Rice burger

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Rice burger
Real rice burrower (Oryzorictes hova)

Real rice burrower ( Oryzorictes hova )

Systematics
Superordinate : Afrotheria
without rank: Afroinsectiphilia
Order : Tenrecus (Afrosoricida)
Family : Tenreks (Tenrecidae)
Subfamily : Travel treks (Oryzorictinae)
Genre : Rice burger
Scientific name
Oryzorictes
Grandidier , 1870

The rice Wühler ( Oryzorictes ), sometimes called Maulwurftenreks referred to are a mammalian species from the group of oryzorictinae within the family of tenrecs (Tenrecidae). They are endemic to Madagascar . The genus consists of two types, the actual rice burrower and the four-toed rice burrower . They are medium-sized representatives of the Reistenreks. Their physique is compact, their nose and ears are small, and their tail is only half the length of the rest of their body. In addition, the animals have wide feet with strong claws. They are thus adapted to a digging way of life. The preferred habitats include tropical rainforests , wetlands and open shrubbery landscapes in higher mountain areas, and the rice burrowers can also be found on rice fields in some cases. The diet consists mainly of invertebrates , otherwise little is known about the way of life of the animals. The genus was first described in 1870.

features

Habitus

The rice burrowers reach a head-trunk length of 9.9 to 12.4 cm, plus a 3.8 to 6.2 cm long tail, the total length of the animals is 13.7 to 17.2 cm. The body weight varies - as far as is known - between 28 and 40 g. Both types are similar in size. The animals are adapted to a burrowing way of life, so their physique shows similarities with that of the moles . The body is compact, the limbs are short and strong and end in wide feet. The hind feet each have five rays, the front feet have five rays in the real rice burrower ( Oryzorictes hova ) and four rays in the four-toed rice burrower ( Oryzorictes tetradactylus ). The three central rays usually have strong long claws, which correspond to grave claws on the front feet. Furthermore, the eyes and ears are relatively small, the tail is bare and is only about half as long as the rest of the body. The fur has a soft texture, the back color is very variable and ranges from a dark gray-brown to a black brown to a light, pale brown. The underside is colored dark or light brown.

Skull and dentition features

The skull of the rice burrower is very solid and clearly stretched , especially in the rostrum region . The skull is short, wide and deep. The length ratio of the anterior to the posterior section of the skull is 0.54 to 0.46. As with all tenreks, the zygomatic arch is not fully developed. Strong bone marks on the brain skull, which function as muscle attachment points, are striking. The bit includes a total of 40 teeth with the following dental formula : . The incisors are similar to those of the Kleintenreks ( Microgale ), but the additional cusps on the tooth crowns are less prominent. The upper third incisor is particularly small. In contrast to the Kleintenreks, the upper and lower canines represent the highest tooth in the respective row of teeth, they have a distinct canine-like shape ( caniniform ). In the rear dentition there are only a few differences to the small tenreks. The molars have a zalambdodontic occlusal surface pattern, which is composed of three main cusps (para-, proto- and metaconus; based on the maxillary molars) in a triangular arrangement.

Skeletal features

The spine consists of 7 cervical, 17 thoracic, 5 to 6 lumbar, 2 sacrum and 19 to 20 tail vertebrae. The adaptation of the rice digger to digging locomotion is mainly confirmed in the anatomy of the forelimbs. The shoulder blade is extremely long and slender and has a long acromion . The deltoid muscle that attaches here ensures that the arm can rotate sufficiently. In contrast to all other rice treks (Oryzorictinae), the humerus has an extremely massive structure and is significantly widened on both the shaft and the joint ends. There is also a massive deltopectoral bar on the shaft for the attachment of the shoulder and arm muscles. The humerus is longer than the spoke . At the ulna, the upper articular process, the olecranon , extends strongly and takes up about 27% of the length of the entire bone. As a result, the forearm muscles attached here can develop a significantly greater leverage force. The hands are very broad and consist of short and compact single bones. The scaphoid bone , the lunar bone and the central os of the wrist form a unit and thus limit the mobility of the hand. The rice diggers thus have the highest degree of bone fusion in the wrist within the tenreks. There are extremely strong claws on rays II and III, which are longer and higher than on the other treks.

distribution

The rice burrowers are endemic to Madagascar . They inhabit the eastern parts of the country, while the distribution area of ​​the actual rice burrower extends over almost the entire length of the island state, that of the four-toed rice burrower is limited to the central and southeastern parts of the country. Both species are associated with moist rainforests , marshland and open areas in mountainous areas, the four-toed rice burrower also lives in areas above the tree line. It is assumed that the animals have opened up new habitats since the colonization of Madagascar by humans and with their cultivation of rice . As a result, they also occur in anthropogenic habitats. In general, both species are relatively rare and difficult to observe due to their subterranean way of life.

