Nootkadrilus
Nootkadrilus Baker, 1982 (ref. ID; 6552 original paper)
Family Tubificidae: Subfamily Phallodrilinae (ref. ID; 5882, 6552)
Synonym Monopylephorus Levinsen, 1884 sensu Brinkhurst, 1971 (in part) (ref. ID; 6552)
ref. ID; 6552
Definition
Marine or brackish water tubificid oligochaetes. Hair setae absent. Ventral setae of XI (penial setae) modified. Ventral setae of X unmodified. Spermathecal and male pores paired in X and XI, respectively. Functional alimentary canal present. Vasa deferentia absent. Atria paired, highly modified, with four distinct parts; ental part of atrium asymmetrical about ciliated lumen with highly modified columnar cells dorsally and laterally, smaller cuboidal cells ventrally. Ectal three parts of atrium tubular, with external muscle layer, lumen may be ciliated. Stalked prostate gland attached to ectal end of atrium; terminal part of atrium as a protrusible pseudopenis. Spermathecae slender with bulbous bases and small distal ampullae. Sperm bundles in ampullae; sperm attached to or embedded in walls of ampullae in some species. Coelomocytes small and sparse or absent. (ref. ID; 6552)
Remarks
The atria of Nootkadrilus gen. nov, are among the most complex within the Tubificidae due to the modifications shown. The columnar cells of the ental modification are very granular and vacuolated while the small cells are not as obviously granular. The modified columnar cells may have a secretory function analogous to that of the prostate cells in other tubificid genera. Figure 1 is representative of a cross section of the ental modification in all Nootkadrilus species; in all other figures of Nootkadrilus the ental modification is shown in lateral view. The single prostate on the atria of Nootkadrilus is referred to as the posterior prostate even though an anterior prostate is absent. This is because the prostate occupies the posterior position of a two prostate condition. In similar cases (Erseus 1981; Erseus & Baker 1982) this convention has already been followed. The ectal three parts of the atrium are tubular and have a continuous outer muscular layer which usually varies in thickness. These three parts will be distinguished in the following descriptions as the anterior ectal part (following ental part of the atrium), the median ectal part, and the posterior ectal part. (ref. ID; 6552)
Etymology
A genus of worms (Greek drilos) named after the Nootka Indian tribe of British Columbia. (ref. ID; 6552)
Type species
Nootkadrilus compressus (ref. ID; 6552)
- Nootkadrilus compressus Baker, 1982 (ref. ID; 6552 original paper) or compresus (ref. ID; 5882)
- Nootkadrilus frigidus (Brinkhurst, 1971) comb. nov. (ref. ID; 6552 redescribed paper) reported author and year? (ref. ID; 5882)
Syn; Monopylephorus frigidus Brinkhurst, 1971 (ref. ID; 6552), Brinkhurst & Baker, 1979 (ref. ID; 6552), Baker & Brinkhurst, 1981 (ref. ID; 6552)
- Nootkadrilus gracilisetosus Baker, 1982 (ref. ID; 6552 original paper) reported author and year? (ref. ID; 5882)
- Nootkadrilus grandisetosus Baker, 1982 (ref. ID; 6552 original paper) reported author and year? (ref. ID; 5882)
- Nootkadrilus hamatus Baker, 1982 (ref. ID; 6552 original paper) reported author and year? (ref. ID; 5882)
- Nootkadrilus verutus Baker, 1982 (ref. ID; 6552 original paper) reported author and year? (ref. ID; 5882)
Nootkadrilus compressus Baker, 1982 (ref. ID; 6552 original paper) or compresus (ref. ID; 5882)
Descriptions
Marine species. (ref. ID; 5882)
Length 4-6 mm, 35-48 segments, width at clitellum 350-530 µm (in fixed, whole-mounted, slightly compressed, sexually mature specimens). Prostomium about as long as broad at peristomium, bluntly conical. Clitellum over 1/2X-XII. Dorsal and ventral setae 3-4 per bundle anteriorly, 3 per bundle posteriorly; anterior somatic setae with upper tooth thinner and as long as or longer than lower; posteriorly upper tooth thinner, shorter than lower; dorsal setae may be simple pointed. Ventral setae of XI modified as penial setae with (4) 5 (6) sigmoid setae per bundle; penial setae 160-215 µm long, very broad and flat distally with sharply recurved tips, flattened distal portion approximately one-half length of seta, 10-13 µm wide. Penial setae arranged in fan shape with setal heads very closely applied, enclosed in muscular sac. Male pores paired posteriorly in XI, slightly medial to ventral setal line; spermathecal pore paired in X at 9/10, in ventral setal line. (ref. ID; 6552)
Male system (all structures paired): Sperm funnel with distint lips; vas deferens absent. Atrium tubular, composed of four parts; an ental part with no visible external muscle layer and three ectal parts with distinct outer muscular layer. Ental part of atrium partially protruded into X, composed of a sigle layer of ciliated cells; tail, columnar, granular cells dorsally and laterally; much smaller, less granular cells ventrally. Anterior ectal part of atrium ciliated, with thin muscle layer; initially approximately 20 µm wide, narrowing posteriorly; median ectal part of atrium apparently nonciliated, 20-32 µm wide, external muscle layer symmetrical (2-3 µm thick); narrowing abruptly posteriorly; posterior ectal part of atrium slender (10-17 µm wide) with very thin muscle layer (1 µm thick or less); posterior prostate stalked, entering atrium near junction of median and posterior ectal portions of atrium. Atrium terminating as protrusible pseudopenis; penial sac apparently absent.
