stegodon

{{Short description|Genus of extinct proboscidean}}

{{Use dmy dates|date=July 2022}}

{{Automatic taxobox

| fossil_range = Late MioceneLate Pleistocene, {{fossil_range|11.6|0.01}}

| image = Giant Mastodon Skeleton (10096915486) (cropped).jpg

| image_upright = 1.1

| image_caption = Stegodon skeleton at the Gansu Provincial Museum

| taxon = Stegodon

| authority = Falconer, 1847

| subdivision_ranks = Species

| subdivision = *{{extinct}}S. aurorae (Matsumoto, 1918)

  • {{extinct}}S. elephantoides (Clift, 1828)
  • {{extinct}}S. florensis Hooijer, 1957
  • {{extinct}}S. ganesha
    (Faloner and Cautley, 1846)
  • {{extinct}}S. kaisensis Hopwood, 1939
  • {{extinct}}S. luzonensis
    von Koenigswald, 1956
  • {{extinct}}S. miensis (Matsumoto, 1941)
  • {{extinct}}S. mindanensis (Naumann, 1890)
  • {{extinct}}S. orientalis Owen, 1870
  • {{extinct}}S. protoaurorae (Aiba et al., 2010)
  • {{extinct}}S. sompoensis Hooijer, 1964
  • {{extinct}}S. sondaari van den Bergh, 1999
  • {{extinct}}S. trigonocephalus (Martin, 1887)
  • {{extinct}}S. zdanskyi Hopwood, 1935

}}

Stegodon (from the Ancient Greek στέγω (stégō), meaning "to cover", and ὀδούς (odoús), meaning "tooth", named for the distinctive ridges on the animal's molars) is an extinct genus of proboscidean, related to elephants. It was originally assigned to the family Elephantidae along with modern elephants but is now placed in the extinct family Stegodontidae. Like elephants, Stegodon had teeth with plate-like lophs that are different from those of more primitive proboscideans like gomphotheres and mammutids.{{Cite journal |last=Saegusa |first=Haruo |date=March 2020 |title=Stegodontidae and Anancus: Keys to understanding dental evolution in Elephantidae |url=https://linkinghub.elsevier.com/retrieve/pii/S0277379119302665 |journal=Quaternary Science Reviews |language=en |volume=231 |pages=106176 |doi=10.1016/j.quascirev.2020.106176|bibcode=2020QSRv..23106176S |s2cid=214094348 |url-access=subscription }} Fossils of the genus are known from Africa and across much of Asia, as far southeast as Timor (with a single record in southeast Europe). The oldest fossils of the genus are found in Late Miocene strata in Asia, likely originating from the more archaic Stegolophodon, subsequently migrating into Africa.{{Cite journal |last1=Ao |first1=Hong |last2=Zhang |first2=Peng |last3=Dekkers |first3=Mark J. |last4=Roberts |first4=Andrew P. |last5=An |first5=Zhisheng |last6=Li |first6=Yongxiang |last7=Lu |first7=Fengyan |last8=Lin |first8=Shan |last9=Li |first9=Xingwen |date=January 2016 |title=New magnetochronology of Late Miocene mammal fauna, NE Tibetan Plateau, China: Mammal migration and paleoenvironments |url=https://linkinghub.elsevier.com/retrieve/pii/S0012821X15007232 |journal=Earth and Planetary Science Letters |language=en |volume=434 |pages=220–230 |doi=10.1016/j.epsl.2015.11.019|bibcode=2016E&PSL.434..220A |hdl=1874/330309 |hdl-access=free }} While the genus became extinct in Africa during the Pliocene, Stegodon persisted in South, Southeast and Eastern Asia into the Late Pleistocene.{{Cite journal |last1=O’Regan |first1=H. J. |last2=Bishop |first2=L. C. |last3=Lamb |first3=A. |last4=Elton |first4=S. |last5=Turner |first5=A. |date=2005-01-01 |title=Large mammal turnover in Africa and the Levant between 1.0 and 0.5 Ma |url=https://sp.lyellcollection.org/content/247/1/231 |journal=Geological Society, London, Special Publications |language=en |volume=247 |issue=1 |pages=231–249 |doi=10.1144/GSL.SP.2005.247.01.13 |bibcode=2005GSLSP.247..231O |s2cid=129900545 |issn=0305-8719|url-access=subscription }}

