Phylum: Annelida Capitella spp. Class: Polychaeta, Sedentaria, Scolecida (Capitella capitata species complex) Order: A thread worm Family: Capitellidae Taxonomy: Once considered a cosmopoli- 1969; Blake 2000) (Fig. 2). Prostomium tan species, Capitella capitata (Fabricius, shape variable between species (sharply 1780) is now regarded as a complex of sev- pointed, conical or swollen) (Blake 2000). eral closely related, morphologically similar Peristomium short and setigerous. but genetically distinct sister species Trunk: Anterior thorax with nine seg- (Grassle and Grassle 1976; Blake 2000; ments, all bearing setae. Abdomen of 90 seg- Blake and Ruff 2007). Currently, this spe- ments beginning at setiger 10. cies complex consists of at least 6 and as Posterior: Pygidium is a simple poste- many as 13 species (Blake 2000; Blake et rior flange (Hartman 1969) without appendag- al. 2009), some of which are recognizable es (Blake 2000). by subtle differences in morphology (Grassle Parapodia: Biramous and inconspicuous and Grassle 1976) or reproductive ecology. (Hartman 1944). Parapodia reduced in tho- Capitella telata was recently described racic region becoming swollen in abdominal (Blake et al. 2009). Teasing apart sister segments (Blake 2000). Notopodia become species based on morphology is difficult and elevated posteriorly in posterior abdominal most researchers refer, instead, to the entire region (Blake 2000). complex of species (e.g. Capitella capitata Setae (chaetae): Simple (not jointed). Anteri- sensu lato, Blake and Ruff 2007). or thoracic parapodia (setigers 1–7) with long, fine capillary spines (Fig. 5a). Abdominal Description segments with stout hooks and transparent Size: Individuals range from 20–100 mm in hoods (Fig. 5b). Hooks composed of a large length and 1–2 mm in width, with at least 90 main fang with a straight row of apical teeth segments (Blake 2000). where each tooth is well separated. Tooth Color: Dark red or brownish, fixed speci- number varies with 1–3 rows of 1–5 teeth per mens are light tan. row (Blake 2000). Eighth and ninth General Morphology: Long and earthworm neuropodia each with two stout yellow -like with pointed anterior (Hartman and Re- copulatory spines (male, Fig. 4a). ish 1950; Hartman 1969; family Capitellidae, Eyes/Eyespots: None in described speci- Blake and Ruff 2007). Body cylindrical, men. Although some members of the species slender and without obvious parapodia or complex may possess small, paired eyespots peristomial appendages. (Blake 2000). Body: Body divided into anterior thoracic Anterior Appendages: None. and posterior abdominal regions. (Fig. 1: Branchiae: None. drawing done from somewhat compressed Burrow/Tube: Individuals inhabit black mem- specimen). Circulatory system lacking branous, mucus-lined burrows in fine mud (Morris et al. 1980). and organic sediments (Fernald et al. 1987). Anterior: Broad and triangular pro- Within the vertically positioned tube, individu- stomium with dorsal depression (Hartman als are situated such that their head is up 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. 2014. Capitella spp. 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. (Ricketts and Calvin 1952). as well as capillary setae on the last two tho- Pharynx: Bears eversible proboscis which racic setigers (Hartman 1969) as well as geni- is rarely seen everted (Hartman 1969). tal spines on setigers eight and nine. Mem- Genitalia: Males with lateral generative pore bers of the Capitella capitata species complex between setigers 7 and 8 and 2 yellow geni- are the only members of this genus to pos- tal spines in each notopodium of setigers sess setae on the first segment (Hartman and eight and nine. Notopodial spines number Reish 1950) (Fig. 2). six or more on setiger eight and 2–4 on se- Ecological Information tiger nine (Blake 2000). Females with corre- Range: Type locality is Naples. Chiefly north- sponding genital pores (Blake 2000). ern distribution including western Canada to Nephridia: California (Hartman 1969). Cosmopolitan. Possible Misidentifications Many species have wide and overlapping dis- The Capitellidae lack conspicuous tribution (Blake 2000). parapodia, branchiae, lobes and prostomial Local Distribution: In Coos Bay stations in- appendages. Their superficial appearance clude South Slough, North Spit and Barview. is earthworm-like. Capitellid genera are de- Also Netarts Bay at several stations (Stout fined by characters (e.g. numbers of thoracic 1976). setigers with and without capillary setae and Habitat: Mudflats, muddy sand to pure mud the first appearance of hooks) which are on- (Porch 1970), can be found in fish wastes, togenically dependent (Blake 2000). Identi- sulfurous sediments and organically enriched fication requires adult specimens as the sediments where it may be a pollution