| Afroinsectivora | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Clade: | Afroinsectiphilia |
| Clade: | Afroinsectivora Waddell, Kishino & Ota 2001 |
| Orders | |
Afroinsectivora is a clade of mammals that includes the macroscelideans and afrosoricidans. [1] This clade includes the elephant shrews, golden moles and tenrecs.
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| A cladogram of Afrotheria based on molecular evidence [2] |
Moles are small mammals adapted to a subterranean lifestyle. They have cylindrical bodies, velvety fur, very small, inconspicuous eyes and ears, reduced hindlimbs, and short, powerful forelimbs with large paws adapted for digging.
Placentalia is one of the three extant subdivisions of the class of animals Mammalia; the other two are Monotremata and Marsupialia. The placentals are partly distinguished from other mammals in that the fetus is carried in the uterus of its mother to a relatively late stage of development. The name is something of a misnomer considering that marsupials also nourish their fetuses via a placenta, though for a relatively briefer period, giving birth to less developed young who are then kept for a period in the mother's pouch.
The order Insectivora is a now-abandoned biological grouping within the class of mammals. Some species have now been moved out, leaving the remaining ones in the order Eulipotyphla, within the larger clade Laurasiatheria, which makes up one of the most basic clades of placental mammals.
Eulipotyphla is an order of mammals suggested by molecular methods of phylogenetic reconstruction, and includes the laurasiatherian members of the now-invalid polyphyletic order Lipotyphla, but not the afrotherian members. Lipotyphla in turn had been derived by removing a number of groups from Insectivora, the previously used wastebasket taxon.
Elephant shrews, also called jumping shrews or sengis, are small insectivorous mammals native to Africa, belonging to the family Macroscelididae, in the order Macroscelidea. Their traditional common English name "elephant shrew" comes from a perceived resemblance between their long noses and the trunk of an elephant, and their superficial similarity with shrews in the order Eulipotyphla. However, phylogenetic analysis revealed that elephant shrews are not classified with true shrews, but are in fact more closely related to elephants than shrews. In 1997, the biologist Jonathan Kingdon proposed that they instead be called "sengis", a term derived from the Bantu languages of Africa, and in 1998, they were classified into the new clade Afrotheria.
The order Afrosoricida contains the golden moles of Southern Africa, the otter shrews of equatorial Africa and the tenrecs of Madagascar. These three families of small mammals have traditionally been considered to be a part of the order Insectivora, and were later included in Lipotyphla after Insectivora was abandoned as a wastebasket taxon, before Lipotyphla was also found to be polyphyletic.
Tenrecomorpha is the suborder of otter shrews and tenrecs, a group of afrotherian mammals indigenous to equatorial Africa and Madagascar, respectively. The two families are thought to have split about 47–53 million years ago. Potamogalid otter shrews were formerly considered a subfamily of Tenrecidae. The suborder is also presumed to contain the extinct genus Plesiorycteropus, a group of possibly fossorial insectivores similar to aardvarks, which is known to be more closely related to tenrecs of subfamily Tenrecinae than to golden moles of suborder Chrysochloridea.
A tenrec is any species of mammal within the afrotherian family Tenrecidae endemic to Madagascar. Tenrecs are widely diverse; as a result of convergent evolution some resemble hedgehogs, shrews, opossums, rats, or mice. They occupy aquatic, arboreal, terrestrial and fossorial environments. Some of these species, including the greater hedgehog tenrec, can be found in the Madagascar dry deciduous forests. However, the speciation rate in this group has been higher in humid forests.
Afrotheria is a clade of mammals, the living members of which belong to groups that are either currently living in Africa or of African origin: golden moles, elephant shrews, tenrecs, aardvarks, hyraxes, elephants, sea cows, and several extinct clades. Most groups of afrotheres share little or no superficial resemblance, and their similarities have only become known in recent times because of genetics and molecular studies. Many afrothere groups are found mostly or exclusively in Africa, reflecting the fact that Africa was an island continent from the early Cenozoic until around 25 million years ago, when the Tethys Sea shrank.
Paenungulata is a clade of "sub-ungulates", which groups three extant mammal orders: Proboscidea, Sirenia, and Hyracoidea (hyraxes). At least two more possible orders are known only as fossils, namely Embrithopoda and Desmostylia.
Lipotyphla is a formerly used order of mammals, including the members of the order Eulipotyphla as well as three other families of the former order Insectivora, Chrysochloridae, Tenrecidae (tenrecs), and Potamogalidae. However, molecular studies found the golden moles, tenrecs, and otter shrews to be unrelated to the others. This made Lypotyphla an invalid polyphyletic order and gave rise to the notion of Eulypotyphla instead, an exclusively laurasiathere grouping.
Mammalia is a class of animal within the phylum Chordata. Mammal classification has been through several iterations since Carl Linnaeus initially defined the class. No classification system is universally accepted; McKenna & Bell (1997) and Wilson & Reader (2005) provide useful recent compendiums. Many earlier ideas from Linnaeus et al. have been completely abandoned by modern taxonomists, among these are the idea that bats are related to birds or that humans represent a group outside of other living things. Competing ideas about the relationships of mammal orders do persist and are currently in development. Most significantly in recent years, cladistic thinking has led to an effort to ensure that all taxonomic designations represent monophyletic groups. The field has also seen a recent surge in interest and modification due to the results of molecular phylogenetics.
Wastebasket taxon is a term used by some taxonomists to refer to a taxon that has the sole purpose of classifying organisms that do not fit anywhere else. They are typically defined by either their designated members' often superficial similarity to each other, or their lack of one or more distinct character states or by their not belonging to one or more other taxa. Wastebasket taxa are by definition either paraphyletic or polyphyletic, and are therefore not considered valid taxa under strict cladistic rules of taxonomy. The name of a wastebasket taxon may in some cases be retained as the designation of an evolutionary grade, however.
The web-footed tenrec, otter shrew, or aquatic tenrec is the only known semiaquatic tenrec, and is found in eastern Madagascar, especially in and around Ranomafana National Park. It grows to between 25 and 39 cm, and was once thought to be extinct. It feeds on crabs, water insects, and crayfish. The population is considered vulnerable. It was formerly placed in the monotypic genus Limnogale, but has been moved to Microgale based on molecular data showing it to be deeply nested within the latter.
The Afroinsectiphilia is a clade that has been proposed based on the results of recent molecular phylogenetic studies. Many of the taxa within it were once regarded as part of the order Insectivora, but Insectivora is now considered to be polyphyletic and obsolete. This proposed classification is based on molecular studies only, and there is no morphological evidence for it.
Soricomorpha is a formerly used taxon within the class of mammals. In the past it formed a significant group within the former order Insectivora. However, Insectivora was shown to be polyphyletic and various new orders were split off from it, including Afrosoricida, Macroscelidea, and Erinaceomorpha, with the four remaining extant and recent families of Soricomorpha shown here then being treated as a separate order. Insectivora was left empty and disbanded.
Amblysomus is a genus of the golden mole family, Chrysochloridae, comprising five species of the small, insect-eating, burrowing mammals endemic to Southern Africa. All five species can be found in South Africa and some are also found in Swaziland and Lesotho.
Oryzorictinae is a subfamily of tenrecs endemic to the island of Madagascar. It is the largest of three tenrec subfamilies. Oryzorictinae is thought to have split from the lineage of its closest relative, Geogale, about 30 million years (Ma) ago. The deepest phylogenetic split within the subfamily, that between Oryzorictes and a clade composed of Microgale plus Nesogale, is thought to have occurred about 28 Ma ago. In turn, Microgale and Nesogale are thought to have diverged about 19 Ma ago.
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