Category:Extinct animals of Indonesia

Morphology

The skull of Stegodon is relatively tall but short, and similar in many respects to those of living elephants. The lower jaw in comparison to early elephantimorphs and its ancestor Stegolophodon is shortened (brevirostrine), and lacks lower tusks/incisors. The molar teeth are superficially like those of elephants, consisting of parallel lamellae that form ridges but are generally relatively low crowned (brachydont),{{Cite journal |last1=Cantalapiedra |first1=Juan L. |last2=Sanisidro |first2=Óscar |last3=Zhang |first3=Hanwen |last4=Alberdi |first4=María T. |last5=Prado |first5=José L. |last6=Blanco |first6=Fernando |last7=Saarinen |first7=Juha |date=2021-07-01 |title=The rise and fall of proboscidean ecological diversity |url=https://www.nature.com/articles/s41559-021-01498-w |journal=Nature Ecology & Evolution |language=en |volume=5 |issue=9 |pages=1266–1272 |doi=10.1038/s41559-021-01498-w |pmid=34211141 |bibcode=2021NatEE...5.1266C |s2cid=235712060 |issn=2397-334X|hdl=10261/249360 |hdl-access=free }} the numbers of ridges are greater in later species.van der Made, J. [https://www.researchgate.net/publication/260869040_The_evolution_of_the_elephants_and_their_relatives_in_the_context_of_changing_climate_and_geography The Evolution of the Elephants and Their Relatives in the Context of Changing Climate and Geography]. In Elefantentreich—Eine Fossilwelt in Europa; Verlag Beier & Beran: Langenweißbach, Germany, 2010; pp. 340–360. ISBN 978-3-939414-48-3. Members of the genus lack permanent premolars.{{Cite journal |last=Sanders |first=William J. |date=2018-02-17 |title=Horizontal tooth displacement and premolar occurrence in elephants and other elephantiform proboscideans |url=https://www.tandfonline.com/doi/full/10.1080/08912963.2017.1297436 |journal=Historical Biology |language=en |volume=30 |issue=1–2 |pages=137–156 |doi=10.1080/08912963.2017.1297436 |bibcode=2018HBio...30..137S |s2cid=89904463 |issn=0891-2963|url-access=subscription }} The tusks are proportionally large, with those of the biggest species being among the largest known tusks in proboscideans, with a particularly large tusk of S. ganesa from the Early Pleistocene of India measured to be {{Convert|3.89|m|ft}} long, with an estimated mass of approximately {{Convert|140|kg|lb}}, substantially larger than the largest recorded modern elephant tusk.{{Cite journal |last=Larramendi |first=Asier |date=2023-12-10 |title=Estimating tusk masses in proboscideans: a comprehensive analysis and predictive model |url=https://www.tandfonline.com/doi/full/10.1080/08912963.2023.2286272 |journal=Historical Biology |language=en |pages=1–14 |doi=10.1080/08912963.2023.2286272 |s2cid=266182491 |issn=0891-2963|url-access=subscription }} These tusks have a slight upward curvature, and project forwards and parallel to each other, with the tusks often so close together that they are almost touching, such that the trunk would probably have had to rest on top of the tusks rather than be freely hanging between them as in living elephants.{{Cite journal |last=Nabavizadeh |first=Ali |date=2024-10-08 |title=Of tusks and trunks: A review of craniofacial evolutionary anatomy in elephants and extinct Proboscidea |url=https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/ar.25578 |journal=The Anatomical Record |language=en |doi=10.1002/ar.25578 |issn=1932-8486 |pmid=39380178|url-access=subscription }}{{gallery|Stegodon orientalis molar.JPG|Molar of Stegodon orientalis|Molaire de stegodon.jpg|Molar of Stegodon trigonocephalus|||||||||width=190|height=|lines=|align=center|title=Stegodon molars}}

= Size =

{{Main|Dwarf_elephant#Indonesia_and_the_Philippines}}

File:Stegodon skeletal.pngThe Chinese S. zdanskyi is suggested to be the largest species, and is known from an old male (50-plus years old) from the Yellow River that is {{cvt|3.87|m|ft}} tall and would have weighed approximately {{convert|12.7|t|LT ST}} in life. It had a humerus {{cvt|1.21|m|ft}} long, a femur {{cvt|1.46|m|ft}} long, and a pelvis {{cvt|2|m|ft}} wide. The Indian S. ganesa is suggested to have a shoulder height of about {{cvt|3.10|m|ft}}, and a body mass of around {{convert|6.5|t|LT ST}}. The Javanese species S. trigonocephalus is suggested to have been around {{cvt|2.75-2.8|m|ft}} tall, with a body mass of around {{convert|5|t|LT ST}}.{{Cite journal |last1=Larramendi |first1=A. |year=2016 |title=Shoulder height, body mass and shape of proboscideans |url=https://www.app.pan.pl/archive/published/app61/app001362014.pdf |journal=Acta Palaeontologica Polonica |volume=61 |doi=10.4202/app.00136.2014 |s2cid=2092950 |doi-access=free}} S. orientalis was around the size of an Asian elephant (Elephas maximus).

