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==Classification== |
==Classification== |
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As indicated by the name, ''Hypselornis'' was originally interpreted as a fossil bird. It was first classified by Davies as belonging to a three-toe ratite similar to but distinct from emus and cassowaries, with a closer resemblance to the latter. Lydekker agreed with this classification when he named it as its own genus and included it within the [[Family (biology)|family]] [[Casuariidae]].<ref name='Lydekker'>{{cite book |title=Catalogue of the fossil birds in the British Museum (Natural History) |last=Lydekker |first=Richard |year=1891 |publisher=British Museum |location=London |page=224 |url=https://www.biodiversitylibrary.org/item/34492#page/258/mode/1up |access-date=6 August 2020}}</ref> |
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Originally interpreted as an emu, a slightly younger revision shifted it to its own genus due to its geographical range as well as the presence of a [[hallux]]. It is nonetheless considered a close relative and classified within [[Casuariidae]]. |
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However, when the fossil was later examined by [[ornithologist]] [[Percy Lowe]] in 1929, he concluded that the bone was certainly not from a bird and instead most likely belonged to a crocodilian. He based this conclusion through comparisons of the bone to those of ratites and a crocodile, and found ''Hypselornis'' to resemble those of crocodiles in a number of ways. The bone is much more proportionately stout compared to those of ratites, and its asymmetry is also inconsistent with the toe bones of ratites. Furthermore, it does not taper towards its tip as it would in most ratites, and is instead constricted in its centre like that of a crocodile's. Rowe further identified six more details of the bone that were inconsistent with ratites, but similar to those of crocodiles. However, he was unable to perform a more conclusive diagnosis of ''Hypselornis'' without further comparison to other fossil Indian crocodilians. This re-identification has since been maintained by later authors.<ref name='Lowe'/><ref name='Brodkorb'/> |
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==Paleogeographical implications== |
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The presence of a casuariiform ratite in India originally puzzled researchers, which proposed a putative but unsatisfactory vicariant origin from [[Insular India|India's gondwanan past]]. In more recent years, ratites have been understood and having lost the ability to fly multiple times and likely having had a laurasian origin, suggesting a more recent aerial dispersal across the various landmasses from northern [[lithornithid]]-like ancestors.<ref>Yonezawa, T.; Segawa, T.; Mori, H.; Campos, P. F.; Hongoh, Y.; Endo, H.; Akiyoshi, A.; Kohno, N.; Nishida, S.; Wu, J.; Jin, H.; Adachi, J.; Kishino, H.; Kurokawa, K.; Nogi, Y.; Tanabe, H.; Mukoyama, H.; Yoshida, K.; Rasoamiaramanana, A.; Yamagishi, S.; Hayashi, Y.; Yoshida, A.; Koike, H.; Akishinonomiya, F.; Willerslev, E.; Hasegawa, M. (2016-12-15). "Phylogenomics and Morphology of Extinct Paleognaths Reveal the Origin and Evolution of the Ratites". Current Biology. 27 (1): 68–77. doi:10.1016/j.cub.2016.10.029. PMID 27989673.</ref><ref>Phillips MJ, Gibb GC, Crimp EA, Penny D (January 2010). "Tinamous and moa flock together: mitochondrial genome sequence analysis reveals independent losses of flight among ratites". Systematic Biology. 59 (1): 90–107. doi:10.1093/sysbio/syp079. PMID 20525622.</ref> Should a casuariiform identity be accurate, it indicates that this particular lineage developed flightlessness multiple times. |
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==Palaeobiology== |
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Due to the presence of a hallux as well as its forest habitat, ''Hypselornis'' is assumed to have been a cassowary-like forest dweller. |
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==References== |
==References== |
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{{Reflist}} |
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{{Taxonbar|from=Q60791479}} |
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[[Category: |
[[Category:Crocodilians]] |
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[[Category: |
[[Category:Prehistoric pseudosuchian genera]] |
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[[Category: |
[[Category:Pliocene reptiles of Asia]] |
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[[Category: |
[[Category:Pliocene crocodylomorphs]] |
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[[Category: |
[[Category:Fossil taxa described in 1891]] |
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Latest revision as of 14:22, 19 October 2022
| Hypselornis Temporal range: Late Pliocene
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Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Archosauromorpha |
| Clade: | Archosauriformes |
| Order: | Crocodilia |
| Genus: | †Hypselornis Lydekker, 1891 |
| Species: | †H. sivalensis
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| Binomial name | |
| †Hypselornis sivalensis Lydekker, 1891
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Hypselornis is an extinct genus of fossil reptile, most likely a crocodilian, from the late Pliocene of India. Known only from a single toe bone, Hypselornis was originally mistakenly identified as a ratite bird related to the living cassowary before being re-identified as belonging to a large reptile, probably a crocodilian.
