Chrysochloris asiatica Cape golden mole adult, showing the digging claw, absence of external eye and a hint of the iridescence of the fur. The rhinarium is not obvious in this photograph.
Golden moles are small insectivorous burrowing mammalsendemic to Sub-Saharan Africa. They comprise the family Chrysochloridae (the only family in the suborder Chrysochloridea) and as such they are taxonomically distinct from the true moles, family Talpidae, and other mole-like families, all of which, to various degrees, they resemble as a result of evolutionary convergence. There are 21 species. Some (e.g., Chrysochloris asiatica, Amblysomus hottentotus) are relatively common, whereas others (e.g., species of Chrysospalax, Cryptochloris, Neamblysomus) are rare and endangered.
Despite their extreme evolutionary convergence with moles, their closest relatives are the otter shrews and tenrecs. They are more distantly related to other insectivorous African mammals such as aardvarks and elephant shrews, and even more distantly related to elephants and sirenians.[3]
Characteristics and affinities
Like most burrowing mammals with similar habits, the Chrysochloridae have short legs with powerful digging claws, very dense fur that repels dirt and moisture, and toughened skin, particularly on the head. The fur varies from black to pale yellow or grey, and has an iridescent sheen of green, blue, violet or copper when viewed in light.[4]
Their eyes are non-functional and covered with furred skin. The external ears are just tiny openings. In particular, golden moles bear a remarkable resemblance to the marsupial moles of Australia, family Notoryctidae, which they resemble so suggestively that at one time, the marsupial/placental divide notwithstanding, some argued that they were related. Considerations that influenced the debate might have included the view that the Chrysochloridae are very primitive placentals and the fact that they have many mole-like specializations similar to specializations in marsupial moles.
The rhinarium is a greatly enlarged, dry leathery pad that protects their nostrils while the animal digs. In this respect, too, they resemble the marsupial moles. Some authors claim their primary sense is of touch, and they are particularly sensitive to vibrations, which may indicate approaching danger.[5] Note below, however, the observations on the malleus in the middle ear.
The species range in size from about 8 centimetres (3.1in) to about 20 centimetres (7.9in). They have muscular shoulders and the forelimbs are radically adapted for digging; all the toes on the forefeet have been reduced, except for a large, pick-like third claw on the third toe. In comparison to true moles, the fifth digit is absent and the first and fourth digits are vestigial. The adaptations of the hind feet are less dramatic: They retain all five toes and are webbed as an adaptation to efficient backward shoveling of soil loosened by the front claws.[4]
At one time, the Chrysochloridae were regarded as primitive. Supporting arguments of this included that they were thought to have originated in Gondwana, that they had a low resting metabolic rate, and that they could switch off thermoregulation when inactive. Like the tenrecs, they possess a cloaca, and males lack a scrotum. However, these points are no longer regarded as strongly suggestive of golden moles as undeveloped "reptilian mammals"; some are seen rather as adaptations to regional climatic conditions. Going into a torpor when resting or during cold weather enables them to conserve energy and reduce urgent requirements for food. Similarly, they have developed particularly efficient kidneys, and some species do not need to drink water at all. They tend to drown if they fall into water.
Habits and ecology
Chrysochloridae are subterranean, afrotherian mammals endemic to sub-Saharan Africa, and most of which are recorded from South Africa in particular. Other regions include Lake Victoria, Western Cape,[6] and Namibia.[7] They live in a variety of environments; forest, swamps, deserts, or mountainous terrain. Chrysospalax species tend to forage above ground in leaf litter in forests or in meadows. Eremitalpa species such as Grant's golden mole live in the sandy Namib desert, where they cannot form tunnels because the sand collapses. Instead during the day, when they must seek shelter, they "swim" through the loose sand, using their broad claws to paddle, and dive down some 50 centimetres (20in) to where it is bearably cool. There they enter a state of torpor, thus conserving energy.[8] At night they emerge to forage on the surface rather than wasting energy shifting sand. Their main prey are termites that live under isolated grass clumps, and they might travel for 6 kilometres (3.7mi) a night in search of food. They seek promising clumps by listening for wind-rustled grass-root stresses and termites' head-banging alarm signals, neither of which can be heard easily above ground, so they stop periodically and dip their heads under the sand to listen.[8]
Most other species construct both foraging superficial burrows and deeper permanent burrows for residence. Residential burrows are relatively complex in form and may penetrate as far as 1 metre (3ft 3in) below ground and include deep chambers for use for refuge, and other chambers as latrines. They push excavated soil up to the surface, as in mole-hills, or compact it into the tunnel walls.
