Abarenicola Pacifica Phylum: Annelida Class: Polychaeta Order: Capitellida the Lugworm, Or Sand Worm Family: Arenicolidae

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Abarenicola pacifica Phylum: Annelida Class: Polychaeta Order: Capitellida The lugworm, or sand worm Family: Arenicolidae

Description reddish and are far from the lateral line. All Size: Individuals often over 10 cm long and 1 parapodia are absent in the caudal region. cm wide. Present specimen is approximately Setae (chaetae): (Fig. 3) Bundles of 4 cm in length (from South Slough of Coos notosetae arise from notopodia near Bay). On the West coast, average length is branchiae. Short neurosetae extend along 15 cm (Ricketts and Calvin 1971). neuropodium. Setae present on segments 1- Color: Head and abdomen orange, body a 19 only (Blake and Ruff 2007). mixture of yellow, green and brown with Eyes/Eyespots: None. parapodial areas and branchiae red (Kozloff Anterior Appendages: None. 1993). Branchiae: Prominent and thickly tufted in General Morphology: A sedentary branchial region with bunched setae. polychaete with worm-like, cylindrical body Hemoglobin makes the branchiae appear that tapers at both ends. Conspicuous bright red (Kozloff 1993). segmentation, with segments wider than they Burrow/Tube: Firm, mucus impregnated are long and with no anterior appendages burrows are up to 40 cm long, with typical (Ruppert et al. 2004). Individuals can be fecal castings at tail end. Head end of burrow identified by their green color, bulbous is collapsed as worm continually consumes pharynx (Fig. 1), large branchial gills (Fig. 2) mud (Healy and Wells 1959). Water is and a J-shaped burrow marked at the surface pumped through burrow by pulsating with distinctive coiled fecal castings (Kozloff movements of the body (Ruppert et al. 2004). 1993). Pharynx: Thin-walled pharynx is simple and Body: The body of arenicolids can be divided used for continually feeding on sediment. into three regions based on the presence or Pharynx described as a large, eversible sack absence of branchiae. with mucus glands called buccal papillae Anterior: A non-retractile prostomium (Healy and Wells 1959) (Fig. 1). is without appendages (Blake and Ruff Genitalia: 2007, Fig. 2). Anterior prebranchial Nephridia: Five pairs of nephridia are naked region of six setigers without (without hoods) and situated between branchiae and with strong setigerous parapodia on segments 5–9 (Fig. 2). They annuli. are sometimes difficult to observe. Trunk: Posterior to the prebranchial region is a medial branchial region Abarenicola specific characters with large branchial gills from setigers Esophageal caeca: Dissection is necessary seven to 19 (13 pairs). Thoracic to identify Abarenicola species. Abarenicola epidermis very thick, strongly pacifica is distinct in having esophageal aerolated (Fauchald 1977). caeca comprised of one large anterior pair Posterior: Caudal region is apodous, and 3–6 smaller pairs (Blake and Ruff 2007, asetigerous and without appendages. Fig. 4). The pygidium tapers gradually to anus, no appendages (Fig. 2). Possible Misidentifications Parapodia: (Fig. 3) Segments 1–19 with Other Arenicolidae have the same bushy gills reduced noto- and neuropodia that are in the middle third of the body. Only the genus Abarenicola has well-separated

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12654 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to [email protected] neuropodia, a non-retractile prostomium, Associates: In a commensal relationship, more than one pair of esophageal caeca, and Pinnixa schmitti is known to cohabit the five pairs of nephridiopores. Both Arenicola burrow of A. pacifica (O’Clair and O’Clair marina and pusilla have been found in 1998). Oregon estuaries. Abarenicola claparedii Abundance: Often to 50/m2 (Kozloff 1974) oceanica, has hooded nephridial pores and and very dense in specialized habitats. esophageal caeca composed of 7–9 smaller Probably 2nd most abundant macroscopic pairs. Abarenicola vagabunda, from Puget animal in Coos Bay (Porch 1970). A. pacifica Sound (but possibly from Oregon) (Oglesby was much less abundant than in preceding 1973), is usually larger and dark brown. It years-- it was sparse (<1/m2) on Portside too, has hooded nephridial pores, and smaller beach in April 2015 (Emlet pers com). esophageal caeca (11–18). Finally, the burrows of A. vagabunda are less permanent Life History Information than A. pacifica's, are found in deep sand and Reproduction: Iteroparous. Eggs and sperm may be more subtidal (Hobson 1966). discharged from nephridiopores, while both sexes are in their burrows. Males release thin Ecological Information membranous spermatophores (0.5–0.2 mm in Range: Type locality is Puget Sound (Healy diameter) which fall into female burrows and and Wells, 1959). Known range includes are ruptured by female setae (Okuda 1936; Humboldt Bay, California to Alaska, Japan. Fernald et al. 1987). Oocytes are pink to pale Local Distribution: A north Pacific form and yellow and 160-190 µm in diameter with the most common lugworm (family conspicuous envelope (Fernald et al. 1987). Arenicolidae) in Puget Sound area intertidally Fertilization occurs in female's burrow. (Hobson 1966). Found in Coos Bay from Broods are found within burrows January- estuary mouth to Coos River mouth (marker early April (Washington) and develop within 15) and at Sunset Bay (Oglesby 1973). gelatinous masses (Fernald et al. 1987). Habitat: Individuals build substantial L- or J- Larva: Planktonic larvae are non-feeding and shaped burrows in sand and mud, mixed hatch from gelatinous masses within adult gravel or mud sediments (South Slough of tubes as 2 setiger stages (Fernald et al. Coos Bay) (Kozloff 1974). Abarenicola 1987). Only the larvae of two local pacifica tolerates a muddier, less permeable, Arenicolidae species are known (Arenicola more poorly sorted sediment than does A. c. marina and Abarenicola claparedii, Crumrine vagabunda (Hobson 1966), but does not live 2001). in very soft mud (Porch 1970). Juvenile: Salinity: This species is not found in waters Longevity: of low salinity or in heavily polluted anaerobic Growth Rate: Relative growth rate of 0–6% conditions (Porch 1970), but is an per day, depending on age and food quality osmoconformer and can tolerate a wide range (Linton and Taghon 2000). of salinities (lower salinity limit 17.5) (Oglesby Food: Primarily detritus, picked up by mucus 1973). of proboscis (Fig. 1) and digested out of sand Temperature: No information is available on and mud, which is then defecated. temperature tolerance, though temperature Depending on sediment type, A. pacificia may fluctuation between 6 and 16° C has been utilize a variety of feeding modes (deposit, found to significantly affect feeding rate suspension, direct dissolved organic matter (Hymel and Plante 2000). uptake) (Hylleberg 1975). Feeding activity by Tidal Level: Individuals are common Abarenicola pacifica is instrumental in intertidally, but no information on specific tide bioturbation and generation of clay laminae level is available. Hobson (1967) suggests (Swinbanks 1981). that distribution is instead based on sediment Predators: Arenicolids have many predators composition. including most estuarine creatures: man (for fish bait), birds, fish.