Spermathecae paired, each with a bulbous basal chamber (approximately 60 µm wide), not strongly cuticularized; spermathecal pore a transverse slit. Spermatheca from 350 to 420 µm long, main body of spermatheca 22-30 µm wide at exit from bulbous base, widening gradually to ampulla; ampulla bipartite, basal portion larger than apical portion. Spermatheca approximately 60 µm wide at basal portion of ampulla. Sperm attached (embedded) in groups to distal wall of ampulla. (ref. ID; 6552)
Remarks
The atria of N. compressus are not as heavily muscularized as the atria of other species of the genus. The penial setae are unique within Nootkadrilus due to the extremely flattened distal tips. The penial setae of the Auke Bay specimens (all five per bundle) are the same as those of the British Columbia specimens. (ref. ID; 6552)
Etymology
After the characteristic manner in which the heads of the penial setae are positioned (Latin, compressus pressed together, squeezed). (ref. ID; 6552)
Type locality
Mainland of British Columbia, west side of Sechelt Inlet; coarse sand with organics under and between rocks at side of stream. Midintertidal among Fucus sp. barnacles and mussels very abundant. Collected March 25, 1980, 49 degrees 40.4'N, 123 degrees 51.7'W. (ref. ID; 6552)
Type material
Holotype: NMCIC1982-0559, a whole mounted specimen. (ref. ID; 6552)
Paratypes: NMCIC (Museum of Natural Science, National Museums of Canada) 1982-0560, two whole mounted specimens from the type locality. (ref. ID; 6552)
USNM (Smithsonian Institution, United States National Museum): 072996-072997, three whole mounted specimens from the type locality. (ref. ID; 6552)
Other material examined:
- Baker collection: Two specimens from type locality. Many other specimens from locations listed in Data Depository. (ref. ID; 6552)
- Brinkhurst collection: Three specimens from Auke Creek, Auke Bay, Alaska. (ref. ID; 6552)
Nootkadrilus frigidus (Brinkhurst, 1971) comb. nov. (ref. ID; 6552 redescribed paper) reported author and year? (ref. ID; 5882)
Synonym
Monopylephorus frigidus Brinkhurst, 1971 (ref. ID; 6552), Brinkhurst & Baker, 1979 (ref. ID; 6552), Baker & Brinkhurst, 1981 (ref. ID; 6552)
Descriptions
Marine species. (ref. ID; 5882)
Revised description
Width at clitellum 600-630 µm (in sectioned specimens), clitellum over 1/2X-XI. Anterior setae bifid, 4 (5) per bundle, posteriorly 3-4 per bundle, upper tooth shorter and thinner than lower. Ventral setae of XI modified as penial setae with 7-13 setae per bundle, setae slightly sigmoid, simple-pointed or with sharply recurved bifid tips, upper tooth reduced; setae approximately 200 µm long. Penial setae arranged in fan shape around median aspect of atrium, enclosed in musculer sac. Male pores paired posteriorly in XI in ventral setal line; spermathecal pores paired in X near 9/10, spermathecal pores transverse slits opening in ventral setal line. Male system (all structures paired, based on USNM61969, 61970, and Brinkhurst material): sperm funnel with distinct lips, upper lip 1.5-2 times as long as lower; vas deferens absent. Atrium composed of four parts; an ental part with no visible external muscle layer and three ectal parts with distinct outer muscular layer. Ental part of atrium partially protruded into X, composed of a single layer of ciliated cells; tall columnar, granular cells laterally and dorsally, much smaller, less granular cells laterally and dorsally, much smaller, less granular cells ventrally. Anterior ectal part of atrium ciliated, with thin muscle layer (approximately 1 µm thick); initially approximately 40 µm wide increasing to approximately 47 µm wide medially, decreasing to approximately 28 µm wide posteriorly, about 600 µm long, with narrow constriction (23 µm wide) posteriorly. Median ectal part of atrium ciliated, approximately 70 µm wide and 350 µm long, external muscle layer symmetrical (8.5-11.3 µm thick). Posterior ectal part of atrium with thin muscle layer 1-2 µm thick, bulbous ectally, bulbous portion 190-240 µm long, 63-80 µm wide; stalked posterior prostate entering posterior ectal part of atrium apically. Atrium terminating as protrusible pseudopenis, in deep penial sac. Spermathecae paired, each bulbous basally (approximately 150-185 µm wide, 100-130 µm high). Basal lumen not strongly cuticularized, external muscle layer approximately 1.0-1.5 µm thick; main body of spermatheca usually 55-60 µm wide at exit from bulbous base, approximately 125-135 µm wide over rest of length, external muscle layer about 2 µm thick. Spermatheca with distal ampulla, sperm embedded in distal walls of ampulla. (ref. ID; 6552)
