Amphiporus Imparispinosus Class: Enopla, Hoplonemertea

Amphiporus imparispinosus Class: Enopla, Hoplonemertea

Order: Monostilifera, Eumonostilifera

Taxonomy: Overlapping species ranges Proboscis: Very long and contained within a and suggested synonymy exists between A. muscular sheath (rhynchocoel) which is al- imparispinosus and A. similis (=A. most as long as the total body length (genus imparispinosus var. similis) and A. leuciodus Amphiporus). The proboscis is armed with a (Coe 1901, 1905). For this reason, A. single stylet (suborder Monostilifera), in which imparispinosus is indicated as species the proximal end of the basal segment is inquirenda (identity requires further rounded and wide (Fig. 3). Three accessory investigation) (Gibson and Crandall 1989; stylet pouches are present, each containing Gibson 1995). two or more reserve stylets (Griffin 1898; Cor- rêa 1964; Stricker and Cloney 1982). (The Description proboscis must be everted or the worm dis- Size: Individuals are 25–50 mm in length sected to see the stylet and pouches.) and very slender (Coe 1905). Tube/Burrow: Amphiporus imparispinosus Color: Solid, opaque-white and sometimes does not inhabit a tube. pale reddish with yellowish tinge. Also pale yellow or flesh-colored. The brain area is Possible Misidentifications pink and intestinal canal brownish (Coe The locally represented (central CA 1905). to OR, Roe et al. 2007) hoplonemerteans General Morphology: Soft, elongate and (the free-living Enopla), with a central pro- not segmented (phylum Nemertea). boscis stylet (suborder Monostilifera), can Body: Long and slender, especially for the be divided into ten families (Chernyshev family Amphiporidae, and slightly flattened 2005). 1) The Ototyphlonemertidae have no posteriorly (Fig. 1). ocelli as adults and possess statocysts; 2) Anterior: Head not strongly differenti- the Emplectonometatidae have a short pro- ated from rest of body (Fig. 2). boscis, usually numerous ocelli (four or Posterior: Tapers to a blunt end. No more); 3) the Prosorhochmidae have a very caudal cirrus (Fig. 1). long, slender proboscis, usually two pairs of Eyes/Eyespots: Many, small eyes present large ocelli and a distinctive smile-like fold in two groups on each side of the head and on the head (the “smiling worms”, Maslako- are positioned anterior to brain. The first is va and Norenburg 2008); 4) The an elongated group of 6–15 ocelli found Tetrastemmatidae usually have four ocelli along the anterior margin. The second, a and are small or medium-sized nemerteans; posterior group of about the same number, 5) The Carcinonemertidae are small (but it can be up to 30) which is internal to nemerteans with 0–2 eyes and are parasitic the first group. Fewer eyes are present in on decapod crustaceans; 6) Neesidae (e.g. younger animals (Fig. 2). Paranemertes) and 7) Zygonemertidae are Mouth: Anterior to brain opens into probos- medium to large nemerteans with numerous cis pore (class Enopla) (Corrêa 1964). eyes; 8) Malacobdellidae include local

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]

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, Charles- ton, OR.

species which are commensal within the flatten, contract, and coil are useful as aids mantle cavity of bivalves; 9) Oerstediidae, to identification of live specimens. consisting of a single local species, are Ecological Information small with four eyes that can be doubled Range: Originally described from specimens (Chernyshev 2005); 10) the Amphiporidae collected in Puget Sound, Washington and have many eyes and are relatively short Alaska (Griffin 1898). Known northeastern and broad although A. imparispinosus is Pacific range from Siberia, Bering Sea and unusual in this respect (Coe 1940). south to Ensenada, Mexico. Amphiporus is There are at least eight species of particularly rare in the tropics (Coe 1940). Amphiporus reported in the Pacific North- Local Distribution: Coos Bay distribution at west, but there are likely more (Roe et al. several mudflats along the South Slough and 2007). Amphiporus formidabilis is the only also open coast sites at Cape Arago. other slender species that resembles A. Habitat: Among algae (e.g. red alga, Coralli- imparispinosus superficially, and can be na vancouveriensis) shells, mussels and other differentiable by 6–12 pouches of growths on rocks. Individuals can exist in accessory stylets, where A. imparispinosus very exposed and surf-swept shores (Coe has 2–3. It is also much larger than A. 1940). imparispinosus, 10–30 cm in length Salinity: Found on the open coast, at salini- (Haderlie 1975). Theother species are ties of 30. rather stout and more strongly colored. Temperature: Latitudinal range would indi- Amphiporus rubellus is a uniform red or cate a wide temperature tolerance, for exam- orange with no pattern and 10–20 ocelli on ple 10–20° C (San Pedro, CA.) to just above each side of its head. Amphiporus freezing (Bering Strait, AK). punctulatus is dark brown, irregularly Tidal Level: Intertidal and below to 50 m blotched on its dorsal surface, and with a (Corrêa 1964). lighter head marked with two dark spots. Associates: Amphiporus bimaculatus Abundance: One of the most common local (=Nipponnemertes bimaculatus) gets its Amphiporus species (Haderlie 1980). name from the same sort of strong spots (which are not ocelli) on its light-colored Life-History Information head. Its general coloration is Reproduction: The development of A. impar- homogenous, not blotchy as in A. ispinosus is not known. However, individuals punctulatus. Amphipours bimaculatus are likely dioecious (separate sexes) (Coe secretes great quantities of mucus when 1905) and some hoplonemerteans are disturbed (Haderlie 1980) and is known to hermaphroditic, with eggs and sperm readily evert its proboscis. A variety of A. released at same time. Ripe specimens of imparispinosus (A. i. similis, Coe, 1905) the congener, A. formidabilis, have been varies only by having two pouches of observed in winter and spring months accessory stylets not three (Coe 1940). (Washington, Stricker 1987) where oocytes Because of the many identifying were 250–350 µm in diameter surrounded by characteristics which are internal and not thick (up to 100 µm thick) egg jelly. Embryos visible, it is sometimes very difficult to dis- cleave after six hours, develop into morulae at tinguish among nemerteans without dis- 20 hours and are ciliated and swimming at 42 secting them. Ways in which the worms hours (9˚ C, Stricker 1987).