Hiebert, T.C. 2014. Abarenicola pacifica. 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. Behavior: Most research into the behavior of concentration. Marine Biology. A. pacific is focused on bioturbation and 136:1019-1027. particle selection (Hylleberg 1975). 9. HYLLEBERG, J. 1975. Selective feeding by Abarenicola pacifica with Bibliography notes on Abarenicola and a concept of gardening in lugworms. Ophelia. 1. BLAKE, J. A., and E. R. RUFF. 2007. 14:113-137. Polychaeta, p. 309-410. In: Light and 10. KOZLOFF, E. 1993. Seashore life of Smith manual: intertidal invertebrates the northern Pacific coast: an from central California to Oregon. J. illustrated guide to northern California, Carlton (ed.). University of California Oregon, Washington, and British Press, Berkeley, CA. Columbia. University of Washington 2. CRUMRINE, L. 2001. Polychaeta, p. Press, Seattle, WA. 39-77. In: Identification guide to larval 11. KOZLOFF, E. N. 1974. Keys to the marine invertebrates of the Pacific marine invertebrates of Puget Sound, Northwest. A. Shanks (ed.). Oregon the San Juan Archipelago, and State University Press, Corvallis, OR. adjacent regions. University of 3. FAUCHALD, K. 1977. The polychaete Washington Press, Seattle. worms: definitions and keys to the 12. LINTON, D. L., and G. L. TAGHON. orders, families, and genera. Natural 2000. Feeding, growth, and fecundity History Museum of Los Angeles of Abarenicola pacifica in relation to County Science Series. 28:1-190. sediment organic concentration. 4. FERNALD, R. L., C. O. HERMANS, T. Journal of Experimental Marine C. LACALLI, W. H. WILSON, JR, and Biology and Ecology. 254:85-107. S. A. WOODIN. 1987. Phylum 13. O'CLAIR, R. M., and C. E. O'CLAIR. Annelida, Class Polychaeta, p. 138- 1998. Southeast Alaska's rocky 195. In: Reproduction and shores: animals. Plant Press, Auke development of marine invertebrates Bay, AK. of the northern Pacific coast. M. F. 14. OGLESBY, L. C. 1973. Salt and water Strathmann (ed.). University of balance in lugworms (Polychaeta: Washington Press, Seattle, WA. Areniocolidae), with particular 5. HEALY, E. A., and G. P. WELLS. reference to Abarenicola pacifica in 1959. Three new lugworms Coos Bay, Oregon. Biological Bulletin. (Arenicolidae, Polychaeta) from the 145:180-199. north Pacific area. Proceedings of the 15. OKUDA, S. 1938. Notes on the Zoological Society of London. spawning habits of Abarenicola 133:315-335. claparedii Levinsen. Annotationes 6. HOBSON, K. D. 1966. Ecological Zoologicae Japonenses. 17:577. obervations on Abarenicola species 16. PORCH, L. L. 1970. Polychaetes of (Polychaeta) of the north Pacific, M. S. Coos Bay. In: OIMB Unpublished University of Washinton, Seattle, WA. Student Report, Summer 1970. 7. HOBSON, K. D. 1967. The feeding 17. RICKETTS, E. F., and J. CALVIN. and ecology of two North Pacific 1971. Between Pacific tides. Stanford Abarenicola species. (Arenicolidae, University Press, Stanford, California. Polychaeta). Biological Bulletin. 18. RUPPERT, E. E., R. S. FOX, and R. 133:323-354. D. BARNES. 2004. Invertebrate 8. HYMEL, S. N., and C. J. PLANTE. zoology: a functional evolutionary 2000. Feeding and bacteriolytic approach. Thomson Brooks/Cole, responses of the deposit-feeder Belmont, CA. Abarenicola pacifica (Polychaeta : 19. SWINBANKS, D. D. 1981. Sediment Arenicolidae) to changes in reworking and the biogenic formation temperature and sediment food of clay laminae by Abarenicola

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12654 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to [email protected] pacifica. Journal of Sedimentary Petrology. 51(4): 1137-1145. Updated 2014 by K. Meyer