Halocynthia igaboja

Halocynthia igaboja
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Subphylum:	Tunicata
Class:	Ascidiacea
Order:	Stolidobranchia
Family:	Pyuridae
Genus:	Halocynthia
Species:	H. igaboja
Binomial name
	Halocynthia igaboja; Oka, 1906
Synonyms
	Cynthia ritteri Oka, 1906; Halocynthia jakoboja Oka, 1906; Halocynthia owstoni Oka, 1906; Halocynthia ritteri (Oka, 1906); Pyura okai (Ritter, 1907); Tethyum igaboja (Oka, 1906);

Last updated October 26, 2024

Halocynthia igaboja, commonly known as sea hedgehog, bristly tunicate or spiny sea squirt,^[2] is a species of tunicate in the family Pyuridae. It is native to the northeastern Pacific Ocean. This species was first described in 1906 by the Japanese marine biologist Asajiro Oka, who gave it the name Cynthia ritteri. It was later transferred to the genus Halocynthia .^[1]

Description

Solitary tunicates like the sea hedgehog have a roughly globular body with a leathery body wall or tunic, and two siphons. The buccal siphon draws water into the body, and the atrial siphon expels water. In this species, the tunic is dark brown but is rendered almost invisible by the numerous large, branching, spine-like processes which cover it. The longest spines bear rings of recurved secondary spines. The siphons are often reddish or orangish in colour; the buccal siphon is at the top of the animal and is surrounded by twelve to fifty tentacles, while the atrial siphon is a third to half of the way down the body. At a maximum height of 10 cm (4 in) and width of 2 to 5 cm (0.8 to 2.0 in), this is one of the largest solitary tunicates in the Pacific Northwest. It could be confused with the cactus sea squirt (Boltenia echinata) but is altogether spinier and larger.^[2]

Distribution and habitat

The sea hedgehog is found in Japan, southeastern Asia, and the Pacific Coast of North America, from Alaska to California. It prefers rocky or gravelly habitats with vigorous currents, with a depth range from the intertidal down to about 165 m (540 ft).^[2]

Ecology

The sea hedgehog is a suspension feeder, drawing water through its body and filtering out the plankton and organic material.^[3] Detritus and diatoms tend to accumulate on the spiny processes when the current is weak, rendering the animal almost invisible.^[2] The spines act as a defence against the Oregon hairy triton, a gastropod mollusc. The bristly sea squirt Boltenia villosa , lives in the same habitat but is less spiny; it defends itself by becoming an epibiont and preferentially settling on the spines of the sea hedgehog.^[4] This species is a semi-gregarious species and is cannibalistic, consuming its own eggs and larvae.^[5]

Related Research Articles

A tunicate is an exclusively marine invertebrate animal, a member of the subphylum Tunicata. This grouping is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords. The subphylum was at one time called Urochordata, and the term urochordates is still sometimes used for these animals. They are the only chordates that have lost their myomeric segmentation, with the possible exception of the seriation of the gill slits. However, doliolids still display segmentation of the muscle bands.

Thaliacea is a class of marine chordates within the subphylum Tunicata, comprising the salps, pyrosomes and doliolids. Unlike their benthic relatives the ascidians, from which they are believed to have emerged, thaliaceans are free-floating (pelagic) for their entire lifespan. The group includes species with complex life cycles, with both solitary and colonial forms.

<span class="mw-page-title-main">Ascidiacea</span> Paraphyletic group of tunicates comprising sea squirts

Ascidiacea, commonly known as the ascidians or sea squirts, is a paraphyletic class in the subphylum Tunicata of sac-like marine invertebrate filter feeders. Ascidians are characterized by a tough outer "tunic" made of a polysaccharide.

<i>Ciona intestinalis</i> Species of ascidian

Ciona intestinalis is an ascidian, a tunicate with very soft tunic. Its Latin name literally means "pillar of intestines", referring to the fact that its body is a soft, translucent column-like structure, resembling a mass of intestines sprouting from a rock. It is a globally distributed cosmopolitan species. Since Linnaeus described the species, Ciona intestinalis has been used as a model invertebrate chordate in developmental biology and genomics. Studies conducted between 2005 and 2010 have shown that there are at least two, possibly four, sister species. More recently it has been shown that one of these species has already been described as Ciona robusta. By anthropogenic means, the species has invaded various parts of the world and is known as an invasive species.

Halocynthia is a genus of ascidian tunicates in the family Pyuridae. Species such as H. roretzi are eaten in parts of Asia as a delicacy.

Corella willmeriana is a solitary tunicate in the family Corellidae. It is native to the eastern Pacific Ocean where it lives on the seabed at depths down to about 75 m (250 ft) between Alaska and California.

Styela montereyensis, also called the stalked tunicate, Monterey stalked tunicate, and the long-stalked sea squirt is a solitary ascidian tunicate. It has a cylindrical, yellow to dark reddish-brown body and a thin trunk that anchors it to rocks. It is found in subtidal areas of the western coast of North America from Vancouver Island to Baja California.

Atriolum robustum is a colonial tunicate or sea squirt in the family Didemnidae. It is native to the western and central Indo-Pacific where it is usually found anchored to a hard surface in shallow water.

Didemnum molle is a species of colonial tunicate in the family Didemnidae. It is commonly known as the tall urn ascidian, the green barrel sea squirt or the green reef sea-squirt. It is native to the Red Sea and the tropical waters of the Indo-Pacific region.