Way of life

The way of life of the Reiiswühler has hardly been researched. They dig underground passages in humus soils near rivers and streams, sometimes in rice fields. Their diet is based on invertebrates such as insects and earthworms , which is proven by analyzes of stomach contents as well as isotope studies . Almost no data are available on reproduction.

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 rice burrowers form a genus within the Tenrek family (Tenrecidae). Together with the Kleintenreks ( Microgale ) and the representatives of the genus Nesogale , they are also grouped together to the Reistenreks (Oryzorictinae), one of the three subfamilies of the Tenreks. The other two include the spiky hedgehog tenreks (Tenrecinae) and the monotypical earth tenreks (Geogalinae). The rice diggers are the sister group of the other two genera of the rice trek, which has been confirmed in several molecular genetic analyzes. In addition to their physique, which is clearly adapted to the digging, the rice burrowers have a more specialized canine tooth as a distinguishing feature. The separation of the rice burrows from the rest of the rice treks took place in the Upper Oligocene around 27.8 million years ago. The further splitting of the rice diggers into the lines that exist today did not take place until the Pliocene a good 4.75 million years ago.

Today two types are distinguished:

  • Real rice burrower ( Oryzorictes hova A. Grandidier , 1870); in eastern Madagascar
  • Four-toed rice burrower ( Oryzorictes tetradactylus A. Grandidier & Milne-Edwards , 1882); in central to southeastern Madagascar

Both species are very similar, in addition to the different number of toes of the forefoot, the not quite so massive structure of the skull of the four- toed rice burner is an important distinguishing feature compared to the actual rice burner . With Oryzorictes talpoides and Oryzoryctes niger , two other species were introduced. The former is now a synonym for the actual rice burrower, the latter the four-toed rice burrower. Genetic studies of the actual rice burrower from 2018 suggest that the shape contains at least three to four cryptic species .

Alfred Grandidier created the genus of the rice digger in 1870 together with the actual rice digger, the species therefore represents the nominate form . Grandidier derived the name Oryzorictes from the Greek words όρυζα ( oryza “rice”) and ορύκτηϛ ( oryctes “ digger ”) . He was referring to the observation that the animals were often found in rice fields and there also damaged the plants through their digging activities. In 1918 Oldfield Thomas established the genus Nesoryctes , in which he classified the four-toed rice burrower due to its slightly more delicate skull structure and the only four-pointed forefoot. In the following time Nesoryctes was either listed as a subgenus of Oryzorictes or understood as a synonym.

Threat and protection

The IUCN classifies the population of the actual rice digger as "not threatened" ( least concern ) due to its widespread distribution and tolerance to human activities . In contrast, the information available on the four-toed rice digger is too thin to assign it to a specific hazard category (“insufficient data basis” or data deficient ). Both species occur in nature reserves, together they can be found in the Andringitra National Park .

literature

  • JF Eisenberg and Edwin Gould: The Tenrecs: A Study in Mammalian Behavior and Evolution. Smithsonian Institution Press, 1970, pp. 1-138
  • 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
  • Nick Garbutt: Mammals of Madagascar. A complete guide. Yale University Press, 2007, pp. 1–304 (pp. 32–56)
  • Ronald M. Nowak: Walker's Mammals of the World . The Johns Hopkins University Press, Baltimore, 1999, ISBN 0-8018-5789-9
  • Don E. Wilson, DeeAnn M. Reeder (Eds.): Mammal Species of the World . 3rd edition. The Johns Hopkins University Press, Baltimore 2005, ISBN 0-8018-8221-4

