Lineus and Micrura are non-monophyletic mega-genera within the family Lineidae (e.g., see Kajihara et al. 2022b). The morphological diagnoses of these genera are based on combinations of non-unique characters (Schwartz 2009). Here we use names Lineus and Micrura as taxonomic artifacts, and not to imply shared common ancestry.

Lineus flavescens Coe, 1904

Lineus flavescens Coe, 1904: 184, pl. XVII, figs 3, 4.

BIN. BOLD:ADS0049.

Material examined. BON6, BON11, BON40, BON50, BON60, BON86.

Morphology. Body 8–52 mm long, with significant variation in color: pale (semi-transparent), tan, reddish brown, and rosy-orange varieties observed (Fig. 5K), with lighter coloration ventrally, and smaller individuals appearing paler in color. Head not demarcated from the body, with pale margins, and 3–7 red, purple, or black ocelli arranged closely in a single row on each side of the anterior tip along the head margin (Fig. 5L, M). In some individuals, there is an irregular transverse band of white pigment granules just posterior to and between the two rows of ocelli (Fig. 5M). Cerebral ganglia are rosy, but this is faint in some individuals. Mouth just posterior to the end of the lateral cephalic slits on the ventral side. Body tapers posteriorly.

Identification. The six individuals included here match closely (99–100% similarity, COI) to Lineus flavescens reported from southern Oregon (Hiebert 2016; Maslakova et al. 2022: OTU 45) and agree with Coe’s description of the species. A closely related species (5–6% divergence, COI) is reported from Dutch Harbor, Alaska (OR590584), Puget Sound, Washington (BBPS027-19 in BOLD) and Charleston, Oregon (Fig. 2; Maslakova et al. 2022: OTU 46). The two species closely resemble each other, but one is known to occur from Alaska to Oregon, while the other from Puget Sound, Washington to Long Beach, California. Because the type locality of L. flavescens Coe, 1904 is San Pedro, California, we assume that we encountered the “real” L. flavescens, and not its more northerly look-alike.

Habitat. Collected from among colonial ascidians, algae, and other low intertidal organisms on rocky intertidal shores (stations 2, 6, 10, 15). Also collected just below the surface on intertidal mudflats (station 8).

Distribution. Puget Sound, WA, USA (BBPS722-19 in BOLD); Charleston, OR, USA (Hiebert 2016; Maslakova et al. 2022); Bodega Bay (this study), Point Mugu (DISA800-19 in BOLD) and Long Beach, CA, USA (DISA619-19 in BOLD).

Notes. With Kulikovia sp. BOBA003 (above) and Siphonenteron gen. sp. BOBA004 (below), this species belongs to the Siphonenteron clade, defined by Chernyshev et al. (2018), also referred to as “lineid lineage N” by Kajihara et al. (2022b), and not closely related to the type species of the genus, Lineus longissimus (Gunnerus, 1770).

Micrura verrilli Coe, 1901

Lineus striatus Griffin, 1898: 214.

Micrura verrilli Coe, 1901: 68, pl. V, figs 1–3.

BIN. BOLD:ADW4746.

Material examined. BON2.

Morphology. Body ~ 12 cm long, margins and ventral surface white, dorsally with an orange patch at the anterior tip, bordered posteriorly by white, and followed by a broad purple stripe, which is interrupted at intervals by thin, transverse white lines (Fig. 5H). With lateral cephalic slits and a slender caudal cirrus.

Identification. Morphologically, specimens from Bodega Bay resemble Lineus striatus briefly described by Griffin (1898) from Puget Sound, Washington and Micrura verrilli described by Coe (1901) from Prince William Sound, Alaska. In addition, three similar species have been reported from the western Pacific: Micrura bella (Stimpson, 1857), Micrura impressa (Stimpson, 1857), and Micrura festiva Takakura, 1898. Coe synonymized Griffin’s taxon with his own (despite Griffin’s having priority), and M. impressa and M. festiva and have been treated as synonyms of M. bella (Crandall and Norenburg 2001), although M. impressa is still listed as an accepted species in WoRMS (WoRMS Editorial Board 2023). ASAP analysis of the COI data suggests that all available M. verrilli sequences from the west coast of USA and Canada comprise a single OTU (Fig. 2). A closely related species is reported by Chernyshev and Polyakova (2022) from the Bering Sea as Evelineus sp., but there is no mention of its appearance, and it has only been encountered at depths 350 m and below. COI sequences suggest that Bodega Bay specimens are conspecific (97–99% similarity COI) with M. verrilli reported from Bamfield, BC, Canada (EF125007), Puget Sound, Washington (KF935508), and Charleston, Oregon (Maslakova et al. 2022: OTU 65). One additional available COI sequence (EF125001) of M. verrilli from Puget Sound, Washington contains many ambiguities, which causes some algorithms (e.g., Geneious Prime distance calculations) to interpret it as substantially different from the others, however ASAP analysis places it within the same OTU. A COI sequence of M. bella reported from the Sea of Japan (NC_027727) is ~ 10% different from that of M. verrilli, and thus belongs to a separate species.

Crandall and Norenburg (2001) suggest the extent of the anterior orange patch may help differentiate the eastern (exclusively dorsal) and western (extends onto ventral side) Pacific forms, however one of the M. verrilli specimens found in Washington had pigmentation on both sides (Schwartz 2009).

Habitat. Collected from the low intertidal zone among colonial ascidians (station 18) and observed among kelp holdfasts washed ashore in the Bodega Bay region.

Distribution. Bamfield, BC, Canada (Schwartz 2009); Puget Sound, WA, USA (Kvist et al. 2014); Charleston, OR, USA (Maslakova et al. 2022); Bodega Bay, CA, USA (this study).

Notes. The species reported here belongs to a clade of lineids with orange or magenta red anterior tip that may be synonymous with Evelineus (Schwartz 2009), also referred to as “lineid lineage A” (Kajihara et al. 2022b) and is not closely related to the type species of the genus, Micrura fasciolata Ehrenberg, 1828 (Chernyshev et al. 2018; Chernyshev and Polyakova 2019).

