Magelona Sacculata Class: Polychaeta, Polychaeta Incertae Sedis

Phylum: Annelida

Magelona sacculata Class: Polychaeta, Polychaeta incertae sedis

Order: A burrowing polychaete Family: Magelonidae

Description tween setigers 10–11 (although more com- Size: Individuals range in size from 20–30 monly 9–10, Blake 2000) and irregularly along mm in length and 0.7–1.5 mm in width with abdomen. These are lateral and open anteri- approximately 100 segments (Hartman orly (Fig. 3) (species sacculata, Blake 1975). 1961). The illustrated specimen (from Coos Posterior: Pygidium tapers and bears Bay) is 30 mm long with 50–80 segments a pair of slender anal cirri (Hartman 1969) and comprises the following description. (Fig. 1a). Color: Ivory, with paired dorsal lavender Parapodia: Begin on setiger one (segment spots (Hartman 1961; Blake 2000). The two). First eight setigers have biramous para- purple color is due to hemerythrin-containing podia, with pointed setae in both rami (Fig. 6). hemocytes, which are unique to magelonids Thoracic setigers 1–8 biramous with noto- (Ruppert et al. 2004). and neuropodia foliaceous and elevated. General Morphology: Long, slender and Thoracic notopodia bear dorsal medial lobe threadlike body bearing extremely long with lateral lamellae while neuropodia have a palps anteriorly with a flattened or shovel- ventral lobe (Blake 2000). Setiger nine with like anterior for burrowing (Blake and Ruff specialized setae (unlike those of setigers 1– 2007). 8) and conspicuous lateral lamellae. Body: Body separated into thoracic, consist- Abdominal parapodia have small dorsal and ing of prostomium, peristomium and the first ventral medial lobes and broad, lateral nine setigers, followed by a distinct ab- lamellae where notch is produced as noto- dominal region. First segment is a smooth and neuropodial lamellae almost overlap (Fig. ring and setiger nine is short (Figs. 1, 3). 5). Lateral pouches present between setigers Setae (chaetae): Several types of setae are nine and 11 (species sacculata) (Blake observed: (1) limbate (simple, capillary, with 2000) (Figs. 1, 3). Body musculature is flattened margin which can be pennoned and cross-striated (Ruppert et al. 2004). is found in both rami in setigers 1–9 and ab- Anterior: Prostomium transparent, dominal notopodia (Fig. 6), (2) crenulate se- flattened, shovel-shaped (Fauchald 1977) tae (clubbed, like a molar), found as special- and often much wider than rest of body. An- ized setae on setiger nine (Jones 1963) (Figs. terior tip rounded, with slight medial ridge 4, 7), (3) mucronate (sharp tip and abruptly (Fig 2). Prostomium widens posteriorly and tapered) found as specialized setae, also on has two strong muscles supporting it from setiger nine (but not on these specimens, Fig. below. Prostomium width can be equal to or 8) and (4) hooded hooks (each with a large greater than length (Jones 1963; Blake fang and two small teeth), of uniform size 2000), but this is not true for our specimens. (species sacculata, Hartman and Reish 1950) Peristomium thicker and greater in length found only abdominally (Blake 2000) (Fig. 9). than setiger one (Blake 2000). Eyes/Eyespots: None. Trunk: Lateral pouches found be- Anterior Appendages: No horns or

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. Magelona sacculata. 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.

appendages, but with a ventral pair of matidae have short thoracic and very long conspicuous, elongate papillate palps abdominal setigers. They have a prostomi- (family Magelonidae). Palps are long um without appendages and a pair of palps (extending to setiger 26), adhesive and as well as filiform branchiae on the thorax. coarsely papillated (Hartman 1961; Blake They do not inhabit the intertidal zone. Poe- 2000). They are attached ventrally at the cilochaetidae are spionids with long, slender junction of peri- and prostomiums (Fauchald bodies. They have a small prostomium with 1977). a single antenna and palps and their para- Branchiae: None. podia have prominent dorsal and ventral cir- Burrow/Tube: Magelonids are good burrow- ri. ers (see Behavior), but do not inhabit a per- Magelona is one of three genera in manent tube or burrow. the family Magelonidae where there are 70 Pharynx: Bears proboscis which is smooth described species (Clark et al. 2010). Mem- and globular when everted (Hartman 1961). bers of the genus Meredithia (Hernández- Genitalia: Alcántara & Solis-Weiss, 2000) possess Nephridia: large hooded and curved spines in some abdominal setigers (Clark et al. 2010). The Possible Misidentifications genus Ocomagelona (Aquirrezabalaga et al. There are three other large, com- 2001) is characterized by eight thoracic seti- mon families of the order Spionida. The gers (instead of nine) (Clark et al. 2010). Spionidae, a very numerous and diverse The characters which are used to dif- group is characterized by grooved palps. ferentiate members of the genus Magelona Unlike Magelonidae, they have palps include the prostomium morphology (size which are not papillate, adhesive, or exce- and presence or absence of frontal horns), edingly long. Their prostomiums are not presence or absence of medial lobes on flattened and they often have eyes, nuchal thoracic notopodia, position or presence of tentacles and/or branchiae, where magelo- lateral pouches, modified setal morphology nids do not. Cirratulidae have long palps on setiger nine, morphology of abdominal and long, filamentous gills, which are hooded hooks, abdominal medial lamellae lacking in the Magelonidae. The and the presence or absence and morpholo- Chaetopteridae, also a Spionida family, gy of inter lamellae on abdominal parapodia have very distinct body regions, thick (Blake and Ruff 2007). Magelona sacculata spines on setiger four, and often have fan- is unique in having large, lateral open like medial parapodia. Their tubes are pouches between setigers 10 and 11, parchment-like or annulated (Fauchald uniform hooded hooks on the abdominal 1977). parapodia and mucronate or crenulate Trochochaetidae and Longoso- specialized setae on setiger nine. matidae (= Heterospionidae) are small, ob- Other species in the genus include: scure spionid families each containing only Magelona pacifica (Monro, 1933), seemingly one genus. Trochochaetidae have bodies a southern species, is unlikely to be found in divided into two regions, a large flattened Oregon (Hartman 1969). Magelona cerae prostomium with a pair of palps, a single (Hartman 1950; Hartman and Reish 1950) occipital tentacle and two pairs of parapo- was found at depths of 37-73 m off Coos dia directed forward. Like the Mageloni- Bay forming beds in sand , but further dae, they are not tube dwellers. Longoso- reports of this species are lacking.

