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Uranotheria

(Order)

Overview

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Paenungulata is a taxon that groups some remarkable mammals, including three orders that are extant: Proboscidea (including elephants), Sirenia (sea cows, including dugongs and manatees), and Hyracoidea (hyraxes, such as the African Rock Hyrax, Procavia habessinica). At least two more orders are known only as fossils, namely Embrithopoda and Desmostylia. Both of these extinct orders were as unique in their ways as the surviving orders. Embrithopods were rhinoceros-like herbivorous mammals with plantigrade feet, and desmostylians were hippopotamus-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.

Of the five orders, hyraxes are the most basal, followed by embrithopods; the remaining orders sirenians, desmostylians and elephants are more closely interrelated. These latter three are grouped as the Tethytheria, because it is believed that their common ancestors lived on the shores of the prehistoric Tethys Sea.

Although morphological evidence continues to support the position of paenungulates with the ungulates, the molecular evidence suggests that Paenungulata is part of the cohort Afrotheria, an ancient assemblage of mainly African mammals of great diversity. The other members of this cohort are the orders Afrosoricida (tenrecs and golden moles), Macroscelidea (elephant shrews) and Tubulidentata (aardvarks).

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George Gaylord Simpson, using traditional taxonomic techniques, in 1945 succeeded in grouping these spectacularly diverse mammals in the superorder he named Paenungulata ("almost ungulates"). But there were many loose threads in unravelling their genealogy. For example, hyraxes in his Paenungulata had some characteristics suggesting they might be connected to the odd-toed ungulates (Perissodactyla, su ch as horses and rhinos). Indeed, early taxonomists placed the Hyracoidea closest to the rhinoceroses, because of their dentition, and even some recent evidence suggested a possible affinity of Hyracoidea to Perissodactyla rather than to the rest of the Paenungulata. This would mean that paenungulates are not a clade.

Later, genetic techniques were developed for inspecting amino acid differences among haemoglobin sequences. The most parsimonious cladograms depicted Simpson's Paenungulata as an authentic clade and as one of the first groups to diversify from the basal placental mammals (Eutheria). The amino acid sequences do not support a connection with perissodactyls (odd-toed ungulates).

Gallery

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b>Paenungulata is a taxon that groups some remarkable mammals, including three orders that are extant: Proboscidea (including elephants), Sirenia (sea cows, including dugongs and manatees), and Hyracoidea (hyraxes, such as the African Rock Hyrax, Procavia habessinica). At least two more orders are known only as fossils, namely Embrithopoda and Desmostylia. Both of these extinct orders were as unique in their ways as the surviving orders. Embrithopods were rhinoceros-like herbivorous mammals with plantigrade feet, and desmostylians were hippopotamus-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.

Of the five orders, hyraxes are the most basal, followed by embrithopods; the remaining orders sirenians, desmostylians and elephants are more closely interrelated. These latter three are grouped as the Tethytheria, because it is believed that their common ancestors lived on the shores of the prehistoric Tethys Sea.

Although morphological evidence continues to support the position of paenungulates with the ungulates, the molecular evidence suggests that Paenungulata is part of the cohort Afrotheria, an ancient assemblage of mainly African mammals of great diversity. The other members of this cohort are the orders Afrosoricida (tenrecs and golden moles), Macroscelidea (elephant shrews) and Tubulidentata (aardvarks).

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George Gaylord Simpson, using traditional taxonomic techniques, in 1945 succeeded in grouping these spectacularly diverse mammals in the superorder he named Paenungulata ("almost ungulates"). But there were many loose threads in unravelling their genealogy. For example, hyraxes in his Paenungulata had some characteristics suggesting they might be connected to the odd-toed ungulates (Perissodactyla, such as horses and rhinos). Indeed, early taxonomists placed the Hyracoidea closest to the rhinoceroses, because of their dentition, and even some recent evidence suggested a possible affinity of Hyracoidea to Perissodactyla rather than to the rest of the Paenungulata. This would mean that paenungulates are not a clade.

Later, genetic techniques were developed for inspecting amino acid differences among haemoglobin sequences. The most parsimonious cladograms depicted Simpson's Paenungulata as an authentic clade and as one of the first groups to diversify from the basal placental mammals (Eutheria). The amino acid sequences do not support a connection with perissodactyls (odd-toed ungulates).

Gallery

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References

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External links

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Taxonomy

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The Order Uranotheria is a member of the Mirorder Altungulata. Here is the complete "parentage" of Uranotheria:

The Order Uranotheria is further organized into finer groupings including:

Families

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Anthracobunidae

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Arsinoitheriidae

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Barytheriidae

[more]

Deinotheriidae

Deinotheriidae ("terrible beasts") is a family of prehistoric elephant-like proboscideans that lived during the Tertiary period, first appearing in Africa, then spreading across southern Asia (Indo-Pakistan) and Europe. During that time they changed very little, apart from growing much larger in size - by the late Miocene they had become the largest land animals of their time. Their most distinctive feature was the downward curving tusks on the lower jaw. [more]

Desmostylidae

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Dugongidae

Dugongidae is a family in the order of Sirenia. [more]

Elephantidae

Elephantidae is a taxonomic family, collectively elephants and mammoths. These are terrestrial large mammals with a trunk and tusks. Most genera and species in the family are extinct. Only two genera, Loxodonta (African elephants) and Elephas (Asiatic elephants), are living. [more]

Gomphotheriidae

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Hemimastodontidae

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Mammutidae

Mammutidae is a family of extinct proboscideans that lived between the Miocene to the Pleistocene or Holocene. The family was first described in 1922, classifying fossil specimens of the type genus Mammut (mastodons), and has since been placed in various arrangements of the order. The name mastodon derives from Greek, ?ast?? "nipple" and ?d??? "tooth", as with the genus, to indicate a characteristic that distinguishes them from allied families. The genus Zygolophodon has also been assigned to this family. [more]

Moeritheriidae

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Numidotheriidae

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Palaeomastodontidae

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Phenacolophidae

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Phiomiidae

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Pliohyracidae

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Procaviidae

A hyrax (from Greek "shrewmouse") is any species of fairly small, thickset, herbivorous mammals in the order Hyracoidea. The rock hyrax Procavia capensis, the yellow-spotted rock hyrax Heterohyrax brucei, the western tree hyrax Dendrohyrax dorsalis, and the southern tree hyrax, Dendrohyrax arboreus live in Africa and the Middle East. [more]

Prorastomidae

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Trichechidae

Manatees (family Trichechidae, genus Trichechus) are large, fully aquatic, mostly herbivorous marine mammals sometimes known as sea cows. There are three accepted living species of Trichechidae, representing three of the four living species in the order Sirenia: the Amazonian manatee (Trichechus inunguis), the West Indian manatee (Trichechus manatus), and the West African manatee (Trichechus senegalensis). They measure up to 13 feet (4.0 m) long, weigh as much as 1,300 pounds (590 kg), and have paddle-like flippers. The name manat? comes from the Ta?no, a pre-Columbian people of the Caribbean, meaning "breast". [more]

At least 9 species and subspecies belong to the Family Trichechidae.

More info about the Family Trichechidae may be found here.

References

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External links

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Sources

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Last Revised: August 24, 2012
2012/08/24 13:15:49