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Eremidrilus Fend & Rodriguez 2003
No full textGenus Eremidrilus Fend & Rodriguez, 2003 Diagnosis (from Fend & Rodriguez 2020): Small or medium-sized worms with a filiform proboscis. Body wall unpigmented and bearing secondary annuli. Posterior lateral blood vessels absent. Nephridia absent from preclitellar segments. Testes paired in both IX and X. One pair of ovaries in XI. One pair of elongate-cylindrical or club-shaped atria in X, each with one pair of functional vasa deferentia, serving funnels on 9/10 and 10/11. Male pores usually on broad, folded porophores posterior to ventral chaetae in X, on or slightly lateral to chaetal lines. Spermathecae paired in XI or in both XI and XII. Spermathecal pores posterior to chaetae, with transverse position ranging from ventral chaetal lines to lateral lines. Key to described Eremidrilus species 1 One pair of spermathecae only, in XI (Fig. 7 in present publication)............................................. 2 - Two pairs of spermathecae, in XI and XII (Fig. 11 in Fend & Rodriguez 2020).................................... 8 2 Spermathecal pores midlateral or distinctly lateral to ventral bundles of chaetae................................... 3 - Spermathecal pores in line with or slightly lateral to ventral bundles of chaetae.................................... 5 3 Spermathecal pores each in a deep cavity, associated with extensive musculature; may be everted to form a porophore. Male and spermathecal porophores more than 100 µm in diameter. Atrium club-shaped, length usually 2–3 times the porophore width, 2/3 body diameter. (Pacific Coastal drainages, Central California to southern Oregon.).................................................................................................. E. felini Fend & Rodriguez, 2003 - Spermathecal pores simple, not on porophores, in a shallow depression at most, at level of lateral line.................. 4 4 Atrium club-shaped, about 4 times longer than wide, and the length 2–3 times the porophore width; male porophore low and rounded (length <diameter). (Coast Range, central California.)..................... E. ritocsi Fend & Rodriguez, 2003 - Atrium cylindrical with very narrow diameter, about 8 times longer than wide, and the length 6 times the porophore width. Male pores open in long, protrusible porophores, narrowly conical when fully extended. (Northern Nevada to southwestern Idaho.)...................................................................................... E. owyhee n. sp. 5 Spermathecal pores surrounded by a ring of small glands, spermathecal duct short (0.1–0.2 body diameter) and ampulla elongate.Atrium length about half body diameter, male pores on dome-shaped porophores. Nephridia with prominent ectal vesicles. (Chalone Creek, central California.)..................................................... E. chalonensis n. sp. - Spermathecal pores not surrounded by glands.............................................................. 6 6 Spermathecal duct length about twice the diameter of the ampulla, or about equal to the body diameter, usually penetrating the posterior septum 11/12. Atria cylindrical, 4–8 times the male porophore width, length usually more than 2/3 the diameter of the body. (Coast Range, central California.)....................................... E. elegans Fend & Rodriguez, 2003 - Spermathecal duct shorter than the diameter of the ampulla, about 1/4 to 1/2 the diameter of the body, gradually narrowing towards the pore. Atria club-shaped and located entirely in X.................................................. 7 7 Body diameter at X 0.6–0.9 mm. Spermathecal pores slightly lateral to the ventral chaetal line, at most 1/2 the distance to the lateral line. Spermathecal duct to body diameter ratio: 0.2–0.5. Atrium length 4–6 times the porophore width; porophore large (width 60–100 µm). (Coyote Creek, Coast Range, central California.)................ E. coyote Fend & Rodriguez, 2003 - Body diameter at X 0.3–0.5 mm. Spermathecal pores close to the line of ventral chaetae. Spermathecal ducts short (ratio to body diameter 0.1–0.2). Atrium length 5–7 times the porophore width. Porophore small (24–45 µm wide). (Smith River, northern California.)............................................................................. E. pinedai n. sp. 8 Male pore opening on a small papilla, porophores inconspicuous or absent. Spermathecal pores close to posterior septum of the segment. (Eureka Creek, Montana)...................................... E. montanensis Fend & Rodriguez, 2020 - Male pores opening on distinct porophores................................................................. 9 9 Male pore opening on a small, conical papilla within a ring shaped, concave male porophore. Spermathecal pores very posterior in the segment. Atrium very long (2/3 the body diameter or more) and wide in ental part (ampulla diameter about 1/3 atrium length), with thick (up to 42 µm) atrial muscular layer, duct narrow and clearly distinct from the ampulla. (Idaho.)................................................................................ E. artzaini Fend & Rodriguez, 2020 - Atrium club-shaped, duct not clearly distinct from ampulla; atrial musculature <10 µm............................ 10 10 Atrium long (about the diameter of the body or even longer). Spermathecal pores mid-way between ventral bundles of chaetae and septum. (Tennessee, cave.)................................................. E. allegheniensis (Cook, 1971) - Atrium short (about half the diameter of body or less). At least the second pair of spermathecal pores in the segment XII, close to septum 12/13..................................................................................... 11 11 Broad male porophore, atrium length about 1/3 body diameter. Vasa deferentia open subapically to the atrial lumen. (Malad River drainage, Idaho.)................................................. E. humboldti Fend & Rodriguez, 2020 - Narrow, cylindrical male porophore. Atrium length about 1/2 body diameter. Vasa deferentia open to the atrial lumen about medially. (Gila River drainage, New Mexico.).................................... E. gilita Fend & Rodriguez, 2020Published as part of Rodriguez, Pilar & Fend, Steven V., 2022, New Nearctic Eremidrilus species (Clitellata: Lumbriculidae). Part 2, western species with one spermathecal segment, pp. 245-264 in Zootaxa 5159 (2) on pages 263-264, DOI: 10.11646/zootaxa.5159.2.4, http://zenodo.org/record/677713
Uktena riparia Fend, Rodriguez & Lenat 2015
No full textUktena riparia (Figure 5) In this lumbriculid species, both well-developed spermathecae (filled with sperm) and spermatophores are present. Spermathophores in U. riparia are long, thin tubes (Fig. 5A,B); they develop in the atrial duct (Fig. 5F), apparently using secretions from a section of the atrial ampulla that has a specialized, highly folded epithelium and unsually elongate prostatic glands (Fig. 5E; Fend et al. 2015: Fig. 4J–L). Therefore, the spermatophores appear wholly formed within the male bursa, before being transferred to the spermathecal bursa of the partner. As in other microdrile species producing spermatophores, several glandular organs are associated with both male and spermathecal bursae (Fig. 5C,D). A muscular copulatory organ within the spermathecal bursa (protruded in Fig. 5A) is probably related to the transfer and attachment of the spermatophores to the concopulant, using a secretion from a large basal gland (Fig. 5C; Fend et al. 2015: Fig. 3H,L,M). When transferred, spermatophores are attached at the base of the partner's copulatory organ, and positioned inside the spermathecal bursa with one end close to the entrance to the spermathecal duct (Fig. 5C). Then, the sperm leave the spermatophore and directly pass to the spermatheca (Fend et al. 2015: Figs. 2A–C, 3 I,L). Sperm transfer by spermatophores is otherwise unknown in microdrile oligochaetes with well-developed spermathecae, although