''Austrominius modestus'' ( syn. ''Elminius modestus'') is a

species In biology, a species is the basic unit of Taxonomy (biology), 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 ...

barnacle A barnacle is a type of arthropod constituting the subclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive ...

in the

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

Elminiidae Elminiidae is a family of symmetrical sessile barnacles in the order Balanomorpha The Balanomorpha are an order of barnacles, containing familiar acorn barnacles of the seashore. The order contains these families: * Austrobalanidae Newman & ...

, native to Australia,

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

and

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 List of islands of New Zealand, smaller islands. It is the ...

, but now spread to

Britain Britain most often refers to: * The United Kingdom, a sovereign state in Europe comprising the island of Great Britain, the north-eastern part of the island of Ireland and many smaller islands * Great Britain, the largest island in the United King ...

and the north west coasts of

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located enti ...

. It reaches a maximum size of about in diameter.

Description

''A. modestus'' is a pearly grey, semi-translucent barnacle. It is composed of four distinct plates and leans a little to one side.

Distribution and habitat

''A. modestus'' originated in Australia and was first seen in British waters, in

Chichester Harbour Chichester Harbour is a large natural harbour in West Sussex and Hampshire. It is situated to the south-west of the city of Chichester and to the north of the Solent. The harbour and surrounding land has been designated as an Area of Outstandi ...

, during the

Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...

. It was believed to have arrived on the hulls of ships, or possibly the larval stages travelled in

bilge water The bilge of a ship or boat is the part of the hull that would rest on the ground if the vessel were unsupported by water. The "turn of the bilge" is the transition from the bottom of a hull to the sides of a hull. Internally, the bilges (usu ...

. It has become very common in southern England and Wales and is spreading northwards, but the spread may be limited by the temperature of the sea. It is found on the upper middle shore and is tolerant of low salinity levels where fresh water enters the sea. It avoids exposed positions. It had reached the

Scottish Borders The Scottish Borders ( sco, the Mairches, 'the Marches'; gd, Crìochan na h-Alba) is one of 32 council areas of Scotland. It borders the City of Edinburgh, Dumfries and Galloway, East Lothian, Midlothian, South Lanarkshire, West Lot ...

by 1960 and

Shetland Shetland, also called the Shetland Islands and formerly Zetland, is a subarctic archipelago in Scotland lying between Orkney, the Faroe Islands and Norway. It is the northernmost region of the United Kingdom. The islands lie about to the ...

by 1978. It is found on the Atlantic coasts of Europe from Gibraltar to Germany.

Ecology

''A. modestus'' is a suspension feeder. It has feathery appendages which beat rhythmically to draw

plankton Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a cr ...

and other organic particles into the shell for consumption. Eggs are laid and develop into nauplius larvae which are released into the

phytoplankton Phytoplankton () are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater ecosystems. The name comes from the Greek words (), meaning 'plant', and (), meaning 'wanderer' or 'drifter'. P ...

. These then develop into cyprid larvae which later settle and cement themselves onto a rocky substrate. In the British Isles, ''A. modestus'' competes with ''

Semibalanus balanoides ''Semibalanus balanoides'' (common barnacle, common rock barnacle, northern rock barnacle) is a common and widespread boreo-arctic species of acorn barnacle. It is common on rocks and other substrates in the intertidal zone of north-western Eu ...

'', whereas in southern Europe it also competes with ''

Chthamalus ''Chthamalus'' (χθαμαλός, "flat" or "on the ground") is a genus of barnacles that is found along almost all non-boreal coasts of the northern hemisphere, as well as many regions in the southern hemisphere. These small barnacles have bee ...

'' spp. It is particularly successful because it grows fast, tolerates reduced salinity, has a lower temperature tolerance than ''Chthamalus'' spp and a higher tolerance than ''

Balanus ''Balanus'' is a genus of barnacles in the family (biology), family Balanidae of the subphylum Crustacea. This genus is known in the fossil record from the Jurassic to the Quaternary periods (age range: from 189.6 to 0.0 million years ago.). F ...

'' spp. It is also a threat to native species because it reaches maturity in its first season and can produce several broods of larvae per year. It has an extended habitat as it grows both high up the shore and in the

neritic zone The neritic zone (or sublittoral zone) is the relatively shallow part of the ocean above the drop-off of the continental shelf, approximately in depth. From the point of view of marine biology it forms a relatively stable and well-illuminated ...

References

External links

''Elminius modestus''

Marine Life Information Network for Britain & Ireland The Marine Life Information Network (MarLIN) is an information system for marine biodiversity for Great Britain and Ireland. MarLIN was established in 1998 by the Marine Biological Association together with the environmental protection agencies ...

* {{Taxonbar, from=Q13896144, from2=Q3051583 Austrobalanidae Crustaceans of Australia Marine crustaceans of New Zealand Crustaceans described in 1854 Taxa named by Charles Darwin