Micrura wilsoni (Coe, 1904)

Lineus wilsoni Coe, 1904: 195, pl. XVI, figs 10, 11.

BIN. BOLD:ADW9830.

Material examined. BON41.

Morphology. Dark brown worm, ~ 45 mm long, slightly paler ventrally, cephalic lobe bordered by white at the anterior tip and along the lateral cephalic slits; thin white transverse bands at irregular intervals along most of the body length (Fig. 5G). No ocelli; rosy cerebral ganglia visible through the body wall. With a small white caudal cirrus.

Identification. Conforms to the description of Micrura wilsoni (Coe, 1904), described from Monterey and San Pedro, California. No look-alikes are currently known in the northeast Pacific. Although we were not able to obtain a high–quality COI sequence, 16S rRNA sequence from the Bodega Bay individual is 99–100% identical to those of M. wilsoni reported by Hiebert (2016) from southern Oregon. These individuals correspond to the COI–delimited M. wilsoni of Maslakova et al. (2022: OTU 90).

Habitat. Collected from kelp holdfasts (Macrocystis pyrifera) in the subtidal (station 6) and very low intertidal zones (station 7), also among holdfasts of subtidal bull kelp (Nereocystis luetkeana) washed ashore. In southern Oregon found on the exposed rocky shore under boulders and in rock crevices of the low intertidal zone.

Distribution. British Columbia, Canada (Gustav Paulay et al., unpublished BOLD records), Charleston, OR, USA (Hiebert 2016; Maslakova et al. 2022); Bodega Bay, CA, USA (this study). Records from San Juan Islands, WA (Maslakova, unpublished) and south to Mexico (Roe et al. 2007) are not currently substantiated by DNA data.

Notes. According to a recent phylogenetic analysis of the family Lineidae this species is not closely related to the type species of the genus, Micrura fasciolata, but is a member of a clade called “lineid lineage G” by Kajihara et al. (2022b).

Siphonenteron gen. sp. BOBA004

BIN. BOLD:ADR9817.

Material examined. BON59.

Morphology. Body 97 mm long, uniformly orange (Fig. 5I). Head the same width as the body, with pale margins, lateral cephalic slits. Ocelli arranged in two rows, one along each anterolateral margin (Fig. 5J), ~ 7 ocelli each, but it is difficult to know the true number as the pigment granules appear broken up and irregular.

Identification. BON59 resembles other species from the Siphonenteron clade (defined by Chernyshev et al. 2018), such as Lineus flavescens, Kulikovia spp. (Kajihara et al. 2022b; this study), and several undescribed representatives of the Siphonenteron clade from southern Oregon previously reported as Lineus sp. 1, Lineus sp. 2, Lineus sp. crescent, Lineus sp. red (Hiebert and Maslakova 2015b; Hiebert 2016) or Lineus sp. and Kulikovia sp. (Maslakova et al. 2022: OTUs 47, 49–51, 59). Among our collections from Bodega Bay, it most resembles Lineus flavescens and Kulikovia sp. BOBA003 (above). COI and 16S sequences do not have any species-level matches in GenBank; both place this species within the Siphonenteron clade (Figs 2, 3).

Habitat. Collected from a wave-exposed, rocky intertidal habitat among colonial ascidians and coralline algae (station 15).

Distribution. Discovery Island, Canada (QHAK2948-23 in BOLD); Bodega Bay, CA, USA (this study).

Notes. Species new to science.

Familial classification suspended as per Kajihara (2021)

Genus Amphiporus Ehrenberg, 1831

A diverse and non-monophyletic genus of the class Hoplonemertea with 74 species listed in the WoRMS database, many more having been declared nomen dubium, or transferred to other genera (Gibson and Crandall 1989). We refer to the species below as Amphiporus merely to emphasize the close relationship to previously described species within the genus, not to imply that they constitute a monophyletic group.

Amphiporus sp. BOBA024

BIN. BOLD:AEI5687.

Material examined. BON36, BON61.

Morphology. Body slender, 13 mm long, yellowish white (Fig. 6B). Red blood vessels show prominently through the body wall (Fig. 6B, inset). Head narrow, with a single row of ~ 8 ocelli on either side (Fig. 6B, inset). Very slender, cylindrical basis slightly longer than the central stylet (Fig. 7A), with two accessory stylet pouches.

Identification. Specimens from Bodega Bay resemble Amphiporus cruentatus Verrill, 1879, originally described from Vineyard Sound, Massachusetts, but later reported from Puget Sound, Washington to San Diego, California (Coe 1905, 1940), in having a small and slender pale yellow body, a single row of ocelli on each side of head, red blood, and a very slender basis of central stylet, with ratio of stylet length to basis length (S/B ratio) close to 1. DNA sequence data are not available for A. cruentatus from the Atlantic Coast of North America. Maslakova et al. (2022) published COI sequences of two other Pacific A. cruentatus look-alikes: one from southern Oregon (OTU 27), and another from the Bay of Panama (OTU 143), and a third from the Caribbean coast of Panama (OTU 274, as Monostilifera gen. sp.). Given this abundance of cryptic species, it seems likely that the Pacific forms are distinct from the originally described Atlantic A. cruentatus. Bodega Bay individuals form a separate OTU from the Oregon individuals (Fig. 2; Maslakova et al. 2022: OTU 27).

Habitat. Collected from wave-exposed rocky shores among surfgrass roots and other low intertidal organisms (stations 14, 18).

Distribution. Bodega Bay, CA, USA (this study).

Notes. Species new to science.

Amphiporus imparispinosus Griffin, 1898 species complex

Amphiporus sp. BOBA017

Amphiporus imparispinosus: Maslakova et al. 2022.

BIN. BOLD:ADR7530.

Material examined. B20, BON47.