it has been described in some megadriles (Omodeo & Rota 1989). The use of spermatophores to transfer sperm from the male duct to the spermatheca, instead of a more typical mating behavior involving a direct sperm transfer by opposition of male and spermathecal pores, suggests an unusual mating behavior and a specific function of the spermatophores (see discussion). The rare occurrence of sperm transfer through spermatophores in microdriles contrasts with its common occurrence in rhynchobdellid leeches. Evolutionary derivation of leeches from a lumbriculid-like ancestor had been suggested by several phylogenetic studies based on morphological characters (Brinkhurst & Nemec 1987; Jamieson et al. 1987) and most recently, by molecular analyses (Erséus 2005; Martin 2000; Siddall et al. 2001). The formation of spermatophores in the lining atrial epithelium of the lumbriculid U. riparia suggests an additional approach to investigating the relationships of leeches and lumbriculids.Published as part of Rodriguez, Pilar & Fend, Steven V., 2018, On spermatophore-producing aquatic microdrile oligochaetes (Annelida: Clitellata), pp. 41-60 in Zootaxa 4497 (1) on pages 51-52, DOI: 10.11646/zootaxa.4497.1.3, http://zenodo.org/record/145109
Eclipidrilus pacificus Steven & Fend, 2005, n. sp.
No full textEclipidrilus pacificus n. sp. (Figures 1–10) HOLOTYPE: USNM 1073033. A whole mounted worm in Kleermount. TYPE LOCALITY: Washington: Jefferson Co.: pool in small spring next to the Hoh River, 47 º 49 ’00”N, 124 º06’ 46 ”W, in mud and macrophyte roots in shallow water. PARATYPES: From the type locality. USNM 1073034–1073037: 2 sectioned worms (1 sagittal, 1 transverse), 1 whole mount, 2 dissected and slide mounted. Collected by S. Fend. 29.IV. 1999. OTHER MATERIAL: Typical specimens: Washington: Clallam Co: muddy seep beside Road 29, Calawah River drainage, 47 º 57 ’ 29 ”N, 124 ° 14 ' 31 "W, 26.IV. 2004. 4 dissected. Jefferson Co: from the type locality, 29.IV. 1999. 1 whole mount, 1 longitudinally dissected. 2.VI. 2003. 4 whole mounts, 4 dissected; 2 partially mature, dissected. Small tributary to Clearwater River at Coppermine Bottom Camp, 47 ° 39 ' 21 "N, 124 ° 11 ' 58 "W, 25.VI. 2004. 8 dissected. Pacific Co.: South Naselle River near Knappton, 46 ° 17 ' 38 "N, 123 ° 48 ' 36 "W, 25.VI. 2004. 5 dissected. All collected by S. Fend. Variant 1: Idaho: Latah Co.: Palouse River at Laird Park, 46 º 56 ’ 35 ”N, 116 º 38 ’ 29 ”W, 2.V. 2000, collected by D. L. Gustafson. 1 dissected. Shoshone Co.: Middle Fork Saint Maries River near Two Bit Creek, 47 °00’08”N, 116 ° 10 ’ 30 ”W, 28.VII. 2003, collected by D. L. Gustafson. 2 dissected. Oregon: Yamhill Co.: small spring west of Peavine Ridge, in mud and macrophyte roots, slow current, 45 º 14 ’ 19 ”N, 123 º 22 ’ 50 ”W, 30.I. 2000. 1 whole mount, 1 dissected, 2 sectioned (1 sagittal, 1 transverse). 10.V. 2001. 6 whole mounts. Lane Co.: small spring and stream beside Fox Hollow Rd., Eugene, in mud, 44 º00’ 36 ”N, 123 º04’ 50 ”W, 29.I. 2000. 3 whole mounts. 1.VI. 2003. 4 dissected, 3 whole mounts, 2 sectioned (1 sagittal, 1 transverse). Spring at mouth of Tenmile Creek, in mud and macrophyte roots, shallow water with slow current, 44 º 13 ’ 30 ”N, 124 º06’ 29 ”W, 30.I. 2000. 2 whole mounts. Washington: Pierce Co.: Taylor Bay Inlet, 9.IX. 2003, collected by M. Allen. 3 dissected. Worms collected by S. Fend unless otherwise noted. Variant 2: Oregon: Clatsop Co.: Columbia River estuary at Snag Island, VIII. 1980, collected by E.J. Clairain and C. Newling. 8 whole mounts, from the Royal Ontario Museum, No. 1989 037, slides labeled 1, 5, 7, 8, 9, 11, 16, 17. Karlson Island (Columbia River estuary), 28.VI. 2002, collected by R. Draheim. 1 whole mount, 3 dissected, 2 sagittally sectioned. Knappa Slough at dock (Columbia River estuary), 24.VI. 2002, collected by R. Draheim. 5 dissected. Warren Slough (Columbia River estuary), 28.VI. 2002, collected by R. Draheim. 