Mammutidae Explained

Mammutidae is an extinct family of proboscideans belonging to Elephantimorpha. It is best known for the mastodons (genus Mammut), which inhabited North America from the Late Miocene until their extinction at beginning of the Holocene, around 11,000 years ago. The earliest fossils of the group are known from the Late Oligocene of Africa, around 24 million years ago, and fossils of the group have also been found across Eurasia. The name "mastodon" derives from Greek, Greek, Ancient (to 1453);: μαστός "nipple" and Greek, Ancient (to 1453);: ὀδούς "tooth", referring to their characteristic teeth.

Description

Mammutids are characterised by their zygodont molars, where pairs of parallel cusps are merged into sharp-sided riges, which are morphologically conservative (showing little variation) amongst all members of the family. Like other members of Elephantimorpha, mammutids exhibited horizontal tooth replacement like modern elephants. Some authors have argued that horizontal tooth replacement evolved in parallel in mammutids and members of Elephantida (which includes gomphotheres and elephants), though this is uncertain.^[1] Early members of the group like Eozygodon and Zygolophodon had elongate mandibular symphysis of the lower jaws with lower incisors/tusks, while in later representatives like Sinomammut and Mammut, the lower incisors/tusks were either lost or only vestigially present, and the lower jaws shortened (brevirostrine). This process happened convergently amongst other elephantimorph proboscideans, including gomphotheres, stegodontids, and elephantids.^{[2] [3]} The mammutid "Mammut" borsoni is one of the largest of all proboscideans with an estimated average male body weight of 16t making it one of the largest land mammals of all time,^[4] with the tusks of this species being the longest known of any mammal, reaching over 5m (16feet) in length.^[5]

Ecology

Members of Mammutidae are thought to have been browsers.^{[6] [7] [8]} Analysis of American mastodon (Mammut americanum) remains suggests that mammutids had a similar social structure to modern elephants, with herds of adult females and juveniles, with adult males living solitarily or in bonding groups with other males,^{[9] [10]} with adult males periodically engaging in musth-like fighting behaviour against other males.

Evolution

Mammutids are the most basal group within Elephantimorpha, with gomphotheres and other members of Elephantida like amebelodonts being more closely related to elephants.^{[11] [12]} Mammutids originated in Africa during the Late Oligocene, with the oldest genus Losodokodon dating to around 27.5-24 million years ago^[13] and entered Eurasia across the "Gomphotherium land bridge" during the early Miocene, around 18 million years ago. Mammutid remains are generally rare in Eurasia in comparison to contemporary gomphotheres and deinotheres. During the late early Miocene, around 16.5 million years ago,^[14] a population of Zygolophodon entered North America, giving rise to Mammut. The youngest confirmed records of mammutids in Africa date to around 13 million years ago, though possible Late Miocene fossils have been reported from North Africa.^[15] At the beginning of the Pleistocene, around 2 to 2.5 million years ago, the last of the Eurasian mammutids, "Mammut" borsoni became extinct, with members of Mammut persisting in North America until the end of the Pleistocene, approximately 11,000 years ago.^[16]