indica- same species could be identified to two dif- tor if found in great numbers and in the ab- ferent genera at different developmental sence of many other invertebrate species stages (Fredette 1982). Several genera oc- (Filice 1959; Reish 1955). This does not hold cur locally in muddy estuarine situations: true in Coos Bay, where it is not found in the Heteromastus spp. have 12 thoracic polluted areas (Porch 1970). Found in verti- segments (not 11) and one is achaetous. cal, dirt-encrusted, black, membranous tubes Capillary setae are present on the first five (Ricketts and Calvin 1971), in the mud of Sali- setigers. Uncini begin on setiger six (not cornia marsh channels, Coos Bay (Porch five) and they have notopodial branchiae on 1970). No real preference for substrate, but distal posterior segments. likes quite intertidal conditions (Filice 1959). Notomastus spp. like Heteromastus, Salinity: Can tolerate low saline condition have 12 thoracic segments (not 11) and one (Porch 1970), collected at salinity of 14, San is achaetous. Some species possess bran- Francisco Bay where it is reported to prefer chiae. All thoracic setigers have capillary saline conditions (Filice 1959). setae (as in Fig. 5). Temperature: Cold waters to tropics, more Mediomastus spp. have an elongat- commonly in temperate waters (Morris et al. ed, pointed prostomium and thorax with 1980). achaetous peristomium and 10 setigers (not Tidal Level: Collected at +0.9 m to -1.2 m, nine). Capillary setae are present on seti- particular about depth, not substrate. Also gers 1–4 (not 1–7) and long-handled hooks found down to approximately 55 m (Filice are present on setigers 5–10. 1959). Capitella spp. are differentiable from Associates: Coos Bay associates include the other genera by the presence of hooks other polychaetes: Abarenicola, Mediomastus 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] (Netarts Bay), Leptochelia, Pinnixa and am- straightforward (Fernald et al. 1987). phipods (Morris et al. 1980). Food: A direct deposit feeder on organic mat- Abundance: Common, cosmopolitan in ter and indicator of polluted sediments. mudflats (Blake 1975). When present in Predators: great numbers in an area with few other in- Behavior: vertebrates, heavy pollution of the habitat Bibliography may be indicated (Reish 1955). Found in great beds of many acres on the Berkeley, 1. BLAKE, J. A. 1975. Phylum Annelida: California mudflats (Ricketts and Calvin Class Polychaeta, p. 151-243. In: Light's 1971). manual: intertidal invertebrates of the cen- tral California coast. S. F. Light, R. I. Life-History Information Smith, and J. T. Carlton (eds.). University Reproduction: Great variability exists within of California Press, Berkeley. this complex of species from sexually dimor- 2. —. 2000. Family Oweniidae, p. 97-127. In: phic to hermaphroditic species (George Taxonomic atlas of the benthic fauna of 1984 in Blake 2000). Special copulatory se- the Santa Maria Basin and the Western tae on setigers eight and nine (Fig. 4). Re- Santa Barbara Channel. Vol. 7. J. A. productively active all year (California) with Blake, B. Hilbig, and P. V. Scotts (eds.). mild peaks summer and winter. Males Santa Babara Museum of Natural History, transfer spermatophores to females which Santa Babara, California. can store them until eggs are ripe. Early de- 3. BLAKE, J. A., J. P. GRASSLE, and K. J. velopment occurs in the female’s tube. De- ECKELBARGER. 2009. Capitella teleta, a velopmental modes also vary from direct or new species designation for the opportun- lecithotrophic development of short duration istic and experimental Capitella sp. I, with (e.g. hours) to planktotrophic development a review of the literature for confirmed rec- with short pelagic duration (weeks) ords. Zoosymposia. 2:25-53. (Crumrine 2001). Egg diameters correspond 4. BLAKE, J. A., and E. R. RUFF. 2007. Pol- to developmental mode and range from 50– ychaeta, p. 309-410. In: Light and Smith 250 µm (Grassle and Grassle 1976). manual: intertidal invertebrates from cen- Larva: Larvae emerge from female tube af- tral California to Oregon. J. Carlton (ed.). ter five days as trochophore larvae or hatch University of California Press, Berkeley, at 7–14 days as juveniles. Trochophore lar- CA. vae have reduced or absent apical tuft, pro- 5. CRUMRINE, L. 2001. Polychaeta, p. 39- totroch and telotroch, with gut that is not 77. In: Identification guide to larval marine subdivided (Crumrine 2001). Metatrocho- invertebrates of the Pacific Northwest. A. phores settle to the benthos (Blake 2000) Shanks (ed.). Oregon State University and settlement may be stimulated by an in- Press, Corvallis, OR. crease in hydrogen sulfide (Cuomo 1985 in 6. FERNALD, R. L., C. O. HERMANS, T. C. Fernald et al. 1987). LACALLI, W. H. WILSON, JR, and S. A. Juvenile: WOODIN. 1987.