Japanese common toad

Japanese common toad
Japanese common toad ( Bufo japonicus )
Systematics
without rank: Amphibians (Lissamphibia) Order : Frog (anura) Subordination : Neobatrachia Family : Toads (Bufonidae) Genre : Real toads ( bufo ) Type : Japanese common toad
Scientific name
Bufo japonicus
Temminck & Schlegel , 1838

The Japanese common toad ( Bufo japonicus , jap. ニ ホ ン ヒ キ ガ エ ル Nihon-Hikigaeru ) is a species from the genus of the real toad , which is common in Japan on all four main islands.

Honshu Shikoku Kyushu Yakushima Tanegashima Iki Gotō Hokkaido Sado Izu-Ōshima Niijima Miyake-jima

Distribution areas of the Japanese common toad (blue: introduced population)

Characteristics and way of life

The body color varies locally between yellowish and dark brown to greenish. The females are usually slightly larger than the males. The shorter front legs have four fingers. The third finger is the longest, followed by the second finger. Adult animals spend most of their lives on land and only come to shallow watering places to reproduce in February to March. Often three to ten males meet one female. The females lay the spawn in the form of strings containing between 640 and 14,000 black eggs. The larvae are dark brown and 3 to 4 cm in size. The metamorphosis takes place in June. The males are able to reproduce after one and the females after two years. In winter, when temperatures drop below 6 ° C, the toads burrow into the ground for hibernation. The diet of toads includes various insects, including beetles and ants, which other animal species avoid because of their chemical ingredients.

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  Japanese common toad with spawning cords

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  Young toad shortly after shore leave

• Play media file

  Adult toad (video)

toxicity

The Japanese common toads produce bufadienolide in their skin glands. These substances, named after the genus of the real toads ( Bufo ), slow down the heart rate of the heart muscle (myocardium) and the conduction of the cardiac muscle cells and therefore have a toxic effect. A study on the subspecies Bufo japonicus formosus showed that even their eggs are toxic to the tadpoles of other frogs ( Rana pirica ) that eat them . Tiger snakes ( Rhabdophis tigrinus ) take advantage of toxicity by eating the toads and accumulating the toad's toxins in their own neck glands . Experiments with different foods (with and without Japanese common toads) show that the snake cannot produce the toxins itself.

Distribution area and endangerment status

The toad species is endemic to Japan and is widespread there on the main islands of Kyūshū , Shikoku and Honshū as well as on the adjacent island of Iki , the Gotō Islands and the Ōsumi Islands of Tanegashima and Yakushima . In addition, a population was introduced in western Hokkaidōs and on the island of Sado and the Izu islands of Izu-Ōshima , Niijima , and Miyake-jima . The toads live at altitudes of up to 2500 m. Due to their large and generally stable distribution area, the species is classified as Least Concern by the IUCN . The population is declining, especially in urban areas. Road construction and introduced predators such as raccoons pose particular threats to toads . In addition, according to a Japanese study from 2018, nocturnal lighting disturbs the reproduction of the toads and is avoided by the animals, whereas noise does not seem to have any influence.

Taxonomy

Subspecies Bufo japonicus formosus

The Japanese common toad was first described as Bufo vulgaris japonicus in 1838 by the Dutch zoologist Coenraad Jacob Temminck and the German ornithologist and herpetologist Hermann Schlegel . The American zoologist Stejneger, however, described it in 1907 as a subspecies ( Bufo bufo japonicus ) of the common toad ( Bufo bufo ) and two other separate species Bufo formosus and Bufo smithi within Japan. Yaichiro Okada, on the other hand, recognized three subspecies in 1966 ( Bufo b. Japonicus , Bufo b. Formosus and Bufo b. Montanus ) and Nakamura and Ueno (1963) combined these three subspecies under Bufo b. japonicus due to morphological criteria and their range. According to several studies, inter alia sterile hybrids between the European and Asian toads indicate the status of the Japanese common toad as a separate species with allopatric subspecies.

Subspecies

A distinction is made between two subspecies (as of June 2021):

• Eastern Japanese common toad ( Bufo japonicus formosus , jap.ア ズ マ ヒ キ ガ エ ル Azuma-Hikigaeru )
• Western Japanese common toad ( Bufo japonicus japonicus , jap.ニ ホ ン ヒ キ ガ エ ル Nihon-Hikigaeru )

The subspecies B. j. japonicus , with a snout-cloacal length of 80–176 mm, is somewhat larger than B. j. formosus (43–162 mm) and lives in warmer regions of Japan.

Similar species

Two other toads of the same genus common in Japan are Bufo gargarizans and Bufo torrenticola . Bufo gargarizans occurs within Japan only on Miyako-jima and adjacent Ryūkyū Islands and is mainly distributed in eastern China to Russia and Korea. Bufo torrenticola , on the other hand, lives in the mountainous regions of the Japanese regions of Chūbu and Kinki in the center of Honshū. Its distribution area is located at altitudes from 50 to 1690 m. Between the Eastern Japan toad Bufo japonicus formosus and Bufo torrenticola was introgression found.