File:Dwarf stegodon size comparison.svg compared to a human|300x300px]]

Similar to modern-day elephants, stegodonts were likely good swimmers,Simpson, G. (1977). "Too Many Lines; The Limits of the Oriental and Australian Zoogeographic Regions". Proceedings of the American Philosophical Society, 121(2), 107–120. Retrieved from http://www.jstor.org/stable/986523{{cite journal | last1=Bird | first1=Michael I. | last2=Condie | first2=Scott A. | last3=O’Connor | first3=Sue | last4=O’Grady | first4=Damien | last5=Reepmeyer | first5=Christian | last6=Ulm | first6=Sean | last7=Zega | first7=Mojca | last8=Saltré | first8=Frédérik | last9=Bradshaw | first9=Corey J. A. | title=Early human settlement of Sahul was not an accident | journal=Scientific Reports | volume=9 | issue=1 | pages=8220 | pmid=31209234 | doi=10.1038/s41598-019-42946-9 | pmc=6579762 | year=2019 | bibcode=2019NatSR...9.8220B }} allowing them to disperse to remote islands in Indonesia, the Philippines and Japan. Once present on the islands, due to the process of insular dwarfism, as a result of decreased land area and the reduction of predation and competition pressure, they reduced in body size, with the degree of dwarfism varying between islands as the result of local conditions. One of the smallest species, Stegodon sumbaensis from Sumba in Indonesia, is estimated at around 8% of the size of mainland Stegodon species, with a body mass of {{Convert|250|kg|lb}}.{{Cite journal |last1=Geer |first1=Alexandra A. E. |last2=Bergh |first2=Gerrit D. |last3=Lyras |first3=George A. |last4=Prasetyo |first4=Unggul W. |last5=Due |first5=Rokus Awe |last6=Setiyabudi |first6=Erick |last7=Drinia |first7=Hara |date=August 2016 |title=The effect of area and isolation on insular dwarf proboscideans |url=https://onlinelibrary.wiley.com/doi/10.1111/jbi.12743 |journal=Journal of Biogeography |language=en |volume=43 |issue=8 |pages=1656–1666 |doi=10.1111/jbi.12743 |bibcode=2016JBiog..43.1656V |s2cid=87958022 |issn=0305-0270}} Sometimes the same island was colonised multiple times by Stegodon, as in Flores, where the Early Pleistocene strongly dwarfed species Stegodon sondaari, which was {{convert|120|cm|ft||abbr=on}} tall at the shoulder and weighed about {{Convert|350-400|kg|lb}}, was replaced by the species Stegodon florensis during the Middle Pleistocene which was initially substantially larger, but progressively reduced in size over time, with the earlier subspecies Stegodon florensis florensis from the Middle Pleistocene estimated to be around 50% the size of mainland Stegodon species with a shoulder height of around {{convert|190|cm|ft||abbr=on}} and a body mass of around 1.7 tons, while the later Stegodon florensis insularis from the Late Pleistocene is estimated to be around 17% the size of mainland Stegodon species, with a shoulder height of around {{convert|130|cm|ft||abbr=on}}, and a body mass of about {{Convert|570|kg|lb}}.Puspaningrum, Mika; Van Den Bergh, Gerrit; Chivas, Allan; Setiabudi, Erick; Kurniawan, Iwan; Brumm, Adam; and Sutikna, Thomas, "[https://ro.uow.edu.au/smhpapers/2035 Preliminary results of dietary and environmental reconstructions of Early to Middle Pleistocene Stegodons from the So'a Basin of Flores, Indonesia, based on enamel stable isotope records]" (2014). Faculty of Science, Medicine and Health - Papers: part A. 2035.

During Pliocene-Early Pleistocene (from around 4-1 million years ago), a succession of endemic dwarf species of Stegodon, probably representing a single lineage lived in the Japanese archipelago, probably derived from the mainland Chinese S. zdanskyi. In chronological succession these species are Stegodon miensis (4-3 million years ago) Stegodon protoaurorae (3-2 million years ago) and Stegodon aurorae, (2-1 million years ago) which show a progressive size reduction through time, possibly as a result of reducing land area of the Japanese archipelago.{{Cite journal |last1=Aiba |first1=Hiroaki |last2=Baba |first2=Katsuyoshi |last3=Matsukawa |first3=Masaki |date=2010-03-10 |title=A new species of Stegodon (Mammalia, Proboscidea) from the Kazusa Group (lower Pleistocene), Hachioji City, Tokyo, Japan and its evolutionary morphodynamics: STEGODON PROTOAURORAE SP. NOV. AND MORPHODYNAMICS |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1475-4983.2010.00953.x |journal=Palaeontology |language=en |volume=53 |issue=3 |pages=471–490 |doi=10.1111/j.1475-4983.2010.00953.x|bibcode=2010Palgy..53..471A |url-access=subscription }} The latest and smallest species S. aurorae is estimated to be 25% the size of its mainland ancestor with a body mass of around {{Convert|2122|kg|lb}}.{{Cite journal |last1=Geer |first1=Alexandra A. E. |last2=Bergh |first2=Gerrit D. |last3=Lyras |first3=George A. |last4=Prasetyo |first4=Unggul W. |last5=Due |first5=Rokus Awe |last6=Setiyabudi |first6=Erick |last7=Drinia |first7=Hara |date=August 2016 |title=The effect of area and isolation on insular dwarf proboscideans |url=https://onlinelibrary.wiley.com/doi/10.1111/jbi.12743 |journal=Journal of Biogeography |language=en |volume=43 |issue=8 |pages=1656–1666 |doi=10.1111/jbi.12743 |bibcode=2016JBiog..43.1656V |issn=0305-0270 |s2cid=87958022}} S. aurorae also shows morphological straits associated with dwarfism, like shortened limbs.

