Little Japanese wood mouse

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Little Japanese wood mouse
Little Japanese wood mouse (Apodemus argenteus)

Little Japanese wood mouse ( Apodemus argenteus )

Systematics
Superfamily : Mice-like (Muroidea)
Family : Long-tailed mice (Muridae)
Subfamily : Old World Mice (Murinae)
Tribe : Apodemini
Genre : Wood mice ( Apodemus )
Type : Little Japanese wood mouse
Scientific name
Apodemus argenteus
( Temminck , 1844)

The little Japanese wood mouse or geisha mouse ( Apodemus argenteus , syn .: Apodemus geisha , Japanese 姫 鼠 Himenezumi 'princess mouse') is a species of old world mice belonging to the forest mice . The small, mainly nocturnal and partly tree-living wood mouse lives in the forests of the four main islands of Japan and some smaller islands and is not endangered. The species is the only one assigned to the argenteus group and forms an old line of descent within wood mice. It was described by Coenraad Jacob Temminck in 1844 as Mus argenteus .

Body features

External features

The Little Japanese Wood Mouse is a small, slender wood mouse with a long tail, large eyes and long ears. It is about the same size as smaller forms of the Western Palearctic wood mice, but more closely resembles the harvest mouse in construction and appearance . Similar to the young of the great Japanese wood mouse , it is on average smaller than this species and than the Korean wood mouse . Their head-torso length is 65 to 100 millimeters and an average of 80 millimeters, the tail length is 70 to 110 millimeters, the hind foot length without claws 17 to 21 millimeters and the body weight 10 to 20 grams. The tail is usually a little longer than the body and the hind foot length is shorter than that of the great Japanese wood mouse. Without a claw, the fifth toe of the hind foot extends almost to the first toe bone of the fourth toe.

The fur of the little Japanese wood mouse is soft and without bristles. The hair is thin and about six millimeters long on the back. The fur is chestnut brown on the top and greyish-white or ivory-colored underneath. There is no eel line . The fur on the underside is sharply delineated on the flanks from that of the upper side and the basal two-thirds of its hair is dark-slate-colored. The head and forehead are slightly lighter than the rump. The ears are light brown with a thin, white border. The outside of the upper arms and the hips are dark, the inside of the upper arms, the roots of the forefoots, and the front and rear feet are white. The soles of the feet are completely hairless and the rearmost ball of the rear foot is elongated. The tail is thinly haired and roughly scaled. The scales are not staggered, but form individual rings, of which an average of twelve come to one centimeter. Both dandruff and hair are brown on the top and light on the underside, but the contrast is not noticeable. Sometimes the skin is partially bleached. The eight teats of the females are divided into two pairs each in the chest area and in the groin area.

The small Japanese wood mouse can be easily distinguished from the similarly sized house mouse by its coat color. It can be differentiated from the large Japanese wood mouse and the Korean wood mouse by the pads on the hind feet.

Skull and teeth

The skull of the Little Japanese Wood Mouse is very smooth, light, delicate and rounded. The interorbital region is shaped like an hourglass. Supraorbital ridges and other bone ridges are not present and the supraorbital ridges are hardly rectangular even in the oldest specimens. The type can be determined from their zygomatic plates . So these are narrow and their straight front edge does not or hardly protrudes over the upper front edge of the zygomatic arches . The cleft palate is of medium length and does not reach back to the first molar. The mesopterygoid fossa is broad, rounded at the front and narrowing at the back. The tympanic bubbles are normal. The largest skull length of a male from Kobe was 21 millimeters, the basilar length 17.5 millimeters, the zygomatic width 12 millimeters, the nasal length 8 millimeters, the interorbital width 3.7 millimeters, the brain skull width 11 millimeters, the palate length 10.4 millimeters, the diastema length 6.5 millimeters and the length of the upper row of teeth 3.4 millimeters. The cleft palates measure 4.7 by 1.7 millimeters.

