''Pyura doppelgangera'', the doppelganger cunjevoi, is a

sessile Sessility, or sessile, may refer to: * Sessility (motility), organisms which are not able to move about * Sessility (botany), flowers or leaves that grow directly from the stem or peduncle of a plant * Sessility (medicine), tumors and polyps that ...

ascidian Ascidiacea, commonly known as the ascidians, tunicates (in part), and sea squirts (in part), is a polyphyletic class in the subphylum Tunicata of sac-like marine invertebrate filter feeders. Ascidians are characterized by a tough outer "tunic" ...

, or sea squirt, that lives in coastal waters of

Australasia Australasia is a region that comprises Australia, New Zealand and some neighbouring islands in the Pacific Ocean. The term is used in a number of different contexts, including geopolitically, physiogeographically, philologically, and ecologica ...

attached to rocks or artificial structures.

Distribution

This species is particularly common in

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

.Rius, M., and Teske, P. R. (2013) Cryptic diversity in coastal Australasia: a morphological and mito-nuclear genetic analysis of habitat-forming sibling species. Zoological Journal of the Linnean Society 168:597-611; article available at https://sites.google.com/site/drpeterteske/all-publications. It has also been reported from

South Gippsland South Gippsland, a region of Gippsland in Victoria, Australia, is a well-watered region consisting of low, rolling hills descending to the coast in the south and the Latrobe Valley in the north. Low granite hills continue into Wilsons Promonto ...

Victoria Victoria most commonly refers to: * Victoria (Australia), a state of the Commonwealth of Australia * Victoria, British Columbia, provincial capital of British Columbia, Canada * Victoria (mythology), Roman goddess of Victory * Victoria, Seychelle ...

( Port Welshpool and

Port Albert Port Albert is a coastal town in Victoria, Australia, on the coast of Corner Inlet on the Yarram - Port Albert Road, south-east of Morwell, south-east of Melbourne, in the Shire of Wellington. At the , Port Albert had a population of 293. L ...

South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...

(

Adelaide Adelaide ( ) is the capital city of South Australia, the state's largest city and the fifth-most populous city in Australia. "Adelaide" may refer to either Greater Adelaide (including the Adelaide Hills) or the Adelaide city centre. The dem ...

) and the extreme north of

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 smaller islands. It is the sixth-largest island count ...

North Island The North Island, also officially named Te Ika-a-Māui, is one of the two main islands of New Zealand, separated from the larger but much less populous South Island by the Cook Strait. The island's area is , making it the world's 14th-largest ...

. Genetic data from rapidly mutating

microsatellite A microsatellite is a tract of repetitive DNA in which certain DNA motifs (ranging in length from one to six or more base pairs) are repeated, typically 5–50 times. Microsatellites occur at thousands of locations within an organism's genome. ...

s indicate that the species is native to Tasmania and that all non-Tasmanian populations were introduced through human activities during the period of European settlement.Teske, P. R., Sandoval-Castillo, J., Waters, J., and Beheregaray, L. B. (2014) Can novel genetic analyses help to identify low-dispersal marine invasive species? Ecology and Evolution 4(14): 2848-2866; article available at: http://onlinelibrary.wiley.com/doi/10.1002/ece3.1129/full. The invasion success of the introduced populations varies depending on the presence of suitable substrates. While the species is rapidly expanding its range in New Zealand (where rocky shore habitat is continuous), the invasion of South Australia has stalled because the region mostly has sandy beaches, and settlement is limited to artificial structures.Teske, P. R., Sandoval-Castillo, J., Sasaki, M., and Beheregaray, L. B. (2015) Invasion success of a habitat-forming marine invertebrate is limited by lower-than-expected dispersal ability. Marine Ecology Progress Series 536:221-227; article available at: https://sites.google.com/site/drpeterteske/all-publications.

Description

''Pyura doppelgangera'' usually does not grow taller than about 50–60 mm. It has a brown

tunic A tunic is a garment for the body, usually simple in style, reaching from the shoulders to a length somewhere between the hips and the knees. The name derives from the Latin ''tunica'', the basic garment worn by both men and women in Ancient Rome ...

that has sand embedded in it.

Taxonomy

''Pyura doppelgangera'' is a member of the "''P. stolonifera'' species complex", which includes at least five species of large, solitary ascidians that are all often incorrectly referred to as ''P. stolonifera'' in the literature. It shares a recent ancestor with '' P. praeputialis'', a larger species commonly referred to a "cunjevoi" or "cunjie", which is common in coastal areas of the south-eastern Australian mainland and which is a

non-indigenous species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there ...

Antofagasta Antofagasta () is a port city in northern Chile, about north of Santiago. It is the capital of Antofagasta Province and Antofagasta Region. According to the 2015 census, the city has a population of 402,669. After the Spanish American wars ...

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

. Although a difference exists regarding the maximum body size of these closely related species, they are indistinguishable externally. Genetic methods have recovered the two species as highly distinct evolutionary lineages.Teske, P. R., et al. (2011): "Nested" cryptic diversity in a widespread marine ecosystem engineer: a challenge for detecting biological invasions. BMC Evolutionary Biology 11:176; doi:10.1186/1471-2148-11-176; article available at: http://www.biomedcentral.com/1471-2148/11/176

Etymology

The species is named ''Pyura doppelgangera'' after the

German German(s) may refer to: * Germany (of or related to) **Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ger ...

word

Doppelgänger A doppelgänger (), a compound noun formed by combining the two nouns (double) and (walker or goer) (), doppelgaenger or doppelganger is a biologically unrelated look-alike, or a double, of a living person. In fiction and mythology, a doppelg ...

, which in its narrowest sense means "look-alike" (i.e. somebody who closely resembles somebody else). The name reflects the difficulty in distinguishing this species from ''P. praeputialis'' because of their very similar morphology.

References

External links

Invasion of North Island, New Zealand, by ''Pyura doppelgangera''
nbsp;• ''3 News'', ''12 August 2010''. {{Taxonbar, from=Q16988972 Stolidobranchia