Testacella haliotidea

Family

Testacellidae

Species

Testacella haliotidea Draparnaud, 1801

Common Name

Shelled slug, Earshell slug

Description

The length of this semi-slug ranges from 80-120 mm. The body of this animal is light grayish-brown (sometimes yellowish), with a pale foot fringe and sole. The small (approx. 7-8 x 5-6 mm) external shell of this animal is located on the dorso-posterior tip of the tail. Members of this group (Testacellidae) characteristically have two distinct, lateral (branched) grooves that originate from the anterior margin of the much-reduced shell.

Two addition species in this group have been reported from Europe and may be distinguished by the following characters:

T. haliotidea: Morphology-the dorsal lateral grooves are approximately 2 mm apart at the point of origin. Genitalia-the penis has a flagellum and the spermathecal duct is short and thick.

T. maugei: Morphology-shell larger than both species (12-16 mm long by 6-7 mm wide) and the dorsal lateral grooves are approximately 5 mm apart at the point of origin. Genitalia-the penis does not have a flagellum, and the spermathecal duct is long and thin.

T. scutulum: Morphology-the shell is of similar size to that of T. haliotidea and the dorsal lateral grooves join (just under the shell) before reaching the the point of origin. Genitalia-the penis does not have a flagellum and the spermathecal duct is intermediate between those of T. haliotidea and T. maugei.

Native Range

Western Europe and Western Mediterranean region

Distribution

North America:

  • U.S.: California
  • Canada

Australia: Australia, New Zealand

Europe

Caribbean: Cuba

Ecology

This carnivorous semi-slug spends most of its time underground, where it hunts and consumes earthworms, snails and slugs. The shelled slug is commonly found in disturbed habitats like gardens, parks and agricultural fields. This slug is able to burrow to depths of up to one meter during periods of aestivation. This animal has not been reported to feed on plant material and as such should not pose a threat to agricultural produce. The ecological impact that this species may have on other terrestrial mollusc species has not been documented.

Synonyms

References

Anderson 2005; Barker 1979; Barker 1999; Kerney et al. 1979; McDonnell et al. 2009

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