Medium-sized dwarf hamsters

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Medium-sized dwarf hamsters
Systematics
Order : Rodents (Rodentia)
Subordination : Mouse relatives (Myomorpha)
Superfamily : Mice-like (Muroidea)
Family : Burrowers (Cricetidae)
Subfamily : Hamster (Cricetinae)
Genre : Medium-sized dwarf hamsters
Scientific name
Allocricetulus
Argyropulo , 1932

The medium-sized dwarf hamsters ( Allocricetulus ) form a genus of hamsters with the species Eversmann dwarf hamster and Mongolian dwarf hamster . Some systematists assign them to the gray dwarf hamsters . They are widespread in the dry steppes of Eurasia and known from fossil sources from the Pleistocene . The International Union for Conservation of Nature IUCN classifies them as not endangered .

Body features

The head-trunk length of the medium-sized dwarf hamsters is 8.5 to 16.0 centimeters. The tail is contrary to the Gray dwarf hamster as long as the hind feet is or only slightly longer and its length not more than a fifth of the body length. From the thickly hairy tail root, individual guard hairs reach back half the length of the tail and make the tail appear conical. The snout is pointed, but less than that of the rat-like dwarf hamsters . The auricles are comparatively short, without a light border and evenly covered with thin hair.

The soles of the medium-sized dwarf hamsters, in contrast to those of the short-tailed dwarf hamsters, are usually not covered by fur or sparsely haired. However, the pronounced pads can be hidden in the sole hair in winter. On the front paw, the claw of the first toe often has the shape of a nail and the fifth toe is comparatively shortened. The fur on the upper side is monotonous gray-brown to reddish-sand-colored. In contrast to the short-tailed dwarf hamsters, it is usually clearly delineated from the white of the underside. If there is a spot on the chest, it is not black. The winter fur does not differ in color from the summer fur .

skull

In the structure of the skull , the medium-sized dwarf hamsters are very similar to the large hamsters and they occupy a middle position between the gray dwarf hamsters and the medium- sized hamsters . The almost circular skull is rounder than that of the gray dwarf hamsters, the snout is shorter and the span between the zygomatic arches is larger. The zygomatic arches are thin, rounded and only run more or less parallel to one another in the central part. The nasal bones are wedge-shaped with a strongly outwardly curved front part and a pronounced depression along the nasal bone seam. In older hamsters, this depression is more pronounced and continues to the frontal bone and along the eye sockets .

Instead of the humps, which are only indicated in the case of the gray dwarf hamsters, older medium-sized dwarf hamsters have pronounced bony humps above the eye sockets between the frontal bone and the front extension of the parietal bone, which is different in length . In contrast to large hamsters, there are no bony ridges between the frontal and parietal bones, or they are weak and do not approach one another along the coronal seam . On the outer edge of the parietal bone there are rounded ridges that extend from the eye sockets to the occiput . As with the rat-like dwarf hamsters, these do not approach each other in the middle either and give the skull its angular shape. The parietal bone is sickle-shaped. With a width that is at least 2 times its length, it is comparatively shorter than that of the large hamster. The original surface of the masseter muscle on the upper jawbone is, in comparison to the same surface in the large hamsters, less angled inwards, especially at the top, and their front wall usually does not cover the under eye hole . With a length of less than 40 millimeters, the condylobasal length is shorter than that of large hamsters. The timpani are larger than those of the gray dwarf hamsters and the wing pits of the cuneiform bone are somewhat narrower. They extend forward to the level of the last molar.

The branches of the lower jaw are more pronounced than in the rat-like dwarf hamsters, curved more steeply upwards and the rear tip usually reaches back to the level of the joint head. The increase in the tooth sockets is usually at the level of the incision between the muscle and articular processes. In contrast to large hamsters, it is pronounced and in older hamsters it reaches back to the level of the upper edge of the articular process. The depression along the outside of the branch of the lower jaw is pronounced.

denture

The lower incisors of the medium-sized dwarf hamsters are strong and curved upwards. The paired cusps of the front upper molars lie opposite one another, as in the gray dwarf hamsters. Those of the first lower molar are also opposite each other, but apart from the middle cusps of a European species, there are no closed depressions between the tooth cusps. The cusps of the second lower molar are offset from one another. The small, roughly the same size front cusps of the first upper molar tooth are clearly separated from the next pair and relatively strongly displaced outwards. The front cusps of the first lower molar are also about the same size, but hardly separated from each other.

The “collars” on the first and second upper molars are weak. In the second molar, the inner and outer collars are about the same size; in the third, the inner collar is often absent. The third upper molar tooth is about half as long as the second and the third lower molar tooth is about three quarters as long as the second.

