Elephantiformes is a suborder within the order Proboscidea.[1] Members of this group are primitively characterised by the possession of upper tusks, an elongated mandibular symphysis (the frontmost part of the lower jaw) and lower tusks, and the retraction of the facial region of the skull indicative of the development of a trunk.[2] The earliest known member of the group, Dagbatitherium is known from the Eocene (Lutetian) of Togo, which is only known from isolated teeth, while other primitive elephantiforms like Phiomia and Palaeomastodon are known from the Early Oligocene onwards.[3] Phiomia and Palaeomastodon are often collectively referred to as "palaeomastodonts" and assigned to the family Palaeomastodontidae.[4] Most diversity of the group is placed in the subclade Elephantimorpha, which includes mastodons (family Mammutidae), as well as modern elephants and gomphotheres (Elephantida).[3] It is disputed as to whether Phiomia is closely related to both Mammutidae and Elephantida with Palaeomastodon being more basal, or if Palaeomastodon is closely related to Mammutidae and Phiomia more closely related to Elephantida.[4]

Elephantiformes
Temporal range: Lutetian–Recent
Skull of Phiomia
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Proboscidea
Suborder: Elephantiformes
Tassy, 1988
Subgroups[1]

Phylogeny of Proboscidea including Elephantiformes, following Hautier et al. 2021[3]

Proboscidea

References

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  1. ^ a b Shoshani, J.; Tassy, P. (2005). "Advances in proboscidean taxonomy & classification, anatomy & physiology, and ecology & behavior". Quaternary International. 126–128: 5–20. Bibcode:2005QuInt.126....5S. doi:10.1016/j.quaint.2004.04.011.
  2. ^ Sanders, William J. (2023-07-07). Evolution and Fossil Record of African Proboscidea (1 ed.). Boca Raton: CRC Press. p. 79. doi:10.1201/b20016. ISBN 978-1-315-11891-8.
  3. ^ a b c Hautier, Lionel; Tabuce, Rodolphe; Mourlam, Mickaël J.; Kassegne, Koffi Evenyon; Amoudji, Yawovi Zikpi; Orliac, Maëva; Quillévéré, Frédéric; Charruault, Anne-Lise; Johnson, Ampah Kodjo Christophe; Guinot, Guillaume (2021-10-13). "New Middle Eocene proboscidean from Togo illuminates the early evolution of the elephantiform-like dental pattern". Proceedings of the Royal Society B: Biological Sciences. 288 (1960). doi:10.1098/rspb.2021.1439. ISSN 0962-8452. PMC 8511763. PMID 34641726.
  4. ^ a b Sanders, William J. (2018-02-17). "Horizontal tooth displacement and premolar occurrence in elephants and other elephantiform proboscideans". Historical Biology. 30 (1–2): 137–156. doi:10.1080/08912963.2017.1297436. ISSN 0891-2963.