Morphology. Body 63 mm long, pale yellow to pale peach color (Fig. 6E). Head rounded and wider than the adjacent body, with 20–25 ocelli on each side, arranged as a row along the anterior margin, and another, more irregular grouping, medially (Fig. 6F). Cerebral ganglia pinkish in color. Basis pear-shaped, broadening posteriorly, S/B ~ 1 (Fig. 7C). With three accessory stylet pouches.

Identification. Specimens from Bodega Bay conform to the description of Amphiporus imparispinosus Griffin, 1898 from Port Townsend, Washington and Sitka, Alaska. Two similar species have been described from the northeast Pacific: Amphiporus leuciodus Coe, 1901, from Victoria, BC, Canada and New Metlakatla and Glacier Bay, Alaska, and Amphiporus similis Coe, 1905, from Monterey, California, though Coe later treated the former as a synonym (1905), and the latter as a variety (1940) of A. imparispinosus. Subsequent authors retained all three as valid species (Gibson and Crandall 1989; Crandall and Norenburg 2001; WoRMS; but see Roe et al. 2007). Coe (1905) notes that A. imparispinosus has a pink brain, small cerebral sense organs, three accessory stylet pouches, and is longer (to 75 mm) than A. similis, which is 10–15 mm, with a clear brain, large cerebral sense organs, fewer ocelli and two accessory stylet pouches. Griffin (1898) does not mention color of the cerebral ganglia in A. imparispinosus.

Maslakova et al. (2022) report, based on COI sequence data, three distinct A. imparispinosus-like species (OTUs 4–6) from the northeast Pacific. One of those (OTU 4) is distributed from Dutch Harbor, AK to Charleston, OR, and overlaps the original range of A. imparispinosus (including samples from Puget Sound, WA), so may represent the true A. imparispinosus. The other two OTUs have not been reported north of Oregon (Maslakova et al. 2022: OTUs 5 and 6). Another look-alike is reported from the Sea of Japan (Chernyshev and Polyakova 2019: MN211508). The pinkish color of cerebral ganglia and the three accessory stylet pouches in our specimens suggests that it is not A. similis, but an undescribed cryptic species.

Habitat. Collected from wave-exposed, rocky intertidal habitats (stations 16, 18), including on holdfasts of the kelp Egregia menziesii and within mid-intertidal mussel beds; among algal turf.

Distribution. Charleston, OR, USA (Maslakova et al. 2022: OTU 6); Bodega Bay (this study); Point Mugu, CA, USA (DISA798-19 in BOLD).

Amphiporus sp. BOBA018

Amphiporus imparispinosus: Maslakova et al. 2022.

BIN. BOLD:AEA1922.

Material examined. BON16, BON44.

Morphology. Body 38–70 mm long, white. Head rounded and wider than body (Fig. 6C). Four clusters of ocelli; two rows following the anterolateral margins, and two more located posteriorly and medially, above the colorless cerebral ganglia (Fig. 6D). The posterior clusters of ocelli appear reddish, while the anterior rows appear brown in reflected light. The neck furrow is obvious and forms a dorsal V-shape posterior to the cerebral ganglia. Basis with rounded posterior margin and slight medial constriction. Central stylet equal in length to the basis (Fig. 7B). Proboscis with three accessory stylet pouches.

Identification. See Amphiporus sp. BOBA018 above. The presence of three pouches of accessory stylets and the length of the worms suggest that this is not A. similis, but an undescribed cryptic species.

Habitat. Collected from wave-exposed, rocky intertidal habitats (stations 18, 19), including on holdfasts of the kelp Egregia menziesii and crawling across other low intertidal surfaces.

Distribution. Charleston, OR, USA (Maslakova et al. 2022: OTU 5); Bodega Bay, CA, USA (this study).

Notes. This is the first record of the species in California.

Genus Emplectonema Stimpson, 1857

Emplectonema viride Stimpson, 1857

Emplectonema viride Stimpson, 1857: 163.

Emplectonema gracile: Coe 1901: 23, pl. VIII, fig. 3; 1905: 207, pl. I, figs 14, 15; 1940: 279, pl. XXX, fig. 40; Roe et al. 2007: 229, pl. 89, fig. I.

BIN. BOLD:AAP1200.

Material examined. B16.

Morphology. Body long and slender, green dorsally, cream-colored ventrally. Head not especially demarcated from the body. With numerous ocelli distributed along the colorless anterolateral margins of the head. Pink cerebral ganglia. Basis of central stylet much longer than the slightly curved central stylet.

Identification. Specimens from Bodega Bay conform to the description of Emplectonema viride Stimpson, 1857, as redescribed by Mendes et al. (2021). There are no known look-alikes in the northeast Pacific. For years, the species has been reported as a synonym of its Atlantic look-alike Emplectonema gracile (Johnston, 1837) (e.g., Roe et al. 2007 and references therein). The two species were recently shown to be distinct, the name E. viride resurrected, and the Pacific species redescribed (Mendes et al. 2021).

Habitat. Collected from a mid-intertidal mussel bed (station 1), and commonly observed in many intertidal habitats throughout the Bodega Bay region. Typically associated with acorn barnacles, which it preys upon.

Distribution: Amaknak (MZ580909) and Fox (MZ580901) Islands, AK, USA; Bamfield (MG423290) and Discovery Islands (QHAK2422-22, QHAK2449-22 in BOLD), BC, Canada; Charleston, OR, USA (Hiebert 2016; Mendes et al. 2021; Maslakova et al. 2022; von Dassow et al. 2022); Bodega Bay, CA, USA (this study). The species is reported as far south as Mexico (Roe et al. 2007), but so far, there are no DNA sequence data to confirm.