Body skeleton

In the structure of the limbs and the sacrum , the medium-sized dwarf hamsters occupy a middle position between the gray dwarf hamsters and the medium hamsters. It is characterized by the presence of a slightly flattened, clearly protruding bone hump on the iliac bone . The thighbone has a long femoral neck and an enlarged small roll mound, the lower edge of which stands out clearly from the bone shaft. The ulna is comparatively short with, compared to large hamsters, long upper and lower ends and a little pronounced, flattened shaft.

genetics

According to Romanenko et al., The assumed original karyotype of the medium-sized dwarf hamster with 32 chromosomes differs from the assumed original karyotype of the Cricetus group by one centromere fission and four centromere fusions .

Way of life

The habitat of the medium-sized dwarf hamsters is the plant-geographical Eurasian steppe area of ​​the Palearctic , outside of which they are hardly or not at all to be found. The Mongolian dwarf hamster, as well as probably the Eversmann dwarf hamster, is not tied to certain biotopes or biotope groups and occurs in small numbers almost everywhere. Allocricetulus prefer the burrows of other rodents and rabbits-like to inhabit or shelters such as grass clods of plowed fields. Their self-dug burrow is similar to that of the Campbell dwarf hamster . They feed from the seeds of grasses , as well as significant quantities of animal food and are referred to as "true predators." During the breeding season , which begins before the snow melts, the females give birth to three to four litters. In the second half of summer, the females from the first litter are already involved in reproduction.

Distribution and Tribal History

The distribution area of the medium-sized dwarf hamsters are the dry steppes and semi-deserts of northern Kazakhstan and neighboring Russia east of the Volga as well as Mongolia and northern China .

The individual species probably originated during the Pleistocene along the steppes that spread to the west due to climatic conditions, whereby the Sajan Mountains and the Altai acted as geographic barriers and enabled allopatric speciation . Molecular genetic studies suggest that the medium-sized dwarf hamsters originated in the Pliocene . However, fossil finds are only known from the Middle Pleistocene . They are close to the late Pliocene Allocricetus from Europe or are identical to them. Until the Holocene , the western border of the distribution area of ​​the medium-sized dwarf hamsters shifted further east from the Dobruja in Romania. This is a typical development for representatives of the Volga fauna .

Nomenclature and systematics

AI Argiropulo described the medium-sized dwarf hamsters in 1932 as a subgenus Allocricetulus of the genus Cricetulus with the type species Cricetulus (Allocricetulus) eversmanni . The name is derived from ancient Greek allos (αλλος, "strange") and the generic name Cricetulus .

Some systematists confirmed the status as a subgenus (Ellerman, 1941; Ellerman and Morrison-Scott, 1951; Ellerman, 1961) and others assigned the medium-sized dwarf hamsters to the genus Cricetulus (Simpson, 1945; Walker, 1975; Corbet, 1978; Corbet and Hill , 1980; Honacki and co-workers, 1982; Nowak and Paradiso, 1983; Corbet and Hill, 1986; Grzimek, 1988; Corbet and Hill, 1991; Nowak, 1991). Igor Michailowitsch Gromow introduced it as an independent genre in 1963, a view that more and more systematists are following (Flint, 1966; Piechocki, 1969; Gromow and Baranowa, 1981; Pavlinow and Rossolimo, 1987; Musser and Carleton, 1993; Gromow and Jerbajewa, 1995 ; Pawlinow and coworkers, 1995; McKenna and Bell, 1997; Pawlinow and Rossolimo, 1998; Nowak, 1999; Pawlinow, 2003; Wang, 2003; Musser and Carleton, 2005; Smith and Hoffmann, 2008).

Molecular genetic studies of mitochondrial cytochrome b - and 12S - rRNA genes and the nuclear vWF gene confirm the status as a separate genus, and the close relationship with the hamster and to a lesser extent with the gray dwarf hamster and the rat-like hamster . Investigations of the chromosomes , on the other hand, suggest a closer relationship with the Sokolow dwarf hamster . In their sensitivity and susceptibility to infections such as tularemia , the medium-sized dwarf hamsters differ significantly from other dwarf hamsters and from each other. They are usually divided into two recent types :

Some systematists assign the Mongolian dwarf hamster as a subspecies to the Eversmann dwarf hamster. The two forms differ in their physical characteristics only slightly from each other and there are populations with transition characteristics, in the adjacent area of distribution. However, the differences in the set of chromosomes and the resulting genetic isolation indicate that they are independent as species.

