Microchaetus, the largest earthworms on Earth?

(writing in progress)

The large-bodied earthworms of the southern hemisphere belong to four families, containing many genera.

Present in Madagascar (distinctive family).








Large earthworms in North America and Australia belong to the family Megascolecidae.

In the USA:

Driloleirus macelfreshi (Oregon giant earthworm), up to 1.3 m long, has a habitat of riparian forest


Driloleirus americanus (giant palouse earthworm), occurs in Washington state (probably the Columbia River basalt area?). It has a length of up to 3 m, and a width of up to 2.5 cm. Its habitat is indigenous shrublands in eastern Washington state and western Idaho.


In Australia:

The largest-bodied of the approximately 1000 spp. of earthworms in Australia is the giant Gippsland earthworm (Megascolides australis, https://en.wikipedia.org/wiki/Giant_Gippsland_earthworm and scroll in https://www.gardenmyths.com/earthworm-myths/ and https://www.sciencedirect.com/science/article/abs/pii/003807179290119I), which has a mean length of 80 cm (in the largest individuals, up to 4 m when stretched), a width of 2 cm, and a body mass of about 200 g (up to 400 g). The body is fragile (https://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=64420).

Megascolides australis is long-lived and slow-growing. Hatchlings have a length of 20 cm, and take up to 5 years to reach maturity. The castings are left underground. The distribution of this species is limited to less than 50,000 hectares, in the Bass River valley, east of Melbourne. The habitat is riparian grassland.


One megascolecid, Amynthas corticis (up to 17 cm long, https://www.inaturalist.org/taxa/196395-Amynthas-corticis), is parthenogenetic. It is capable of autotomy, shedding the posterior of the body in order to escape from predators.

Amynthas https://www.inaturalist.org/observations?place_id=any&taxon_id=196397&view=species

The largest earthworms on Earth apparently belong to the genus Microchaetus, in the family Glossoscolecidae (or Microchaetidae). Their bodies are up to about 7 m long. They penetrate the soils to depths of 30-70 cm.











The giant golden mole (Chrysospalax trevelyani, https://en.wikipedia.org/wiki/Giant_golden_mole and https://pascal-francis.inist.fr/vibad/index.php?action=getRecordDetail&idt=PASCAL8110060554 and https://www.tandfonline.com/doi/abs/10.1080/02541858.1985.11447950) is the largest-bodied chrysochlorid in southern Africa.

It is up to 23 cm long. Its distribution is in the Eastern Cape, from East London to southern Pondoland. Its main diet is said to be Microchaetus (https://www.cambridge.org/core/journals/oryx/article/giant-golden-mole/918E35A64B0631A18128B57621FC4B8F).

(writing in progress)

Publicado el mayo 26, 2023 06:38 MAÑANA por milewski milewski


A colleague, who is familiar with the ecosystem dominated by Portulacaria afra (https://www.inaturalist.org/taxa/326086-Portulacaria-afra) in Eastern Cape province in South Africa, has observed that castings of an extremely large earthworm are common here.

This ecosystem is fire-free and extremely rich in folivorous mammals.

My colleague reports that he encountered an individual earthworm (about 70 cm long) dying on the road in this area, after being run over by a motor vehicle (similar to https://www.inaturalist.org/observations/10823373).

I surmise that the identity was https://www.inaturalist.org/taxa/675691-Microchaetus-rappi.

What was noteworthy was that its body was intact, as opposed to showing autotomy or shattering.

This suggests that Microchaetus of South Africa and Megascolides of Australia differ greatly in reaction to injury, the former being 'tough' and the latter being remarkably fragile.

Publicado por milewski hace 12 meses

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