Larva: Planuliform and lecithotrophic A. tion citation, synonyms, current taxonomic formbidabilis larvae have an apical tuft and status, habitats and recorded zoogeo- swim for one day before settlement (9˚ C, graphic distribution. Journal of Natural His- Stricker 1987). tory. 29:271-562. Juvenile: 8. GIBSON, R., and F. B. CRANDALL. 1989. Longevity: The genus Amphiporus Ehrenberg Growth Rate: (Nemertea, Enopla, Monostiliferoidea). Zo- Food: Predatory, killing prey with an armed ologica Scripta. 18:453-470. proboscis that secretes toxins (Bacq 1936) 9. GRIFFIN, B. B. 1898. Description of some and kills prey before ingestion (Jennings and marine nemerteans of Puget Sound and Gibson 1969). Alaska. Annals of the New York Academy Predators: of Sciences. xi:pp. 193-218. Behavior: Does not swim or roll up spirally 10. HADERLIE, E. C. 1975. Phylum Nemertea (genus Amphiporus) (Coe 1905). (Rhynchocoela), p. 112-120. In: Light's manual: intertidal invertebrates of the cen- Bibliography tral California coast. S. F. Light, R. I. 1. BACQ, Z. M. 1936. Le poisons des nem- Smith, and J. T. Carlton (eds.). University ertiens. Bulletin of the Academie Royale of California Press, Berkeley. de Belgique. Classe des Sciences. 11. —. 1980. Polychaeta: The Marine annelid 5:1072-1079. worms, p. 448-489. In: Intertidal inverte- 2. CHERNYSHEV, A. V. 2005. System of brates of California. R. H. Morris, D. P. Ab- families of enoplan nemerteans of the bott, and E. C. Haderlie (eds.). Stanford order Eumonostilifera (Nemertea: Eno- University Press, Stanford, CA. pla). Russian Journal of Marine Biology. 12. JENNINGS, J. B., and R. GIBSON. 1969. 31:S27-S33. Observations on the nutrition of seven 3. COE, W. R. 1901. Papers from the Harri- species of Rhynchocoelan worms. Biologi- man Alaska Expedition. The Nemerte- cal Bulletin. 136:405-433. ans. Proceedings of the Washington 13. MASLAKOVA, S. A., and J. L. NOREN- Academy: 1-110. BURG. 2008. Revision of the smiling 4. —. 1905. Nemerteans of the west and worms, genus Prosorhochmus Keferstein, northwest coasts of North America. Bul- 1862, and description of a new species, letin of the Museum at Harvard College. Prosorhochmus belizeanus sp. nov. xlvii:1-318. (Prosorhochmidae, Hoplonemertea, Ne- 5. —. 1940. Revision of the nemertean fau- mertea) from Florida and Belize. Journal of na of the Pacific coasts of north, central Natural History. 42:1219-1260. and northern South America. Allan Han- 14. ROE, P., J. L. NORENBURG, and S. cock Pacific Expeditions. Reports. 2:247- MASLAKOVA. 2007. Nemertea, p. 221- 323. 233. In: Light and Smith manual: intertidal 6. CORRÊA, D. D. 1964. Nemerteans from invertebrates from Central California to Or- California and Oregon. Proceedings of egon. J. T. Carlton (ed.). University of Cali- the California Academy of Sciences fornia Press, Berkeley, CA. (series 4). 31:515-558. 15. STRICKER, S. A. 1987. Phylum Nemer- 7. GIBSON, R. 1995. Nemertean genera tea, p. 129-137. In: Reproduction and de- and species of the world: an annotated velopment of marine invertebrates of the checklist of original names and descrip- northern Pacific coast. University of Wash-

ington Press, Seattle, WA. 16. STRICKER, S. A., and R. A. CLONEY. 1982. Stylet formation in nemerteans. The Biological Bulletin. 162:387-403. Updated 2014 T.C. Hiebert