Four-toed rice grinder

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Four-toed rice grinder
Systematics
without rank: Afroinsectiphilia
Order : Tenrecus (Afrosoricida)
Family : Tenreks (Tenrecidae)
Subfamily : Travel treks (Oryzorictinae)
Genre : Rice burrower ( oryzorictes )
Type : Four-toed rice grinder
Scientific name
Oryzorictes tetradactylus
Milne-Edwards & Grandidier , 1882

The four toes rice Wühler ( Oryzorictes tetradactylus ) is a mammalian species from the kind of rice agitators within the family of tenrecs . Its distribution area is limited to a high mountain region in central and south-eastern Madagascar . There the animals inhabit the areas above the tree line, the habitats include wetlands and open shrubbery. They are adapted to a digging way of life, the body is compact and has strong limbs with wide feet. The tail is only half the length of the rest of the body. There is no information available about the way of life of the four-toed rice digger. In general, it is rarely seen, which is why no information can be given about the endangerment of the population. The species was scientifically introduced in 1882.

features

Habitus

The four-toed rice burrower is a medium-sized representative of the tenreks. It reaches a head-torso length of 10.5 to 11.5 cm and a tail length of 4.3 to 5.7 cm. The total length of the animals is between 14.8 and 17.2 cm. The weight of a single weighed individual was 36 g. In its external appearance, the four-toed rice burrower resembles the closely related actual rice burrower ( Oryzorictes hova ). He has a compact build and short limbs with wide feet. The almost bare tail is only about half the length of the rest of the body. In addition, the eyes and ears are relatively small, the latter being 12.5 mm long in one of the animals examined. The fur dress is very soft. It is characterized by a predominantly dark brown color, with light brown spots on the back. But there are also animals with almost black backs and greyish undersides known. The hands have four fingers and the feet have five toes. The claws are strong, they correspond to those of the actual rice grinder, but are on average shorter. The hind foot of an individual measured 16.5 mm in length.

Skull and dentition features

The skull resembles that of the actual rice grinder, but the four-toed rice grinder is not quite as strong and does not have as robust bone marks as muscle attachment points. Likewise, it is not as widened on the brain and less elongated on the rostrum . There are hardly any differences in the dentition.

distribution

Distribution area of ​​the four-toed rice burrower

The four-toed rice burrower is endemic to Madagascar and occurs there in the central and southeastern part of the country. The main distribution area is in the Andringitra Mountains in the province of Fianarantsoa , where the species can be found in high mountain areas from 2050 to 2450 m above sea level. The animals colonize regions above the tree line, their preferred habitat consists of heather bush landscapes, open grass areas and marshland . Altogether, the four-toed rice burrower has so far been found in fewer than ten localities, including the Plateau d'Andohariana and the Pic Boby. Most of the known individuals come from collections at the end of the 19th century, for example by Charles Immanuel Forsyth Major during his research trip from 1894 to 1896. The species has only rarely been sighted in recent times. Reports of four observed individuals come from scientific expeditions in the Andringitra Mountains in the 1970s; field research there in the 1990s recorded at least two animals. Therefore, no information can be given on the frequency and population size of the four-toed rice burrower. It may be difficult to watch. The actual rice burrower also occurs in the region, but its distribution area in the Andringitra Mountains usually includes altitudes below 2000 m.

Way of life

No information is available on the way of life. It is assumed that the animals live partly underground, but also that the adaptations to a digging activity are not quite as developed as in the real rice burrower.

Systematics

Internal systematics of the Tenreks according to Everson et al. 2016
 Tenrecidae  
  Tenrecinae  


 Echinops


   

 Setifer



   

 Hemicentetes


   

 Tenrec




   
  Geogalinae  

 Geogals


  Oryzorictinae  
  Oryzorictes  

 Oryzorictes hova


   

 Oryzorictes tetradactylus



   

 Nesogale


   

 Microgale






Template: Klade / Maintenance / Style

The four-toed rice burrower is next to the actual rice burrower ( Oryzorictes hova ) one of the two species from the genus of the rice burrower ( Oryzorictes ). The rice burrowers in turn belong to the Tenreks family (Tenrecidae), mammals endemic to Madagascar with various adaptations to an insect and carnivorous diet. Within the Tenreks, the rice diggers are combined with the Kleintenreks ( Microgale ) and the representatives of the genus Nesogale to form the subfamily of the Reistenreks (Oryzorictinae). In contrast to the ground-living to tree-climbing Nesogale species and the richly shaped small tenreks with varied ways of life, the rice burrowers are much more adapted to underground locomotion due to their physique. According to genetic studies, the rice diggers are the sister group of the other two genus of the Reistenreks. Their separation from the further line of development took place relatively early in phylogenetic terms , for example in the Upper Oligocene around 27 million years ago.

