''Amynthas'' is a genus of

earthworm An earthworm is a soil-dwelling terrestrial invertebrate that belongs to the phylum Annelida. The term is the common name for the largest members of the class (or subclass, depending on the author) Oligochaeta. In classical systems, they we ...

s in the family

Megascolecidae Megascolecidae is a family of earthworms native to Madagascar, Australia, New Zealand, Asia, and North America. At up to 2 meters in length, their large size distinguishes the Megascolecidae from other earthworm families. They are an essential par ...

. They are known as jumping worms, snake worms, or crazy worms because of their erratic thrashing behaviour when disturbed. The genus is native to East Asia, but they are invasive in many areas of the United States. They are a matter of concern in many states, as they disrupt the native forest ecology by affecting soil structure and chemistry.

Appearance

''Amynthas'' species can be differentiated from other earthworms by their

clitellum The clitellum is a thickened glandular and non-segmented section of the body wall near the head in earthworms and leeches that secretes a viscid sac in which eggs are stored. It is located near the anterior end of the body, between the fourteenth ...

, which is pale, annular, is close to the head, and lies flat against the body.''Wisconsin DNR Forest Health.''
Jumping Worms (''Amynthas spp.'') Fact Sheet
. Updated April 2015. Accessed Dec 22 2022. They vary in size between .

Life cycle

''Amynthas'' species' faster reproduction rate and their ability to reproduce asexually (parthenogenesis) has contributed to their spread into the United States. The worms reach maturity in 60 days, which allows them to have two hatches per year. Eggs are wrapped in small cocoons, which overwinter while the adults die off at the first freeze each year. The young then emerge the next spring.

Species

* '' Amynthas agrestis'' (Goto and Hatai, 1899) * ''Amynthas alexandri'' (Beddard, 1900) * ''Amynthas assimilis'' (Hong & Kim, 2002) * ''Amynthas borealis'' (Panha & Bantaowong, 2011) * ''Amynthas comptus'' (Gates, 1932) * ''Amynthas defecta'' (Gates, 1930) * ''Amynthas dorualis'' * ''Amynthas exiguus'' (Gates, 1930) * ''Amynthas fucosus'' (Gates, 1933) * ''Amynthas gracilis'' (Kinberg, 1867) * ''Amynthas hilgendorfi'' (Michaelsen, 1892) * ''Amynthas hupbonensis'' (Stephenson, 1931) * '' Amynthas japonicus'' (Horst, 1883) * ''Amynthas kinmenensis'' * ''Amynthas longicauliculatus'' (Gates, 1931) * ''Amynthas luridus'' (Shen, Chang, & Chih, 2019) * ''

Amynthas mekongianus ''Amynthas mekongianus'', the Mekong worm or Mekong giant earthworm, previously known as ''Megascolex mekongianus'', is a species of earthworm in the family Megascolecidae. It is native to the vicinity of the Mekong, River Mekong in southeastern ...

'' (Cognetti, 1922) * ''Amynthas minimus'' * ''Amynthas mirifius'' * ''Amynthas moakensis'' * ''Amynthas morrisi'' (Beddard, 1892) * ''Amynthas mujuensis'' * ''Amynthas obsoletus'' * ''Amynthas papulosus'' (Rosa, 1896) * ''Amynthas phatubensis'' (Panha & Bantaowong, 2011) * ''Amynthas polyglandularis'' * ''Amynthas pulvinus'' * ''Amynthas ruiyenensis'' (Shen, Chang, & Chih, 2019) * ''Amynthas sangumburi'' * ''Amynthas siam'' (Blakemore, 2011) * ''Amynthas srinan'' (Panha & Bantaowong, 2011) * ''Amynthas taiwumontis'' * ''Amynthas tessellatus'' * '' Amynthas tokioensis'' (Beddard, 1892) * ''Amynthas tontong'' (Panha & Bantaowong, 2011) * ''Amynthas wuhumontis'' * ''Amynthas wujhouensis''

References

{{Taxonbar, from=Q4749574 Haplotaxida Annelid genera Megascolecidae