Notes. For photographs of this species, see Mendes et al. (2021: fig. 3)

Genus Ototyphlonemertes Diesing, 1863

Species of Ototyphlonemertes are exclusively mesopsammic, living in the interstices of well-sorted, coarse marine sediments. They are easily distinguished from other small, slender, white eumonostiliferans by the presence of a pair of statocysts in the cerebral ganglia, and the lack of ocelli in adults, but most of the described species appear to represent cryptic species complexes (e.g., Leasi and Norenburg 2014; Leasi et al. 2016). Two species of Ototyphlonemertes with spirally sculpted stylets are described from the Pacific coast of the U.S.: O. americana Gerner, 1969 and O. spiralis Coe, 1940, and a third species, with a smooth stylet, was reported near San Francisco (Roe et al. 2007). However, the Ototyphlonemertes spp. of the Pacific coast are not well sampled, and “forms that key out to either of the known species have a reasonable probability of not being those species” (Roe et al. 2007).

Ototyphlonemertes sp. BOBA030

Ototyphlonemertes lactea: Leasi et al. 2016.

BIN. BOLD:ADM3126.

Material examined. BON77, BON78.

Morphology. Body 3.5 mm long and less than 1 mm wide, white; foregut region transparent, intestinal region cream-colored. Head slightly demarcated from the body by a transverse cephalic groove. With a pair of statocysts, one in each of the two ventral cerebral ganglia. Statocysts of the polygranular type. Basis slender, irregularly cylindrical, and longer than the spirally sculpted central stylet (Fig. 7D). Proboscis diaphragm not especially long, middle chamber bulbous.

Identification. Specimens from Bodega Bay conform to the description of O. americana Gerner, 1969 from Puget Sound, Washington, but DNA sequence data are not available from Puget Sound region to confirm identification. COI sequences from Bodega Bay specimens in this study match closely (> 99% similarity, COI) with a species previously reported from San Diego, California as Ototyphlonemetes lactea by Leasi et al. (2016: KU230123). O. lactea was described from Brazil (Corrêa 1954), but the name was later used to refer to a group of species with similar morphologies and presumed shared ancestry, called phylomorphs (Envall and Norenburg 2001). O. americana belongs to the lactea type, which was later synonymized with the macintoshi type (Kajihara et al. 2018), a decision supported by a multigene phylogenetic analysis (Leasi et al. 2016). Relative to macintoshi type worms, O. americana and O. lactea have a shorter proboscis diaphragm and a bulbous middle chamber, as opposed to a long, tubular one. Another OTU of a lactea type reported from Half Moon Bay, California by Leasi et al. (2016: KU230128) is likely to be confused with the Bodega Bay species. Sampling of Ototyphylonemertes in Puget Sound is needed to resolve the specific identity of these lineages.

Habitat. Collected from low intertidal, coarse marine sediments on a wave-exposed sandy beach (station 13).

Distribution. Wright’s Beach, CA, USA (Leasi et al. 2016); Bodega Bay, CA, USA (this study).

Genus Paranemertes Coe, 1901

Paranemertes sp. BOBA009

Paranemertes peregrina: Hiebert 2016: 78.

Paranemertes sp.: Hao et al. 2015: 572, fig. 1J.

BIN. BOLD:ADM0221.

Material examined. B2.

Morphology. Body ~ 5 cm long, orangish purple dorsally, paler ventrally. Head slightly demarcated from the body, with red cerebral ganglia visible through the body wall. Stylet apparatus not observed.

Identification. Paranemertes peregrina is a cryptic species complex composed of at least seven distinct lineages (Hao et al. 2015). A single widely distributed lineage likely corresponding to the P. peregrina Coe, 1901 originally described from Alaska has been identified on the basis of proximity to the type locality and habitat, and is confirmed by DNA sequence data to occur from British Columbia, Canada to southern Oregon, USA on the northeast Pacific coast, and from Kuril Islands, Russia to Shandong, China on the northwest Pacific coast (Hao et al. 2015). The remaining six species, including the two previously reported from Bodega Bay, remain undescribed.

Habitat. Collected from kelp holdfasts in shallow subtidal zone within Bodega Harbor (station 6).

Distribution. Unalaska Island, AK, USA (DUTCH345-19 in BOLD); Discovery Islands, BC, Canada (QHAK177-20 in BOLD); Charleston, OR, USA (Hiebert 2016; Maslakova et al. 2022: OTU 10); Bodega Bay, CA, USA (Hao et al. 2015; this study).

Notes. Hao et al. (2015) report that the two Paranemertes cf. peregrina OTUs from Bodega Bay are well-separated by habitat, with one occurring in mudflats and the other in rocky intertidal contexts, under stones, among algae, etc. Interestingly, the species encountered in this survey came from among kelp holdfasts but matches the one previously found in mudflats by Hao et al. (2015). This might not be as surprising as it appears at first because the kelp holdfasts collected by us (station 6) were from a small kelp bed within Bodega Harbor immediately adjacent to extensive mudflats. For photographs of this species, see Hao et al. (2015: fig. 1J).

Genus Poseidonemertes Kirsteuer, 1967

Poseidonemertes sp. BOBA010

BIN. BOLD:AEK1697.

Material examined. B14.

Morphology. Stout, pale, rust-colored worm with thick, clear margins; body widens posteriorly. Anterior end sharply pointed, with two ocelli near its tip (Fig. 6G). Basis cylindrical, slender, of a similar length as the central stylet (Fig. 7E). With two accessory stylet pouches.

Identification. The two Poseidonemertes specimens from this study (B14 and BON35 listed below) resemble Poseidonemertes collaris Roe & Wickham, 1984 described from Bodega Bay, California, and other light-colored members of the genus, e.g., Poseidonemertes maslakovae Chernyshev, 2002 and Poseidonemertes sp. 508 from the Sea of Japan. P. collaris is the only member of the genus previously reported from the Pacific coast of the U.S. COI sequence data suggest B14 represents a distinct OTU (8.2% divergent) from what was reported as P. collaris by Thollesson and Norenburg (2003) and from BON35 (described below, 19% divergent), or any other previously sequenced members of the genus.