1 · 0 · 0 · 3  =  16
1 · 0 · 0 · 3
Little Japanese wood mouse tooth formula

The teeth of the small Japanese wood mouse has one in each half of the jaw incisors and three small molar teeth ( molars on). Compared to most other species of wood mice, the anterior outer hump (t3 according to the t-nomenclature ) of the first maxillary molar is smaller and approximates the anterior middle hump (t2), but not as strong as in the fire mouse . The anterior outer cusp (t3) of the second maxillary molar can be greatly reduced, but is usually large and prominent. It was absent in six of 266 fossil and recent teeth examined, was present as a cingulum in 31 teeth, moderately developed in 172 teeth and well developed in 57 teeth. The first and second maxillary molars have a thick, elongated posterior cingulum that makes up a significant portion of the chewing surface. It is connected to the posterior middle hump (t8) and can also touch the posterior outer hump (t9) front-outside. So its front edge merges with the rear edge of the outer hump after only slight wear. This feature was found in all examined fossil and recent teeth, including 234 second upper jaw teeth, and is not found in any other species of wood mouse. While the presence of the posterior cenulum is an original feature, its size in comparison to the occlusal surface and the contact with the outer cusp is considered a derived feature .

The third upper molar of the Japanese Little Wood Mouse is not reduced in size. Its chewing surface consists of a large anterior inner cusp (t1) and two almost horizontal rows of cusps resembling enamel ridges. The front row is formed from a small central inner hump and the elongated central and outer humps (t5 and t6) fused with it. The back row consists of either an elongated hump or two fused elliptical humps. The origin as a cusp tooth can sometimes still be recognized when the teeth are not worn. After only moderate wear, however, the cusps can no longer be seen in the horizontal melt strips. The groin pattern is enhanced by the absence of the anterior outer hump (t3). This was missing in 120 of the 127 teeth examined. The tendency towards the groin pattern is believed to be a derived trait.

The first maxillary molar usually has four roots . Out of 159 teeth examined, only two had a single inner root. In contrast, 157 teeth had a double inner root. 14 of 126 teeth also had a smaller, additional inner root.

genetics

According to Nakata and co-workers (2009), the karyotype of male and female specimens of the Japanese small wood mouse usually has 46  chromosomes with 48 chromosome arms in the double set of chromosomes . However, B chromosomes were found on Hokkaido . According to Musser and co-workers (1996), all autosomes are acrocentric except for three pairs of small, metacentric autosomes. The X chromosome has a large heterochromatic area, which is characterized by delayed fluorescence when the Q change occurs. There are sequence data of the mitochondrial cytochrome - b gene available.

Habitat and way of life

Habitat and nest

The habitat of the frequent, mainly nocturnal and partly arboreal little Japanese wood mouse belongs to a large number of different, but always forested areas from the lowlands to the alpine altitude . It prefers climax forests , which mainly consist of old trees and have a thick layer of leaves, but also inhabits bushland and plantations . Their nest , usually made of leaves, is mostly underground, but occasionally also in tree hollows or nesting boxes for birds.

Action space and social structure

The action space of the Little Japanese Wood Mouse measures 200 to 1325 square meters, varies depending on the habitat and the season and can shrink, especially outside the breeding season. In habitats shared with the large Japanese wood mouse , the small Japanese wood mouse has the smaller action spaces in comparison. Both the action spaces of opposite-sex and same-sex animals overlap. Observations of mating patterns between males and females suggest a monogamous mating system. However, other studies could not confirm this and DNA studies showed polygynous pairings. It has been reported that males leave their place of birth for reproduction.

Food, predators and parasites

The diet of the small Japanese wood mouse consists of seeds , green parts of plants, fruits and invertebrates , especially insects . The predators include various predators and birds of prey ; the red fox and owls are documented, weasels , sables and the Japanese marten are also suspected .

