Phylum: Cnidaria Diadumene lineata Class: Anthozoa, Hexacorallia Order: Actiniaria, Enthemonae Orange-striped anemone Family: Metridioidea, Diadumenidae Taxonomy: Diadumene lineata was first de- smooth, low cylinder that tapers towards the scribed by Verrill in 1869 as Sagartia lineata. top and has vertical stripes (often 7-19) The subclass Zoantharia has been synony- (Fautin et al. 1987). Dark mesenteries show mized with Hexacorallia (Hoeksema 2015). through the column. It is dotted with cinclides Synonyms include Haliplanella luciae (portholes through which acontia can pro- (Fautin and Hand 2007). trude) that can be seen by the naked eye. The column is often scarred by longitudinal fission Description Medusa: No medusa stage in Anthozoans (asexual reproduction) (Hand 1955). Collar: The collar includes the Polyp: parapet and capitulum. The capitulum is the Size: A large specimen can be 30 top part of the anemone, separated from the mm high (Kozloff 1983). It is usually not column by the parapet (Fig. 2). The capitulum more than 20 mm high and 10 mm diameter is transparent, usually light green, and without (Fautin and Hand 2007) cinclides. There are tentacles around the up- Color: The color is variable; speci- per margin of the capitulum. The parapet is mens are usually green with single or double noticeable only when anemone is fully extend- vertical orange, white or yellow stripes ed, and rings the top of the column. (Fautin and Hand 2007), but they can have Oral Disc: The mouth is dark a brownish or olive column. Gonads are pink and ribbed. The ribs correspond to number of or orange and may be visible on the lower mesenteries. There are 0-3 siphonoglyphs column. Mesenteries appear as dark vertical (ciliated grooves on the ends of the mouth lines. Tentacles are usually colorless, that direct water into the pharynx) (none fig- though they can be gray to light green with ured). The margin is plain, rather than frilled white flecks (nematocysts) (Hand 1955). or lobed (Fautin and Hand 2007). A large area The oral disc is transparent and can appear of the disc around the mouth is tentacle-free, dark because of the dark interior. Lips are with radiating rows of white flecks on the en- dark gray. docoels (spaces between the pairs of mesen- Body: This anemone is cylindrical teries) (Hand 1955) (Fig. 4). with many fine long tentacles (Fig. 1). Mes- Tentacles: The number of ten- enteries divide the internal structure. Defen- tacles is greater than 24 but fewer than 100 sive tentacles called acontia can extend (Fautin and Hand 2007). They are retractile through pores called cinclides in the column. and smooth, short and blunt when contracted, The parapet rings the end of the column, and they are not capitate (knobbed). There from which the capitulum extends distally are only one kind, and there’s no oral ring of (Fig. 2). On the oral disc, specimens occa- tentacles. 2 pairs of "directives" (a kind of ten- sionally have ciliated grooves to direct water tacle close to the ends of mouth) (not figured) (siphonoglyphs) and spaces between the are typically present, but this can vary (Hand mesenteries (endocoels). 1955); when present, these tentacles are Column: The column is a A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: https://oimb.uoregon.edu/oregon-estuarine-invertebrates and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] Piazzola, C.D. and T.C. Hiebert. 2015. Diadumene lineata. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to Common Species, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biol- ogy, Charleston, OR. marked no differently than the others (Fautin dish, cream or brown. Other Diadumene spe- and Hand 2007). They can have up to 18 cies are not usually green (Fautin and Hand "catch" tentacles near the mouth, which are 2007). short, blunt and opaque (Williams 1975). If the specimen is orange striped "it This species has acontia, which are thread- can only be [D. lineata]” (Hand 1955). like defensive structures discharged through Ecological Information the column wall when the anemone is dis- Range: The type locality is Hong Kong harbor turbed (Fautin and Hand 2007). (Verrill 1869). This anemone is more wide- Mesenteries: Mesenteries are spread than any other anemone species vertical internal partitions (usually 6 in this (Fautin and Hand 2007), and has been found species) visible as dark vertical lines. There in Europe, North America, and Asia. It was are usually more mesenteries distally than likely introduced to Europe through the Suez near the base (Hand 1955). Gonads appear Canal in Egypt (Streftaris et al. 2005). In the as thickened bands on mesentery filaments. US Atlantic, it is found on the New England Pedal Disc: At the base, there coast, and on the Pacific it