Individual evidence

  1. ^ A b c J. F. Eisenberg and Edwin Gould: The Tenrecs: A Study in Mammalian Behavior and Evolution. Smithsonian Institution Press, 1970, pp. 1-138
  2. ^ A b Steven M. Goodman, Paulina D. Jenkins and Mark Pidgeon: Lipotyphla (Tenrecidae and Soricidae) of the Réserve Naturelle Intégrale d'Andohahela, Madagascar. Fieldiana Zoology 94, 1999, pp. 187-216
  3. ↑ a b c d Nick Garbutt: Mammals of Madagascar. A complete guide. Yale University Press, 2007, pp. 1–304 (pp. 32–56)
  4. ↑ a b c d Wilhelm Leche: On the history of the development of the mammalian tooth system, at the same time a contribution to the tribal history of this group of animals. Part two: phylogeny. Second booklet: Families of the Centetidae, Solenodontidae and Chrysochloridae. Zoologica 20, 1906/1908, pp. 1–157 ( [1] )
  5. ^ Justine A. Salton and Eric J. Sargis: Evolutionary morphology of the Tenrecoidea (Mammalia) carpal complex. Biological Journal of the Linnean Society, 93, 2008, pp. 267-288
  6. ^ Justine A. Salton and Eric J. Sargis: Evolutionary Morphology of the Tenrecoidea (Mammalia) Forelimb Skeleton. In: EJ Sargis and M. Dagosto (Eds.): Mammalian Evolutionary Morphology: A Tribute to Frederick S. Szalay, Springer Science, 2008, pp. 51-71
  7. ↑ Melanie Dammhahn, Voahangy Soarimalala and Steven M. Goodman: Trophic Niche Differentiation and Microhabitat Utilization in a Species-rich Montane Forest Small Mammal Community of Eastern Madagascar. Biotropica 45 (1), 2013, pp. 111-118
  8. ↑ a b c d 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
  9. ↑ Link E. Olson and Steven M. Goodman: Phylogeny and biogeography of tenrecs. In: Steven M. Goodman and Jonathan P. Benstead (Eds.): The natural history of Madagascar. University of Chicago Press, 2003, pp. 1235-1242
  10. ^ Matjaž Kuntner, Laura J. May-Collado and Ingi Agnarsson: Phylogeny and conservation priorities of afrotherian mammals (Afrotheria, Mammalia). Zoologica Scripta 40 (1), 2011, pp. 1-15
  11. ^ A b Alfred Grandidier: Description de quelques animaux nouveaux découverts à Madagascar en November 1869. Revue et Magasin Zoologie Pure et Appliquée 22, 1870, pp. 49-50 ( [2] )
  12. ↑ Alphonse Milne-Edwards and Alfred Grandidier: Description d'une nouvelle espèce d'insectivore de Madagascar. Le Naturaliste 4, 1882, p. 55 ( [3] )
  13. ↑ a b 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 ( [4] )
  14. ↑ Guillaume Grandidier and G. Petit: Description d'une espèce nouvelle d'Insectivore Malagache, suiviede remarques critiques sur le genre Oryzoryctes. Bulletin du Muséum national d'histoire naturelle 2 (2), 1930, pp. 498–505 ( [5] )
  15. ^ Charles Immanuel Forsyth Major: Diagnoses of new mammals from Madagascar. The Annals and magazine of natural history 18, 1896, pp. 318–321 ( [6] )
  16. ^ A b Don E. Wilson and DeeAnn M. Reeder: Mammal Species of the World. A taxonomic and geographic Reference. Johns Hopkins University Press, 2005 ( [7] )
  17. ↑ Kathryn M. Everson, Kyndall BP Hildebrandt, Steven M. Goodma and Link E. Olson: Caught in the act: incipient speciation across a latitudinal gradient in a semifossorial mammal from Madagascar, the mole tenrec Oryzorictes hova (Tenrecidae). Molecular Phylogenetics and Evolution, 2018 doi: 10.1016 / j.ympev.2018.02.024
  18. ↑ Link E. Olson and Voahangy Soarimalala: Two - or three, or maybe even four - new species of mole tenrec on Madagascar, and the importance of continued scientific collecting for conservation. Afrotherian Conservation 14, 2018, pp. 15-19
  19. ^ Henri Heim de Balsac: Insectivores. In: R. Battistini and G. Richard-Vindard (eds.): Biogeography and ecology in Madagascar. The Hague, 1972, pp. 629-660
  20. ↑ PJ Stephenson, Voahangy Soarimalala and Stephen M. Goodman: Oryzorictes LORD. The IUCN Red List of Threatened Species 2016. e.T40589A97203050 ( [8] ); last accessed on January 21, 2017
  21. ↑ PJ Stephenson, Voahangy Soarimalala and Stephen M. Goodman: Oryzorictes tetradactylus. The IUCN Red List of Threatened Species 2016. e.T40591A97203290 ( [9] ); last accessed on January 21, 2017

Web links

Commons : Reiswühler ( Oryzorictes )  - Collection of images, videos and audio files