Limax maximus (literally, "biggest slug"), known by the common names great grey slug and leopard slug, is a species of slug in the family Limacidae, the keeled slugs. It is among the largest keeled slugs, Limax cinereoniger being the largest. Limax maximus is the type species of the genus Limax. The adult slug measures 10–20 cm (3.9–7.9 in) in length and is generally a light grey or grey-brown with darker spots and blotches, although the coloration and exact patterning of the body of this slug species is quite variable. This species has a very unusual and distinctive mating method, where the pair of slugs use a thick thread of mucus to hang suspended in the air from a tree branch or other structure. Although native to Europe, this species has been accidentally introduced to many other parts of the world. It was first discovered outside its native range in Philadelphia, USA in 1867.
Description
External anatomy The adult body length is 10-20 cm (4-8 in). The greater part of the body is rounded, but there is a short keel on its tail, with about 48 longitudinal rows of elongate, detached tubercles. The body color is pale-grey, ash-colored, brownish or sometimes yellowish-white. The body is longitudinally streaked or spotted with black. The pattern of spotting is variable. The shield is always black-spotted. The sole of the foot is a uniform ash or yellowish-ash color. The foot-fringe is pale, with a row of minute submarginal blackish tubercles.
The tentacles are very long and slender. The reproductive pore is near the base of the right upper tentacle. The shield is oblong, about one third of the total length of the animal. The shield is rounded in front, angular behind, and forming an angle of about 80 degrees when in motion, usually of a similar tint to the body, but boldly marbled or maculate with black, somewhat concentrically and interruptedly ridged around a sub-posterior nucleus. The pneumostome is just posterior to the midpoint of the mantle, as it is in all Limacidae. The mucus is colorless and iridescent, and not very adhesive. Although color varieties have no actual taxonomic significance, a large number of color varieties have been described, prominent among them being the varieties serpentinus, vulgaris, cellarius (typical), johnstoni, maculatus, ferrussaci, obscurus, fasciatus and rufescens, of Alfred Moquin-Tandon, and cornaliee, of Pini.
Internal anatomy
The shell of Limax maximus is reduced and internal, under the shield. The occurrence of this internal shell was known to Pliny the Elder; the shell was used by the ancient physicians for the sake of its carbonate of lime. The calcitic shell is situated beneath the hinder part of the shield, and is perceptible through the skin. The color of the shell is whitish. The shape of the shell is oblong-oval and thin, slightly convex above, and correspondingly concave beneath, with a membranous margin. The apex or nucleus is at the posterior margin but inclined towards the left side, and forming the apophysis by which the shell is organically attached to the animal. The length of the shell is 13 mm (1⁄2 in) and the width of the shell is 7 mm (1⁄4 in). Shells of different Limacidae species are undiagnostic: in other words, they are not helpful for identification purpose. Digestive system: The formula of the radula is: 62-73/ × 138–157. The intestine has six convolutions and is without a caecum. Of the six convolutions of the intestine, four are imbedded in the liver, and two hang freely in the body cavity. The nervous system is composed of the typical ganglia. The pedal ganglia are placed beneath the radula sac and joined by an anterior and a posterior commissure. The abdominal ganglion lies a little to the right of the median line. The visceral ganglia occupy the angle between the lingual sheath and the oesophagus and the buccal ganglia are widely separated but joined by a commissure nearly as thick as the ganglia themselves. Reproductive system: The hermaphrodite gland (HG) is elongated and large, and is connected with spermoviduct (SO) by means of the hermaphrodite duct (HD) which takes its course through a portion of the albumen gland (AG). The spermoviduct is thick and well convoluted, and separates further down into a vas deferens or sperm-duct (VD) and an oviduct (OV). The former opens into the upper end of a very long penis (P), to which a strong retractor muscle (PRM) is attached. The lower portion of the penis unites with that of the oviduct at the genital orifice, so that there is no vestibule. The receptaculum seminis (RS) opens into the lower end of the penis near the junction of the two ducts.
Distribution
Fossil distribution The internal shells of the different species of Limacidae are not recognizable to the species level. Therefore, the fossil distribution of Limax maximus (and other Limacidae species) is unknown. Unidentified calcitic shells of Limacidae are known from European Tertiary and Quaternary deposits.
Indigenous distribution This species is now widely distributed around the world, but it is generally considered to be native to Europe and Mediterranean countries of Africa. Western Europe:
Great Britain - Limax maximus was first described in England in Animalium Angliae Tres Tractatus … Alter de Cochleis tum Terrestribus tum Fluviatilibus by Martin Lister in 1678. The presence of Limax maximus in England had been noted twelve years earlier in Christopher Merret's Pinax Rerum Naturalium Britannicarum. Ireland Benelux: Belgium, Netherlands, Luxembourg France Germany Italy Switzerland Spain Portugal Eastern Europe:
Albania Bosnia-Hercegovina Bulgaria Croatia Greece Serbia Africa:
Egypt Algeria Morocco
Nonindigenous distribution The non-indigenous distribution of Limax maximus includes many countries worldwide:
Europe: all remaining countries not already listed above. Africa
Mozambique South Africa North America:
Canada (present in 5 of 10 provinces) Mexico United States (present in 46 of 50 states) South America:
Argentina Brazil Chile Colombia Asia:
China Japan India Oceania:
Australia New Zealand
… excerpt ends here. Continue reading the full article.