Notes and References

1. Sanders . William J. . 2018-02-17 . Horizontal tooth displacement and premolar occurrence in elephants and other elephantiform proboscideans . Historical Biology . en . 30 . 1–2 . 137–156 . 10.1080/08912963.2017.1297436 . 2018HBio...30..137S . 89904463 . 0891-2963.
2. Mothé . Dimila . Avilla . Leonardo S. . Zhao . Desi . Xie . Guangpu . Sun . Boyang . Mothé . Dimila . Avilla . Leonardo S. . Zhao . Desi . Xie . Guangpu . 2016 . A new Mammutidae (Proboscidea, Mammalia) from the Late Miocene of Gansu Province, China . Anais da Academia Brasileira de Ciências . 88 . 1 . 65–74 . 10.1590/0001-3765201520150261 . 0001-3765 . 26839998 . free.
3. Mothé . Dimila . Ferretti . Marco P. . Avilla . Leonardo S. . 2016-01-12 . Beatty . Brian Lee . The Dance of Tusks: Rediscovery of Lower Incisors in the Pan-American Proboscidean Cuvieronius hyodon Revises Incisor Evolution in Elephantimorpha . PLOS ONE . en . 11 . 1 . e0147009 . 10.1371/journal.pone.0147009 . 1932-6203 . 4710528 . 26756209 . free . 2016PLoSO..1147009M .
4. Larramendi . A. . 2016 . Shoulder height, body mass and shape of proboscideans . Acta Palaeontologica Polonica . 61 . 10.4202/app.00136.2014 . free.
5. Larramendi . Asier . 2023-12-10 . Estimating tusk masses in proboscideans: a comprehensive analysis and predictive model . Historical Biology . en . 1–14 . 10.1080/08912963.2023.2286272 . 0891-2963.
6. Saarinen . Juha . Lister . Adrian M. . 2023-08-14 . Fluctuating climate and dietary innovation drove ratcheted evolution of proboscidean dental traits . Nature Ecology & Evolution . en . 7 . 9 . 1490–1502 . 2023NatEE...7.1490S . 10.1038/s41559-023-02151-4 . 2397-334X . 10482678 . 37580434 . free.
7. Janis . C . May 2004 . The species richness of Miocene browsers, and implications for habitat type and primary productivity in the North American grassland biome . Palaeogeography, Palaeoclimatology, Palaeoecology . en . 207 . 3–4 . 371–398 . 2004PPP...207..371J . 10.1016/j.palaeo.2003.09.032.
8. Rivals . Florent . Semprebon . Gina M. . Lister . Adrian M. . September 2019 . Feeding traits and dietary variation in Pleistocene proboscideans: A tooth microwear review . Quaternary Science Reviews . en . 219 . 145–153 . 2019QSRv..219..145R . 10.1016/j.quascirev.2019.06.027 . 200073388.
9. Miller . Joshua H. . Fisher . Daniel C. . Crowley . Brooke E. . Secord . Ross . Konomi . Bledar A. . 2022 . Male mastodon landscape use changed with maturation (late Pleistocene, North America) . Proceedings of the National Academy of Sciences . en . 119 . 25 . e2118329119 . 2022PNAS..11918329M . 10.1073/pnas.2118329119 . 0027-8424 . 9231495 . 35696566 . free.
10. Haynes . G. . Klimowicz . J. . 2003 . Mammoth (Mammuthus spp.) and American mastodont (Mammut americanum) bonesites: what do the differences mean? . Advances in Mammoth Research . 9 . 185–204.
11. Shoshani. J.. Ferretti. M.P.. Lister. A.M.. Agenbroad. L.D.. Saegusa. H.. Mol. D.. Takahashi. K.. July 2007. Relationships within the Elephantinae using hyoid characters. Quaternary International. 169-170. 174–185. 10.1016/j.quaint.2007.02.003. 2007QuInt.169..174S . 1040-6182.
12. Baleka . Sina . Varela . Luciano . Tambusso . P. Sebastián . Paijmans . Johanna L.A. . Mothé . Dimila . Stafford . Thomas W. . Fariña . Richard A. . Hofreiter . Michael . December 2021 . Revisiting proboscidean phylogeny and evolution through total evidence and palaeogenetic analyses including Notiomastodon ancient DNA . iScience . en . 25 . 1 . 103559 . 10.1016/j.isci.2021.103559 . 8693454 . 34988402.
13. Book: Sanders, William J. . Evolution and Fossil Record of African Proboscidea . 2023-07-07 . CRC Press . 978-1-315-11891-8 . 1 . Boca Raton . 48,117 . en . 10.1201/b20016.
14. Koenigswald, Widga & Göhlich (2021): New mammutids (Proboscidea) from the Clarendonian and Hemphillian of Oregon – a survey of Mio-Pliocene mammutids from North America
15. Pickford, M. 2007. New mammutid proboscidean teeth from the middle Miocene of tropical and southern Africa. Palaeontologia Africana 42: 29–35.
16. Koenigswald . Wighart . Březina . Jakub . Werneburg . Ralf . Göhlich . Ursula . 2022 . A partial skeleton of "Mammut" borsoni (Proboscidea, Mammalia) from the Pliocene of Kaltensundheim (Germany) . Palaeontologia Electronica . 27 . 1 . 1–20 . 10.26879/1188. free .