Ecology

File:Stegodon ganesaDB.jpg

Like modern elephants, but unlike more primitive proboscideans, Stegodon is thought to have chewed using a proal movement (a forward stroke from the back to the front) of the lower jaws. This jaw movement is thought to have evolved independently in elephants and stegodontids. Stegodon populations from the Late Pliocene of the India (including Stegodon insignis) are suggested to have been variable mixed feeders, while those from the earliest Pleistocene (including Stegodon ganesa) of the same region are suggested to have been nearly pure grazers based on isotopic analysis.{{Cite journal |last1=Patnaik |first1=Rajeev |last2=Singh |first2=Ningthoujam Premjit |last3=Paul |first3=Debajyoti |last4=Sukumar |first4=Raman |date=November 2019 |title=Dietary and habitat shifts in relation to climate of Neogene-Quaternary proboscideans and associated mammals of the Indian subcontinent |url=https://linkinghub.elsevier.com/retrieve/pii/S027737911930263X |journal=Quaternary Science Reviews |language=en |volume=224 |pages=105968 |doi=10.1016/j.quascirev.2019.105968|bibcode=2019QSRv..22405968P |s2cid=210307849 |url-access=subscription }} Based on dental microwear analysis, populations of Stegodon from the Pleistocene of China (Stegodon orientalis and Stegodon huananensis) and mainland southeast Asia (S. orientalis) were found to be browsers, with clear niche differentiation from sympatric Elephas populations, which tended towards mixed feeding (both browsing and grazing),{{Cite journal |last1=Zhang |first1=Hanwen |last2=Wang |first2=Yuan |last3=Janis |first3=Christine M. |last4=Goodall |first4=Robert H. |last5=Purnell |first5=Mark A. |date=2017-07-25 |title=An examination of feeding ecology in Pleistocene proboscideans from southern China (Sinomastodon, Stegodon, Elephas), by means of dental microwear texture analysis |journal=Quaternary International |series=VIth International Conference on Mammoths and their Relatives, Part 3 |language=en |volume=445 |pages=60–70 |doi=10.1016/j.quaint.2016.07.011 |bibcode=2017QuInt.445...60Z |issn=1040-6182|doi-access=free |hdl=1983/4f6a743a-7b6d-47c8-a56a-fee7e2c515df |hdl-access=free }}{{Cite journal |last1=Ma |first1=Jiao |last2=Wang |first2=Yuan |last3=Jin |first3=Changzhu |last4=Hu |first4=Yaowu |last5=Bocherens |first5=Hervé |date=2019-05-15 |title=Ecological flexibility and differential survival of Pleistocene Stegodon orientalis and Elephas maximus in mainland southeast Asia revealed by stable isotope (C, O) analysis |url=https://www.sciencedirect.com/science/article/pii/S0277379118309648 |journal=Quaternary Science Reviews |language=en |volume=212 |pages=33–44 |doi=10.1016/j.quascirev.2019.03.021 |bibcode=2019QSRv..212...33M |s2cid=135056116 |issn=0277-3791|url-access=subscription }} though isotopic analysis of Stegodon cf. orientalis specimens from the late Middle Pleistocene of Thailand suggests that these individuals were mixed feeders that consumed a significant amount of C4 grass.{{Cite journal |last1=Suraprasit |first1=Kantapon |last2=Bocherens |first2=Hervé |last3=Chaimanee |first3=Yaowalak |last4=Panha |first4=Somsak |last5=Jaeger |first5=Jean-Jacques |date=August 2018 |title=Late Middle Pleistocene ecology and climate in Northeastern Thailand inferred from the stable isotope analysis of Khok Sung herbivore tooth enamel and the land mammal cenogram |url=https://linkinghub.elsevier.com/retrieve/pii/S0277379117308247 |journal=Quaternary Science Reviews |language=en |volume=193 |pages=24–42 |doi=10.1016/j.quascirev.2018.06.004|bibcode=2018QSRv..193...24S |url-access=subscription }} Specimens of Stegodon trigonocephalus from the Early-Middle Pleistocene of Java were found to be mixed feeders to grazers, with a diet similar to that of sympatric Elephas hysudrindicus.{{Cite journal |last1=Puspaningrum |first1=Mika R. |last2=van den Bergh |first2=Gerrit D. |last3=Chivas |first3=Allan R. |last4=Setiabudi |first4=Erick |last5=Kurniawan |first5=Iwan |date=January 2020 |title=Isotopic reconstruction of Proboscidean habitats and diets on Java since the Early Pleistocene: Implications for adaptation and extinction |url=https://linkinghub.elsevier.com/retrieve/pii/S0277379119303178 |journal=Quaternary Science Reviews |language=en |volume=228 |pages=106007 |doi=10.1016/j.quascirev.2019.106007|bibcode=2020QSRv..22806007P |s2cid=212876762 |url-access=subscription }} The dwarf species from Flores, Stegodon sondaari and Stegodon florensis, are suggested to have been mixed feeders and grazers, respectively, based on stable carbon isotopes. Specimens of Stegodon kaiesensis from the Pliocene of East Africa were found to be browsers to mixed feeders, based on mesowear analysis.{{Cite journal |last1=Saarinen |first1=Juha |last2=Lister |first2=Adrian M. |date=2023-08-14 |title=Fluctuating climate and dietary innovation drove ratcheted evolution of proboscidean dental traits |journal=Nature Ecology & Evolution |volume=7 |issue=9 |pages=1490–1502 |language=en |doi=10.1038/s41559-023-02151-4 |issn=2397-334X|doi-access=free |pmid=37580434 |bibcode=2023NatEE...7.1490S |pmc=10482678 }}