They feed on small insects and earthworms or small vertebrates such as lizards or burrowing snakes. They depend on their sense of hearing to locate much of their prey, and the cochleas of a number of golden mole species have been found to be long and highly coiled, which may indicate a greater ecological dependence on low frequency auditory cues than seen in Talpid moles.[9]
Morphology
Golden Moles share a number of features, varying by species, seldom seen elsewhere among living mammals, including three forearm long-bones, hyoid-mandible articulation, and a hypertrophied malleus.[6] Some species have hypertrophied (enlarged) middle ear ossicles, in particular the malleus. These animals have the largest malleus relative to body size of any animal.[10] This morphology may be adapted for the detection of seismic signals.[11][12][13] In this respect there is some apparent convergent evolution to burrowing reptiles in the family Amphisbaenidae.
Reproduction
Females give birth to one to three hairless young in a grass-lined nest within the burrow system. Breeding occurs throughout the year. The adults are solitary, and their burrowing territory may be aggressively defended from intruders, especially where resources are relatively scarce.[5]
Status
Of the 21 species of golden mole, no fewer than 11 are threatened with extinction. The primary cause being human-induced habitat loss. Additionally sand mining, poor agricultural practices, and predation by domestic cats and dogs are causes of population decline.
The taxonomy of the Chrysochloridae is undergoing a review in the light of new genetic information. They have traditionally been listed with the shrews, hedgehogs and a grab-bag of small, difficult-to-place creatures as part of the order Insectivora. Some authorities retain this classification, at least for the time being. Others group the golden moles with the tenrecs in a new order, which is sometimes known as Tenrecomorpha, while others call it Afrosoricida and reserve Tenrecomorpha for the family Tenrecidae.
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.
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 basal clades of placental mammals.
The clade Afrosoricida contains the golden moles of Southern Africa, the otter shrews of equatorial Africa and the tenrecs of Madagascar. These three groups of small mammals were for most of the 19th and 20th centuries regarded as a part of the Insectivora or Lipotyphla, but both of those groups, as traditionally used, are polyphyletic.
The Somali golden mole is a golden mole endemic to Somalia. In 1964, Dr. Alberto Simonetta of the University of Florence discovered the mole's jaw and ear bone fragments in a barn owl pellet in Jowhar, Somalia. The Somali golden mole differs from the other species in its family (Chrysochloridae) because the shape of its jaw is distinct; although the length of the lower jaw fits within the size range of the skulls of species Amblysomus leucorhinus and Amblysomus sclateri, the width of the ascending parts of the jaw is much bigger (2mm) than that of the species it most closely matches.
Grant's golden mole is a golden mole species. It is the only member of the genus Eremitalpa.
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 Eswatini and Lesotho.
Marley's golden mole is a species of burrowing mammal in the golden mole family, Chrysochloridae. It is found in South Africa and possibly Eswatini. It has been separated from Amblysomus hottentotus by Bronner. Its natural habitat is indigenous forests and moist grassland, and also gardens. It is classified as Endangered in the IUCN Red List of Threatened Species. The main threats it faces are habitat degradation, either through overgrazing by cattle or the removal of vegetation for firewood, and urbanization.
Arends' golden mole is a species of mammal in the family Chrysochloridae. It is found in Mozambique and Zimbabwe. Its natural habitats are temperate forests, subtropical or tropical dry, and moist montane forests, dry lowland grassland, arable land, pasture, plantations, rural gardens, and urban areas.
Chrysochloris is a genus of mammal in the family Chrysochloridae. It contains the following species:
The rough-haired golden mole is a species of mammal that live mostly below ground. They have shiny coats of dense fur and a streamlined, formless appearance. They have no visible eyes or ears; in fact, they are blind - the small eyes are covered with hairy skin. The ears are small and are hidden in the animal's fur.
De Winton's golden mole is a species of mammal in the family Chrysochloridae. It is endemic to South Africa. Its natural habitats are subtropical dry shrubland, Mediterranean-type shrubby vegetation, and sandy shores. It is threatened by habitat destruction and is "critically endangered". It was named after British zoologist William Edward de Winton.
Microgale is a genus of mammal in the family Tenrecidae. There are 21 living species on the island of Madagascar and one extinct species known from a fossil. Some species have been discovered in the last twenty years.
1 2 Skinner, John D.; Chimimba, Christian T. (2005). The mammals of the southern African subregion (third reviseded.). Cambridge: Cambridge university press. ISBN0521844185.
↑ Crumpton, Nick; Kardjilov, Nikolay; Asher, Robert J. (August 2015). "Convergence vs. Specialization in the ear region of moles (mammalia)". Journal of Morphology. 276 (8): 900–914. doi:10.1002/jmor.20391. PMID25858660. S2CID10039064.
↑ Mason, Matthew J. (August 2003). "Morphology of the middle ear of golden moles (Chrysochloridae)". Journal of Zoology. 260 (4): 391–403. doi:10.1017/S095283690300387X.
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