Medium-sized dwarf hamsters and human

The economic importance of the medium-sized dwarf hamsters for humans is low and their importance for epidemics is insufficiently researched. They can be found in rural buildings and dwellings such as yurts , storage sheds and temporarily abandoned winter camps. The German trivial names used are “medium-sized dwarf hamsters” (Honigs, 2005; Fox, 2006) and “Mongolian dwarf hamsters” (Macdonald, 2004). Very rarely they are in captivity held .

literature

Mainly used literature:

  • Wladimir Evgenjewitsch Flint: The dwarf hamsters of the Palearctic fauna . In: The New Brehm Library . 2nd Edition. tape 366 . Westarp Wissenschaften, Hohenwarsleben 2006, ISBN 3-89432-766-9 (first edition: 1966, German, reprint of the 1st edition from 1966, 99 pages).
  • Igor Michailowitsch Gromow, Margarita Alexandrovna Jerbajewa: [The mammals of Russia and neighboring regions. Rabbits and rodents] . Russian Academy of Sciences (Zoological Institute), Saint Petersburg 1995 ( full text - original Russian title: Mljekopitaiuschtschije fauny Rossii i soprjedjelynch tjerritorij. Saizeobrasnyje i grysuny , 520 pages).
  • Guy G. Musser, Michael D. Carleton: Superfamily Muroidea . In: Don E. Wilson, DeeAnn M. Reeder (Eds.): Mammal Species of the World . A Taxonomic and Geographic Reference . 3. Edition. Johns Hopkins University Press, Baltimore 2005, ISBN 0-8018-8221-4 , pp. 894-1531 (English).