Ectoparasites of the small Japanese wood mouse are mites and ticks of the genera Leptotrombidium , Neotrombicula , Gahrliepia , Myobia , Demacarus , Hypoaspis , Laelaps , Eulaelaps , Haemogamasus , Hirstionyssus and Ixodes , fleas of the genera Atyphloceras , Stenoponia , Ctenophthalmus , Neopsylla , Catallagia , Hystrichopsylla , Nearctopsylla , Monopsylla and Peromyscopsylla and animal lice of the genera Polyplax and Hoplopleura . As endoparasites some representatives of the coming flukes , the tapeworms and roundworms before. Protozoa of the Apicomplexa and Metamonada groups have also been described .

Reproduction, Development and Life Expectancy

The breeding season of the little Japanese wood mouse varies by region. In colder climates it ranges from April to October or November, in warmer climates from October to March. The resulting dependence on temperatures is, however, questioned due to the fluctuating population sizes over several years . Rather, a connection to population density and population phase was established. The proportion of breeding females fluctuates within a year and from year to year and is lower at high densities. The same was found in the males. Research on trapped animals showed that most females give birth to one or two litters in their lifetime . The litter size ranges from one to nine young animals and averages 3.3 to 4.9 young animals depending on the region. It also depends on the density, phase and body size. It is lower in overwintered females at high density than at low density and increases with body size in non-overwintered females.

At birth , the Little Japanese Wood Mouse cubs are naked and their eyes are closed. In nature, females become sexually mature with a body weight of eight grams or more and males with a body weight of ten grams or more . Based on data from live catches, the maximum lifespan in nature is assumed to be 27 months, but only a few animals survive a year.

Distribution and fossil finds

Little Japanese Wood Mouse (Japan)
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Distribution of the small Japanese wood mouse on the smaller islands of Japan (see text for numbers)

The distribution area of the small Japanese wood mouse is limited to Japan . It extends over the four main islands Hokkaidō , Honshū , Shikoku and Kyūshū as well as peripheral smaller islands. This is how it comes to Kinkasan (# 1 on the map) in Miyagi Prefecture, Awashima (# 2) and Sadoshima (# 3) in Niigata Prefecture, Okinoshima (# 4) and Nishinoshima (# 5) on the Oki Islands in Shimane Prefecture, on Awajishima (# 6) in Hyōgo Prefecture, on Shōdoshima (# 7) in Kagawa Prefecture, on Miyajima (# 8) in Hiroshima Prefecture, on Tsushima (# 9) and on the Goto Islands Nakadōrijima (# 10) and Fukuejima (# 11) in Nagasaki Prefecture, on Amakusa Island Shimoshima (# 12) in Kumamoto Prefecture and on the Ōsumi Islands Tanegashima (# 13) and Yakushima (# 14) in the prefecture Kagoshima before. The altitude distribution ranges from sea level to an altitude of 2500 meters.

Fossil finds come from the Middle and Young Pleistocene Honshūs and from the Holocene Honshūs, Shikokus and Kyūshūs. Since even the fossil finds from the Middle Pleistocene hardly differ from today's animals, the species probably arose in the previous periods.

Systematics and nomenclature

External system

Within the wood mice, Musser and Carleton (2005) assign the small Japanese wood mouse as the only species of the argenteus group. Thomas (1905) already pointed out the small body size, the adaptation to the tree life and the body structure which deviates from the other wood mice. Ellerman (1941) included the Little Japanese Wood Mouse as the only species in his geisha group and considered it to be closely related to the western Palearctic sylvaticus group. Ellerman and Morrison-Scott (1951) even listed them as subspecies of the wood mouse . Zimmerman (1962), on the other hand, assigned them to the Eastern Palearctic sub-genus Alsomys . The entirety of almost all features and in particular the extremely flattened skull show that they belong to this group. What these species have in common is the number of only three main roots on the first maxillary molar. According to Corbet (1978), however, the small Japanese wood mouse resembles the western Palearctic species most and, like these, all of the specimens he studied had a double inner root.

