The red triangle slug, ''Triboniophorus graeffei'', is a species of air-breathing land

slug Slug, or land slug, is a common name for any apparently shell-less Terrestrial mollusc, terrestrial gastropod mollusc. The word ''slug'' is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced ...

, a

terrestrial Terrestrial refers to things related to land or the planet Earth, as opposed to extraterrestrial. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on o ...

pulmonate Pulmonata or pulmonates is an informal group (previously an order, and before that, a subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills. The group inclu ...

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

s in the family

Athoracophoridae Athoracophoridae, common name the leaf-veined slugs, are a family of air-breathing land slugs, terrestrial pulmonate gastropod mollusks in the order Stylommatophora, the stalk-eyed snails and slugs. Many of the species have an attractive patter ...

, the leaf-veined slugs. Native to eastern Australia, this species is named after the distinctive red triangle marking on its back. Reaching lengths of up to 15 centimeters (about 6 inches), it is not only striking in appearance but also holds the title of Australia's largest native land slug.''Red Triangle Slug Fact File''
. Australian Museum, 2009, accessed 22 February 2009. It’s a familiar and widespread presence in its natural habitat. ''Triboniophorus graeffei'' is the type species of its genus, '' Triboniophorus'', the key representative of the group.Solem A. 1959
''Systematics of the land and fresh-water mollusca of the New Hebrides''
Fieldiana Zoology, volume 43, number 1, Chicago Natural History Museum
page 45
46 A closely related and visually unique species of ''Triboniophorus'' has been identified from

Mount Kaputar Mount Kaputar, a mountain with an elevation of above sea level, is located near Narrabri in northern New South Wales. It is part of the Nandewar Range and has been preserved within the Mount Kaputar National Park. The mountain is a prominent ...

, though it has yet to be formally described.

Distribution

This slug species is native to the east coast of Australia, where it ranges from

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

Queensland Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Austr ...

.(June) 2004
''Red Triangle Slug Diversity''
An Australian Museum Website, Australian Museum, accessed 22 February 2009. A closely related and brightly colored pink form, referred to as ''Triboniophorus aff. graeffei'', is found only on

in New South Wales. In 1959,

malacologist Malacology, from Ancient Greek μαλακός (''malakós''), meaning "soft", and λόγος (''lógos''), meaning "study", is the branch of invertebrate zoology that deals with the study of the Mollusca (molluscs or mollusks), the second-largest ...

Alan Solem suggested the species might have been introduced to the

New Hebrides New Hebrides, officially the New Hebrides Condominium () and named after the Hebrides in Scotland, was the colonial name for the island group in the South Pacific Ocean that is now Vanuatu. Native people had inhabited the islands for three th ...

(now Vanuatu), although no specimens were available to confirm this at the time.

Habitat

Red triangle slugs are found in damp situations in various habitats, including city gardens,

forest A forest is an ecosystem characterized by a dense ecological community, community of trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, ...

woodland A woodland () is, in the broad sense, land covered with woody plants (trees and shrubs), or in a narrow sense, synonymous with wood (or in the U.S., the '' plurale tantum'' woods), a low-density forest forming open habitats with plenty of sunli ...

and

heath A heath () is a shrubland habitat found mainly on free-draining infertile, acidic soils and is characterised by open, low-growing woody vegetation. Moorland is generally related to high-ground heaths with—especially in Great Britain—a coole ...

Life habits

These slugs feed by grazing on

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

that grow on the smooth bark of certain

eucalyptus ''Eucalyptus'' () is a genus of more than 700 species of flowering plants in the family Myrtaceae. Most species of ''Eucalyptus'' are trees, often Mallee (habit), mallees, and a few are shrubs. Along with several other genera in the tribe Eucalyp ...

trees and on nearby rocks. Occasionally, they make their way into houses, where they’ve been observed feeding on

mold A mold () or mould () is one of the structures that certain fungus, fungi can form. The dust-like, colored appearance of molds is due to the formation of Spore#Fungi, spores containing Secondary metabolite#Fungal secondary metabolites, fungal ...

that develops on bathroom walls. One of the most fascinating features of this species is its unusual defense mechanism. When threatened, the slug can release a special kind of sticky

mucus Mucus (, ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both Serous fluid, serous and muc ...

