| Paenungulata | |
|---|---|
 | |
| Top:rock hyrax (Hyracoidea),Arsinoitherium zitteli (†Embrithopoda); bottom:Asian elephant (Proboscidea),West Indian manatee (Sirenia). | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Superorder: | Afrotheria |
| Clade: | Paenungulatomorpha |
| Grandorder: | Paenungulata Simpson, 1945 |
| Subgroups | |
 | |
Paenungulata (fromLatinpaene 'almost' andungulātus 'havinghoofs'), also known asUranotheria, is aclade of "sub-ungulates", which groups threeextantmammalorders:Proboscidea (includingelephants),Sirenia (sea cows, includingdugongs andmanatees), andHyracoidea (hyraxes). At least two more possible orders are known only as fossils, namelyEmbrithopoda andDesmostylia.[a]
Molecular evidence indicates that Paenungulata (or at least its extant members) is part of the cohortAfrotheria, an ancient assemblage of mainlyAfrican mammals of great diversity. The other members of this cohort are the ordersAfrosoricida (tenrecs andgolden moles), Macroscelidea (elephant shrews) and Tubulidentata (aardvarks).[2]
Of the five orders, hyraxes are the most basal, followed by embrithopods; the remaining orders (sirenians and elephants) are more closely related. These latter three are grouped as theTethytheria, because it is believed that their common ancestors lived on the shores of the prehistoricTethys Sea; however, recentmyoglobin studies indicate that evenHyracoidea had an aquatic ancestor.[3]
In 1945,George Gaylord Simpson used traditionaltaxonomic techniques to group these spectacularly diverse mammals in the superorder he named Paenungulata ("almostungulates"), but there were many loose threads in unravelling their genealogy.[4] For example, hyraxes in his Paenungulata had some characteristics suggesting they might be connected to thePerissodactyla (odd-toed ungulates, such as horses and rhinos). Indeed, early taxonomists placed the Hyracoidea closest to the rhinoceroses because of their dentition.
When genetic techniques were developed for inspectingamino acid differences amonghaemoglobin sequences the mostparsimoniouscladograms depicted Simpson's Paenungulata as an authenticclade and as one of the first groups to diversify from the basal placental mammals (Eutheria). The amino acid sequences reject a connection between extant paenungulates andperissodactyls (odd-toed ungulates).[4]
However, a2014 cladistic analysis placedanthracobunids and desmostylians, two major extinct groups that have been considered to be non-African afrotheres, close to each other withinPerissodactyla.[5]
| A cladogram ofAfrotheria based on molecular evidence[6] |
Each of theextinct orders, theEmbrithopoda andDesmostylia,[a] was as unique in its members' ways of making a living as the three orders that survive. Embrithopods wererhinoceros-like herbivorous mammals withplantigrade feet, and desmostylians werehippopotamus-like amphibious animals. Their walking posture and diet have been the subject of speculation, but tooth wear indicates that desmostylians browsed on terrestrial plants and had a posture similar to other large hoofed mammals.[2]
.jpg)
_colourised.png)
_(Chrysochloris_asiatica).jpg)
_(Tenrec_ecaudatus).jpg)