Kawamura (1989), who compared the molars and skull fragments of the small Japanese wood mouse from the Pleistocene and Holocene with recent material, noted that it had relatively primitive tooth features and was perhaps close to the ancestral forms of wood mice. Based on the interorbital region, the arrangement of the zygomatic plate and zygomatic arch, the double inner root of the first maxillary molar, the unique chewing surface pattern of the maxillary molars, the number of teats and the karyotype, Musser and coworkers (1996) could not assign the species to any existing subgenus. Various molecular genetic studies have shown that it differs from all other investigated species in Europe and Asia and represents an old lineage within the wood mice. Musser and Carleton (2005) provide an overview of investigations into the systematic position of the species.

Internal system

Six subspecies of the small Japanese wood mouse can be distinguished:

  • Apodemus argenteus hokkaidi (Thomas, 1906) on Hokkaidō
  • Apodemus argenteus argenteus (Temminck, 1844) on Honshū , Kyūshū and Shikoku ; with the synonym geisha (Thomas, 1905)
  • Apodemus argenteus celatus (Thomas, 1906) on the Oki Islands
  • Apodemus argenteus sagax Thomas, 1908 on Tsushima
  • Apodemus argenteus tanei Kuroda, 1924 on Tanegashima
  • Apodemus argenteus yakui (Thomas, 1906) on Yakushima

The subspecies are mainly characterized by small differences in body size and coat color. Ellerman (1941) differentiates all six subspecies, Ellerman and Morrison-Scott (1951), on the other hand, assign the forms hokkaidi , yakui and tanei to the subspecies Apodemus sylvaticus argenteus and only list celatus and sagax as further subspecies. Corbet (1978) lists all six subspecies, but considers delimitations from the nominate form argenteus to that of the rather short-tailed form celatus to be doubtful.

nomenclature

Little Japanese Wood Mouse (Japan)
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Type localities of the small Japanese wood mouse (see text for numbers)

The small Japanese wood mouse was described by Coenraad Jacob Temminck in the series Fauna Japonica as Mus argenteus (from Latin argenteus "silver"). The year of publication of the first description is usually given as 1845, but it almost certainly appeared as early as December 1844. The type material was probably collected by Heinrich Bürger . A male collected in May 1904 in Kobe (# 1 on the map) at an altitude of 300 to 400 meters and presented by Richard Gordon Smith described Oldfield Thomas in 1905 as Micromys geisha (from Japanese 芸 者 " Geisha ").

In 1906 Thomas described an adult male collected in Noboribetsu (# 2) on Hokkaido in November 1904 as Micromys geisha hokkaidi , and a male collected in July 1905 in the interior of the Oki island of Okinoshima (# 3) at a height of 30 meters as Micromys geisha celatus (from Latin celatus "hidden") and a female collected in June 1905 in the central mountains of Yakushima (# 4) at an altitude of 1070 meters as Micromys geisha yakui . Another adult male collected in January 1907 in the south of Tsushima (# 5) at an altitude of 60 to 90 meters was described by Thomas in 1908 as Apodemus geisha sagax (from Latin sagax "astute"). Kuroda Nagamichi finally described a specimen from Nishinoomote (# 6) on Tanegashima as Apodemus geisha tanei in 1924 .

Thomas and other authors after him still considered Mus argenteus to be young, bristle-free specimens of the great Japanese wood mouse . Later also listed as a dubious kind of unexplained assignment, it was increasingly viewed as a representative of the small Japanese wood mouse. Ellerman and Morrison-Scott (1951) found it unlikely that Temminck was not familiar with such a common form. Smeenk and co-workers (1982) examined the type material of Mus argenteus . Since the type series is a compound, they determined the specimen as the lectotype which Temminck labeled Mus argenteus and which corresponds to the illustration and description in Fauna Japonica . While this corresponds to Micromys geisha in the skull features , they identified the two paralectotypes as young specimens of the great Japanese wood mouse. The lectotype of Mus argenteus cannot be assigned to a single population of the species, neither on the basis of body size nor of coat color . Its exact origin can no longer be traced either. Since most of the mammalian specimens collected by Philipp Franz von Siebold and Heinrich Bürger come from the Nagasaki area , a correspondence with the geisha found on Honshū, Kyūshū and Shikoku is assumed. Smeenk and co-workers (1982) give an overview of the taxonomic history of the species.