Habitat. Collected just offshore, < 200 m from an open coast beach, among subtidal sand/mud sediments from a depth of 6–7 m (station 3).

Distribution. Bodega Bay, CA, USA (this study).

Notes. Species new to science.

Poseidonemertes sp. BOBA033

BIN. BOLD:AEK1698.

Material examined. BON35.

Morphology. Stout, cream-colored worm, ~ 25 mm long, with branched intestinal diverticula, greenish in color, highly visible through the body wall (Fig. 6H). Body widens posteriorly. Head pointed, with two ocelli near its tip (Fig. 6H, inset). Stylet apparatus not observed.

Identification. See B14 above.

Habitat. Collected from an intertidal mudflat, just below the surface of the sediment, among polychaete tubes (station 8).

Distribution. Bodega Bay, CA, USA (this study).

Notes. Species new to science.

Genus Tetrastemma Ehrenberg, 1831

This non-monophyletic genus of small four eyed eumonostiliferans containing > 100 species was recently redefined by Chernyshev et al. (2021a) based on a multigene phylogenetic analysis. Tetrastemma nigrifrons is part of the Tetrastemma clade sensu Chernyshev et al. 2021a. The other two species are included here tentatively.

Tetrastemma nigrifrons Coe, 1904

Tetrastemma nigrifrons Coe, 1904: 159, pl. XV, fig. 7, pl. XVI, figs 6–9, pl. XVII, fig. 1, pl. XX, fig. 16, pl. XXI, figs 15–23; Maslakova et al. 2022.

Quasitetrastemma nigrifrons Chernyshev, 2004: 154; Chernyshev et al. 2021a.

BIN. BOLD:ADX0572.

Material examined. BON1.

Morphology. Body 27 mm long, brown dorsally, pale ventrally. Head rounded with colorless margins and a broad brown patch, differentiated only slightly from the body by the colorless transverse band (Fig. 6I). With four eyes; the anterior pair halfway between the anterior tip and the cerebral organ furrows, the posterior pair just below the posterior furrow. With bright red blood vessels. Cylindrical basis, slightly longer than the central stylet (Fig. 7F). With two accessory stylet pouches.

Identification. Fits the description of Tetrastemma nigrifrons Coe, 1904, described from Monterey Bay, California. A look-alike, Tetrastemma stimpsoni Chernyshev, 1992 occurs in the northwest Pacific and the Sea of Japan (Chernyshev et al. 2021a). A third, closely related species has been documented from Dutch Harbor, Alaska (6–7% divergence, BIN: BOLD:AEC4254). No pictures are available, but the description (“brown dorsally, white band separates head, 2 prs eye spots”) matches that of this species.

Habitat. Collected from the low intertidal zone among red algal blades and colonies of the kamptozoan Barentsia conferta (station 17). Similar specimens also observed intertidally among low zone tunicates and algae (station 2), kelp holdfasts (station 7), and surfgrass roots (station 14). Subtidally, among organisms on marina docks (station 9).

Distribution. Unalaska, AK, USA (DUTCH209-19 in BOLD); Canada (Chernyshev et al. 2021a); Charleston, OR, USA (Chernyshev et al. 2021a; Maslakova et al. 2022); CA, USA (Chernyshev et al. 2021a); Bodega Bay, CA, USA (this study).

Notes. This species has variable coloration, both in terms of pattern and the amount of pigmentation (Roe et al. 2007; Maslakova, unpublished). Some specimens are almost completely dark brown dorsally with a colorless transverse bar separating the cephalic patch from the dorsum, while others have much less dorsal pigment (e.g., it may be separated into two more or less continuous stripes by a pigment-less mid-dorsal region). Some specimens may be almost entirely devoid of pigment, except for the cephalic patch (which may be broken into two by a mid-dorsal gap). With four ocelli. Blood vessels are red, and clearly show through the body wall.

Tetrastemma sp. BOBA029

Tetrastemma sp. 1: Hiebert 2016: 84, fig. 2.14.

Tetrastemma sp.: Maslakova et al. 2022.

BIN. BOLD:ADW8618.

Material examined. B4.

Morphology. Small and slender, transparent, fast-moving worm; internal structures appear yellowish through the body wall. Anterior tip with a small white patch. With four ocelli (Fig. 6J). Stylet apparatus not observed.

Identification. Anterior white patch and otherwise featureless body distinguishes this from other species of Tetrastemma reported from northeast Pacific (Roe et al. 2007). DNA sequences from the Bodega Bay specimen match those of Tetrastemma sp. 1 first reported from southern Oregon by Hiebert (2016) and Maslakova et al. (2022: OTU 19 as Tetrastemma sp.). Two other overall similar species lacking the anterior white patch occur in southern Oregon (Maslakova et al. 2022: OTUs 15 and 20).

Habitat. Collected from Bodega Harbor within the holdfasts of subtidal Giant Kelp (Macrocystis pyrifera) at a depth of 3–4 m (station 6). In Oregon, collected from among surfgrass (Phyllospadix spp.) in the rocky intertidal zone (Hiebert 2016).

Distribution. Charleston, OR, USA (Maslakova et al. 2022); Bodega Bay, CA, USA (this study).

Notes. First record of the species in California. This species is very common in southern Oregon. Reproductive individuals were found in July in southern Oregon, and deposited egg masses in laboratory dishes upon collection, with crawl-away juveniles hatching a week or two later.

Tetrastemma sp. BOBA020

BIN. BOLD:AEJ7493.

Material examined. BON75.

Morphology. Body 1.7 mm long, transparent, with an orange gut. With four eyes and two pairs of cephalic furrows: cerebral organ furrows at the level of the posterior pair of eyes, and a V-shaped neck furrow posteriorly, overlying the anterior portion of the cerebral ganglia. Conical basis, significantly longer than the central stylet (Fig. 7O).

Identification. Resembles other featureless species of Tetrastemma. COI sequences show it to be distinct from any previously sequenced species.

