afrotheria
Afrotheria ( from Latin ''Afro-'' "of Africa" + ''theria'' "wild beast") is a superorder of placental mammals, the living members of which belong to groups that are either currently living in Africa or of African origin: golden moles, elephan ...
n mammals. Although there are many fossil species, the only species surviving today is the
aardvark
Aardvarks ( ; ''Orycteropus afer'') are medium-sized, burrowing, nocturnal mammals native to Africa. Aardvarks are the only living species of the family Orycteropodidae and the order Tubulidentata. They have a long proboscis, similar to a pi ...
, ''Orycteropus afer''. Orycteropodidae is recognized as the only family within the order Tubulidentata, from the Latin words ''tubulis'' (tubule) and ''dentis'' (tooth), referring to the tubule-style teeth., so the two are effectively synonyms.
Evolution
The first aardvark fossil discovered was originally named ''Orycteropus gaudryi'' (now '' Amphiorycteropus'') and was found in
Turolian
The Turolian age is a period of geologic time (9.0–5.3 Ma) within the Miocene used more specifically with European Land Mammal Ages. It precedes the Ruscinian age and follows the Vallesian age. The Turolian overlaps the Tortonian and Messinia ...
deposits on the island of
Samos
Samos (, also ; , ) is a Greek island in the eastern Aegean Sea, south of Chios, north of Patmos and the Dodecanese archipelago, and off the coast of western Turkey, from which it is separated by the Mycale Strait. It is also a separate reg ...
. Since then, representatives of the order Tubulidentata have been located from the
Oligocene
The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...
in what is now Europe, and it is believed that the order probably originated around 65–70 million years ago or in the
Paleocene
The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...
. They are thought to be closely related to the now extinct
Ptolemaiida
Ptolemaiida is a taxon of wolf-sized Afrotheria, afrothere mammals that lived in northern and eastern Africa during the Paleogene. The oldest fossils are from the latest Eocene strata of the Jebel Qatrani Formation, near the Fayum oasis in Egypt. ...
, a lineage of carnivorous afrotheres. The family arose in Africa in the Early
Miocene
The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...
epoch, and spread to Eurasia later in the Miocene. Most of the family's diversity had become extinct by the end of the
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58
Characteristics
Aardvarks had originally been categorized as relatives of American anteaters in the order Edentata. But their unique type of teeth and other morphological characteristics had made it clear that aardvarks are not closely related to any other living mammals. Since the end of the 19th century, they are placed in their own separate order Tubulidentata. Both the fossil record and genetic studies have corroborated that separate status. All similarities to American anteaters have evolved independently as adaptations to eating ants and termites.
One of the most distinctive features of the animals is that their teeth have a "tubulidentate" microstructure, lacking enamel, and are just rounded structures of dentine. They lack incisors and canines, and have 20–22 teeth, which are evergrowing, unrooted, and
diphyodont
A diphyodont is any animal with two sets of teeth, initially the ''deciduous'' set and consecutively the '' permanent'' set. Most mammals are diphyodonts—as to chew their food they need a strong, durable and complete set of teeth.
Diphyodonts ...
. Another unique trait is that their small milk teeth are lost before the animal is born.
A few anatomical characters unite the Orycteropodidae and Tubulidentata. The occipital region of the skull has extensive
mastoid
The mastoid part of the temporal bone is the posterior (back) part of the temporal bone, one of the bones of the skull. Its rough surface gives attachment to various muscles (via tendons) and it has openings for blood vessels. From its borders, t ...
exposure, the
femur
The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg.
The Femo ...
diaphysis
The diaphysis (: diaphyses) is the main or midsection (shaft) of a long bone. It is made up of cortical bone and usually contains bone marrow and adipose tissue (fat).
It is a middle tubular part composed of compact bone which surrounds a centr ...
of the
tibia
The tibia (; : tibiae or tibias), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two Leg bones, bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outsi ...
is curved mediolaterally.
Modern aardvarks are polygynous, the females providing care for the young. They are territorial, and only cross paths to breed. The males' genitals create a musk while females create this musk from glands in their elbows, this scent helps mating occur. The gestation period lasts about seven months, and they are dependent upon the mother until they are six months of age, becoming sexually mature at two years of age. Breeding occurs once a year, they produce one offspring, and will have maybe one to two more in their lifetime. Aardvarks are myrmecophagous, feeding almost exclusively on termites and ants. They rely on their sense of smell to find most of their food and hunt at night.
type species
In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...
Aardvark
Aardvarks ( ; ''Orycteropus afer'') are medium-sized, burrowing, nocturnal mammals native to Africa. Aardvarks are the only living species of the family Orycteropodidae and the order Tubulidentata. They have a long proboscis, similar to a pi ...