The umbrella slug (''Umbraculum umbraculum'') is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of large

sea snail Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...

limpet Limpets are a group of aquatic snails that exhibit a conical shell shape (patelliform) and a strong, muscular foot. Limpets are members of the class Gastropoda, but are polyphyletic, meaning the various groups called "limpets" descended indep ...

, a marine

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Umbraculidae Umbraculidae are a taxonomic family of unusual sea snails or limpets, marine opisthobranch gastropod molluscs in the clade Umbraculida. Distribution This family has a global distribution in tropical and subtropical seas. Genera Genera ...

. It is found in tropical to warm temperate parts of the Indo-Pacific and Atlantic Oceans, where it feeds on

sponge Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through t ...

Description

The umbrella slug is a large mollusc growing to a length of up to , with a relatively small external shell on the dorsal surface. This shell is a flattish cone and is usually encrusted with

epiphytic An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphytes grow are called phoroph ...

organisms, both plant and animal. The

mantle A mantle is a piece of clothing, a type of cloak. Several other meanings are derived from that. Mantle may refer to: *Mantle (clothing), a cloak-like garment worn mainly by women as fashionable outerwear **Mantle (vesture), an Eastern Orthodox ve ...

is roughly circular in outline, and is covered with pustules; the ground colour of the mantle varies, usually being orange or brownish, and the pustules are usually white. The mollusc does not elongate when crawling and the location of the head is revealed when it thrusts out its rolled

rhinophore A rhinophore is one of a pair of chemosensory club-shaped, rod-shaped or ear-like structures which are the most prominent part of the external head anatomy in sea slugs, marine gastropod opisthobranch mollusks such as the nudibranchs, sea har ...

s from beneath the shell. At the base of the rhinophores are a pair of eyes, and beneath is a cleft which contains the

mouth In animal anatomy, the mouth, also known as the oral cavity, or in Latin cavum oris, is the opening through which many animals take in food and issue vocal sounds. It is also the cavity lying at the upper end of the alimentary canal, bounded on ...

. The

radula The radula (, ; plural radulae or radulas) is an anatomical structure used by molluscs for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food ...

is broad and is armed with many small teeth. The sole of the foot is smooth and flat; the gills are bipinnate and are located in the right side of the body.

Distribution and habitat

The umbrella slug is found in the Pacific Ocean in both the tropics and in warm temperate regions. Its range includes Indonesia, Australia, New Zealand, Hawaii, Mexico and Panama. It also occurs in the Red Sea, the Mediterranean Sea and the warmer parts of the Atlantic Ocean. In 2016, researchers reported that it had been observed for the first time in the

Bay of Biscay The Bay of Biscay (), known in Spain as the Gulf of Biscay ( es, Golfo de Vizcaya, eu, Bizkaiko Golkoa), and in France and some border regions as the Gulf of Gascony (french: Golfe de Gascogne, oc, Golf de Gasconha, br, Pleg-mor Gwaskogn), ...

in surveys undertaken between 2011 and 2014, in what seemed to be a northward shift in its range; this "tropicalisation" was attributed to a rise in sea temperature. It occurs in both shallow water and at depths down to about .

Ecology

The umbrella slug feeds on sponges and its colouring often makes it well camouflaged. It rasps the surface of the sponge with its radula, opening the cleft on its base wide so that it can press its mouth against the surface of the sponge. This slug has been found on ''

Tethya ''Tethya'' is a genus of sea sponges belonging to the family Tethyidae. Members of this genus all have a spherical body formBranch, G.M., Branch, M.L, Griffiths, C.L. and Beckley, L.E. 2010. ''Two Oceans: a guide to the marine life of southern ...

'' spp., ''

Aaptos aaptos ''Aaptos aaptos'' is a species of sea sponge belonging to the family Suberitidae. This particular species is known to contain adrenoreceptor-blocking compounds. While it is highly toxic to fish, it is known to be preyed upon by the hawksbill tur ...

'', ''

Ancorina alata ''Ancorina'' is a genus of sea sponges belonging to the family Ancorinidae. It is the type genus of its family. This genus is characterized by a high density of siliceous spicules. Members of this genus are known to be eaten by hawksbill turtles ...

'' and ''

Plakina trilopha ''Plakina trilopha'' is a species of sponge in the order Homosclerophorida. It is native to the Mediterranean Sea and the Canary Islands. It was first described in 1880 by the German zoologist Franz Eilhard Schulze Franz Eilhard Schulze (22 Ma ...

''. The eggs are laid in a long, coiled ribbon and the larvae are

plankton Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...

ic.

Gallery

File:Umbraculum umbraculum.jpg File:Umbraculum umbraculum Réunion.jpg File:Umbraculum umbraculum 000.jpg File:Umbraculum umbraculum 001.png File:Umbraculum umbraculum 1.jpg

References

External links

Scheda Umbraculum mediterraneum – Acquarioitalia.it
{{Taxonbar, from=Q1056697 Umbraculidae Molluscs of the Atlantic Ocean Molluscs of the Indian Ocean Molluscs of the Pacific Ocean Molluscs of the Mediterranean Sea Gastropods described in 1786