Tracks of a group of Stegodon from the Late Pliocene of Japan suggest that like modern elephants, Stegodon lived in social herds.{{Cite journal |last1=Matsukawa |first1=Masaki |last2=Shibata |first2=Kenichiro |date=2015-10-02 |title=Review of Japanese Cenozoic (Miocene–Modern) Vertebrate Tracks |url=http://www.tandfonline.com/doi/full/10.1080/10420940.2015.1064407 |journal=Ichnos |language=en |volume=22 |issue=3–4 |pages=261–290 |doi=10.1080/10420940.2015.1064407 |bibcode=2015Ichno..22..261M |s2cid=129206332 |issn=1042-0940|url-access=subscription }}

On Flores, where dwarf Stegodon species were the only large herbivores, they were likely the main prey of the Komodo dragon.Diamond, Jared M. (1987). "Did Komodo dragons evolve to eat pygmy elephants?". Nature. 326 (6116): 832.

Taxonomy

File:Stegodon aurorae and Stegodon orientalis.jpg, Tokyo]]

File:Stegodon sondaari.jpg]]

File:Stegodon ganesa.JPG

In the past, stegodonts were believed to be the ancestors of the true elephants and mammoths, but currently they are believed to have no modern descendants. Stegodon is likely derived from Stegolophodon, an extinct genus known from the Miocene of Asia, with transitional fossils between the two genera known from the Late Miocene of Southeast Asia and Yunnan in South China. Stegodon is more closely related to elephants and mammoths than to mastodons. Like elephants, stegodontids are believed to have derived from gomphotheres.{{Cite journal |last1=Wu |first1=Yan |last2=Deng |first2=Tao |last3=Hu |first3=Yaowu |last4=Ma |first4=Jiao |last5=Zhou |first5=Xinying |last6=Mao |first6=Limi |last7=Zhang |first7=Hanwen |last8=Ye |first8=Jie |last9=Wang |first9=Shi-Qi |date=2018-05-16 |title=A grazing Gomphotherium in Middle Miocene Central Asia, 10 million years prior to the origin of the Elephantidae |journal=Scientific Reports |language=en |volume=8 |issue=1 |page=7640 |doi=10.1038/s41598-018-25909-4 |issn=2045-2322 |pmc=5956065 |pmid=29769581|bibcode=2018NatSR...8.7640W }}

=Phylogeny=

The following cladogram shows the placement of the genus Stegodon among other proboscideans, based on hyoid characteristics:{{Cite journal | last1 = Shoshani | first1 = J. | last2 = Tassy | first2 = P. | doi = 10.1016/j.quaint.2004.04.011 | title = Advances in proboscidean taxonomy & classification, anatomy & physiology, and ecology & behavior | journal = Quaternary International | volume = 126–128 | pages = 5–20 | year = 2005 |bibcode = 2005QuInt.126....5S }}

{{clade | style = font-size: 90%;

|1={{clade

|1={{clade

|1=Mammut americanum (American mastodon)

|2={{clade

|1=Gomphotherium sp.

|2={{clade

|1=Stegodon zdanskyi

|2={{clade

|1=Loxodonta africana (African bush elephant)

|2={{clade

|1=Elephas maximus (Asian elephant)

|2=Mammuthus columbi (Columbian mammoth)