Remarks
Examination of the type material of N. frigidus (USNM35520, 35521) and of sectioned material (USNM61969, 61970) from the type series, as well as other type series material still in the Brinkhurst collection has enabled me to redescribe the species. The holotype of N. frigidus has 11 and 13 simple-pointed penial setae per bundle, respectively, while the sectioned material has 12 penial setae per bundle of which some are clearly bifid. The Brinkhurst material has from 7 to 11 penial setae per bundle of which 1-4 are clearly bifid; the others are simple pointed. The paratypes (USNM35521) have no visible penial setae, appear to be immature, and are unidentificable to species. The holotype and whole mounted specimens in the Brinkhurst collection were mounted in polyvinyl lactophenol while the sectioned specimens were mounted in a permanent mounting media. Polyvinyl lactophenol gradually macerates organic tissue so that histological details are lost although the overall outline and shape of organs appears to remain the same. The effect of polyvinyl lactophenol on chitinous structures, such as penial setae, appears to be a softening of the structure. This can lead to a flattening of the setae (H.R. Baker, unpublished observations) and may alter the shape of the setae. The shape of the penial setae in the holtype and Brinkhurst material are considered to represent an altered state; the setae of the sectioned material are considered to represent the original state. Nootkadrilus frigidus is the only member of the genus to display large variation in penial setal shape within one bundle. In the other species the shape of the penial setae is usually more constant. The holotype of N. frigidus is probably immature as the bases of the penial setae are not formed. This may account for the differences in the proportions of the male ducts and spermathecae between the holotype and the other type-series material. As there are specimens of N. frigidus that display bifid and simple-pointed penial setae with in one bundle, the differences noted between the holotype and other material are not sufficient to warrant separation. (ref. ID; 6552)
Type locality
Olsen Creek, Prince William Sound, Alaska. (ref. ID; 6552)
Material examined
USNM35520 (holotype), USNM35521 (paratypes), 61969, 61970 (from type series); three specimens in Brinkhurst collection. (ref. ID; 6552)
Nootkadrilus gracilisetosus Baker, 1982 (ref. ID; 6552 original paper) reported author and year? (ref. ID; 5882)
Descriptions
Marine species. (ref. ID; 5882)
Length 4.5-6.5 mm, 32-38 segments, width at X 310-400 µm (in fixed, slightly compressed, sexually mature specimens), width at X in sectioned material 120-225 µm. Prostomium rounded, slightly shorter than broad at peristomium. Clitellum thin over 1/2X-1/2XII. Somatic setae bifid, (2) 3 (4) per bundle; anteriorly upper tooth shorter and thinner than lower; posteriorly upper tooth reduced. Ventral setae of XI modified as penial setae with 11-14 long, slender (85-140 µm long, 3.0-3.5 µm thick) ectally hooked setae per bundle; setae enclosed in muscular sac in fan shape with setal heads clumped ventrolaterally around male pore; the longest penial setae lie medially in the bundle with shorter setae on both sides. Male pores paired posteriorly in XI opening on small papillae, in ventral setal line; spermathecal pores paired in X near 9/10, in ventral setal line. (ref. ID; 6552)