Bufo gargarizans	Bufo torrenticola

See also

• List of amphibians of Japan

further reading

• Hirai, T., and Matui, M. (2002). Feeding ecology of Bufo japonicus formosus from the montane region of Kyoto, Japan. Journal of Herpetology, 36 (4), 719-723.
• Ishii, S., Kubokawa, K., Kikuchi, M., and Nishio, H. (1995). Orientation of the toad, Bufo japonicus, toward the breeding pond. Zoological Science, 12 (4), 475-84.
• Kawamura, T., M. Nishioka, M. Sumida, and M. Ryuzaki. (1990). An electrophoretic study of genetic differentiation in 40 populatons of Bufo japonicus distributed in Japan . Scientific report of the Laboratory for Amphibian Biology, Hiroshima University 10: 1-51.
• Maeda, N. and Matsui, M. (1990). Frogs and Toads of Japan , 2nd edition. Bun-Ichi Sogo Shuppan Co., Ltd., Tokyo, Japan.

Web links

Commons : Japanese Common Toad ( Bufo japonicus )  - Collection of images and videos

• Bufo japonicus Temminck and Schlegel, 1838. Amphibian Species of the World 6.1, an Online Reference, accessed February 8, 2021 . 
• Japanese common toad ( Bufo japonicus ) sightings . iNaturalist, accessed June 27, 2021 . 

Individual evidence

1. ↑ ^{a b c} Bufo japonicus. amhibiaweb.org, accessed June 22, 2021 . 
2. ↑ ^{a b c} Bufo japonicus in the endangered Red List species the IUCN 2021. Posted by: IUCN SSC Amphibian Specialist Group, 2020. Accessed June 16, 2021st
3. ↑ DL Wang, FH Qi, W. Tang, FS Wang: Chemical constituents and bioactivities of the skin of Bufo bufo gargarizans Cantor. In: Chemistry & biodiversity. Volume 8, number 4, April 2011, pp. 559-567, doi : 10.1002 / cbdv.201000283 . PMID 21480502 .
4. ↑ Okamiya H., Takai K., Kishida O. (2021). The Japanese Common Toad, Bufo japonicus formosus, Contains Toxin in the Egg Stage . Current Herpetology pp. 103-106, link
5. ↑ Hutchinson, DA, Savitzky, AH, Mori, A. et al. Chemical investigations of defensive steroid sequestration by the Asian snake Rhabdophis tigrinus . Chemoecology 22, 199-206 (2012). PDF
6. ^ Tokuda T. 2011. Compact picture guide to Hokkaido reptiles and amphibians. Hokkaido Shimbun Press, Sapporo.
7. ↑ Suzuki, D., T. Kawase, T. Hoshina, and T. Tokuda. 2020. Origins of nonnative populations of Bufo japonicus formosus (Amphibia: Bufonidae) in Hokkaido, Japan, as inferred by a molecular approach. Current Herpetology. Kyoto 39: 47-54.
8. ↑ Ishiguro, H. and Iwai, N. 2018. Effects of noise and light on breeding and oviposition site selection by frogs in urban ponds . Japanese Journal of Conservation Ecology 23: 177-186.
9. ↑ Okada, Y. (1966). Fauna Japonica. Anura (Amphibia) . Tokyo: Biogeographical Society of Japan.
10. ^ Stejneger, L. (1907). Herpetology of Japan and adjacent territory . Bulletin of the United States National Museum 58
11. ↑ Nakamura, K., and S.-I. Ueno. (1963). Genshoku Nihon ryosei hachuri zukan [= Japanese Reptiles and Amphibians in Color] . Osaka, Japan: Hoikusha Publishing Company.
12. ↑ ^{a b} Japan, Genus: Bufo. American Museum of Natural History, Amphibian Species of the World 6.1, an Online Reference, accessed June 24, 2021 . 
13. ↑ Kawamura, T., M. Nishioka, and H. Ueda. (1980). Inter- and intraspecific hybrids among Japanese, European and American toads . Scientific report of the Laboratory for Amphibian Biology, Hiroshima University 4: 111-112. PDF
14. ↑ Dubois, A., and R. Bour. 2010. The nomenclatural status of the nomina of amphibians and reptiles created by Garsault (1764), with a parsimonious solution to an old nomenclatural problem regarding the genus Bufo (Amphibia, Anura), comments on the taxonomy of this genus, and comments on some nomina created by Laurenti (1768) . Zootaxa 2447: 1-52.
15. ↑ Bufo gargarizans in the endangered Red List species the IUCN 2021. Posted by: IUCN SSC Amphibian Specialist Group, 2018. Accessed June 28, 2021st
16. ↑ Matsui, M. 1988. A review of the Japanese stream toad . Natural History of Japan 1988: 48-55.
17. ↑ Bufo torrenticola in the endangered Red List species the IUCN 2021. Posted by: IUCN SSC Amphibian Specialist Group, 2020. Accessed June 28, 2021st
18. ↑ Yamazaki, Y., S. Kouketsu, T. Fukuda, Y. Araki, and H. Nambu. (2008). Natural hybridization and directional introgression of two species of Japanese toads Bufo japonicus formosus and Bufo torrenticola (Anura: Bufonidae) resulting from changes in their spawning habitat . Journal of Herpetology 42: 427-436.