Family ACHATINIDAE Swainson, 1840

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Family ACHATINIDAE Swainson, 1840

Giant African Snails

Compiler and date details

July 2012 - Dr John Stanisic

1992 - Brian J. Smith, Museum Victoria, Melbourne

Introduction

Members of the family Achatinidae are native to tropical Africa. One species in particular, the Giant African Snail, Achatina fulica, has become an aggressive pest species throughout the tropical Asian and Pacific region, and in North America. Its progress and pest potential has been extensively documented by Mead (1961). The only known major Australian introduction has been recorded in northern Queensland. The infestation was subsequently eradicated (Colman 1977). A minor incident was reported with the collection of a single specimen in an industrial estate at Currumbin in southern Queensland in 2004 (Stanisic, pers comm.). However, specimens are intercepted by quarantine officers on a regular basis at all major Australian ports and there is a high probability that further outbreaks will be reported in tropical and subtropical Australia.

Achatinids are oviparous and lay relatively large hard-shelled eggs. They may be either arboreal, ground dwellers or both. Achatinids are herbivores and many eat living plant material. A number of species have adapted successfully to living in human-modified environments where they feed on crops.

Most species occur in the wet tropics of western and central Africa where more than 200 species are known. One species, Achatina fulica, has spread through much of the tropical world from its native Africa through commerce and has inflicted enormous damage on vegetable and fruit crops. The species briefly established in Queensland on two recent occasions but was successfully eradicated. The species is still present on the Australian territory of Christmas Island in the Indian Ocean, and nearby in Papua New Guinea and on the islands of the SW Pacific.

Diagnosis

The Achatinidae are large, (up to 200 mm in length) narrowly to broadly conical snails. Sculpture may be smooth, wrinkled, cancellate or consist of longitudinal growth lines. Most species are dextral, a few are sinistral. Whorls are generally rounded and sutures moderately impressed. Apertures are ovate and the outer lip may or may not be thickened. The columella may be truncated or entire (more or less) and is generally narrow to moderately wide and often thickened. The columella usually bears a twist or fold and may be straight, slanted, curved or sinuous. The parietal area may also be moderately thickened. The umbilicus is very small or absent. Colour varies considerably from white to various shades of brown and yellow, often as longitudinal stripes or flame-like zigzags. The periostracum is thin and yellowish-brown in colour. Shells are generally opaque and may be dull or relatively glossy or polished.