Male system (all structures paired): Sperm funnel small, vas deferens absent. Atrium tubular, composed of four parts, an ental part with no visible external muscle layer and three ectal parts with distinct external muscle layer. Ental part of atrium partially protruded into X, composed of a single layer of ciliated cells distributed about the lumen with tall, columnar, granular cells dorsally and laterally, much smaller, less granular cells ventrally. Anterior ectal part of atrium ciliated, long and slender (110-130 µm long, 12-17 µm wide), external muscle layer 1.5-2.6 µm thick; median ectal part of atrium bulbous (47-55 µm wide, muscle layer 4-6 µm thick) with large lumen (ental portion ciliated), joining posterior ectal part of atrium through small constriction. Posterior ectal part atrium thick, nonciliated (50-60 µm long, 21-28 µm wide), leading to male pore, muscle layer thin; posterior prostate entering posterior ectal part of atrium just ectal to constriction. Atrium terminating as protrusible(?) pseudopenis, penial sac absent. Spermathecae paired, each long and slender (225-275 µm long, 27-31 µm wide), with constriction 14-17 un wide just above slightly bulbous base (34-50 µm wide), lumen of bulbous base not especially cuticularized; external muscle layer over spermatheca less than or equalling 1 µm in thickness. (ref. ID; 6552)
Remarks
The separation between the median and posterior ectal parts of the ectal are not as clearly demarcated in N. gracilisetosus as in the other members of Nootkadrilus. The bulbous median ectal part of the atria is characteristic for N. gracilisetosus. (ref. ID; 6552)
Etymology
With slender or graceful (Latin, gracil) penial setae. (ref. ID; 6552)
Type locality
Near mouth of Grapper Inlet, Bamfield. A cobble beach with sand under cobble containing organic debris, freshwater seepage over, high intertidal. Collected by H.R. Baker November 3, 1979, 48 degrees 50.2'N, 125 degrees 07.85'W. (ref. ID; 6552)
Type material
Holotype: NMCIC1982-0551, a whole mounted specimen. (ref. ID; 6552)
Paratypes: NMCIC1982-0552 - NMCIC1982-0555, three whole mounted specimens and one sectioned specimen from the type locality. (ref. ID; 6552)
USNM 072999-073001: Three whole mounted specimens and one sectioned specimen from the type locality. (ref. ID; 6552)
Other material examined: Baker collection: Two whole mounted and seven sectioned specimens from the type locality; 17 other specimens from British Columbia. (ref. ID; 6552)
Nootkadrilus grandisetosus Baker, 1982 (ref. ID; 6552 original paper) reported author and year? (ref. ID; 5882)
Descriptions
Marine species. (ref. ID; 5882)
Length 6-9 mm, width at clitellum 350-490 µm (in fixed, slightly compressed, sexually mature specimens), 44-52 segments. Prostomium shorter than or as long as broad at peristomium. Clitellum thin over 1/2X-XII. Somatic setae (3) 4 (5) per bundle anteriorly, (2) 3 (4) per bundle posteriorly; setae bifid with upper tooth as long as or slightly longer than the lower anteriorly, posteriodorsally upper tooth reduced or setae simple pointed. Ventral setae of XI modified as penial setae with 5 large (210-235 µm long, 11.5-15.5 µm wide), sigmoid, faintly bifid setae (upper tooth much reduced) per bundle; ectal tip of penial setae hooked, setae enclosed in large muscular sac in fan shape with setal heads closer together than bases. Male and spermathecal pores opening in ventral setal line, male pores paired posteriorly in XI, opening on small papillae slightly dorsolateral to penal setae; spermathecal pores paired in X near 9/10. (ref. ID; 6552)
Male system (all structures paired): Sperm funnel with large lips, vas deferens absent. Atrium tubular, composed of four parts, an ental part with no visible external muscle layer and three ectal parts with distinct external muscle layer. Ental part of atrium partially protruded into X, composed of a single layer of ciliated cells; columnar, granular cells ventrally. Anterior ectal part of atrium ciliated, long and narrow (180-240 µm wide), composed of nongranular cells, thin external muscle layer present; median ectal part of atrium ciliated (?), 48-67 µm wide with thick, symmetrical muscle layer (18.5-21.5 µm thick); joining posterior ectal part of atrium though abrupt narrowing. Posterior ectal part of atrium long and slender (115-195 µm long, 55-72 µm wide) with relatively thin muscle layer (4.0-6.5 µm thick); stalked posterior prostate entering posterior ectal part of atrium subapically. Atrium terminating as protrusible pseudopenis, penial sac absent. Spermathecae paired, bulbous basally. Basal part with distinct curcular lining. Main body spermatheca long and narrow (90-130 µm long, 22-26 µm wide) with small distal ampulla, sperm embedded (?) in distal walls of ampulla. External muscle layer over spermatheca 2.5-4.0 µm thick. (ref. ID; 6552)