Individual evidence

  1. ↑ a b c d Andrew T. Smith, Robert S. Hoffmann: Subfamily Cricetinae . In: Andrew T. Smith, Xie Yan (Eds.): A Guide to the Mammals of China . Princeton University Press, Princeton / Oxford 2008, ISBN 978-0-691-09984-2 , pp. 239-247 (English).
  2. ↑ a b c d e Flint, 1966 ("Systematics, Descriptions, Distribution" pp. 10-12).
  3. ↑ a b c d e f Gromow and Jerbajewa, 1995 ( "Cricetinae" ).
  4. ↑ a b c d e f g h i j k l m n o p q Gromow and Jerbajewa, 1995 ( " Allocricetulus " ).
  5. ↑ Guy G. Musser, Michael D. Carleton: Family Muridae . In: Don E. Wilson, DeeAnn M. Reeder (Eds.): Mammal Species of the World . A Taxonomic and Geographic Reference . 2nd Edition. Smithsonian Institution Press, Washington 1993, ISBN 1-56098-217-9 , pp. 501-755 , Cricetinae, p. 536 (English).
  6. ↑ a b Ronald M. Nowak: Allocricetulus . In: Walker's Mammals of the World . 6th edition. Johns Hopkins University Press, Baltimore / London 1999, ISBN 0-8018-5789-9 , pp. 1421 (English, 1936 pp.).
  7. ↑ a b Swetlana Anatoljewna Romanenko u. a .: Karyotype Evolution and Phylogenetic Relationships of Hamsters (Cricetidae, Muroidea, Rodentia) Inferred from Chromosomal Painting and Banding Comparison . In: Chromosome Research . tape 15 , no. 3 , 2007, ISSN  0967-3849 , p. 283–297 , Fig. 6 , doi : 10.1007 / s10577-007-1124-3 (English).
  8. ↑ WW Kutscheruk: [The faunistic complex of the steppe mammals and its place in the Palearctic fauna] . In: [The geography of the distribution of continental vertebrates and the methods of their exploration] . Moscow 1959 (Russian). Quoted in: Flint, 1966 (“Biotopes and Settlements” p. 22).
  9. ↑ Flint, 1966 (“Biotopes and Settlements”, p. 24).
  10. ↑ Flint, 1966 ("Baue" pp. 61–62).
  11. ^ Igor Jakowlewitsch Pawlinow: [Mammals of Russia] . (Russian: Mlekopitaiuschtschije Rossii . after two publications from 1999).
  12. ↑ a b Karsten Neumann, Johan Michaux, Wladimir S. Lebedew, Nuri Yigit, Ercüment Çolak, Natalja W. Iwanowa, Andrei B. Poltoraus, Alexei Surow, Georgi Markow, Steffen Maak, Sabine Neumann, Rolf Gattermann: Molecular Phylogeny of the Cricetinae Subfamily Based on the Mitochondrial Cytochrome b and 12S rRNA Genes and the Nuclear vWF Gene . In: Molecular Phylogenetics and Evolution . tape 39 , no. 1 , 2006, p. 135–148 , doi : 10.1016 / j.ympev.2006.01.010 (English).
  13. ^ AI Argiropulo: [Genera and species of dwarf hamsters (Cricetinae) of the Palearctic] . In: Trudy soologitscheskowo instituta Akademii Nauk SSSR . tape 1 , no. 3–4 , 1932, pp. 242 (Russian). Quoted in: Musser and Carleton, 2005 ( “ Allocricetulus ” p. 1040).
  14. ↑ John Reeves Ellerman: The Families and Genera of Living Rodents, Volume 2. Family Muridae . British Museum (Natural History), London 1941 (English, 690 pages). Quoted in: Musser and Carleton, 2005 ( “ Allocricetulus ” p. 1040).
  15. ↑ John Reeves Ellerman, Terence Charles Stuart Morrison-Scott: Checklist of Palaearctic and Indian Mammals 1758 to 1946 . British Museum (Natural History), London 1951 (English, 810 pages). Quoted in: Musser and Carleton, 2005 ( “ Allocricetulus ” p. 1040).
  16. ↑ John Reeves Ellerman: Rodentia. Volume 3 . In: The Fauna of India Including Pakistan, Burma and Ceylon. Mammalia . 2nd Edition. Manager of Publications, Zoological Survey of India, Kolkata 1961, p. 1-482, 483-884 (English). Quoted in: Musser and Carleton, 2005 ( “ Allocricetulus ” p. 1040).
  17. ^ George Gaylord Simpson: The Principles of Classification and a Classification of Mammals . In: Bulletin of the American Museum of Natural History . tape 85 , 1945, ISSN  0003-0090 , p. 86 (English, 350 pp., Hdl: 2246/1104 ).
  18. ↑ Ernest P. Walker: Cricetulus . In: Mammals of the World . 3. Edition. Johns Hopkins University Press, Baltimore / London 1975, ISBN 0-8018-1657-2 , pp. 816 (English, 1500 pp.).
  19. ^ Gordon Barclay Corbet: The Mammals of the Palaearctic Region. A Taxonomic Review . British Museum (Natural History) / Cornell University Press, London 1978, ISBN 0-8014-1171-8 , pp. 90 (314 pp.). Quoted in: Musser and Carleton, 2005 ( “Cricetinae” p. 1040).
  20. ^ Gordon Barclay Corbet, John Edwards Hill: A World List of Mammalian Species . British Museum (Natural History) / Comstock Publishing Associates (Cornell University Press), London / Ithaca 1980, ISBN 0-8014-1260-9 , pp. 157 (English, 226 pp.).
  21. ↑ James H. Honacki, Kenneth E. Kinman, James W. Koeppl: Cricetulus . In: Mammal Species of the World . A Taxonomic and Geographic Reference . Allen Press / Association of Systematics Collections, Lawrence (Kansas) 1982, ISBN 0-942924-00-2 , pp. 405 (English, 694 pp.).