Individuals are up to 10 mm in length, the but it has no specialized setae on the ninth prostomium has slight, blunt horns at the setiger (Blake 2000). Magelona berkeleyi is corners. The thoracic notopodia have a reported from central California to dorsal cirrus which disappears by the ninth Washington (Blake 2000). segment. Each of the abdominal hooded Ecological Information hooks has one large fang with a small Range: Type locality is San Pedro Shelf, Cali- tooth above it. Magelona californica fornia (Hartman 1969). NE Pacific distribution (Hartman, 1944), although found in ranges from British Columbia (Hobson and southern California, is considered a Banse 1981) to southern California (Hartman northeastern Pacific species by Hartman 1969). (1969). It has a rounded prostomium like Local Distribution: Oregon distribution, Ya- that of M. sacculata, but it lacks lateral quina Bay and Umpqua estuaries. Coos Bay pouches and its abdomen is abruptly wider sites include the inner bay and South Slough. than the thorax (Hartman 1969). Magelona Habitat: Fine sands, silt (Blake 1975) and pitelkai (Hartman, 1944), has been sandy mud in Coos Bay (South Slough). reported from Coos Bay as well as Builds poorly supported burrows with no Washington and British Columbia, but its distinct or permanent tube. identify has not been confirmed (Jones Salinity: Found at salinities of 30 in Coos 1978). This is a large species with 54 Bay. segments reaching 35 mm in length. The Temperature: prostomium has a truncate margin and the Tidal Level: More likely to be found subtidally special setae on setiger nine have than intertidally in Oregon. Occurs subtidal to pennoned tips, not mucronate ones. 50 m in southern California (Hartman 1969; Magelona pitelkai lacks lateral pouches Blake 2000). and is the most common magelonid in Associates: central and northern California (Blake Abundance: Considered rare from central 1975). Magelona pitelkai can be California to Oregon, where M. pitelkai is distinguished from M. sacculata in that the more common (Blake and Ruff 2007). How- former species has small, deeply ever, in Oregon it may be the most common embedded and modified hooks in addition magelonid. to the larger hooks. Magelona sacculata, on the other hand has only one hook type Life-History Information (Blake 2000). Magelona longicornis Reproduction: The development of M. sac- (Johnson, 1901), (=M. japonica Okuda, culata is not known. Wilson (1982) described 1937 (Jones 1971)) has prostomial horns, the development of three magelonid species lateral parapodial lamellae in setigers 1–8, from the southern coast of England including no modification on the ninth parapodium, Magelona alleni, M. filiformis and M. mirabilis. bidentate hooded hooks (Jones 1971) and Among these three species, which reproduce no lateral pouches. This species is the one by broadcast spawning, oocyte diameters most likely to be found in Puget Sound ranged from 100–150 µm in diameter with (Kozloff 1974). Magelona berkeleyi (Jones, natural spawning speculated in late summer 1971) has inconspicuous anterior prosto- (August), near Plymouth, England (Wilson mial horns, extended lateral lamellae on its 1982; Blake 2006). parapodia and no lateral pouches. Like M. Larva: Magelonid larvae are pelagic. They sacculata, it has tridentate hooded hooks, are recognizable by long anterior larval tenta-

