Body size range

robblakemore at bigpond.com robblakemore at bigpond.com
Tue Apr 5 23:08:09 EST 2005

Regarding size range of "true" terrestrial earthworms (as opposed to their 
aquatic relatives), here a section from Blakemore (2002: 13)* ....

"Size range
Peregrines are often characterized by sizes as small as 10 or 20 mm length and 
about one mm width in adults, e.g. Drawida spp., Microscolex spp., 
Ocnerodrilus occidentalis and Dichogaster spp., and the cocoons of such 
species are proportionately small, which probably facilitates their dispersal. 
Several endemic litter dwelling or arboreal species are also in the range 10-
20 mm in length and about 1-2 mm diameter (see e.g. Lee, 1959; 1981; 1985). 
For example, Metapheretima agathis and M. buckerfieldi both by Lee (1981) from 
Vanuatu, measure less than 17 mm. 
Various earthworm families have ‘giant’ members, Stephenson (1930:1) 
listed several of these, in the main they are endemic sub-soil dwellers that 
are presumed to require relatively long life-spans to attain their full 
dimensions. Some examples of ‘giant’ worms are:
Family Moniligastridae: Drawida nilamburensis (Bourne, 1894) and Drawida 
grandis (Bourne, 1887) from India which may be as much as 760 or 1,080 mm, 
Family Octochaetidae: Eutyphoeus gammiei (Beddard, 1888) in India may 
reach a size of 405 mm. 
Family Megascolecidae: Megascolides australis McCoy, 1878, the “The Giant 
Gippsland Earthworm” from southern Victoria, Australia was originally recorded 
with a size of 1.23 m, or a little over 4 ft., but specimens attaining lengths 
of about 6 ft., and even 7 ft. 2 in. (2.184 m) have been measured that weighed 
400-450 g (Spencer, 1888). However, the average size is about 1 m according 
to Dr Beverley Van Praagh of the Museum of Victoria who has studied the 
biology and conservation of this remarkable worm (Van Praagh, 1992). 
Notoscolex grandis Fletcher, 1886 from Burrawang, NSW measures 760-1060 mm 
long by 11 mm wide ( Fig. 0.2 ). Several other Australian natives in the 
genera Digaster, Heteroporodrilus, Fletcherodrilus and Diporochaeta have 
species in the range 600-1500 mm (see Blakemore, 1994) ( Fig. 0.3 ; Fig. 0.4 
). The largest known species from Tasmania is Vesiculodrilus tasmanianus 
(Fletcher, 1887) which was described at over 610 mm, or about 2 ft. long and 
while this is much shorter than sizes attained by Megascolides australis, 
these two species are of equivalent width, about 25 mm. Specimens of V. 
tasmanianus dug during forest trail building operations were found at about 1- 
1.5 m depth, but some burrows descended to 5 m (Blakemore, 2000e). New 
Zealand’s Celeriella gigantea (Benham, 1906) may measure 990 mm when 
preserved, but 1.3-1.4 mm when alive and extended, with a width of 11 mm and 
ca. 450 segments (Lee, 1959). From southeast Asia, the Vietnamese Megascolex 
mekongianus Cognetti, 1922 is about 1 m long, and while Polypheretima elongata 
(Perrier, 1872) has a usual range of 40-360 mm long, a specimen in the current 
studies reached >450 mm in life (mass 8 g), but both these taxa are relatively 
Family Microchaetidae: in South Africa is a group of sometimes ‘gigantic’ 
species all to about 1 m or more long (Plisko, 1999), these are: Microchaetus 
microchaetus (Rapp, 1849) which has a length of 1.80 m by 16-18 mm wide with 
792 segments (!); the recently reinstated M. rappi Beddard, 1886; Michaelsen’s 
(1899) M. braunsi and M. decipiens; and M. klopperi and M. stuckenbergi both 
of Plisko (1991). Newspaper reports of a South African specimen measuring 7 m 
by 75 mm were thought improbable by Lee (1985: 9).
Family Glossoscolecidae: South American ‘giants’ are Rhinodrilus horsti 
(Beddard, 1891), 860 mm; Thamnodrilus gigas (Perrier, 1872), 1.16 m; and 
Glossoscolex giganteus (Michaelsen, 1892), 1.26 m. Stephenson (1930) states 
that Rhinodrilus fafner Michaelsen, 1917, which measures when extended 2.1 m. 
in length and 24 mm in diameter, rates with Megascolides australis as probably 
one of the largest of all earthworms. 
Family Lumbricidae: Lumbricus terrestris Linnaeus, 1758 and Octodrilus 
frivaldszkyi (Örley, 1885) both grow to about 360 mm, and Scherotheca 
(Scherotheca) gigas Dugès, 1828 from Montpellier measures up to 720 mm. The 
largest of lumbricids, with a name almost as long, was considered by Lee 
(1985) to be the French Scherotheca (Opothedrilus) occidentalis thibauti 
Bouché, 1972 that measures 1.05 m by 25 mm and weighs 106 g." 

I have recently updated these statistics and added the following species that 
probably represent the extremes of size range: 

In family Megascolecidae Amynthas infantilis (Chen, 1938) from Hainan is only 
10-20 mm long. In Myanmar (Burma), Tonoscolex birmanicus Gates, 1926 from 
Pyin U Lwin or Pyin Oo Lwin (formerly Maymyo) is over 600 mm long by 10-15 mm 
and up to 7ft or 10ft (=2,130 or 3,050 mm) long in some reports according to 
Gates (1972: 227); also from southeast Asia, Amynthas mekongianus (Cognetti, 
1922) is reported as 2.9m long by 4-8mm wide with more than 500 segments 
(pers. obs. and Blakemore et al. in press). The type species of the 
Acanthodrilidae from New Caledonia is Acanthodrilus ungulatus Perrier, 1872 
that reaches sizes up to 700mm, but most other members of the family are small 

Hope this is helpful. 
Rob B

Blakemore, R.J., (2002). Cosmopolitan Earthworms – an Eco-Taxonomic Guide to 
the Peregrine Species of the World. VermEcology, PO BOX 414 Kippax, ACT 2615, 
Australia. Pp. 426 + 80 figs.

On 5 Apr 2005 at 22:15, Craig McClain wrote:

> I am still trying to find largest and smallest for the leeches and
> earthworms and for the Siboglinidae. Several good suggestions...but I
> am only counting published lengths/sizes. Any help would be
> appreciated 

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