Existence and importance for people

The International Union for Conservation of Nature IUCN classified the small Japanese wood mouse as not endangered in 2008. This was justified with the frequency of the species, its wide distribution, the lack of essential threats and the stable populations. It is also found in numerous protected areas . In 1996 it was also classified as not endangered.

The little Japanese wood mouse causes damage to the seedlings of the Sakhalin fir and the catkins of birch trees . However, by capturing plant wasp pupae and caterpillars in larch populations , it may prevent their mass reproduction. It often invades cottages and houses in the countryside, especially in the fall.

Web links

Commons : Little Japanese Wood Mouse  - Collection of images, videos and audio files

literature

Used literature

  • Gordon Barclay Corbet: The Mammals of the Palaearctic Region: A Taxonomic Review . British Museum (Natural History) / Cornell University Press, London / Ithaca 1978, ISBN 0-8014-1171-8 (reprint).
  • Fritz Dieterlen : Family Mice . 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, Zurich 1969, p. 348-380 .
  • John Reeves Ellerman: The Families and Genera of Living Rodents. Volume II: Family Muridae . British Museum (Natural History), London 1941, doi : 10.5962 / bhl.title.8323 .
  • John Reeves Ellerman, Terence Charles Stuart Morrison-Scott: Checklist of Palaearctic and Indian Mammals 1758 to 1946 . British Museum (Natural History), London 1951 ( biodiversitylibrary.org ).
  • Yukibumi Kaneko, Nobuo Ishii: Apodemus argenteus . In: The IUCN Red List of Threatened Species. Version 2014.3 . 2008 ( iucnredlist.org ).
  • 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 .
  • Musser and co-workers: Taxonomy and distributional records of Oriental and European Apodemus, with a review of the Apodemus-Sylvaemus problem . In: Booner Zoological Contributions . tape 46 , 1996, pp. 143–190 ( PDF on ZOBODAT ).
  • Keisuke Nakata, Masahiro A. Iwasa: Apodemus peninsulae (Thomas, 1907) . In: Satoshi D. Ohdachi, Yasuyuki Ishibashi, Masahiro A. Iwasa, Takashi Saitoh (eds.): The Wild Mammals of Japan . Shoukadoh, Kyōto 2009, ISBN 978-4-87974-626-9 , p. 167-168 (reprint).
  • Keisuke Nakata, Takashi Saitoh, Masahiro A. Iwasa: Apodemus argenteus (Temminck, 1844) . In: Satoshi D. Ohdachi, Yasuyuki Ishibashi, Masahiro A. Iwasa, Takashi Saitoh (eds.): The Wild Mammals of Japan . Shoukadoh, Kyōto 2009, ISBN 978-4-87974-626-9 , p. 172-173 (reprint).
  • Chris Smeenk, Yukibumi Kaneko, Kimiyuki Tsuchiya: On the type material of Mus argenteus Temminck, 1844 . In: Zoological Medelingen . tape 56 , no. 9 , 1982, pp. 121-129 ( repository.naturalis.nl ).
  • Coenraad Jacob Temminck: Mammifères . In: Philipp Franz von Siebold, Coenraad Jacob Temminck, Hermann Schlegel (eds.): Fauna Japonica . Arnz et Socii, Leiden 1844, p. 1-59 ( bookviewer.naturalis.nl ).
  • Oldfield Thomas: On some new Japanese mammals presented to the British Museum by Mr. R. Gordon Smith . In: The Annals and Magazine of Natural History . 7th row, volume 15 , no. 89 , 1905, pp. 487-495 ( biodiversitylibrary.org ).
  • Oldfield Thomas: The Duke of Bedford's zoological exploration in Eastern Asia ― I. List of mammals obtained by Mr. MP Anderson in Japan . In: Proceedings of the Zoological Society in London . tape 1905 , no. 2 , 1906, p. 331-363 ( biodiversitylibrary.org ).
  • Oldfield Thomas: The Duke of Bedford's zoological exploration in Eastern Asia ― VII. List of mammals from the Tsu-shima Islands . In: Proceedings of the Zoological Society in London . tape 1908 , no. 1 , 1908, p. 47-54 ( biodiversitylibrary.org ).
  • Murray Wrobel: Elsevier's Dictionary of Mammals . Elsevier, Amsterdam a. a. 2007, ISBN 978-0-444-51877-4 .
  • Klaus Zimmermann : The subgenus of the genus Apodemus Kaup . In: Bonn zoological contributions . tape 13 , 1962, pp. 198-208 ( biodiversityheritagelibrary.org ).