}}

}}

}}

}}

}}

}}

}}

= List of species =

  • Stegodon kaisensis Late Miocene – Pliocene, Africa
  • Stegodon zdanskyi Late Miocene – Pliocene, China
  • Stegodon huananensis Early Pleistocene, China
  • Stegodon orientalis Middle – Late Pleistocene, China, Southeast Asia, Japan, Taiwan
  • Stegodon namadicus/S. insignis/S. ganesa Pliocene – Late Pleistocene, India
  • Stegodon miensis Pliocene, Japan
  • Stegodon protoaurorae Late Pliocene – Early Pleistocene, Japan
  • Stegodon aurorae Early Pleistocene – early Middle Pleistocene, Japan
  • Stegodon sondaari Early Pleistocene, Flores, Indonesia
  • Stegodon florensis Middle – Late Pleistocene, Flores, Indonesia
  • Stegodon luzonensis Middle Pleistocene, Luzon, Philippines
  • Stegodon trigonocephalus late Early Pleistocene – early Late Pleistocene, Java, Indonesia
  • Stegodon sompoensis Late Pliocene – Early Pleistocene, Sulawesi, Indonesia
  • Stegodon sumbaensis Middle – Late Pleistocene, Sumba, Indonesia
  • Stegodon timorensis Middle Pleistocene, Timor, Indonesia
  • Stegodon mindanensis Pleistocene Mindanao, Philippines

An indeterminate Stegodon molar of an uncertain locality and age is known from Greece, representing the only record of the genus in Europe.{{Citation |last1=Konidaris |first1=George E. |title=The Fossil Record of the Neogene Proboscidea (Mammalia) in Greece |date=2022 |url=https://link.springer.com/10.1007/978-3-030-68398-6_12 |work=Fossil Vertebrates of Greece Vol. 1 |pages=299–344 |editor-last=Vlachos |editor-first=Evangelos |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-030-68398-6_12 |isbn=978-3-030-68397-9 |access-date=2023-02-28 |last2=Tsoukala |first2=Evangelia|s2cid=245023119 |url-access=subscription }} Indeterminate remains are also known from the Early Pleistocene and early Middle Pleistocene of Israel.{{Cite journal |last1=Lister |first1=Adrian M. |last2=Dirks |first2=Wendy |last3=Assaf |first3=Amnon |last4=Chazan |first4=Michael |last5=Goldberg |first5=Paul |last6=Applbaum |first6=Yaakov H. |last7=Greenbaum |first7=Nathalie |last8=Horwitz |first8=Liora Kolska |date=September 2013 |title=New fossil remains of Elephas from the southern Levant: Implications for the evolutionary history of the Asian elephant |url=https://linkinghub.elsevier.com/retrieve/pii/S003101821300237X |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=386 |pages=119–130 |doi=10.1016/j.palaeo.2013.05.013|bibcode=2013PPP...386..119L |url-access=subscription }}