2 whole mounts, 1 dissected. Tillamook Co.: spring beside Nestucca River, 7 km upstream of Blaine, 4.VI. 2003, collected by S. Fend. 1 dissected. Partially mature, undetermined: Pacific Co.: small spring along the Naselle River, 46 º 24 ’00”N, 123 º 43 ’ 42 ”W, in mud and macrophyte roots, 30.IV. 1999, collected by S. Fend. 1 dissected. Pierce Co.: Little Mashell Creek, 20.IX. 2001, collected by M. Allen. 1 whole mount. Description Typical specimens Length of preserved worms 17–32 mm, 69–107 segments; width 0.52–0.80 mm in X, maximum width to 0.82 mm. Secondary segmentation prominent in segments V–X, resulting in a narrow anterior ring in each segment; variable in posterior segments (Fig. 1 A–B). Chaetae sigmoid, simplepointed, with nodulus 29–38 % of chaeta length from tip (Fig. 2 A). Chaeta length 125–170 µm in midbody; slightly shorter in posterior segments, but proportions similar in anterior and posterior segments. Dorsal and ventral chaetae approximately equal in length; within each bundle, the outer (more lateral) chaeta slightly shorter than the inner. Prostomium roundedconical, about 0.3 mm long, width about equal to length. Brain in I, not strongly lobed. Pharynx in II–IV; dorsal wall with columnar cells; ventral wall much thinner than dorsal anterior to IV (Fig. 2 B, cf. Fig. 14 A). Pharyngeal glands in V–VII(VIII). Longitudinal muscle layer 20–35 µm thick in preclitellar segments; circular muscle layer 5–7 µm; both layers thinner in posterior segments. Epidermis 10–20 µm thick anterior to clitellum; to about 35 µm in clitellum. Dorsal blood vessel passes under the brain in I before dividing; the two forks pass around the buccal cavity and rejoin in V as a single ventral vessel. One pair of lateral, commissural blood vessels joins dorsal vessel in segments anterior to XII; each commissure strongly convoluted, and those in the first few segments usually enter the next segment before joining the ventral vessel (Fig. 2 B). Commissures in X and XI loop into sperm and egg sacs. Dorsal vessel without lateral vessels between the clitellar segments and about the posterior 1 / 2 to 1 / 3 of the body. Beginning near midbody or posteriorly, two pairs of short, blind lateral blood vessels usually branch off the dorsal vessel in each segment. Lateral vessels are longer, with up to 5–10 short branches in the posterior 1 / 3 to 1 / 4 of some specimens (Fig. 2 D), but remain short and inconspicuous in others (Fig. 2 C). Perivisceral sinus begins in VII; chloragogen cells begin in VII or VIII. First nephridia usually paired on 6 / 7, the next on 12 / 13 or posterior; nephridia in few to most posterior segments, paired or on one side only. Each nephridium has a small anteseptal funnel, a granular postseptal thickening, and an irregular, posterior duct 18–20 µm in diameter. The posterior duct branches, with a short branch to the nephropore anterior to ventral chaetae. Another branch extends along the ventral blood vessel as a convoluted mass, entering posterior and/or anterior segments; posterior to XIII it appears continuous with ducts from other nephridia across multiple segments. Nephropores simple, inconspicuous. Testes paired in IX and X, smaller in IX. Ovaries paired in XI; usually elongate, extending to 11 / 12 or into XII. Sperm sacs paired, extending back as far as XXII; egg sacs may extend 1 or 2 segments beyond sperm sacs. Female funnels up to 120 µm tall, with the posterior side much longer than the anterior; female pore intersegmental, on 11 / 12. Clitellum IX–XIII. Single male pore midventral (beneath the ventral nerve cord) in X, behind the ventral chaetae (Figs. 1 A–B, 3 A, 4 A). A short, cylindrical penis is contained within a shallow concavity, within a ring of thickened epidermis 170–340 µm in diameter (Figs. 4 A, 5 B,D, 8 A–B). Epidermal cells within the concavity interspersed with narrow ducts from large (160–300 µm tall), petiolate accessory glands; gland mass to 550 µm wide (Figs. 4 A, 8 A). Penis variably extended, 20–160 µm long and 40–50 µm wide, formed by extrusion of the atrial duct epithelium. Epithelial