Amphiporus Imparispinosus Class: Enopla Order: Hoplonemertea, Monostylitera Family: Amphiporidae

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Phylum: Nemertea Amphiporus imparispinosus Class: Enopla Order: Hoplonemertea, Monostylitera Family: Amphiporidae

Taxonomy: Overlapping species ranges and the proximal end of the basal segment is suggested synonymy exists between A. rounded and wide (Fig. 3). Three accessory imparispinosus and A. similis (=A. stylet pouches are present, each containing imparispinosus var. similis) and A. leuciodus two or more reserve stylets (Griffin 1898; (Coe 1901, 1905). For this reason, A. Corrêa 1964; Stricker and Cloney 1982). (The imparispinosus is indicated as species proboscis must be everted or the worm inquirenda (identity requires further dissected to see the stylet and pouches.) investigation) (Gibson and Crandall 1989; Tube/Burrow: Amphiporus imparispinosus Gibson 1995). does not inhabit a tube.

Description Possible Misidentifications Size: Individuals are 25–50 mm in length and The locally represented (central CA very slender (Coe 1905). to OR, Roe et al. 2007) hoplonemerteans Color: Solid, opaque-white and sometimes (the free-living Enopla), with a central pale reddish with yellowish tinge. Also pale proboscis stylet (suborder Monostilifera), yellow or flesh-colored. The brain area is pink can be divided into ten families (Chernyshev and intestinal canal brownish (Coe 1905). 2005). 1) The Ototyphlonemertidae have General Morphology: Soft, elongate and not no ocelli as adults and possess statocysts; segmented (phylum Nemertea). 2) the Emplectonometatidae have a short Body: Long and slender, especially for the proboscis, usually numerous ocelli (four or family Amphiporidae, and slightly flattened more); 3) the Prosorhochmidae have a very posteriorly (Fig. 1). long, slender proboscis, usually two pairs of Anterior: Head not strongly large ocelli and a distinctive smile-like fold differentiated from rest of body (Fig. on the head (the “smiling worms”, 2). Maslakova and Norenburg 2008); 4) The Posterior: Tapers to a blunt end. No Tetrastemmatidae usually have four ocelli caudal cirrus (Fig. 1). and are small or medium-sized nemerteans; Eyes/Eyespots: Many, small eyes present in 5) The Carcinonemertidae are small two groups on each side of the head and are nemerteans with 0–2 eyes and are parasitic positioned anterior to brain. The first is an on decapod crustaceans; 6) Neesidae (e.g. elongated group of 6–15 ocelli found along Paranemertes) and 7) Zygonemertidae are the anterior margin. The second, a posterior medium to large nemerteans with numerous group of about the same number, (but it can eyes; 8) Malacobdellidae include local be up to 30) which is internal to the first species which are commensal within the group. Fewer eyes are present in younger mantle cavity of bivalves; 9) Oerstediidae, animals (Fig. 2). consisting of a single local species, are Mouth: Anterior to brain opens into proboscis small with four eyes that can be doubled pore (class Enopla) (Corrêa 1964). (Chernyshev 2005); 10) the Amphiporidae Proboscis: Very long and contained within a have many eyes and are relatively short and muscular sheath (rhynchocoel) which is broad although A. imparispinosus is unusual almost as long as the total body length (genus in this respect (Coe 1940). Amphiporus). The proboscis is armed with a There are at least eight species of single stylet (suborder Monostilifera), in which Amphiporus reported in the Pacific