cles that coil (Wilson 1982; Crumrine 2001; productive Biology and Phylogeny of An- Pernet et al. 2002), reaching lengths of or nelida. G. Rouse and R. Pleijel (eds.). Sci- exceeding the larval body length. Magelonid ence Publishers, Enfield, New Hampshire. larvae also have two bunches of long setae 3. BLAKE, J. A., and R. E. RUFF. 2007. Pol- (four in each bunch, Wilson 1982) that arise ychaeta, p. 309-410. In: The Light and from chetal sacs just below the larval tenta- Smith Manual: Intertidal Invertebrates from cles. The three Magelona species with de- Central California to Oregon. J. T. Carlton scribed development (Wilson 1982) devel- (ed.). University of California Press, Berke- oped into trochophore larvae after about a ley, CA. day. In these species, Wilson (1982) noted 4. CLARKE, D. T., G. L. J. PATERSON, W. the elongation of the prototrochal region (= K. FLORENCE, and M. J. GIBBONS. tentacles) and two eyes once larvae were 2010. A new species of Magelona three days old. An unidentified megalonid (Polychaeta: Magelonidae) from southern larva is commonly seen in plankton samples Namibia. African Natural History. 6:77-82. in Coos Bay which may be the larva of M. 5. CRUMRINE, L. 2001. Polychaeta, p. 39- cercae (Crumrine 2001) or M. sacculata. 77. In: Identification Guide to Larval Ma- (http://invert-embryo.blogspot.com/2010/05/ rine Invertebrates of the Pacific Northwest. nechtochaete-larva-of-polychaete.html). A. Shanks (ed.). Oregon State University Juvenile: Press, Corvallis, OR. Longevity: 6. FAUCHALD, K. 1977. The polychaete Growth Rate: worms: definitions and keys to the orders, Food: A motile surface deposit feeder which families, and genera. Natural History Mu- chooses large particles of detritus and dia- seum of Los Angeles County Science Se- toms. Small crustaceans are captured on ries. 28:1-190. papillated surface of palps. A looping motion 7. FAUCHALD, K., and P. A. JUMARS. moves food up the palp and mucus may 1979. Diet of worms: a study of polychaete help final movement into mouth. Some sus- feeding guilds. Oceanography and Marine pension feeding may also take place. Biology. 17:193-284. Magelonid larvae feed on veligers (Fauchald 8. HARTMAN, O. 1961. Polychaetous anne- and Jumars 1979, Johnson and Brink 1998). lids from California. University of Southern Predators: California Press, Los Angeles, CA. Behavior: Megalona sacculata is a good 9. —. 1969. Atlas of the Sedentariate Poly- burrower which is aided by its shovel-like chaetous Annelids from California. Allan head. Hancock Foundation, University of South- ern California, Los Angeles, CA. Bibliography 10. HARTMAN, O., and D. J. REISH. 1950. 1. BLAKE, J. A. 2000. Family Mageloidae The Marine Annelids of Oregon. Oregon Cunningham and Ramage, 1888, p. 253- State College, Corvallis, Oregon. 261. In: Taxonomic Atlas of the Benthic 11. HOBSON, K. D., and K. BANSE. 1981. Fauna of the Santa Maria Basin and Sedentariate and archiannelid polychaetes Western Santa Barbara Channel. J. A. of British Columbia and Washington. Ca- Blake, B. Hilbig, and P. H. Scott (eds.). nadian Bulletin of Fisheries and Aquatic Santa Barbara Museum of Natural Histo- Sciences. 209:1-144. ry, Santa Barbara, CA. 12. JOHNSON, K. B., and L. A. BRINK. 1998. 2. —. 2006. Spionida, p. 565-638. In: Re- Predation on bivalve veligers by poly-

chaete larvae. Biological Bulletin. 194:297-303. 13. JONES, M. L. 1963. Four new species of Magelona (Annelida, Polychaeta) and a redescription of Magelona longicornis Johnson. American Museum of Natural History, New York, N.Y. 14. —. 1971. Magelona berkeleyi n.sp. from Puget Sound (Annelida: Polychaeta), with a further redescription of Magelona longicornis Johnson and a consideration of recently described species of Magelo- na. Journal of the Fisheries Research Board of Canada. 28:1445-1454. 15. —. 1978. Three new species of Magelo- na (Annelida, Polychaeta) and a description of Magelona pitelkai. Proceedings of the Biological Society of Washington. 91:336-363. 16. KOZLOFF, E. N. 1974. Keys to the Ma- rine Invertebrates of Puget Sound, the San Juan Archipelago, and Adjacent Re- gions. University of Washington Press, Seattle. 17. PERNET, B., P. Y. QIAN, G. ROUSE, C. M. YOUNG, and K. J. ECKELBARGER. 2002. Phylum Annelida: Polychaeta. In: Atlas of Marine Invertebrate Larvae. C. M. Young, M. A. Sewell, and M. E. Rice (eds.). Academic Press, San Diego, CA. 18. RUPPERT, E. E., R. S. FOX, and R. D. BARNES. 2004. Invertebrate Zoology: A Functional Evolutionary Approach. Thomson Brooks/Cole, Belmont, CA. 19. WILSON, D. P. 1982. The Larval development of three species of Magelona (Polychaeta) from localities near Plym- outh. Journal of the Marine Biological As- sociation of the United Kingdom. 62:385- 401.

Updated 2014 T.C. Hiebert