Didemnum vexillum is a species of colonial tunicate in the family Didemnidae. It is commonly called sea vomit, marine vomit, pancake batter tunicate, or carpet sea squirt. It is thought to be native to Japan, but it has been reported as an invasive species in a number of places in Europe, North America and New Zealand. It is sometimes given the nickname "D. vex" because of the vexing way in which it dominates marine ecosystems when introduced into new locations; however, the species epithet vexillum actually derives from the Latin word for flag, and the species was so named because of the way colonies' long tendrils appear to wave in the water like a flag.

Ciona savignyi is a marine animal sometimes known as the Pacific transparent sea squirt or solitary sea squirt. It is a species of tunicates in the family Cionidae. It is found in shallow waters around Japan and has spread to the west coast of North America where it is regarded as an invasive species.

Perophora viridis, the honeysuckle tunicate, is a species of colonial sea squirt in the genus Perophora found in the tropical western Atlantic Ocean.

Molgula citrina is a species of solitary tunicate in the family Molgulidae. It is found on both sides of the northern Atlantic Ocean and in the Arctic Ocean. In 2008 it was found in Kachemak Bay in Alaska, the first time it had been detected in the Pacific Ocean.

Polycarpa pomaria is a species of tunicate or sea squirt in the family Styelidae. It is native to the northeastern Atlantic Ocean where it lives on the seabed at depths down to about 450 metres (1,500 ft).

Dendrodoa grossularia is a species of tunicate or sea squirt in the family Styelidae, commonly known as the baked bean ascidian. It is native to the northeastern Atlantic Ocean where it is common in shallow water and on the lower shore in exposed rocky sites.

Boltenia villosa is a species of tunicate, a marine invertebrate of the family Pyuridae. Common names include spiny-headed tunicate, hairy sea squirt, stalked hairy sea squirt and bristly tunicate. This species was first described in 1864 by the American marine biologist William Stimpson who gave it the name Cynthia villosa. It was later transferred to the genus Boltenia. The type locality is Puget Sound, Washington state, United States.

Cnemidocarpa finmarkiensis is a species of solitary ascidian tunicate in the family Styelidae. Common names include broad base sea squirt, orange sea squirt, red sea squirt, shiny orange sea squirt, shiny red tunicate and Finmark's tunicate. It is native to shallow waters in the northern and northeastern Pacific Ocean.

Pyura haustor is a species of sessile ascidian, or sea squirt, that lives in coastal waters in the north-eastern Pacific Ocean, attached to rocks or artificial structures. Common names for this species include the wrinkled seapump, the wrinkled sea squirt and the warty tunicate.

Boltenia echinata, commonly known as the cactus sea squirt, is a species of tunicate, a marine invertebrate in the genus Boltenia of the family Pyuridae. It is native to the Arctic Ocean and the northern Atlantic Ocean.

Clavelina ossipandae, the skeleton panda sea squirt or skeleton panda ascidian, is a species of colonial ascidian, a group of sessile, marine filter-feeding invertebrates. Originally discovered near Kume Island in Japan by local divers, pictures of the animal attracted attention in the media for its appearance prior to its formal taxonomic description in 2024.

References

1 2 3 Gittenberger, Arjan (2019). "Halocynthia igaboja Oka, 1906". WoRMS. World Register of Marine Species . Retrieved 5 May 2019.
1 2 3 4 Cowles, Dave (2009). "Halocynthia igaboja Oka, 1906". Invertebrates of the Salish Sea. Retrieved 5 May 2019.
↑ Ruppert, Edward E.; Fox, Richard, S.; Barnes, Robert D. (2004). Invertebrate Zoology, 7th edition. Cengage Learning. p. 945. ISBN 978-81-315-0104-7.{{cite book}}: CS1 maint: multiple names: authors list (link)
↑ Young, Craig M. (1986). "Defenses and refuges: alternative mechanisms of coexistence between a predatory gastropod and its ascidian prey". Marine Biology. 91 (4): 513–522. doi:10.1007/BF00392603.
↑ Young, Craig M. (1988). "Ascidian cannibalism correlates with larval behavior and adult distribution". Journal of Experimental Marine Biology and Ecology. 117 (1): 9–26. doi:10.1016/0022-0981(88)90068-8.

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[WoRMS-1] 1 2 3 Gittenberger, Arjan (2019). "Halocynthia igaboja Oka, 1906". WoRMS. World Register of Marine Species . Retrieved 5 May 2019.

[WallaWalla-2] 1 2 3 4 Cowles, Dave (2009). "Halocynthia igaboja Oka, 1906". Invertebrates of the Salish Sea. Retrieved 5 May 2019.

[Ruppert-3] Ruppert, Edward E.; Fox, Richard, S.; Barnes, Robert D. (2004). Invertebrate Zoology, 7th edition. Cengage Learning. p. 945. ISBN 978-81-315-0104-7.{{cite book}}: CS1 maint: multiple names: authors list (link)

[4] Young, Craig M. (1986). "Defenses and refuges: alternative mechanisms of coexistence between a predatory gastropod and its ascidian prey". Marine Biology. 91 (4): 513–522. doi:10.1007/BF00392603.

[5] Young, Craig M. (1988). "Ascidian cannibalism correlates with larval behavior and adult distribution". Journal of Experimental Marine Biology and Ecology. 117 (1): 9–26. doi:10.1016/0022-0981(88)90068-8.

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