Discovery and naming
[edit]The holotype specimen of Hypselornis (no. 39733) was found in the late Pliocene aged Siwalik Hills of northern India, and was collected by Proby Cautley who presented it to the Natural History Museum in London. This specimen consists of a single toe bone (phalanx), and was initially mistakenly thought to have been referred to Struthio asiaticus by Richard Lydekker in 1879. This mistake was corrected by palaeontologist William Davies in 1880, who concluded that the phalanx was from the middle toe of a new species of ratite distinct from the contemporary Struthio asiaticus and Dromaius sivalensis (a purported species of emu from India also known from toe bones that themselves likely belong to an ungulate mammal).[1][2]
Lydekker would later classify the fossil as "Genus, non det." in 1884, and in 1891 he referred the fossil to its own genus and species, Hypselornis sivalensis (despite using the same specific name, Lydekker named H. sivalensis as a new species independent of D. sivalensis).[3][4] An etymology for the name was never given by Lydekker, but one was offered by ornithologist Charles Wallace Richmond as deriving from the Ancient Greek "ὑψηλός" (lofty, towering) and "ὄρνις" (bird).[5]
Classification
[edit]As indicated by the name, Hypselornis was originally interpreted as a fossil bird. It was first classified by Davies as belonging to a three-toe ratite similar to but distinct from emus and cassowaries, with a closer resemblance to the latter. Lydekker agreed with this classification when he named it as its own genus and included it within the family Casuariidae.[3]
However, when the fossil was later examined by ornithologist Percy Lowe in 1929, he concluded that the bone was certainly not from a bird and instead most likely belonged to a crocodilian. He based this conclusion through comparisons of the bone to those of ratites and a crocodile, and found Hypselornis to resemble those of crocodiles in a number of ways. The bone is much more proportionately stout compared to those of ratites, and its asymmetry is also inconsistent with the toe bones of ratites. Furthermore, it does not taper towards its tip as it would in most ratites, and is instead constricted in its centre like that of a crocodile's. Rowe further identified six more details of the bone that were inconsistent with ratites, but similar to those of crocodiles. However, he was unable to perform a more conclusive diagnosis of Hypselornis without further comparison to other fossil Indian crocodilians. This re-identification has since been maintained by later authors.[4][2]
References
[edit]- ^ Davies, W. (1880). "On some Fossil Bird-Remains from the Siwalik Hills in the British Museum". Geological Magazine. 7 (1): 18–27. Bibcode:1880GeoM....7...18D. doi:10.1017/S0016756800146904.
- ^ a b Brodkorb, P. (1978). "Catalogue of fossil birds, Part 5 (Passeriformes)". Bulletin of the Florida State Museum, Biological Sciences. 23 (3): 139–228.
- ^ a b Lydekker, Richard (1891). Catalogue of the fossil birds in the British Museum (Natural History). London: British Museum. p. 224. Retrieved 6 August 2020.
- ^ a b Lowe, P. R. (1929). "Some remarks on Hypselornis sivalensis Lydekker". Ibis. 71 (4): 571–576. doi:10.1111/j.1474-919X.1929.tb08775.x.
- ^ Richmond, C. W. (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,"". Proceedings of the United States National Museum. 24 (1267): 663–730. doi:10.5479/si.00963801.1267.663. hdl:2027/coo.31924090189725.