cells in the most ectal part of the duct have basal nuclei and fibrous, ectallydirected extensions that appear continuous with the penis (Figs. 4 A, 5 D, 8 B). Lumen at ectal end appears slightly cuticular, and may appear irregular or sinuous (Fig. 5 D, 8 B). Atrium extending as far as XIX, with distinct ectal duct and ental ampulla (Fig. 3 A). Atrial duct 600–2300 (1530) µm long. The ectal half is a 60–100 µm diameter tube of loose, mostly longitudinal muscle, about 20 µm thick, with an inner epithelium that changes from columnar to elongatefibrous in about the ectal 200 µm, near the male pore (Figs. 4 A, 5 B). Ental portion of duct about 40 µm in diameter with a thinner (4–6 µm) muscle layer that is mostly longitudinal, with a very thin (ca. 1 µm) inner circular layer. Ampulla nearly cylindrical, but tapered ectally; length 520–1900 (890) µm, maximum diameter of muscle tube 130–220 (180) µm. Ampulla with an outer layer of longitudinal muscle 22–50 (38) µm thick, an inner transversecircular layer 10–25 (15) µm thick, and epithelium 8–19 µm thick (Figs. 5 A, 9 A–C). Fibers in the longitudinal muscle layer in radially arranged lamellae (Fig. 9 B), parallel to the long axis of the ampulla, slightly sinuate, but not arranged in opposing layers. The inner, transverse muscle layer has parallel fibers arranged orthogonally to the long axis of the atrium (Fig. 9 A–C). Lumen of ampulla variable, 12–100 (42) µm wide, or 0.08–0.61 (0.27) times atrium diameter. The atrial ampulla is covered with a single layer of small cells (possibly nuclei of muscle cells) and a layer of densely packed, multicellular prostate glands (Fig. 5 A, 9 A–C). Prostatic cells are narrowly petiolate, usually occurring in small bundles of up to about 10 cells; individual bundles 40–90 µm tall. Male funnels paired on 9 / 10 and 10 / 11; the anterior pair smaller than the posterior (median height 100 µm vs. 160); the posterior pair usually extends back into XI within the sperm sac. Both anterior and posterior male funnels usually functional, with associated sperm. Both anterior and posterior vasa deferentia narrow (8–16 µm diameter). All four vasa deferentia join the atrial duct, running outside the muscle layer until the ampulla, where they gradually pass through the muscle layers (Fig. 9 B) and eventually the epithelium, and enter the ental part of the lumen. Posterior vasa deferentia enter X directly, without penetrating 10 / 11 and forming a loop in XI. Spermathecae paired in IX; pores on ventral chaetal lines, near the anterior septum (8 / 9), usually within the narrow, secondary annulus (Fig. 1 A–B). Pores usually prominent, sometimes on low mounds. Each spermatheca has a narrow ectal duct 230–720 (370) µm long, and a distinct ental ampulla 420–1330 (680) µm long by 130–410 µm wide (Fig. 6 A,D). The ectal end of the duct widens into a narrow vestibule 145–310 (215) µm deep by 64–96 (77) µm wide, with a mostly longitudinal muscle layer surrounding a very thin transversecircular layer and columnar lining cells with basal nuclei (Figs. 6 A, 10 A). Entally, the duct narrows abruptly, forming a short, convoluted section inside the muscle tube (Fig. 6 A). A short band of thickened, transversecircular muscle surrounds and constricts the beginning of this section (Fig. 10 A). Near the midpoint, the duct widens; the ental half is 40–50 µm in diameter; a thin (3–4 µm), muscle layer surrounds a columnar epithelium. Spermathecal ampullae in IX or IX and X, covered by a very thin muscle layer. Ampullar epithelium thin (4–5 µm) in about the ectal 1 / 5, but entally becomes thicker (18– 42 µm) with columnar, granular cells having basal nuclei (Figs. 6 A, 10 B). Cells may appear increasingly vacuolated, with very small nuclei, toward ental end; apparent sperm cells are visible within the vacuoles in some specimens. In most specimens the sperm is strongly concentrated near the duct (Fig. 10 B). The ental part of the ampulla usually contains only scattered sperm cells, and may contain an unknown, eosinstaining