  22. ↑ Ronald M. Nowak, John L. Paradiso: Cricetulus . In: Walker's Mammals of the World . 4th edition. Johns Hopkins University Press, Baltimore / London 1983, ISBN 0-8018-2525-3 , pp. 623 (English, 1362 pp.).
  23. ^ Gordon Barclay Corbet, John Edwards Hill: A World List of Mammalian Species . 2nd Edition. Facts on File Publications / British Museum (Natural History), New York / London 1986, ISBN 0-8160-1548-1 , pp. 175 (English, 254 pages, ISBN 0-565-00988-5 ).
  24. ↑ Bernhard Grzimek: Systematic overview of the mammals . In: Bernhard Grzimek (Ed.): Grzimek's Encyclopedia of Mammals . tape 11 , p. 11–55 (German, eleven-volume licensed edition of the original edition from 1988; p. 34).
  25. ^ Gordon Barclay Corbet, John Edwards Hill: A World List of Mammalian Species . 3. Edition. British Museum (Natural History), London 1991, ISBN 0-19-854017-5 (243 pages). Quoted in: Nowak, 1999 (“ Allocricetulus ” p. 1421).
  26. ↑ Ronald M. Nowak: Cricetulus . In: Walker's Mammals of the World . 5th edition. Johns Hopkins University Press, Baltimore / London 1991, ISBN 0-8018-2525-3 , pp. 705-707 (English, 1630 pp.).
  27. ^ Rudolf Piechocki: Family Wühler . In: Irenäus Eibl-Eibesfeldt, Martin Eisentraut, Hans-Albrecht Freye, Bernhard Grzimek, Heini Hediger, Dietrich Heinemann, Helmut Hemmer, Adriaan Kortlandt, Hans Krieg, Erna Mohr, Rudolf Piechocki, Urs Rahm, Everard J. Slijper, Erich Thenius ( Ed.): Grzimeks Tierleben : Encyclopedia of the Animal Kingdom. Eleventh volume: Mammals 2 . Kindler-Verlag, Zurich 1969, p. 301-344 (German; pp. 306-307, p. 517).
  28. ↑ Igor Michailowitsch Gromow, GI Baranowa (ed.): [Catalog of the mammals of the Soviet Union. Pliocene to the present] . Verlag Nauka, Sankt Petersburg 1981 (Russian original title: catalog mlekopitaiuschtschich SSSR. Pliozen-sowremennost , 456 pages; pp. 153–154). Quoted in: Honacki and co-workers, 1982 (“ Cricetulus ” p. 405).
  29. ^ Igor Jakowlewitsch Pawlinow, Olga Leonidowna Rossolimo: [Systematics of Mammals of the Soviet Union] . Moscow State University, Moscow 1987 ( full text - original Russian title: Sistematika mlekopitaiuschtschich SSSR, 285 pages). Quoted in: Musser and Carleton, 2005 ( “Cricetinae” p. 1040).
  30. ↑ Musser and Carleton, 1993 (“ Allocricetulus ” p. 536).
  31. ^ Igor Jakowlewitsch Pawlinow, Je. L. Jachontow, Alexander Karenowitsch Agadschanjan: [Mammals of Eurasia. 1. Rodents: Taxonomic and Geographical Guide] . In: Sbornik trudow soologitscheskowo museia Moskowski Gossudarstwenny Uniwersitet . tape 32 , 1995 (original Russian title: Mlekopitaiuschtschije Evrasii. I. Rodentia: sistematiko-geografitscheski sprawotschnik). Quoted in: Musser and Carleton, 2005 ( “Cricetinae” p. 1040).
  32. ↑ Malcolm C. McKenna, Susan K. Bell: Classification of Mammals Above the Species Level . Columbia University Press, New York 1997, ISBN 0-231-11012-X , pp. 151 (English, 631 pages).
  33. ^ Igor Jakowlewitsch Pawlinow, Olga Leonidowna Rossolimo: [Systematics of the mammals of the Soviet Union. Addenda. M] . In: Archives of the Zoological Museum . tape 38 . Moscow State University, Moscow 1998 (Russian, 190 pages). Quoted in: Musser and Carleton, 2005 ( “Cricetinae” p. 1040).
  34. ↑ Ronald M. Nowak: Allocricetulus . In: Walker's Mammals of the World . 6th edition. Johns Hopkins University Press, Baltimore / London 1999, ISBN 0-8018-5789-9 , pp. 1421 (English, 1936 pp.).
  35. ^ Igor Jakowlewitsch Pawlinow: [Systematics of recent mammals] . Moscow State University, Moscow 2003 ( full text - original Russian title: Sistematika sowremennych mlekopitaiuschtschich, 297 pages).
  36. ↑ Wang Ying-Xiang: A Complete Checklist of Mammal Species and Subspecies in China. A Taxonomic and Geographic Reference . China Forestry Publishing House, Beijing 2003 (English, 394 pages). Quoted in: Musser and Carleton, 2005 (“ Cricetinae ” p. 1040).
  37. ↑ Musser and Carleton, 2005 ( “ Allocricetulus ” p. 1040).
  38. ↑ TN Dunayewa: [The importance of mammals in the epizootology of tularemia] . In: Soologitscheski schurnal . tape 42 , no. 5 , 1963, ISSN  0044-5134 (Russian). Quoted in: Flint, 1966 (“Systematics, Descriptions, Distribution” pp. 10-12).
  39. ↑ Musser and Carleton, 2005 ( “ Allocricetulus curtatus ” p. 1040).
  40. ↑ Flint, 1966 ("Synanthropismus" pp. 75-77).
  41. ↑ a b Sandra Honigs: Dwarf Hamsters. Biology. Attitude. Breeding . 2nd Edition. Natur- und Tier-Verlag, Münster 2005, ISBN 3-931587-96-7 , p. 12-13 (80 pp.).
  42. ↑ Judy Fox: My dwarf hamster at home . 4th edition. Bede-Verlag, Ruhmannsfelden 2006, ISBN 3-89860-121-8 , p. 5 (64 pp.).
  43. ↑ David W. Macdonald (ed.): The great encyclopedia of mammals . Könemann (Tandem-Verlag), Königswinter 2004, ISBN 3-8331-1006-6 , p. 868 (930 pp., Original title: Encyclopedia of Mammals . 2001.).