Remarks
The layer of spermathecal tissue about the distal tips of the ampullar is very thin in this species so that it is difficult to determine if the sperm heads are free or embedded in the wall of the ampullae. (ref. ID; 6552)
Etymology
After the very large (Latin, grandis, large) penial setae. (ref. ID; 6552)
Type locality
South tip of Smith Island, Skeena River estuary; coarse sand with some fine silts, in a humic (brown water) creek, wood chips present, midintertidal. Collected by H.R. Baker July 29, 1979, 56 degrees 6.88'N, 130 degrees 14.45'W. (ref. ID; 6552)
Type material
Holotpe: NMCIC1982-0556, a whole mounted specimen. (ref. ID; 6552)
Paratypes: NMCIC1982-0557 - NMCIC1982-0558, two whole mounted specimens from the type locality. (ref. ID; 6552)
USNM 072998: One whole mounted specimen from the type locality. (ref. ID; 6552)
Other material examined: Baker collection: One specimen from type locality; 19 other specimens from British Columbia. (ref. ID; 6552)
Nootkadrilus hamatus Baker, 1982 (ref. ID; 6552 original paper) reported author and year? (ref. ID; 5882)
Descriptions
Marine species. (ref. ID; 5882)
Length 4.5-8 mm, 35-43 segments, width at citellum 600-700 µm (in fixed, slightly compressed, sexually mature specimens). Prostomium rounded, about as long as broad at peristomium. Clitellum over X-XII. Setae bifid, 3-4 per bundle. Anteriorly upper tooth as thick and as long as lower, posteriorly upper tooth mcuh shorter and thinner than lower. Ventral setae of XI modified as penial setae with (9) 10 strongly hooked setae per bundle, setae 160-210 µm long, approximately 3 µm wide basally, up to 6 µm wide apically; setae enclosed in large muscular sac in fan shape with ectal, hooked portion of setae closely arranged in a half circle about the pseudopenis. Male pores paired posteriorly in XI, pores opening on ventral aspects of small papillae in ventral setal line; spermathecal pores paired in X at 9/10, in ventral setal line. (ref. ID; 6552)
Male system (all structures paired): Sperm funnel small, vas deferens absent. Atrium tubular, composed of four parts; an ental part with no visible external muscle layer and three ectal parts with distinct external muscle layer. Ental portion of atrium partially protruded into X, composed of a single layer of ciliated cells; tall, columnar, granular cells dorsally and laterally; much smaller, less granular cells ventrally. Ental part of atrium recurved to bring sperm funnel near 10/11. Anterior ectal part of atrium 310-335 µm long, 25-57 µm wide with very thin muscle layer and nongranulated cells; joining median ectal part of atrium through narrow constriction; median ectal part of atrium ciliated, 185-210 µm long, 25-57 µm wide, with thickened muscle layer anteriorly (up to 8.6 µm thick) thinning posteriorly (as thin as 4.2 µm); posterior ectal part of atrium with thin muscle layer (approximately 2 µm thick), bulbous ectally; stalked posterior prostate entering posterior ectal part of atrium medially. Atrium terminating as protrusible pseudopenis contained in deep penial sac. Spermathecae paired, each bulbous basally (approximately 115-145 µm wide). Basal lumen not strongly cuticularized, with long, narrow body (72-77 µm wide), and narrow granular apical tip (47-51 µm wide) containing small ampulla. Total length of spermatheca 400-460 µm; with thin external muscle layer; sperm embedded in walls of ampulla. (ref. ID; 6552)
Remarks
As in N. compressus, the median ectal part of the atria is the only part to bear a thickened external muscle layer. The extremely hooked penial setae are characteristic for N. hamatus. (ref. ID; 6552)
Etymology
After the characteristic hooked (Latin, hamatus, with hooks, hooked) tips of the penial setae. (ref. ID; 6552)
Type locality
Kitgoro Inlet, west coast of Moresby Island, Queen Charlotte Islands. Coarse sand with large amounts of wood and other organic debris. Midintertidal among Fucus sp., freshwater flow near. Collected May 15, 1980, 53 degrees 4.3'N, 132 degrees 30.2'W. (ref. ID; 6552)
Type materials
Holotype: NMCIC1982-0545, a whole mounted specimen. (ref. ID; 6552)
Paratype: NMCIC1982-0546 - NMCIC1982-0550, five whole mounted specimens from the type locality. (ref. ID; 6552)
