Styelidae

Family: Styelidae

Group: Marine Invertebrate, Species

Scientific Name	Common Name	Summary
Botrylloides violaceus	Chain tunicate	This invasive species is fairly common as a fouling organism on boat hulls, on mooring structures, and under docks. Any sighting in a remote setting, or further than half a mile from harbors, floathouses, and docks, should be reported as soon as convenient to the Alaska Department of Fish and Game, 1-877-INVASIV. This species can be identified thanks to the organization of its zooids into rows. each individual has one incurrent siphon, and those tend to be organized in parallel rows or elongated ovals. The colonies start flat, and eventually acquire lobes. The color varies from almost black to bright yellow. orange is the most common color. Colonies are a few square feet in area, and grow easily on everything from PVC to steel and ropes. Marine vomit (Didemnum vexillum), in contrast, generally does not appear to thrive on PVC or steel in our region.
Botryllus schlosseri	Golden star tunicate	This invasive species is fairly common as a fouling organism on boat hulls, on mooring structures, and under docks. Any sighting in a remote setting, or further than half a mile from harbors, floathouses, and docks, should be reported as soon as convenient to the Alaska Department of Fish and Game, 1-877-INVASIV. This species can be identified thanks to the organization of its zooids into stars, or circles. each individual has one incurrent siphon, and those tend to be organized in circles. The colonies are generally rather flat, with few lobes if any. The color varies from almost black to bright yellow. orange is the most common color. Colonies are generally not larger than a few square feet.
Cnemidocarpa finmarkiensis	Broadbase tunicate	This is a common species under rocks at low tide, and attached to man-made floating or hanging structures in harbors. It is often overlooked, however, because unlike Sea peach (Halocynthia aurantium) which is much like a little balloon, the broadbase tunicate turns into an orange-pink bump when it is out of the water. This leads many beachcombers to think that it is a non-descript blob, or a cryptic life stage of a better-known creature. When under water, however, the two siphons typical of the tunicates become evident, and it is quite a charming and unique species.
Metandrocarpa taylori	Orange Social Tunicate	Like all tunicates, this one is like us in that it has a notochord in the larval stage, but beyond that fun fact, it also is like strawberries in that it develops asexually via stolons. This places it in the colonial tunicates, but it really isn't colonial since it does not have a common tunic or excurrent siphon. It is a bit like Yellow social tunicate (Perophora annectens), except that that species is more transparent, lighter in color, and quite a bit smaller (Each M. taylori zooid is about half a millimeter high, as opposed to the three millimeters of the sea grapes). This species is usually orange, but can be yellowish. These are sometimes found as fouling organisms on floating man-made structures, but they are often so common on rocks at low tide as to smother parts of them, especially in recessed areas where large rocks are piled on top of each other and there is a fair bit of current.
Styela coriacea	Leathery Tunicate	looks a bit like Spiny-headed tunicate (Boltenia villosa), but without any hint of a stalk, like Sea Hedgehog (Halocynthia igaboja) without being truly hairy, like Warty tunicate (Pyura haustor) except for the long siphons, and like Cone tunicate (Styela truncata) without the tapering top and warty or ridged appearance. Doyne Kessler's book on "Alaska's Saltwater Fishes and Other Sea Life" may lead some naturalists to identify this species as Styela rustica. In our region, this refers to Styela rustica macrenteron, now accepted as Styela macrenteron, an apparently more northern subtidal species which can be distinguished by the greater average size, lack of branched spines, and presence of an apical spine.
Styela truncata	Cone tunicate	This species may be seen intertidally and on floating man-made structures. It is recognized by its orange siphons, irregular cone-shaped body, wide at the base, and narrow at the top, 3 centimeters long at the most (much shorter than most other species in this genus in the area). The tunic is lumpy and smooth, or lumpy and grooved, with the lumps nearer the top. When pulled out of the water, the cone-shaped animals tend to look crooked, and their siphons are almost invisible. When observed under a hand lens, the siphons are bright orange, and look like they are covered by four triangular flaps that leave an X pattern across the siphon where they meet.
Styela yakutatensis	Corrugated club tunicate	This solitary tunicate is reported as having stumpy bright red siphons, one of which bends over halfway to the side. It is club-shaped, about 5 cm tall, smaller and less warty than the unconfirmed invasive Styela clava. Specimens longer than 5cm should be reported, as they may be S. clava, or Styela montereyensis from further south.