Habitat. Collected from low intertidal, coarse marine sediments on a wave-exposed sandy beach (station 13).

Distribution. Bodega Bay, CA, USA (this study).

Notes. Species new to science.

Genus Zygonemertes Montgomery, 1897

Members of the genus Zygonemertes are distinct from other eumonostiliferans in having a single row of post cerebral ocelli on each side, along the lateral nerve cords, in addition to the more typical ocelli found in rows or groups on the head. In addition, all species we have had the opportunity to examine possess sickle-shaped microscopic inclusions in the epidermis, and most have a characteristically truncated basis of the central stylet.

Three species of Zygonemertes are reported from the northeast Pacific coast: Z. albida Coe, 1901, Z. thalassina Coe, 1901, and Z. virescens (Verrill, 1879). The first two were described by Coe from British Columbia and Alaska, respectively. Zygonemertes thallasina has never been reported outside its type locality, Z. albida was subsequently reported by Coe to occur as far south as Ensenada, Mexico (Coe 1944), and Z. virescens is reported to have a very wide geographic distribution including Pacific (British Columbia to Mexico), Atlantic (Maine to Florida) and Gulf coasts of North America, as well as Curaçao (Coe 1940; Gibson 1995; Roe et al. 2007), but clearly represents a large cryptic species complex (Maslakova, unpublished). The type locality of Z. virescens is New England. Presently we are aware of several genetically distinct Atlantic look-alikes (e.g., from Florida, Colombia, and Caribbean Panama); these are also distinct from several Pacific Z. virescens-like forms. Based on this, it seems most reasonable to exclude Z. virescens from the list of Pacific fauna, and to describe the Pacific forms as new species.

Zygonemertes thalassina was regarded as being extremely similar to Z. virescens, except often longer (to 60 mm), darker in color (olive green), with a smaller S/B ratio, a shorter, stubbier central stylet, and with five stylets per accessory pouch, rather than two or three (Coe 1901, 1905). Zygonemertes albida was distinguished on the basis of its small size, lack of color, longer proboscis, and differences in the stylet apparatus, appearing similar to juveniles of the other two species. Among individuals of Z. virescens, Coe noted variation in color, number and arrangement of ocelli, and relative proportions of central stylet and basis. While some of these features may be variable (e.g., with age or environment), we consider it likely that he encountered more than one species, as there are at least four Z. virescens-like species in southern Oregon alone (Maslakova et al. 2022: OTUs 23–26), and we identified an additional two species in this study. The increasing number of Zygonemertes species uncovered with genetic data, and the lack of barcodes from type localities make it difficult to assign existing names to these species. For now, we refer to them as Zygonemertes spp. until formal descriptions are made. We consider reports of Z. albida from the Atlantic coast dubious (Zattara et al. 2019).

Zygonemertes sp. BOBA012

Zygonemertes sp. 1: Hiebert 2016: 70.

Zygonemertes sp.: Maslakova et al. 2022.

Nemertea sp.: Leray and Paulay unpublished (MH242861).

BIN. BOLD:ADL9636.

Material examined. B5, B6, B9.

Morphology. Body somewhat transparent, greenish yellow with clear margins; 15–25 ocelli arranged in two irregular rows on each side of the head, with a single row of post cerebral ocelli on each side along the lateral nerve cords. Cerebral ganglia pink, visible through the body wall (Fig. 6K). With two pairs of cephalic furrows; cerebral organ furrows are simple ventrolateral arches located 1/2 to 2/3 of the way between the anterior tip and the neck furrow, which overlays the anterior portion of the cerebral ganglia. Specimens B5 and B9 had long slender basis with a slightly concave to flat posterior margin, B6 had a flared stylet basis similar to the illustration for Z. virescens in Roe et al. (2007). Central stylet shorter than basis, S/B ~ 0.5 (Fig. 7G); two accessory stylet pouches, with two stylets each.

Identification. See above on species of Zygonemertes. COI sequences from Bodega Bay specimens match those of Nemertea sp. from Puget Sound, Washington (Paulay and Leray, unpublished, MH242862) and those reported as Zygonemertes sp. 1 (Hiebert 2016) or Zygonemertes sp. (Maslakova et al. 2022: OTU 23) from southern Oregon.

Habitat. Collected from Bodega Harbor within the holdfasts of subtidal Giant Kelp (Macrocystis pyrifera) at a depth of 3–4 m (station 6).

Distribution. Puget Sound, WA, USA (MH242861; Maslakova, unpublished); Charleston, OR, USA (Maslakova et al. 2022); Bodega Bay, CA, USA (this study).

Notes. Species not previously reported from California. In the first round of PCR with universal primers, we apparently amplified the gut contents of these worms, the barnacle Balanus glandula. Like another barnacle-eating nemertean, Emplectonema viride, some specimens of this species have a long, slender basis of central stylet. The basis in this species appears slightly narrower than in other species of Zygonemertes.

Zygonemertes sp. BOBA013

Zygonemertes sp. 1: Hiebert 2016: 70.

Zygonemertes sp.: Maslakova et al. 2022; O’Mahoney et al. unpublished (MZ580839).

BIN. BOLD:ADW7912.

Material examined. BON27, BON76, BON80, BON87.

Morphology. Body 4–15 mm long; color ranging from white with a tinge of yellow to orange, sometimes with dark pigment spots along the sides of the body or at the posterior (Fig. 6M). 25–50+ ocelli arranged in four irregular rows on the head, a single row of ~ 10 post-cerebral ocelli along the lateral nerve cords (Fig. 6N). With two pairs of cephalic furrows: cerebral organ furrows are simple ventrolateral arches located 2/3 of the distance from the tip of the head to the V-shaped neck furrow, which overlies the cerebral ganglia. Basis slender, much longer than the central stylet, S/B ~ 0.5–0.65, sometimes with slight medial constriction posteriorly, and with flat or slightly concave posterior margin (Fig. 7I). Two accessory stylet pouches with two or three stylets each.

