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Arctiostrotus vancouverensis McKey-Fender
Family: Acanthodrilidae


© William Leonard     (Photo ID #8702)


Earthworm distribution in BC
Distribution of Arctiostrotus vancouverensis in British Columbia.
(Click on the map to view a larger version.)


The earthworms of British Columbia are a little known faunal group. We would like to thank the Royal Ontario Museum for providing permissions to use extracts, including illustrations, from the following publication in the atlas pages: Reynolds, John W. 1977. The Earthworms (Lumbricidae and Sparganophilidae) of Ontario. Thanks also to John Reynolds for provision of substantial information on earthworms and review of the atlas pages.

Species Information

This native species is considered an ancient species (Marshall and Fender 2005). McKey-Fender et al. (1994) described this species; John Reynolds has summarized the description as follows: “Length 167-381 mm, diameter 3.2-4.5 mm, segments number 147-204, prostomium tanylobic, dorsal pores absent. Clitellum annular, basically xiii-xviii, except extending to ½ xii dorsally and lacking ventrally in area of male field. Setae separate: AA:AB:BC:CD:DD = 2.1:1.0:1.5:1.8: 8.5 on x and 2.7; 1.0:1.5:1.9:9.9 midbody. DD:U < 0.5 (0.43-0.44). Penial setae small and delicate, 430-570 x 8-9 μ. Male field with glandular bands in grooves 17/18 and 18/19 B to B. Genital markings paired, transverse elongate in 19/20 and 20/21, sometimes unilaterial in 21/22, sometimes missing in 20/21, large, centering just media to A. Proventriculus in iv, with thickened wall almost as conspicuous as gizzard, but soft. Pre-intestinal constriction (xvi). Gizzard entirely in v or partly in vi, 5/6 adherent or even not dissectible from gizzard posteriorly, oesophagus in vii-xv is especially enlarged. Typhlosole xxi to Ixxiv-Ixxxiii, rudimentary, does not project into lumen of the intestine. Holandric, prostates long, confined to xviii but bulging septa, length of gland at least 20 times width, duct slender, nearly straight or looped in a C or S shape, slightly broader ectally. Spermathecae, sexthecal, in vii, viii, and ix, ampulla ovoide to subglobular, duct one-third length of ampulla, spermathecal pores in groves 6/7, 7/8, and 8/9, anterior to furrows, in or lateral to B. Nephropores inconspicuous, irregularly alternating in C or dorsal to D. Colour, young specimens unpigmented, but with age development an orange-brown flush over entire body, especially over dorsum anteriorly and posteriorly.”

Source: Marshall, Valin G. and William M. Fender. 2007. Native and Introduced Earthworms (Oligochaeta) of British Columbia. Megadrilogica 11 (4): 29-52.


Species Biology

This genus is generally very intolerant of heat (Hendrix 1995). When disturbed, this species “will flip back and forth, jumping several centimeters off the ground” (Hendrix 1995).


This species was first found in the Olympic Peninsula in Washington, and is considered characteristic of the forests of Vancouver Island, where it is important in humus formation (McKey-Fender et al. 1994). It is nearly always found in humous.


Global Range

Known only from Canada and the United States, in the US, it has been reported from WA (Reynolds and Wetzel 2008).
Canadian and BC Range

In Canada this species is known only from BC (Reynolds and Wetzel 2008), where it has been collected from several locations in the western part of Vancouver Island, and Cowichan Lake (Marshall and Fender 2007). BEC zones: CWH, MH (Marshall and Fender 2007)

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)

BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

General References