Ascidia incrassata

Invasion History

First Non-native Panama (Pacific) Tidal Record: 2009

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Panama Invasion History:

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Invasion history elsewhere in the world:

None

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Description

Ascidia incrassara is a large solitary tunicate are erect, and only attached on the left posterir side, The tunic is translucent, hard, and somewhat cartilaginous, up to 20 mm thick and usuually covered with epibionts. The siphons are naked and protrude, the oral siphon pointing to the anterior, whilte the cloacal siphon is also directed towards the anterior quarter of the body. Both siphons have 6-8 lobes, and a red spot between each lobe.The 'live; color is purple or red and faces in formalin, The largest specimens are ~100 mm long (Monniot et al. 2001). Muscles occur only on the dorsal surface of the body, contirbuting to erect posture and stiffness of the body. In small specimens, there may be as many as 160 oral tentacles, with an underlying muscular ring, but in larger specimens, these can be reduced to about 60. In small specimens, the gut, gonads, and eggs can be easily seen, but in larger specimens, the organs are more difficult to distinguish. 'The branchial sac of small specimens has a similar number of longitudinal vessels as larger ones (36 on the right and 34 on the left), but the branchial meshes are square and enclose an average of seven stigmata. We found numerous duplications of the stigmata rows marked by intermediate papillae. The gut makes a double loop (Fig. 34E, F). The ovary is located in the primary loop andconsists of numerous tight lobes that do not protrude beyond the gut loop. The testis covers most of the gut on both sides Monniot et al. 2001).

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Taxonomy

Ecology

General:

Most solitary tunicates attach to substrates by their side or base, but some attach with a conspicuous stalk. They are sessile filter feeders with two siphons, an oral and an atrial siphon. Water is pumped in through the oral siphon, where phytoplankton and detritus is filtered by the gills, and passed on mucus strings to the stomach and intestines. Waste is then expelled in the outgoing atrial water.

Solitary ascidians are hermaphroditic, meaning that both eggs and sperm are released to the atrial chamber. Eggs may be self-fertilized or fertilized by sperm from nearby animals, but many species have a partial block to self-fertilization. Depending on species, eggs may be externally or internally fertilized. In external fertilizers, eggs and sperm are released through the atrial siphon into the surrounding water column were fertilization takes place. In internal fertilizers, eggs are brooded and fertilized within the atrial chamber and then released into the water column upon hatching. Fertilized eggs hatch into a tadpole larva with a muscular tail, notochord, eyespots, and a set of adhesive papillae. The lecithotrophic (non-feeding, yolk-dependent) larva swims briefly before settlement. Swimming periods are usually less than a day and some larvae settle immediately after release, but the larval period can be longer at lower temperatures. Once settled, the tail is absorbed, the gill basket expands, and the tunicate begins to feed by filtering (Barnes 1983). Ascidia incrassata , in South Africa, occurs on shallow reef dowwn to abput 20 m depth (anonymous 2021).

Food:

Phytoplankton; Detrtus

Trophic Status:

Suspension Feeder

SusFed

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Habitats

General Habitat	Marinas & Docks	None
General Habitat	Rocky	None
Salinity Range	Polyhaline	18-30 PSU
Salinity Range	Euhaline	30-40 PSU
Tidal Range	Subtidal	None
Vertical Habitat	Epibenthic	None

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Tolerances and Life History Parameters

Minimum Length (mm)	100	Monniot et al. 2001
Maximum Height (mm)	100	Monniot et al.2002
Broad Temperature Range	None	Cold Temperate-Tropical
Broad Salinity Range	None	Polyhaline-Euhaline

General Impacts

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References

Anonymous 2021 Ascidians of the Eastern Cape. <missing URL>



Carman, Mary R. and 7 authors 2010 Ascidians at the Pacific and Atlantic entrances to the Panama Canal. <missing URL>



Carman, Mary, and 8 authors (2011) Ascidians at the Pacific and Atlantic entrances to the Panama Canal, Aquatic Invasions 6(4): 371-380

Monniot, Claude (1970) Phleobranch and stolidobranch ascidians of the Kerguelen Islands collected by P. Grua] (French), Bulletin du Museum National d'Histoire Naturelle. 4e Serie. Section A. Zoologie, Biologie et Ecologie Animales 42(2): 340-354

Monniot, Claude; Monniot, Francoise; Griffiths, Charles; Schleyer, Michael (2001) South African Ascidians., Annals of the South African Museum 108(1): 1-141

Primo, Carmen; Vasquez, Elsa (2008) Zoogeography of the southern New Zealand, Tasmania, and southern Africa ascidian fauna., New Zealand Journal of Marine and Freshwater Research 42: 233-256

U.S. National Museum of Natural History 2002-2021 Invertebrate Zoology Collections Database. http://collections.nmnh.si.edu/search/iz/



US National Museum Department of Botany 2021 Byrd Antarctic Expedition. <missing URL>

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