Evolution and Systematics
Functional Adaptations
Functional adaptation
The metabolism of tenrecs allows them to survive cold temperatures if necessary via hibernation.
"Certain mammals are known to estivate. Perhaps the best-known examples are tenrecs - Madagascan insectivores related to hedgehogs. During the abnormally hot summer weather, they enter a state of inactivity resembling hibernation. Moreover, when outside temperatures plummet, they undergo true hibernation, becoming stiff and cold to the touch. This behavior has been noted on a number of occasions with captive zoo specimens of tenrecs maintained in countries with cooler average temperatures than that of their tropical Madagascan homeland." (Shuker 2001:105)
"Prior to the start of the Austral winter (May to September) they eat more and lay down fat reserves within their bodies in order to hibernate, which they usually do in burrows with the entrance plugged with soil. The long-tailed or shrew tenrecs (Microgale) also store fat in their tails, and in Dobson's shrew tenrec (Microgale dobsoni) the nomad weight of 1 1/2 ounces (46 g) is almost doubled by the fat stored for hibernation. Madagascan winters are quitter mild, and could be termed the cool, dry season rather than winter. In the highlands at 4,100 feet (1,250 m) the temperature averages 59° F (15° C) in the dry season, just a few degrees lower than summer levels, but the vegetation, and consequently the food supplies, suffer from lack of rain and the tenrecs become dormant in their burrows…Dormant tenrecs dug out of their burrows were cold to the touch, had a very low breathing rate, and had neither food in their stomach or feces in the intestine. Even when active the tenrecs have a variable body temperature that ranges from 75.2° F (24°C) to 95°F (35°C). This is considerable lower than other mammals, which average 98.6°F (37°C), and the tenrec shares with the sloths the title of the most cold-blooded mammal. The body temperature of hibernating tenrecs is usually just 1.8° F (1°C) above the ambient temperature." (Roots 2006: 191)
Learn more about this functional adaptation.
- Shuker, KPN. 2001. The Hidden Powers of Animals: Uncovering the Secrets of Nature. London: Marshall Editions Ltd. 240 p.
- Roots C. 2006. Hibernation. Westport, CT: Greenwood Press.
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Functional adaptation
Tenrecs survive hot summer weather by entering a state of dormancy called estivation.
"Certain mammals are known to estivate. Perhaps the best-known examples are tenrecs - Madagascan insectivores related to hedgehogs. During the abnormally hot summer weather, they enter a state of inactivity resembling hibernation. Moreover, when outside temperatures plummet, they undergo true hibernation, becoming stiff and cold to the touch. This behavior has been noted on a number of occasions with captive zoo specimens of tenrecs maintained in countries with cooler average temperatures than that of their tropical Madagascan homeland." (Shuker 2001:105)
"Prior to the start of the Austral winter (May to September) they eat more and lay down fat reserves within their bodies in order to hibernate, which they usually do in burrows with the entrance plugged with soil. The long-tailed or shrew tenrecs (Microgale) also store fat in their tails, and in Dobson's shrew tenrec (Microgale dobsoni) the nomad weight of 1 1/2 ounces (46 g) is almost doubled by the fat stored for hibernation. Madagascan winters are quitter mild, and could be termed the cool, dry season rather than winter. In the highlands at 4,100 feet (1,250 m) the temperature averages 59° F (15° C) in the dry season, just a few degrees lower than summer levels, but the vegetation, and consequently the food supplies, suffer from lack of rain and the tenrecs become dormant in their burrows…Dormant tenrecs dug out of their burrows were cold to the touch, had a very low breathing rate, and had neither food in their stomach or feces in the intestine. Even when active the tenrecs have a variable body temperature that ranges from 75.2° F (24°C) to 95°F (35°C). This is considerable lower than other mammals, which average 98.6°F (37°C), and the tenrec shares with the sloths the title of the most cold-blooded mammal. The body temperature of hibernating tenrecs is usually just 1.8° F (1°C) above the ambient temperature…These tenrecs also experience a daily temperature range of several degrees between their active and rest periods during the spring and summer, and they also estivate during the hottest times of the year." (Roots 2006: 191)
Learn more about this functional adaptation.
- Shuker, KPN. 2001. The Hidden Powers of Animals: Uncovering the Secrets of Nature. London: Marshall Editions Ltd. 240 p.
- Roots C. 2006. Hibernation. Westport, CT: Greenwood Press.
© The Biomimicry Institute
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Molecular Biology and Genetics
Barcode
Statistics of barcoding coverage
| Specimen Records: | 4 |
| Specimens with Sequences: | 4 |
| Specimens with Barcodes: | 4 |
| Public Records: | 4 |
| Species: | 1 |
| Species With Barcodes: | 1 |
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Barcode data
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Wikipedia
Tenrecidae
Tenrecidae (common name tenrecs) is a family of mammals found on Madagascar and parts of Africa. Tenrecs are widely diverse, resembling hedgehogs, shrews, opossums, mice and even otters, as a result of convergent evolution. They occupy aquatic, arboreal, terrestrial and fossorial environments. Some of these species can be found in the Madagascar dry deciduous forests, including the greater hedgehog tenrec.