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Northwest, but there are likely more (Roe et exist in very exposed and surf-swept shores al. 2007). Amphiporus formidabilis is the (Coe 1940). only other slender species that resembles Salinity: Found on the open coast, at A. imparispinosus superficially, and can be salinities of 30. differentiable by 6–12 pouches of accessory Temperature: Latitudinal range would stylets, where A. imparispinosus has 2–3. It indicate a wide temperature tolerance, for is also much larger than A. imparispinosus, example 10–20° C (San Pedro, CA.) to just 10–30 cm in length (Haderlie 1975). above freezing (Bering Strait, AK). Theother species are rather stout and more Tidal Level: Intertidal and below to 50 m strongly colored. Amphiporus rubellus is a (Corrêa 1964). uniform red or orange with no pattern and Associates: 10–20 ocelli on each side of its head. Abundance: One of the most common local Amphiporus punctulatus is dark brown, Amphiporus species (Haderlie 1980). irregularly blotched on its dorsal surface, and with a lighter head marked with two Life-History Information dark spots. Amphiporus bimaculatus Reproduction: The development of A. (=Nipponnemertes bimaculatus) gets its imparispinosus is not known. However, name from the same sort of strong spots individuals are likely dioecious (separate (which are not ocelli) on its light-colored sexes) (Coe 1905) and some head. Its general coloration is hoplonemerteans are hermaphroditic, with homogenous, not blotchy as in A. eggs and sperm released at same time. Ripe punctulatus. Amphipours bimaculatus specimens of the congener, A. formidabilis, secretes great quantities of mucus when have been observed in winter and spring disturbed (Haderlie 1980) and is known to months (Washington, Stricker 1987) where readily evert its proboscis. A variety of A. oocytes were 250–350 µm in diameter imparispinosus (A. i. similis, Coe, 1905) surrounded by thick (up to 100 µm thick) egg varies only by having two pouches of jelly. Embryos cleave after six hours, develop accessory stylets not three (Coe 1940). into morulae at 20 hours and are ciliated and Because of the many swimming at 42 hours (9˚ C, Stricker 1987) identifying characteristics which are Larva: Planuliform and lecithotrophic A. internal and not visible, it is sometimes formbidabilis larvae have an apical tuft and very difficult to distinguish among swim for one day before settlement (9˚ C, nemerteans without dissecting them. Stricker 1987). Ways in which the worms flatten, Juvenile: contract, and coil are useful as aids to Longevity: identification of live specimens. Growth Rate: Food: Predatory, killing prey with an armed Ecological Information proboscis that secretes toxins (Bacq 1936) Range: Originally described from specimens and kills prey before ingestion (Jennings and collected in Puget Sound, Washington and Gibson 1969). Alaska (Griffin 1898). Known northeastern Predators: Pacific range from Siberia, Bering Sea and Behavior: Does not swim or roll up spirally south to Ensenada, Mexico. Amphiporus is (genus Amphiporus) (Coe 1905). particularly rare in the tropics (Coe 1940). Local Distribution: Coos Bay distribution at Bibliography several mudflats along the South Slough and also open coast sites at Cape Arago. 1. BACQ, Z. M. 1936. Le poisons des Habitat: Among algae (e.g. red alga, nemertiens. Bulletin of the Academie Corallina vancouveriensis) shells, mussels Royale de Belgique. Classe des and other growths on rocks. Individuals can Sciences. 5:1072-1079.

Hiebert, T.C. 2015. Amphiporus imparispinosus. 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 Biology, Charleston, OR. 2. CHERNYSHEV, A. V. 2005. System of 12. JENNINGS, J. B., and R. GIBSON. families of enoplan nemerteans of the 1969. Observations on the nutrition of order Eumonostilifera (Nemertea: seven species of Rhynchocoelan Enopla). Russian Journal of Marine worms. Biological Bulletin. 136:405- Biology. 31:S27-S33. 433. 3. COE, W. R. 1901. Papers from the 13. MASLAKOVA, S. A., and J. L. Harriman Alaska Expedition. The NORENBURG. 2008. Revision of the Nemerteans. Proceedings of the smiling worms, genus Prosorhochmus Washington Academy: 1-110. Keferstein, 1862, and description of a 4. —. 1905. Nemerteans of the west and new species, Prosorhochmus northwest coasts of North America. belizeanus sp. nov.(Prosorhochmidae, Bulletin of the Museum at Harvard Hoplonemertea, Nemertea) from College. xlvii:1-318. Florida and Belize. Journal of Natural 5. —. 1940. Revision of the nemertean History. 42:1219-1260. fauna of the Pacific coasts of north, 14. ROE, P., J. L. NORENBURG, and S. central and northern South America. MASLAKOVA. 2007. Nemertea, p. Allan Hancock Pacific Expeditions. 221-233. In: Light and Smith manual: Reports. 2:247-323. intertidal invertebrates from Central 6. CORRÊA, D. D. 1964. Nemerteans California to Oregon. J. T. Carlton from California and Oregon. (ed.). University of California Press, Proceedings of the California Berkeley, CA. Academy of Sciences (series 4). 15. STRICKER, S. A. 1987. Phylum 31:515-558. Nemertea, p. 129-137. In: 7. GIBSON, R. 1995. Nemertean genera Reproduction and development of and species of the world: an annotated marine invertebrates of the northern checklist of original names and Pacific coast. University of description citation, synonyms, current Washington Press, Seattle, WA. taxonomic status, habitats and 16. STRICKER, S. A., and R. A. CLONEY. recorded zoogeographic distribution. 1982. Stylet formation in nemerteans. Journal of Natural History. 29:271-562. The Biological Bulletin. 162:387-403. 8. GIBSON, R., and F. B. CRANDALL. 1989. The genus Amphiporus Ehrenberg (Nemertea, Enopla, Monostiliferoidea). Zoologica Scripta. 18:453-470. 9. GRIFFIN, B. B. 1898. Description of some marine nemerteans of Puget Sound and Alaska. Annals of the New York Academy of Sciences. xi:pp. 193- 218. 10. HADERLIE, E. C. 1975. Phylum Nemertea (Rhynchocoela), p. 112- 120. In: Light's manual: intertidal invertebrates of the central California coast. S. F. Light, R. I. Smith, and J. T. Carlton (eds.). University of California Press, Berkeley. 11. —. 1980. Polychaeta: The Marine annelid worms, p. 448-489. In: Intertidal invertebrates of California. R. H. Morris, D. P. Abbott, and E. C. Haderlie (eds.). Stanford University Press, Stanford, CA.