Hello,
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,
respectively.
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
slender.
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
sized.
Hope this is helpful.
Regards,
Rob B
*Reference:
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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