Contents |
Characteristics
Tenrecs are small mammals of variable body form. The smallest species are the size of shrews, with a body length of around 4.5 centimetres (1.8 in), and weighing just 5 grams (0.18 oz), while the largest, the common or tailless tenrec, is 25 to 39 centimetres (9.8 to 15 in) in length, and can weigh over 1 kilogram (2.2 lb).[2] Although they may resemble shrews, hedgehogs, or otters, they are not closely related to any of these groups, their closest relatives being other African, insectivorous mammals such as golden moles and elephant shrews. The common ancestry of these animals, along with aardvarks, hyraxes, elephants, and sea cows in the group Afrotheria, was not recognized until the late 1990s.[3] Continuing work on the molecular[4][5] and morphological[6][7][8][9] diversity of afrotherian mammals has provided ever increasing support for their common ancestry.
Unusual among placental mammals, the anus and urogenital tracts of tenrecs share a common opening, or cloaca, a feature more commonly seen in birds, reptiles, and amphibians. They have low body temperatures, sufficiently so that they do not require a scrotum to cool their sperm as most other mammals do.[2]
All species appear to be at least somewhat omnivorous, with invertebrates forming the largest part of their diets. The three species found on the African mainland (Potamogale velox, Micropotamogale lamottei, M. ruwenzorii) have a more specialized diet, centered on their habitat in fast-running streams of the African tropics, from Liberia in the west to Lake Victoria in the east. One species from Madagascar, Limnogale mergulus, is also semiaquatic.[10] All of the species from Madagascar, semiaquatic or not, appear to have evolved from a single, common ancestor, with the mainland tenrecs comprising the next, most-closely related mammalian species.[11][12] While the fossil record of tenrecs is scarce, at least some specimens from the early Miocene of Kenya show close affinities to living species from Madagascar,[13] such as Geogale aurita.
Most species are nocturnal and have poor eyesight. Their other senses are well developed, however, and they have especially sensitive whiskers. As with many of their other features, the dental formula of tenrecs varies greatly between species; they can have from 32 to 42 teeth in total. Unusual for mammals, the permanent dentition in tenrecs tends not to completely erupt until well after adult body size has been reached.[14] This is one of several anatomical features shared by elephants, hyraxes, sengis, and golden moles (but apparently not aardvarks), consistent with their descent from a common ancestor.
Tenrecs have a gestation period of 50 to 64 days, and give birth to a number of relatively undeveloped young. While the otter shrews have just two young per litter, the tailles tenrec can have as many as 32, and females possess up to 29 teats, more than any other mammal.[2] At least some species of tenrecs are social, living in multigenerational family groups with over a dozen individuals.
Use
In the island nation of Mauritius, some of the inhabitants eat tenrec meat, though it is difficult to obtain (as it is not sold in shops or markets) and difficult to prepare correctly.
The lesser hedgehog tenrec (Echinops telfairi) is one of 16 mammalian species that will have its genome sequenced as part of the Mammalian Genome Project. It is increasingly popular in the pet trade, and in the future may serve as an important model organism in biomedicine, as it is only distantly related to the mice, rats, guinea pigs, and rhesus macaques that comprise the most common research animals.
Species
There are four subfamilies, 10 genera, and 34 species of tenrecs.
FAMILY Tenrecidae
- Subfamily Geogalinae
- Genus Geogale
- Subfamily Oryzorictinae
- Genus Limnogale
- Genus Microgale
- Short-tailed Shrew Tenrec (Microgale brevicaudata)
- Cowan's Shrew Tenrec (Microgale cowani)
- Dobson's Shrew Tenrec (Microgale dobsoni)
- Drouhard's Shrew Tenrec (Microgale drouhardi)
- Dryad Shrew Tenrec (Microgale dryas)
- Pale Shrew Tenrec (Microgale fotsifotsy)
- Gracile Shrew Tenrec (Microgale gracilis)
- Microgale grandidieri
- Naked-nosed Shrew Tenrec (Microgale gymnorhyncha)
- Jenkins' Shrew Tenrec Microgale jenkinsae
- Northern Shrew Tenrec (Microgale jobihely)
- Lesser Long-tailed Shrew Tenrec (Microgale longicaudata)
- Microgale macpheei (extinct)
- Major's Long-tailed Tenrec (Microgale majori)
- Montane Shrew Tenrec (Microgale monticola)
- Nasolo's Shrew Tenrec (Microgale nasoloi)
- Pygmy Shrew Tenrec (Microgale parvula)
- Greater Long-tailed Shrew Tenrec (Microgale principula)
- Least Shrew Tenrec (Microgale pusilla)
- Shrew-toothed Shrew Tenrec (Microgale soricoides)
- Taiva Shrew Tenrec (Microgale taiva)
- Talazac's Shrew Tenrec (Microgale talazaci)
- Thomas's Shrew Tenrec (Microgale thomasi)
- Genus Oryzorictes
- Subfamily Potamogalinae
- Subfamily Tenrecinae
See also
References
- Bronner, Gary N.; Jenkins, Paulina D. (16 November 2005). "Order Afrosoricida (pp. 71-81)". In Wilson, Don E., and Reeder, DeeAnn M., eds. Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press, 2 vols. (2142 pp.). pp. 72-77. ISBN 978-0-8018-8221-0. OCLC 62265494. http://www.bucknell.edu/msw3.
