Arsinoitheriidae

{{Short description|Extinct family of mammals}} {{Automatic taxobox | fossil_range = {{fossilrange|Late Eocene|Early Oligocene}} | image = Arsinoitherium zitteli.jpg | image_caption = Skeleton of ''Arsinoitherium zitteli'' | taxon = Arsinoitheriidae | authority = Andrews, 1904 | subdivision_ranks = Genera | subdivision = * †''Arsinoitherium'' * †''Namatherium'' }}

'''Arsinoitheriidae''' is a family of mammals belonging to the extinct order Embrithopoda.<ref>{{Cite journal |last=Sanders |first=William J. |last2=Nemec |first2=Wojciech |last3=Aldinucci |first3=Mauro |last4=Janbu |first4=Nils E. |last5=Ghinassi |first5=Massimiliano |date=2014-07-29 |title=Latest evidence of Palaeoamasia (Mammalia, Embrithopoda) in Turkish Anatolia |url=https://doi.org/10.1080/02724634.2014.850430 |journal=Journal of Vertebrate Paleontology |volume=34 |issue=5 |pages=1155–1164 |doi=10.1080/02724634.2014.850430 |issn=0272-4634|url-access=subscription }}</ref> Remains have been found in the Middle East, Africa, Asia and Romania. Arsinotheriids were closely related to hyraxes, elephants, sirenians, and possibly desmostylians (as part of the superorder Afrotheria).<ref>{{Cite journal |last=Gheerbrant |first=Emmanuel |last2=Schmitt |first2=Arnaud |last3=Kocsis |first3=László |date=2018-07-09 |title=Early African Fossils Elucidate the Origin of Embrithopod Mammals |url=https://www.sciencedirect.com/science/article/pii/S0960982218306687 |journal=Current Biology |volume=28 |issue=13 |pages=2167–2173.e2 |doi=10.1016/j.cub.2018.05.032 |issn=0960-9822}}</ref> The name of the clade honors the wife of Ptolemy II, Queen Arsinoe II of Egypt, as the first fossils of ''Arsinoitherium'' were found near the ruins of her palace.<ref name=":0">{{Cite book |last=Beadnell |first=H. J. L. |url=https://www.biodiversitylibrary.org/item/147984 |title=A preliminary note on Arsinoitherium zitteli, Beadn., from the Upper Eocene strata of Egypt |last2=Beadnell |first2=H. J. L. |last3=Egypt |date=1902 |publisher=National Printing Department |location=Cairo}}</ref>

== Description == thumb|left|Reconstruction of an undetermined ''Arsinoitherium'' speciesArsinoitheriids are easily recognized by their prominent nose horns, which, in life, were likely covered in keratin.<ref>{{Cite journal |last=Von |first=Koenigswald W. |date=2013 |title=Unique differentiation of radial enamel in Arsinoitherium (Embrithopoda, Tethytheria) |url=https://jglobal.jst.go.jp/en/detail?JGLOBAL_ID=201302251205955582 |journal=Historical Biology |language=en |volume=25 |issue=2 |pages=183–192 |issn=0891-2963}}</ref> The horns are derived from the nasal bones.<ref>{{Citation |last=Kampouridis |first=Panagiotis |title=The Eocene–Oligocene Vertebrate Assemblages of the Fayum Depression, Egypt |date=2023 |work=The Phanerozoic Geology and Natural Resources of Egypt |pages=373–405 |editor-last=Hamimi |editor-first=Zakaria |url=https://doi.org/10.1007/978-3-030-95637-0_14 |access-date=2025-10-01 |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-030-95637-0_14 |isbn=978-3-030-95637-0 |last2=Hartung |first2=Josephina |last3=Augustin |first3=Felix J. |editor2-last=Khozyem |editor2-first=Hassan |editor3-last=Adatte |editor3-first=Thierry |editor4-last=Nader |editor4-first=Fadi H.|url-access=subscription }}</ref> They are also characterized by pseudolophodont molars.<ref>{{Cite journal |date=2025 |title=New data on the earliest known arsinoitheriid embrithopod (Mammalia, Paenungulata), Namatherium Pickford, Senut, Morales, Mein & Sanchez, 2008 from the middle Eocene of Namibia |url=https://sciencepress.mnhn.fr/en/periodiques/geodiversitas/47/8 |journal=Geodiversitas |language=en |volume=47 |issue=8 |pages=343–368}}</ref> They also had small incisors, which may have asked as some form of tusk.<ref name=":0" />

==Fossil record== Based on the less derived traits of ''Namatherium'', it is assumed that Arsinoitheriidae underwent a divergent evolution sometime during the Lutetian.<ref>{{Cite journal |date=2025 |title=New data on the earliest known arsinoitheriid embrithopod (Mammalia, Paenungulata), Namatherium Pickford, Senut, Morales, Mein & Sanchez, 2008 from the middle Eocene of Namibia |url=https://sciencepress.mnhn.fr/en/periodiques/geodiversitas/47/8 |journal=Geodiversitas |language=en |volume=47 |issue=8 |pages=343–368}}</ref> The latest living genus, ''Arsinoitherium'', was first recovered from the Latest Eocene of the Fayum;<ref name=":1">{{Cite journal |last=Vialle |first=Nicolas |last2=Merzeraud |first2=Gilles |last3=Delmer |first3=Cyrille |last4=Feist |first4=Monique |last5=Jiquel |first5=Suzanne |last6=Marivaux |first6=Laurent |last7=Ramdarshan |first7=Anusha |last8=Vianey-Liaud |first8=Monique |last9=Essid |first9=El Mabrouk |last10=Marzougui |first10=Wissem |last11=Ammar |first11=Hayet Khayati |last12=Tabuce |first12=Rodolphe |date=2013-11-01 |title=Discovery of an embrithopod mammal (Arsinoitherium?) in the late Eocene of Tunisia |url=https://www.sciencedirect.com/science/article/pii/S1464343X13001337 |journal=Journal of African Earth Sciences |volume=87 |pages=86–92 |doi=10.1016/j.jafrearsci.2013.07.010 |issn=1464-343X|url-access=subscription }}</ref> it disappears from the fossil record altogether before the end of the Early Oligocene.<ref name=":1" />

==References== {{Reflist}}

==External links== *[https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=43310 The Paleobiology Database] *[https://web.archive.org/web/20060621070910/http://www.fmnh.helsinki.fi/users/haaramo/Metazoa/Deuterostoma/Chordata/Synapsida/Eutheria/Basal_Ungulata/Embrithopoda.htm Mikko's Phylogeny Archive]

Category:Embrithopods Category:Oligocene mammals Category:Eocene first appearances Category:Rupelian extinctions Category:Prehistoric mammal families