Relationship with humans

Remains at a number of sites suggest that humans (in a broad sense, including archaic humans) interacted with Stegodon.{{Cite journal |last=Haynes |first=Gary |date=March 2022 |title=Late Quaternary Proboscidean Sites in Africa and Eurasia with Possible or Probable Evidence for Hominin Involvement |journal=Quaternary |language=en |volume=5 |issue=1 |pages=18 |doi=10.3390/quat5010018 |issn=2571-550X |doi-access=free}} At a cave deposit on Gele Mountain near Chongqing in southwest China, a mandible of Stegodon orientalis was used to make a handaxe, with dating suggesting the bone is around 170,000 years old.{{Cite journal |last1=Wei |first1=Guangbiao |last2=He |first2=Cunding |last3=Hu |first3=Yue |last4=Yu |first4=Kefu |last5=Chen |first5=Shaokun |last6=Pang |first6=Libo |last7=Wu |first7=Yan |last8=Huang |first8=Wanbo |last9=Yuan |first9=Wenge |date=April 2017 |title=First discovery of a bone handaxe in China |url=https://linkinghub.elsevier.com/retrieve/pii/S1040618214009732 |journal=Quaternary International |language=en |volume=434 |pages=121–128 |doi=10.1016/j.quaint.2014.12.022|bibcode=2017QuInt.434..121W |url-access=subscription }} At the late Middle Pleistocene Panxian Dadong cave site in southern Guizhou Province, southwest China, dating to around 300-190,000 years ago,{{Cite journal |last1=Zhang |first1=Jia-Fu |last2=Huang |first2=Wei-Wen |last3=Hu |first3=Yue |last4=Yang |first4=Shi-Xia |last5=Zhou |first5=Li-Ping |date=October 2015 |title=Optical dating of flowstone and silty carbonate-rich sediments from Panxian Dadong Cave, Guizhou, southwestern China |url=https://linkinghub.elsevier.com/retrieve/pii/S1871101415000126 |journal=Quaternary Geochronology |language=en |volume=30 |pages=479–486 |doi=10.1016/j.quageo.2015.01.011|bibcode=2015QuGeo..30..479Z |url-access=subscription }} numerous remains of juvenile (0-12 years of age) and a much smaller number of adult remains of adult Stegodon orientalis, representing a minimum of 12 individuals were found at the site in association with stone tools and human remains. It suggested that Stegodon remains were brought to the cave by humans though none of the elements show clear evidence of processing.Schepartz, Lynne, and Sari Miller-Antonio. 2010. “[https://www.researchgate.net/publication/235350991_Large_mammal_exploitation_in_Late_Middle_Pleistocene_China_a_comparison_of_rhinoceros_stegodonts_at_Panxian_Dadong Large Mammal Exploitation in Late Middle Pleistocene China: A Comparison of Rhinoceros & Stegodonts at Panxian Dadong].” Before Farming 4: 1–14.{{Cite journal |last1=Schepartz |first1=L.A. |last2=Stoutamire |first2=S. |last3=Bekken |first3=D.A. |date=January 2005 |title=Stegodon orientalis from Panxian Dadong, a Middle Pleistocene archaeological site in Guizhou, South China: taphonomy, population structure and evidence for human interactions |url=https://linkinghub.elsevier.com/retrieve/pii/S1040618204000886 |journal=Quaternary International |language=en |volume=126-128 |pages=271–282 |doi=10.1016/j.quaint.2004.04.026|url-access=subscription }} At the Xinlong Cave site in the Three Gorges area of Chongqing, suggested to date to around 200-130,000 years ago, two Stegodon cf. orientalis tusks have been found along with human remains. These tusks appear to have been delibrately engraved with patterns and are suggested to have been brought into the cave by humans.{{Cite journal |last1=Peng |first1=Hongxia |last2=Ma |first2=Zhibang |last3=Huang |first3=Wanpo |last4=Gao |first4=Jing |date=December 2014 |title=230Th/U chronology of a paleolithic site at Xinglong Cave in the three-Gorge region of south China |url=https://linkinghub.elsevier.com/retrieve/pii/S1871101414000594 |journal=Quaternary Geochronology |language=en |volume=24 |pages=1–9 |doi=10.1016/j.quageo.2014.07.001|url-access=subscription }} At the Late Pleistocene Ma’anshan site also in Guizhou, remains of Stegodon orientalis including both adults and juveniles among other animals are found in two layers, the older dating to around 53,000 years Before Present (BP), with the younger dates to around 19,295-31,155 years BP with the minimum number of individuals being 7 and 2 for the older and younger layers respectively, with the older layer containing adults and juveniles while in the younger later only juveniles are present. Bones at the site display cut marks indicating butchery, and are thought to have been accumulated at the site by people, likely by hunting or possibly scavenging in the case of the large adults found in the older layer.{{Cite journal |last1=Zhang |first1=Yue |last2=Stiner |first2=Mary C. |last3=Dennell |first3=Robin |last4=Wang |first4=Chunxue |last5=Zhang |first5=Shuangquan |last6=Gao |first6=Xing |date=August 2010 |title=Zooarchaeological perspectives on the Chinese Early and Late Paleolithic from the Ma'anshan site (Guizhou, South China) |url=https://linkinghub.elsevier.com/retrieve/pii/S0305440310001123 |journal=Journal of Archaeological Science |language=en |volume=37 |issue=8 |pages=2066–2077 |doi=10.1016/j.jas.2010.03.012|bibcode=2010JArSc..37.2066Z |url-access=subscription }}

At Liang Bua cave on Flores dating to around 80-50,000 years ago, remains of the dwarf Stegodon species Stegodon florensis are associated with stone tools produced by the dwarf archaic human species Homo floresiensis, with a small number of the bones bearing cut marks. The ambiguous circumstantial association between bones and stone tools, and the rarity of cut marks makes it unclear to what if to any degree, hunting of Stegodon was practiced by Homo floresiensis.{{Citation |author=Matthew W. Tocheri, Thomas Sutikna, Jatmiko, E. Wahyu Saptomo |title=Homo floresiensis |date=2022-02-14 |work=The Oxford Handbook of Early Southeast Asia |pages=38–69 |url=https://academic.oup.com/edited-volume/42054/chapter-abstract/355842802 |access-date=2023-03-13 |publisher=Oxford University Press |doi=10.1093/oxfordhb/9780199355358.013.2 |isbn=978-0-19-935535-8|url-access=subscription }}{{Cite journal |last1=Sutikna |first1=Thomas |last2=Tocheri |first2=Matthew W. |last3=Faith |first3=J. Tyler |last4=Jatmiko |last5=Due Awe |first5=Rokus |last6=Meijer |first6=Hanneke J.M. |last7=Wahyu Saptomo |first7=E. |last8=Roberts |first8=Richard G. |date=November 2018 |title=The spatio-temporal distribution of archaeological and faunal finds at Liang Bua (Flores, Indonesia) in light of the revised chronology for Homo floresiensis |journal=Journal of Human Evolution |language=en |volume=124 |pages=52–74 |doi=10.1016/j.jhevol.2018.07.001 |pmid=30173885 |doi-access=free|bibcode=2018JHumE.124...52S }}

Evolution and extinction

The oldest fossils of Stegodon in Asia date to the Late Miocene, around 8-11 million years ago, with the oldest fossils of the genus in Africa being around 7-6 million years old.{{Cite journal |last1=Saegusa |first1=Haruo |last2=Thasod |first2=Yupa |last3=Ratanasthien |first3=Benjavun |date=2005 |title=Notes on Asian stegodontids |url=https://linkinghub.elsevier.com/retrieve/pii/S1040618204000758 |journal=Quaternary International |language=en |volume=126-128 |pages=31–48 |doi=10.1016/j.quaint.2004.04.013|bibcode=2005QuInt.126...31S |url-access=subscription }} Stegodon became extinct in Africa during the late Pliocene, around 3 million years ago suggested to be the result of expansion of grassland habitats.