- ^ Savage, RJG, & Long, MR (1986). Mammal Evolution: an illustrated guide. New York: Facts on File. pp. 53. ISBN 0-8160-1194-X.
- ^ a b c Nicholl, Martin (1984). Macdonald, D.. ed. The Encyclopedia of Mammals. New York: Facts on File. pp. 744–747. ISBN 0-87196-871-1.
- ^ Stanhope, M.J. et al. (1998) Molecular evidence for multiple origins of Insectivora and for a new order of endemic African insectivore mammals. Proc. Natl. Acad. Sci. U. S. A. 95, 9967–9972
- ^ Springer MS, Stanhope MJ, Madsen O, de Jong WW: Molecules consolidate the placental mammal tree. Trends Ecol Evol 2004, 19(8):430-438.
- ^ Robinson, T. J. Fu, B. Ferguson-Smith, M. A. Yang, F. 2004. Cross-species chromosome painting in the golden mole and elephant-shrew: support for the mammalian clades Afrotheria and Afroinsectiphillia but not Afroinsectivora. PROCEEDINGS- ROYAL SOCIETY OF LONDON B. 271(1547): 1477-1484
- ^ Asher RJ, Bennet N, Lehmann T. 2009. The new framework for understanding placental mammal evolution. BioEssays 31:853–864
- ^ Tabuce, R., Marivaux, L., Adaci,M., Bensalah,M., Hartenberger, J. L., et al. Early tertiary mammals from north Africa reinforce the molecular afrotheria clade. Proc Royal Soc B-Biol Sci 2007. 274: 1159–1166.
- ^ Seiffert, E., A new estimate of afrotherian phylogeny based on simultaneous analysis of genomic, morphological, and fossil evidence. BMC Evol Biol 2007. 7: 13.
- ^ Sanchez-Villagra, M. R., Narita, Y. and Kuratani, S., Thoracolumbar vertebral number: the first skeletal synapomorphy for afrotherian mammals. Syst Biodivers 2007. 5: 1–17.
- ^ Benstead, J. P., and L. E. Olson. 2003. Limnogale mergulus, web-footed tenrec or aquatic tenrec. Pages 1267–1273 in The natural history of Madagascar (S. M. Goodman and J. P. Benstead, eds.). University of Chicago Press, Chicago.
- ^ Olson LE, Goodman SM: Phylogeny and biogeography of tenrecs. In The Natural History of Madagascar Edited by: Goodman SM, Benstead JP. Chicago: Chicago University Press; 2003:1235-1242.
- ^ Poux C, Madsen O, Glos J, de Jong WW, Vences M. 2008. Molecular phylogeny and divergence times of Malagasy tenrecs: influence of data partitioning and taxon sampling on dating analyses. BMC Evol Biol. 8:102
- ^ Asher RJ, Hofreiter M: Tenrec phylogeny and the noninvasive extraction of nuclear DNA. Syst Biol 2006, 55:181-194.
- ^ Asher, R. J. and Lehmann, T. 2008. Dental eruption in afrotherian mammals. BMC Biol 6: 14.
Source:
Wikipedia
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Oryzorictinae
Oryzorictinae is a subfamily of Tenrec.
Species
- Genus Limnogale
- Genus Microgale
- Short-tailed Shrew Tenrec (Microgale brevicaudata)
- Cowan's Shrew Tenrec (Microgale cowani)
- Dobson's Shrew Tenrec (Microgale dobsoni)
- Drouhard's Shrew Tenrec (Microgale drouhardi)
- Dryad Shrew Tenrec (Microgale dryas)
- Pale Shrew Tenrec (Microgale fotsifotsy)
- Gracile Shrew Tenrec (Microgale gracilis)
- Microgale grandidieri
- Naked-nosed Shrew Tenrec (Microgale gymnorhyncha)
- Jenkins' Shrew Tenrec Microgale jenkinsae
- Northern Shrew Tenrec (Microgale jobihely)
- Lesser Long-tailed Shrew Tenrec (Microgale longicaudata)
- Microgale macpheei (extinct)
- Major's Long-tailed Tenrec (Microgale majori)
- Montane Shrew Tenrec (Microgale monticola)
- Nasolo's Shrew Tenrec (Microgale nasoloi)
- Pygmy Shrew Tenrec (Microgale parvula)
- Greater Long-tailed Shrew Tenrec (Microgale principula)
- Least Shrew Tenrec (Microgale pusilla)
- Shrew-toothed Shrew Tenrec (Microgale soricoides)
- Taiva Shrew Tenrec (Microgale taiva)
- Talazac's Shrew Tenrec (Microgale talazaci)
- Thomas's Shrew Tenrec (Microgale thomasi)
- Genus Oryzorictes
References
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