, not the usual slippery

slime Slime or slimy may refer to: Science and technology Biology * Slime coat, the coating of mucus covering the body of all fish * Slime mold, an informal name for several eukaryotic organisms * Biofilm, or slime, a syntrophic community of micr ...

used for movement. This adhesive secretion is strong enough to trap predators for days. Interestingly, the mucus works best in wet conditions and gradually loses its stickiness as it dries. The cells responsible for producing this glue-like substance are spread across the slug’s upper surface (dorsal side).

Description

Red triangle slugs are easily recognized by their two

tentacles In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work main ...

; unlike many other slugs, they don’t have four. Like other leaf-vein slugs, they also have a distinctive indented pattern on their back that resembles the veins of a leaf. These slugs can grow up to 14 centimeters in length. They are highly variable in color. Individuals can appear white, off-white, yellow, light or dark grey, beige, pink, red, or olive green. Regardless of color, all adults display a red (sometimes orange, magenta, or maroon) triangular mark on the mantle around the breathing pore (

pneumostome The pneumostome or breathing pore is a respiratory opening of the external body anatomy of a pulmonate land slug or land snail. It is a part of the respiratory system of gastropods. It is an opening in the right side of the mantle of a st ...

), as well as a red line along the edge of the foot. The texture of their backs can also differ: some are smooth, while others are rough. Juvenile slugs look quite different from the adults. They lack the red markings but instead have three dark grey stripes running down their backs and a grey outline around the triangular mantle shield.pers. comm. Michael Shea, Australian Museum Scientists are currently studying whether some of these different color forms might actually belong to separate species or subspecies.

Gallery

Various shots of ''Triboniophorus graeffei'' on the bark of Sydney Blue Gums, near

Dungog Dungog is a country town on the Williams River in the Hunter region and a small part of the Mid North Coast region of New South Wales, Australia. Located in the middle of dairy and timber country, it is the centre of the Dungog Shire Local Go ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

, showing color variation, varying degrees of contraction and body shape. File:Triboniophorus graeffei - Dungog7.jpg, Close-up of a pale pink individual with the

open and a narrow body, tentacles fully extended File:Triboniophorus graeffei - Dungog1.jpg, An off-white individual with a very pale "red triangle" File:Triboniophorus graeffei - Dungog2.jpg, A beige individual with a very wide body and a pale orange "triangle" and foot edge. Tentacles partially retracted File:Triboniophorus graeffei - Chatswood West.jpg, Two individuals of the green form of ''Triboniophorus graeffei'', in the forest in

Chatswood West, New South Wales Chatswood West is a suburb on the Lower North Shore of Sydney, in the state of New South Wales, Australia. Chatswood West is located 11 kilometres north-west of the Sydney central business district, in the local government areas of the City of ...

. The slug on the right is starting to become active, the other is in the contracted state. File:Triboniophorus graeffei - Dungog4.jpg, Two individuals, one fully contracted and with pneumostome closed File:Triboniophorus graeffei - Dungog5.jpg, Same two individuals from the side showing the body shape in profile File:Triboniophorus graeffei - Dungog6.jpg, Same two individuals, the previously contracted one has retreated to a less exposed position among old flakes of bark File:Triboniophorus graeffei juvenile.jpg, Juvenile Red Triangle Slug on moist

Hawkesbury Sandstone Sydney sandstone, also known as the Hawkesbury sandstone, yellowblock, and yellow gold, is a sedimentary rock named after Sydney, and the Hawkesbury River north of Sydney, where this sandstone is particularly common. It forms the bedrock f ...

Chatswood West Chatswood West is a suburb on the Lower North Shore (Sydney), Lower North Shore of Sydney, in the state of New South Wales, Australia. Chatswood West is located 11 kilometres north-west of the Sydney central business district, in the Local gover ...

References

External links

Photographs on the life history etc.:
Photo of about-to-hatch eggs and newly hatched juvenile, from Bill Rudman's site

Feeding tracks on a tree trunk

Showing detail of the head and triangle with pneumostome open
Photographs of the various different color forms:
A mating pair of the white form on a tree trunk

A yellow one with magenta markings, in the contracted state

A dark yellow or orange individual with dark red markings

* ttps://www.flickr.com/photos/phanimals/2905885581/ A photo showing a wide red margin of the foot on a cream-colored individual
A cream-colored individual wrapped around a twig with pneumostome closed

A beige individual with orange markings

A solidly bright red individual
{{Taxonbar, from=Q3075433 Athoracophoridae Gastropods described in 1863