The Javanese species Stegodon trigonocephalus became extinct around 130-80,000 years ago during the latest Middle Pleistocene-early Late Pleistocene (Marine Isotope Stage 5) following a change to more humid conditions, which may have reduced grazing habitat. The last records of Stegodon florensis date to around 50,000 years ago, around the time of arrival of modern humans to Flores (the earliest evidence of which dates to 46,000 years ago), suggesting that effects of modern human activity were likely the cause of their extinction.{{Cite journal |last1=van den Bergh |first1=Gerrit D. |last2=Alloway |first2=Brent V. |last3=Storey |first3=Michael |last4=Setiawan |first4=Ruly |last5=Yurnaldi |first5=Dida |last6=Kurniawan |first6=Iwan |last7=Moore |first7=Mark W. |last8=Jatmiko |last9=Brumm |first9=Adam |last10=Flude |first10=Stephanie |last11=Sutikna |first11=Thomas |last12=Setiyabudi |first12=Erick |last13=Prasetyo |first13=Unggul W. |last14=Puspaningrum |first14=Mika R. |last15=Yoga |first15=Ifan |date=October 2022 |title=An integrative geochronological framework for the Pleistocene So'a basin (Flores, Indonesia), and its implications for faunal turnover and hominin arrival |url=https://linkinghub.elsevier.com/retrieve/pii/S0277379122003523 |journal=Quaternary Science Reviews |language=en |volume=294 |pages=107721 |bibcode=2022QSRv..29407721V |doi=10.1016/j.quascirev.2022.107721 |s2cid=252290750 |hdl-access=free |hdl=10072/418777}}

Stegodon became extinct in the Indian subcontinent (Stegodon namadicus/Stegodon sp.), mainland Southeast Asia and China (S. orientalis) at some point during the Late Pleistocene epoch, while Asian elephants, which existed in sympatry with Stegodon in these regions, are still extant. The precise timing of extinction is uncertain for these regions,{{Cite journal |last1=Jukar |first1=A. M. |last2=Lyons |first2=S. K. |last3=Wagner |first3=P. J. |last4=Uhen |first4=M. D. |date=2021-01-15 |title=Late Quaternary extinctions in the Indian Subcontinent |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=562 |pages=110137 |doi=10.1016/j.palaeo.2020.110137 |bibcode=2021PPP...56210137J |issn=0031-0182|doi-access=free }}{{Cite journal |last1=Turvey |first1=Samuel T. |last2=Sathe |first2=Vijay |last3=Crees |first3=Jennifer J. |last4=Jukar |first4=Advait M. |last5=Chakraborty |first5=Prateek |last6=Lister |first6=Adrian M. |date=January 2021 |title=Late Quaternary megafaunal extinctions in India: How much do we know? |url=https://linkinghub.elsevier.com/retrieve/pii/S0277379120307022 |journal=Quaternary Science Reviews |language=en |volume=252 |pages=106740 |bibcode=2021QSRv..25206740T |doi=10.1016/j.quascirev.2020.106740 |s2cid=234265221}} though in India records of Stegodon may date as recently as 35-30,000 years ago. The survival of the Asian elephant as opposed to Stegodon orientalis in Southeast Asia and South China has been suggested to be due to its more flexible diet in comparison to S. orientalis. Although some authors have claimed a Holocene survival in China for S. orientalis,H. Saegusa, [http://www.cq.rm.cnr.it/elephants2001/pdf/345_349.pdf "Comparisons of Stegodon and Elephantid Abundances in the Late Pleistocene of Southern China"] {{webarchive|url=https://web.archive.org/web/20060508112826/http://www.cq.rm.cnr.it/elephants2001/pdf/345_349.pdf|date=2006-05-08}}, The World of Elephants – Second International Congress, (Rome, 2001), 345–349. these claims cannot be substantiated due to loss of specimens and issues regarding dating.{{Cite journal |author=Samuel T. Turvey, Haowen Tong, Anthony J. Stuart and Adrian M. Lister |year=2013 |title=Holocene survival of Late Pleistocene megafauna in China: a critical review of the evidence |journal=Quaternary Science Reviews |volume=76 |pages=156–166 |bibcode=2013QSRv...76..156T |doi=10.1016/j.quascirev.2013.06.030}}

References