USNM073003-073007: Five whole mounted specimens from the type locality. (ref. ID; 6552)
Other material examined: Baker collection: 10 specimens from type locality, many other specimens from locations given in the Depository list. (ref. ID; 6552)
Nootkadrilus verutus Baker, 1982 (ref. ID; 6552 original paper) reported author and year? (ref. ID; 5882)
Descriptions
Marine species. (ref. ID; 5882)
Length 3.2-5.9 mm; 36-47 segments. Width at clitellum 270-325 µm (in fixed, slightly compressed, sexually mature specimens). Prostomium rounded, blunt, about as long as broad at peristomium. Clitellum thin over X-XII. Somatic setae bifid, 2-3 per bundle; anteriorly upper tooth thinner and as long as or longer than lower, posteriorly upper tooth reduced (dorsal posterior setae may be simple pointed). Ventral setae of XI modified as penial setae with 6-7 short (140-168 µm long), ectally hooked setae and 4-6 longer (185-230 µm long) setae with elongate, distally flattened, ectally hooked tips per bundle. Penial setae approximately 2.5 µm wide basally, apically up to 6 µm wide; enclosed in muscular sac in fan shape with ectal tips of small setae clumped together around the ventral aspect of each male pore, larger setae protruded. Male pores paired posteriorly in XI opening on small papillae, spermathecal pores paired in X near 9/10; male and spermathecal pores in ventral setal line. (ref. ID; 6552)
Male system (all structures paired): Sperm funnel small, vas deferens absent. Atrium tubular, composed of four parts; an ental part with no external muscle layer and three ectal parts with distinct external muscular layer. Ental part of atrium partially protruded into X, composed of a single layer of ciliated cells; tall, columnar, granular cells dorsally and laterally; much smaller, less granular cells ventrally. Anterior ectal part of atrium 143-170 µm long, from 15 µm wide anteriorly to 26 µm posteriorly (ciliated?); external muscle layer from 2.8 µm thick near ental part of atrium to 8.6 µm thick posteriorly; median ectal part of atrium 47-54 µm thick with asymmetrical muscle layer surrounding atrial lumen, muscle layer maximally 32-37 µm thick, minimally 5-10 µm thick, narrowing posteriorly; posterior ectal part of atrium upright, 150-195 µm long, 27-33 µm wide, external muscle layer 5-10 µm thick; small, stalked, posterior prostate entering apically at junction of median and posterior ectal parts of atrium. Atrium terminating as protrusible pseudopenis, with short penial sac.
Spermatheca paired, and short (up to 150 µm long). Each with bulbous base (approximately 50 µm wide), median narrowing (approximately 20 µm wide) and distal elongate ampulla (approximately 35 µm wide). Lumen of bulbous base slightly cuticularized; external muscle layer very thin over bulbous base (approximately 1 µm thick), increasing to 5 µm thick over medial narrowing, up to 6.5 µm over ampulla. Ampulla of spermatheca small, containing bundled sperm, sperm apparently not embedded in walls of ampulla. (ref. ID; 6552)
Remarks
The very asymmetrical muscle layer of the medial ectal part of the atrium is unique within Nootkadrilus. In the other species this layer is symmetrical. Nootkadrilus verutus is the only species in the genus in which two forms of penial setae can be distinguished. The smaller setae are not distally flattened, are grouped around the male pore and are not protruded, while the larger setae are protruded and are distally flattened. (ref. ID; 6552)
Etymology
After the shape of the penial setae (Latin, verutus, armed with a spear or javelin). (ref. ID; 6552)
Type locality
Southeast side of Texada Island (facing Malaspina Stait), gravel beach with fine sediments; freshwater over. Collected March 24, 1981, 49 degrees 33.63'N, 124 degrees 10.8'W. (ref. ID; 6552)
Type material
Holotype: NMCIC1982-0543, a whole mounted specimens. (ref. ID; 6552)
Paratype: NMCIC1982-0544, two whole mounted specimens from the type locality. (ref. ID; 6552)
USNM073008-073009: Two whole mounted specimens from the type locality. (ref. ID; 6552)
Other material examined: Baker collection: One whole mount and one sectioned specimen from type locality; 15 specimens from Southern Vancouver Island and East Sound, Orcas Island, Washington, U.S.A. (ref. ID; 6552)