Identification. See above on species of Zygonemertes. COI sequences from Bodega Bay specimens match a subset of those reported as Zygonemertes sp. 1 (Hiebert 2016) and Zygonemertes sp. (Maslakova et al. 2022: OTU 26) from southern Oregon, and two specimens from Dutch Harbor, Alaska. This species may correspond to Z. albida or a cryptic undescribed species.

Habitat. Collected from the low intertidal zone among colonial ascidians and polychaete worm tubes (stations 7, 10). Collected subtidally from within holdfasts of bull kelp (Nereocystis luetkeana), station 11.

Distribution. Amaknak (MZ580839) and Unalaska Islands, AK, USA (MZ580813); San Juan Island, WA, USA (Maslakova, unpublished), Charleston, OR, USA (Hiebert 2016; Maslakova et al. 2022); Bodega Bay, CA, USA (this study).

Notes. First record of the species in California. Reproductive individuals encountered in August in Bodega Bay.

Zygonemertes sp. BOBA014

BIN. BOLD:AEK0256.

Material examined. B7, B8, BON88, BON91.

Morphology. Body up to 31 mm long, greenish yellow, digestive tract appearing bright reddish orange ventrally. With ~ 15 ocelli on each side of the head, arranged in four irregular rows, and a single row of post-cerebral ocelli (~ 8) along each lateral nerve cord (Fig. 6L). Cerebral organ furrows 2/3 the distance between the anterior tip and the posterior V-shaped neck furrow. Cylindrical basis, longer than the central stylet, with truncated posterior margin (Fig. 7H). S/B ~ 0.5–0.65. Two accessory stylet pouches, with two or three stylets each.

Identification. See above on species of Zygonemertes.

Habitat. Collected from Bodega Harbor within the holdfasts of subtidal Giant Kelp (Macrocystis pyrifera) in the shallow subtidal zone (< 5 m depth, station 6).

Distribution. Bodega Bay, CA, USA (this study).

Notes. Species new to science. Closely related to Zygonemertes sp. BOBA015 (6% divergence, COI).

Zygonemertes sp. BOBA015

BIN. BOLD:AEJ0120, BOLD:ADR7155.

Material examined. BON62, BON63, BON81.

Morphology. Body 4–15 mm long, brownish, with numerous ocelli arranged in four irregular rows on the head, ~ 25+ on each side (Fig. 6O). Basis quite massive compared to central stylet, in terms of length and width (Fig. 7J), though this is not as obvious in smaller specimens (BON63). S/B 0.4–0.75. One individual (BON81) had an unusual triangle-shaped basis, widening significantly posteriorly, with a flat posterior margin. Two accessory stylet pouches with two or three stylets each.

Identification. See above on species of Zygonemertes.

Habitat. Low intertidal zone among surfgrass roots (station 14) and colonial ascidians (station 10).

Distribution. Calvert Island, BC, Canada (BHAK2541-20 in BOLD). Bodega Bay, CA, USA (this study); Point Mugu, CA, USA (DISA797-19 in BOLD).

Notes. Species new to science. Closely related to Zygonemertes sp. BOBA014 (6% divergence, COI).

Amphiporina incertae sedis

Eumonostilifera sp. BOBA016

Monostilifera sp.: Maslakova et al. 2022.

BIN. BOLD:AEJ6897.

Material examined. B15.

Morphology. Body orange, with 15 ocelli on each side of the cephalic lobe. Basis nearly conical, rounded at the bottom, a bit shorter than the central stylet (Fig. 7N). Two accessory stylet pouches with two stylets each.

Identification. Resembles individuals of Amphiporus sp. BOBA017 and BOBA018 described above, but COI sequences do not match any previously sequenced species, and do not group closely with Amphiporus cf. imparispinosus. Taxonomic affiliation is uncertain until a more thorough phylogenetic analysis (with more conservative markers than COI and 16S) is carried out. Overall morphology and 16S tree (Fig. 3) suggest it belongs within Amphiporina.

Habitat. Among fouling organisms on marina docks (station 9).

Distribution. San Juan Island, WA, USA (Maslakova, unpublished); Charleston, OR, USA (Maslakova et al. 2022); Bodega Bay, CA, USA (this study).

Notes. First record of the species in California. The eggs of this species (which have a polyhedral chorion) have been collected in the plankton in Charleston, OR (Maslakova et al. 2022: OTU 13) and matching COI barcodes have been obtained from adults collected from Friday Harbor, WA (Maslakova, unpublished).

Infraorder Oerstediina Kajihara, 2021

Family Oerstediidae Chernyshev, 1993

Genus Antarctonemertes Friedrich, 1955

Antarctonemertes phyllospadicola (Stricker, 1985)

Tetrastemma phyllospadicola Stricker, 1985: 682, figs 1–28; Stricker and Cavey 1986: 2188; McDermott 1997: 254; Stricker and Folsom 1997: 57; Stricker et al. 2001: 214.

BIN. BOLD:ACH3602.

Material examined. BON67, BON68.

Morphology. Body short and stout, pale yellow to pale peach color, 6–7 mm long (Fig. 6P), with four eyes occupying the corners of a square, and a prominent pointed snout (not apparent on Fig. 6P). Cephalic lobe at its widest at the level of cerebral organ furrow, between the first and second pairs of eyes. Cerebral organ furrows are limited to the ventral side. Transverse neck furrow posterior to the second pair of eyes. Rounded in cross section, proboscis extending to posterior end of the body. Basis oval, widening a bit posteriorly, with a slender central stylet, S > B (Fig. 7K). With two accessory stylet pouches, with one or two stylets each.

Identification. Specimens from Bodega Bay conform to the description of Antarctonemertes phyllospadicola (Stricker, 1985) described from San Juan Island, Washington, and the COI sequences match those of A. phyllospadicola from San Juan Island, Washington (Thollesson and Norenburg 2003) and southern Oregon (Maslakova, unpublished).

