Iwasaki's snail-eater

Iwasaki's snail-eater
Conservation status
Near Threatened  (IUCN 3.1) [1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Pareidae
Genus:	Pareas
Species:	P. iwasakii
Binomial name
Pareas iwasakii (Maki, 1937)
Synonyms
Amblycephalus formosensis iwasakii Maki, 1937 Pareas iwasakii — Takara, 1962 [2]

Iwasaki's snail-eater (Pareas iwasakii) is a species of snake in the family Pareidae. The species is endemic to the Yaeyama Islands in the southern Ryukyu Islands, Japan. ^[2]

Etymology

The specific name, iwasakii, is in honor of Japanese meteorologist Takuji Iwasaki. ^[3]

Habitat

The preferred natural habitats of P. iwasakii are forest, shrubland, and grassland. ^[1]

Ecology

Snail-eater in action

Skull of Pareas iwasakii

P. iwasakii is a snail-eating specialist; ^[4] even newly hatched individuals feed on snails. ^[5] It has asymmetric dentition on its jaws, with more teeth on the right mandible (about 25 teeth compared to 15 teeth on the left mandible) which facilitates feeding on snails with dextral (clockwise coiled) shells. ^[6] A consequence of this asymmetry is that P. iwasakii is much less adept at preying on sinistral (counterclockwise coiled) snails. ^[7] It systematically directs its attack on snails from the right in order to insert its lower jaw into the shell opening.

The selection pressure of this predator on snails of the genus Satsuma has led to a significant increase in the proportion of snails with left-facing shells, known as levogyres, compared to snails with right-facing shells, known as dextrogyres, because the two forms have difficulty mating with each other. This proportion is a local originality, the levorotatory form being very rare on a worldwide scale. ^[7]

Reproduction

P. iwasakii is oviparous. ^[2]

Taxonomy

Originally described as the subspecies Amblycephalus formosensis iwasakii by Moichirō Maki, ^[8] it was placed in the genus Pareas and elevated to the species P. iwasakii by Tetsuo Takara in 1962. ^[9]

References

1. Kidera, N.; Ota, H. (2017). "Pareas iwasakii ". IUCN Red List of Threatened Species . 2017 e.T16220A96877422. doi: 10.2305/IUCN.UK.2017-3.RLTS.T16220A96877422.en . Retrieved 16 November 2021.
2. Pareas iwasakii at the Reptarium.cz Reptile Database
3. Beolens B, Watkins M, Grayson M (2011). The Eponym Dictionary of Reptiles. Baltimore: Johns Hopkins University Press. xiii + 296 pp. ISBN   978-1-4214-0135-5. (Pareas iwasakii, p. 131).
4. Hoso, M.; Hori, M. (2006). "Identification of molluscan prey from feces of Iwasaki's slug snake, Pareas iwasakii ". Herpetological Review. 37: 174–176.
5. Hoso, M. (2007). "Oviposition and hatchling diet of a snail-eating snake Pareas iwasakii (Colubridae: Pareatinae)". Current Herpetology. 26: 41–43. doi:10.3105/1345-5834(2007)26[41:OAHDOA]2.0.CO;2. S2CID   83645579.
6. Hoso, Masaki; Asami, Takahiro; Michio Hori (2007). "Right-handed snakes: convergent evolution of asymmetry for functional specialization". Biology Letters. 3 (2): 169–173. doi:10.1098/rsbl.2006.0600. PMC   2375934 . PMID   17307721.
7. Hoso, Masaki; Kameda, Yuichi; Wu, Shu-Ping; Asami, Takahiro; Kato, Makoto; Hori, Michio (2010). "A speciation gene for left-right reversal in snails results in anti-predator adaptation". Nature Communications. 1 (9): 133. Bibcode:2010NatCo...1..133H. doi:10.1038/ncomms1133. PMC   3105295 . PMID   21139578.
8. Maki, M. (1937). "A new subspecies, Amblycephalus formosensis iwasakii, belonging to Amblycephalidae Ishigaki-jima". Transactions of the Natural History Society of Formosa. 27: 217–218.
9. Ota, Hidetoshi; Lin, Jun-Tsong; Hirata, Toru; Chen, Szu-Lung (1997). "Systematic review of colubrid snakes of the genus Pareas in the East Asian islands". Journal of Herpetology. 31 (1): 79–87. doi:10.2307/1565332. JSTOR   1565332.

Further reading

• Goris, Richard C.; Maeda, Norio (2004). Guide to the Amphibians and Reptiles of Japan. Malabar, Florida: Krieger Publishing Company. 285 pp. ISBN   978-1575240855.
• Hoso, Masaki; Hori, Michio (2008). "Divergent Shell Shape as an Antipredator Adaptation in Tropical Land Snails". American Naturalist. 172 (5): 726–32. doi:10.1086/591681. PMID   18834301. S2CID   19259125.
• Ota, Hidetoshi (2000). "Current status of threatened amphibians and reptiles of Japan". Population Ecology42: 5–9.
• Takara, Tetsuo (1962). "[Studies on the terrestrial snakes in the Ryukyu Archipelago]". [Science Bulletin of the Division of Agriculture, Home Economics and Engineering, University of the Ryukyus ] 9: 1–202. (in Japanese, with an abstract in English). (Pareas iwasakii, new combination).