Alphonse Milne-Edwards and Alfred Grandidier carried out the first scientific description of the four-toed rice burner in 1882. They used an individual from the "Plateau d'Emirne", which today corresponds to the Imerina region in central Madagascar; it represents the type area of ​​the species. Both authors differentiate their new species from the actual rice burrower through the absence of the thumb, the narrower and longer skull and the relatively shorter tail. They described the fur as slate gray and silky. In 1896, Charles Immanuel Forsyth Major established the species Oryzoryctes niger on the basis of an individual measuring 10.6 cm in length and 4.9 cm in tail length from marshland near Antsirabe, also in central Madagascar. As a special characteristic, Major emphasized the dark color of the fur, on which the scientific species name is based. He recognized the great resemblance to the four- toed rice digger, but saw Oryzoryctes niger in a middle position between the former and the actual rice digger. About two decades later, in 1918, Oldfield classified Thomas Oryzorictes niger only as a dark color variant of the four-toed rice burner. Henri Heim de Balsac shared this opinion in 1972 ; Oryzorictes niger is now generally considered a synonym for Oryzorictes tetradactylus . Thomas had created the genus Nesoryctes in an attempt at structuring the Tenreks in 1918 , which was reserved for the four-toed rice digger. Thomas justified the spin-off from Oryzorictes with the more delicate skull structure of the four-toed rice digger and its not quite so strong adaptation to a digging way of life compared to the actual rice digger. In the following years Nesoryctes was partly led as a subgenus of Oryzorictes or regarded as identical with the latter.

Threat and protection

All in all, little information is available about the four-toed rice burrower with regard to biological needs, the size of the population and the exact distribution. Therefore the degree of threat to the stock cannot be determined. The IUCN lists the species in the category "insufficient data basis" ( data deficient ). It is proven in the Andringitra National Park . To protect the animals, field research into their biology and their occurrence is necessary.

literature

  • Paulina D. Jenkins: Tenrecidae (Tenrecs and Shrew tenrecs). In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 8: Insectivores, Sloths and Colugos. Lynx Edicions, Barcelona 2018, pp. 134-172 (p. 166) ISBN 978-84-16728-08-4
  • Alphonse Milne-Edwards and Alfred Grandidier: Description d'une nouvelle espèce d'insectivore de Madagascar. Le Naturaliste 4, 1882, p. 55 ( [6] )

Individual evidence

  1. ^ A b Nick Garbutt: Mammals of Madagascar. A complete guide. Yale University Press, 2007, pp. 1–304 (pp. 32–56)
  2. ↑ a b c d Charles Immanuel Forsyth Major: Diagnoses of new mammals from Madagascar. The Annals and magazine of natural history 18, 1896, pp. 318–321 ( [1] )
  3. ^ JF Eisenberg and Edwin Gould: The Tenrecs: A Study in Mammalian Behavior and Evolution. Smithsonian Institution Press, 1970, pp. 1-138
  4. ↑ a b c Paulina D. Jenkins: Tenrecidae (Tenrecs and Shrew tenrecs). In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 8: Insectivores, Sloths and Colugos. Lynx Edicions, Barcelona 2018, pp. 134-172 (p. 166) ISBN 978-84-16728-08-4
  5. ↑ a b c Oldfield Thomas: On the arrangement of the small Tenrecidae hitherto referred to Oryzorictes and Microgale. Annals and magazine of natural history 14, 1918, pp. 302–307 ( [2] )
  6. ↑ a b c Steven M. Goodman and Bernardin PN Rasolonandrasana: Elevational zonation of birds, insectivores, rodents and primates on the slopes of the Andringitra Massif, Madagascar. Journal of Natural History 35 (2), 2001, pp. 285-305
  7. ^ CI Forsyth Major: On the general results of a zoological expedition to Madagascar in 1894-96. Proceedings of the Zoological Society London 1896, pp. 971-981 ( [3] )
  8. ↑ Paulina D. Jenkins and Michael D. Carleton: Charles Immanuel Forsyth Major's expedition to Madagascar, 1894 to 1896: beginnings of modern systematic study of the island's mammalian fauna. Journal of Natural History 39 (20), 2005, pp. 1779-1818
  9. ↑ Steven M. Goodman, Christopher J. Raxworthy and Paulina D. Jenkins: Insectivore ecology in the Réserve Naturelle Intégrale d'Andringitra, Madagascar. Fieldiana Zoology 85, 1996, pp. 218-231
  10. ↑ a b c P. J. Stephenson, Voahangy Soarimalala and Stephen M. Goodman: Oryzorictes tetradactylus. The IUCN Red List of Threatened Species 2016. e.T40591A97203290 ( [4] ); last accessed on January 15, 2017
  11. ↑ a b Kathryn M. Everson, Voahangy Soarimalala, Steven M. Goodman and Link E. Olson: Multiple loci and complete taxonomic sampling resolve the phylogeny and biogeographic history of tenrecs (Mammalia: Tenrecidae) and reveal higher speciation rates in Madagascar's humid forests. Systematic Biology 65 (5), 2016, pp. 890-909 doi: 10.1093 / sysbio / syw034
  12. ↑ a b c Don E. Wilson and DeeAnn M. Reeder: Mammal Species of the World. A taxonomic and geographic Reference. Johns Hopkins University Press, 2005 ( [5] )
  13. ↑ Alphonse Milne-Edwards and Alfred Grandidier: Description d'une nouvelle espèce d'insectivore de Madagascar. Le Naturaliste 4, 1882, p. 55
  14. ^ A b Henri Heim de Balsac: Insectivores. In: R. Battistini and G. Richard-Vindard (eds.): Biogeography and ecology in Madagascar. The Hague, 1972, pp. 629-660

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