is found from the is a distinct pedal disc, which is circular and Puget Sound to California. It was likely intro- attaches to the substrate. duced to the US from Asia with oyster spat Cnidae: The cnidae are stinging or- (Ricketts et al. 1985). ganelles. There are several types present in Local Distribution: It is found in Oregon es- this species; on the acontia there are 3 kinds tuaries. Locally (in Coos Bay), it is found on (Fig. 5) (Haliplanellidae) (Hand 1955). the Charleston docks and in South Slough. Possible Misidentifications Habitat: Diadumene lineata lives high in the Metridium senile is another anemone intertidal on rocks and pilings, often in barna- found on docks and pilings. However, while cle tests and cracks in wood, in estuarine situ- D. lineata usually has a darker brown or ol- ations, but they have not been found on the ive-colored column and stripes, M. senile outer coast (Hand 1955; Fautin and Hand has a lighter white or gray column and lacks 2007). Specimens can tolerate a variety of stripes. Metridium senile is also often larger habitats, from rocks high in the intertidal to (if only by a centimeter or two) than D. line- eelgrass in mudflats (MacGinitie and MacGini- ata. tie 1968; Ricketts et al. 1985). They are often The anemone most likely to be con- found in fouling communities (Fautin and fused with Diadumene lineata is D. francis- Hand 2007). cana, which can be cream to light green with Salinity: This species is euryhaline (Ricketts white stripes. It has one pair of directive ten- et al. 1985), and adapts to variations in salini- tacles (long, retractable tentacles that point ty. toward the mouth), which are yellow at their Temperature: Diadumene lineata is euryther- bases, while D. lineata’s are identical to their mal, living in cold and temperate waters other tentacles (Fautin and Hand 2007). Di- (Ricketts et al. 1985; Fautin and Sebens adumene franciscana usually has 2 siphono- 1987). Contraction and encystment can occur glyphs, pink lips, a rough column, and often with extreme high temperatures (East Coast) an irregular base. Its parapet is poorly devel- (Williams 1975). oped compared to D. lineata’s. Tidal Level: Shallow waters, high in the inter- The Puget Sound Diadumene is not tidal. green but orange, yellowish, grayish, red- Associates: Metridium sp. are often found in A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: https://oimb.uoregon.edu/oregon-estuarine-invertebrates and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] conjunction with Diadumene lineata. They Growth Rate: Unknown are also found on the mussel Mytilus edulis Food: Diadumene lineata eats small crusta- with its accompanying fauna, and they have ceans and annelids (Hausmann 1919). been reported growing on the stems and Predators: In San Francisco Bay, the nudi- roots of the cordgrass Spartina alterniflora branch Cuthona perca eats Diadumene line- (Molina et al. 2009). ata (McDonald 2007). Other nudibranchs, like Abundance: This species is usually found in Hermissenda crassicornis, also eat this spe- clonal aggregations (Fautin and Hand 2007). cies (McDonald 2007). These aggregations can completely cover Behavior: The catch tentacles are used only the surface of logs or pilings. Though stable for stinging, not feeding, and serve to keep populations are present year-round, they anemones separate (Williams 1975). Diadu- can have a higher abundance in the summer mene is considered one of the faster anemo- (Molina et al. 2009). nes and, in some studies, has been reported moving three to four inches in an hour Life-History Information (MacGinitie and MacGinitie 1968). It also Reproduction: This specimen can repro- shows a sensitivity to light in laboratories, and duce both sexually and asexually, the latter will contract when exposed to bright lights by longitudinal fission of the column or pedal (MacGinitie and MacGinitie 1968). laceration (Haderlie et al. 1980). Pedal lacer- ation occurs when the anemone spreads out Bibliography its base and then tears itself away at the 1. FAUTIN, D. G., and C. HAND. 2007. An- center, leaving parts of the outer base at- thozoa, p. 173-184. In: The Light and tached to the substrate that can then mature Smith Manual: intertidal invertebrates from into clonal anemones (MacGinitie and Mac- central California to Oregon. J. T. Carlton Ginitie 1968). This process can only occur (ed.). University of California Press, Berke- when the anemone is well-fed and relatively ley. large, and it usually takes many hours 2. FAUTIN, D. G., and K. P. SEBENS. 1987. (MacGinitie and MacGinitie 1968). Its suc- Phylum Cnidaria, Class Anthozoa, p. 83- cess is largely due to its ability to colonize 104. In: Reproduction and development of quickly (Hausmann 1919; Ricketts et al.