Habitat. Collected with intertidal samples of surfgrass, Phyllospadix scouleri (station 14). In the San Juan Islands, WA this species is found on blades and inside female inflorescences of P. scouleri in the low intertidal zone.

Distribution. Bamfield Marine Science Centre, Canada (Chernyshev and Polyakova 2019); Puget Sound, WA, USA (Maslakova and von Döhren 2009); Charleston, OR (Maslakova, unpublished); Bodega Bay, CA, USA (this study).

Notes. This is the first record of this genus and species for California.

Genus Nemertellina Friedrich, 1935

The genus Nemertellina has never been reported from the northeast Pacific and currently contains five valid species, three occurring in Kiel Bay, Germany, and one each in Madagascar and Japan. Members of this genus have four eyes, with the anterior and posterior pairs widely separated; small and simple cerebral organs located far anterior to the brain and opening ventrally near the tip of the head; short rhynchocoel; conical or pear-shaped basis, with 2–4 accessory stylet pouches. Nemertellina canea Friedrich, 1935b, N. minuta Friedrich, 1935a, N. oculata Friedrich, 1935b and N. tropica Kirsteuer, 1965 are reported to completely lack cephalic furrows, while N. yamaokai Kajihara, Gibson & Mawatari, 2000 has two pairs.

Nemertellina sp. BOBA011

BIN. BOLD:AEJ4336.

Material examined. B3, B21, BON69.

Morphology. Body small and slender, ~ 15 mm long, cylindrical in cross-section (Fig. 6Q). Head the same width as adjacent body. Four eyes occupy the corners of a rectangle, the distance between the anterior and posterior pairs of eyes is considerably larger than the distance between the two eyes of each pair. With two pairs of cephalic furrows: cerebral organ furrows are just posterior to the anterior pair of eyes, and the posterior neck furrow overlies the anterior margin of the cerebral ganglia, which are translucent. Stylet basis cylindrical, rounded posteriorly, S/B ~ 1 (Fig. 7L); two accessory stylet pouches. The rhynchocoel extends 3/4 of the body length.

Identification. The species encountered here is most similar to Nemertellina yamaokai in possessing two sets of cephalic furrows. The Bodega Bay specimens are ~ 10% divergent (COI) from N. yamaokai, suggesting the presence of a sixth Nemertellina species, and the first reported from the northeast Pacific.

Habitat. Collected subtidally in Bodega Harbor from kelp holdfasts (station 6) and among fouling organisms on boat marina docks (station 9). Collected intertidally from rocky shores on the open coast among surfgrass roots (station 14).

Distribution. Charleston, OR, USA (Maslakova, unpublished); Bodega Bay, CA, USA (this study).

Notes. Species new to science, and new record of the genus for North America.

Genus Oerstedia Quatrefages, 1846

Oerstedia sp. BOBA022

BIN. BOLD:AEJ2779.

Material examined. BON32, BON33.

Morphology. Short and stout cylindrical body, 3–6 mm long, with a head narrower than the body. One individual pale, with a bright orange gut (Fig. 6S), the other with the dorsal surface completely covered with blotches of various shades of brown (Fig. 6R). With four large eyes. Basis conical, rounded posteriorly, shorter than the slender central stylet (Fig. 7M). Two accessory stylet pouches, with three or four stylets each.

Identification. The only species of Oerstedia reported to occur in the northeast Pacific (from Washington to Mexico) is Oerstedia dorsalis (Abildgaard, 1806). The type locality of O. dorsalis is northern Europe, but the species has been reported throughout the northern hemisphere and is famously polymorphic. Sundberg et al. (2009) demonstrated that there are at least nine cryptic species within O. dorsalis in northern Europe alone, each exhibiting color polymorphism. Reports of Oerstedia on this coast likely refer to undescribed species. Bodega Bay specimens are sufficiently divergent from any previously sequenced Oerstedia, including a species occurring in southern Oregon (Maslakova, unpublished).

Habitat. Collected among low intertidal red algae on the rocky boulders of a breakwater (station 4).

Distribution. Bodega Bay, CA, USA (this study).

Notes. Species new to science.

Oerstediina incertae sedis

Tetrastemma bilineatum Coe, 1904

Tetrastemma bilineatum Coe, 1904: 164, pl. XIV, fig. 6, pl. XXI, figs 13, 14, pl. XXII, fig. 4.

BIN. BOLD:ADW8130.

Material examined. B18.

Morphology. Small, slender worm with two dorsal longitudinal brown stripes, each 1/3 of the body width, upon a cream-colored background (Fig. 6T). Brown stripes narrow and terminate towards the anterior tip. Head triangular in shape, with four eyes; the anterior pair located halfway between the tip of the head and the posterior pair.

Identification. Specimens from Bodega Bay conform to the description of Tetrastemma bilineatum Coe, 1904, originally from San Diego, California, though sequence data are not available from southern California. COI sequence of the Bodega Bay specimen matches those of T. bilineatum individuals reported from southern Oregon (Hiebert 2016; Maslakova et al. 2022: OTU 29).

Habitat. Collected from a wave-exposed mussel bed (station 1) and found in similar habitat in southern Oregon.

Distribution. Bamfield Marine Science Centre, Canada (Chernyshev et al. 2021a); Charleston, OR, USA (Hiebert 2016; Maslakova et al. 2022); Bodega Bay, CA, USA (this study).

Notes. Coe’s (1904) original record of the species from San Diego, California is not verified by DNA sequence data, but given the distinctiveness of this species, and the absence of known look-alikes on this coast, the reported distribution seems likely. According to a recent molecular phylogeny of Tetrastemma and its allies (Chernyshev et al. 2021a) this species does not belong to Tetrastemma sensu stricto or the infraorder Amphiporina, but instead is a member of Oerstediina. Its generic placement remains uncertain.