Remarks

  1. ↑ Wrobel, 2007 (p. 28)
  2. ↑ Dieterlen, 1969 (p. 361)
  3. ↑ a b c d e f g h i j Nakata and co-workers, 2009 (p. 172)
  4. ↑ a b c d e f g h i j k Thomas, 1905 ( p. 491. )
  5. ↑ a b c d e f g h i j k l m n o Nakata and colleagues, 2009 (p. 173)
  6. ↑ a b c Ellerman, 1941 ( p. 96. )
  7. ↑ a b c d e Ellerman, 1941 ( p. 93. )
  8. ↑ Nakata and Iwasa, 2009 (p. 167)
  9. ↑ a b Musser and coworkers, 1996 ( p. 179. )
  10. ↑ a b c d Musser and co-workers, 1996 ( p. 180. )
  11. ↑ a b Thomas, 1905 ( p. 492. )
  12. ↑ Musser and co-workers, 1996 (Fig. 4, p. 182. )
  13. ↑ Musser and co-workers, 1996 (Tab. 6, p. 175. )
  14. ↑ a b c Musser and co-workers, 1996 (Fig. 5, p. 183. )
  15. ↑ Musser and co-workers, 1996 (Tab. 8, p. 178. )
  16. ↑ a b c Musser and co-workers, 1996 ( p. 184. )
  17. ↑ Musser and co-workers, 1996 (Tab. 7, p. 176. )
  18. ↑ a b c d Kaneko and Ishii, 2008 ( Apodemus argenteus )
  19. ↑ a b c Musser and Carleton, 2005 (p. 1263, Apodemus argenteus )
  20. ↑ Musser and coworkers, 1996 ( p. 169. )
  21. ↑ a b Ellerman, 1941 ( p. 96. )
  22. ^ A b Ellerman and Morrison-Scott, 1951 ( p. 571. )
  23. ^ Ellerman and Morrison-Scott, 1951 ( p. 572. )
  24. ↑ Zimmermann, 1962 ( p. 202. )
  25. ↑ Zimmermann, 1962 ( p. 199. )
  26. ↑ Zimmermann, 1962 (Tab. 1, p. 207. )
  27. ↑ Zimmermann, 1962 ( p. 201 )
  28. ↑ a b c Corbet, 1978 (p. 136)
  29. ↑ a b c Smeenk and co-workers, 1982 ( p. 127. )
  30. ↑ a b c Ellerman and Morrison-Scott, 1951 ( p. 570. )
  31. ↑ Temminck, 1844 (p. 51)
  32. ↑ Musser and Carleton, 2005 (p. 1264, Apodemus argenteus )
  33. ↑ Smeenk and co-workers, 1982 ( p. 121. )
  34. ↑ a b Smeenk and co-workers, 1982 ( p. 124. )
  35. ↑ Thomas, 1906 ( p. 350. )
  36. ↑ Thomas, 1906 ( p. 351. )
  37. ↑ Thomas, 1906 ( p. 359. )
  38. ↑ Thomas, 1906 ( p. 362. )
  39. ↑ Thomas, 1908 ( p. 54. )
  40. ^ Smeenk et al., 1982 ( p. 122. )
  41. ^ Smeenk and co-workers, 1982 ( p. 123. )
  42. ↑ a b Smeenk and co-workers, 1982 ( p. 126. )
  43. ↑ Smeenk and co-workers, 1982 ( p. 125. )