substance. In partially mature worms the male pore is on a pad of slightly thickened epidermis, with welldeveloped accessory glands. Ectal end of duct with columnar (not fibrous) lining cells, protruding slightly as a small papilla (Fig. 5 C), similar to mature E. pacificus Va ri a nt 1 (see below). Atrial duct and ampulla weakly differentiated; muscle layers thin (less than 10 µm total), but inner epithelium of ampulla distinct, 5–15 µm thick. Atrial ampulla and duct covered by a dense layer of cells, which are not in clusters. Spermathecal ampulla not strongly differentiated from duct in early stages (Fig. 6 C), but becomes distinct prior to mating (Fig. 6 B). Ectal vestibule of spermatheca distinct, even at an early development stage (Fig. 6 C). Variant 1 Length of preserved worms 12–26 mm, 53–86 segments; width 0.38–0.65 mm in X. Chaeta length in clitellar region 101–136 µm, nodulus 28–36 % of chaeta length from tip. Blood vessels sometimes as described for typical E. pacificus, but in many specimens the lateral blood vessels of posterior segments are very short and appear unbranched; in some specimens posterior lateral vessels are difficult to see, and may be absent. Male pore less prominent than in typical E. pacificus (Fig. 1 C); usually surrounded by a concave pad of slightly thickened epidermis 75–180 µm wide, within a patch of nonclitellar epidermis. Atrial duct terminates on a small, conical papilla, which appears to be a simple continuation of the duct (Fig. 8 D), without extremely elongated or extruded lining cells. Atrium usually extending to XII–XVI, but sometimes entirely in X. Atrial duct 330– 1870 (585) µm long; ampulla length 300–1480 (455) µm, diameter 84–194 (112) µm. Musculature of atrial ampulla variable, but usually much thinner than in typical specimens: longitudinal muscle 6–22 (8) µm thick; inner, transversecircular muscle 3–12 (6) µm (Fig. 9 D). Longitudinal muscle fibers parallel to ampulla or slightly spiral, with angle less than 20 º from longitudinal axis. Epithelium of ampulla very thin, usually less than 3 µm; lumen 0.3–0.8 (0.64) times total ampulla width. Prostate glands to 25–50 µm tall. Both pairs of vasa deferentia very thin, diameter 6–12 µm. Anterior male funnels 60–110 µm wide, cupshaped; with or without sperm. Posterior funnels 100–200 µm wide, usually convoluted, and entering sperm sac to about the middle of XI. Spermathecal pores inconspicuous; anterior to ventral chaetae, but position variable, usually posterior to the anterior, secondary annulus in IX (Fig. 1 C). Ectal vestibule of spermathecal duct with thinner musculature than in typical specimens; vestibule usually distinct, 55–150 µm long by 30–44 µm wide, but sometimes weakly developed. Remainder of duct 150–280 µm long. Spermathecal duct narrows near ectal end, but is not convoluted as in typical specimens (Figs. 7 A–C, 10 C). Spermathecal ampulla 200–800 (350) µm long; may be as described for typical E. pacificus, but usually less elongate. In most specimens the epithelial cells are not thickened or vacuolated entally, and the sperm cells are usually distributed throughout the ampulla in a loose bundle (Fig. 10 D). Variant 2 Length of preserved worms 19–25 mm, 78–98 segments; width 0.40–0.65 mm in X. Blind lateral blood vessels well developed in posterior segments: from about XXX to about L there are anterior and posterior groups of 1–3 short, digitiform vessels; posterior to L, two pairs of lateral vessels have 4–6 (or more) long branches (Fig. 2 E). Male pore on a short papilla, as described for Variant 1 specimens; epidermal pad surrounding pore 86–145 µm wide (Fig. 8 C). Atrial duct 360–1030 (690) µm long; ampulla length 360–740 (560) µm, maximum diameter 89–132 µm. Poor specimen fixation limits histological observations, but longitudinal muscle layer of atrium appears to be 10–19 µm thick, inner circular muscle 4–7 µm. Longitudinal muscle appears to be parallel to longitudinal axis of ampulla. Maximum diameter of atrial lumen 0.41–0.66 (0.55) times ampulla diameter. Anterior male funnels smaller than posterior, usually with sperm. Spermathecal morphology similar to Variant 1, but placement of spermathecal pores varies. In the material collected in 2002, five specimens have paired spermathecal pores anterior to ventral chaetae, usually in the secondary annulus groove in IX; an additional pore is near the midventral line, posterior to the chaetae (Fig. 3 B, 7 D). Six specimens have a single, midventral spermathecal pore, posterior to or between the ventral chaetal bundles; one worm has a single anterolateral pore in addition to the posteromedian one. Anterior pores inconspicuous, but posteromedian pores usually more prominent, on low mounds. Ectal vestibule of spermathecal duct 70–120 µm long; remainder of duct 140– 240 µm long. Spermathecal ampulla nearly spherical to elongate, 210–730 µm long; histology variable. Posteromedian spermathecal ampulla often larger than anterior ones (if present), extending into X or XI (Fig. 7 E–F). Sperm usually present in all ampullae. Specimens from the Royal Ontario Museum are highly contorted, in poor condition. Four appear to have paired, anteriorly placed pores; three also have midventral pores posterior to the chaetal bundles; and one has a single midventral pore. The single specimen from a spring near the Nestucca River has the 3 spermatheca arrangement (Fig. 7 D). Remarks The elongate, petiolate atria with numerous small prostate glands, and the very thin vasa deferentia, embedded in the thick, muscular wall of the atrium, resemble those of other Eclipidrilus species. As is usual for the genus, E. pacificus has reduced (although functional) male funnels associated with small anterior testes in IX. Morphology of the pharynx, blood vessels and nephridia are also typical for the genus (see discussion). Median, unpaired male pores also occur in Eclipidrilus asymmetricus (Smith, 1896) and E. lacustris, but neither of those species has laterally paired spermathecal pores on the chaetal lines, anterior to the chaetae. Although the general proportions of the atrium and the accessory glands at the male pore are similar to those of E. pacificus, E. asymmetricus is described as having a conspicuous proboscis and median, longitudinally paired spermathecal pores. Eclipidrilus asymmetricus is also described as lacking anterior vasa deferentia, male funnels on 9 / 10, and testes in IX, but most other characters related to the reproductive organs are inadequately described for comparison. Unfortunately, the single mature specimen used in the original description has disappeared, and a subsequent search of the type locality was unsuccessful (Wassell 1984). Typical E. pacificus specimens are distinguished from all variant populations by a penis formed of extruded atrial duct lining, and by the larger spermathecal vestibules. The atrium, the concave, epidermal pad and the accessory glands surrounding the male pore also are much larger and well developed, and the musculature surrounding both spermathecal and atrial ducts is also more extensive. The penis appears structurally similar to that of E. frigidus, but it is much more extensively developed in the latter species (see below). In the variant populations, the penis is reduced to a small papilla without obviously extrudable lining cells. The occurrence of a posteromedian spermathecal pore in IX usually distinguishes the Variant 2 specimens, from the lower Columbia River and one other site, but the variable number (1–3) of spermathecae makes it difficult to define limits that would indicate formal taxonomic status. A similar problem was noted for Eclipidrilus ithys Brinkhurst, 1998, in which atria may be paired or single. Eclipidrilus pacificus specimens from the southernmost Washington collection site (South Naselle River) may be intermediate between the typical form and Variant 1: they resemble the typical Olympic Peninsula material except that the lining cells of the penial structure are not as highly developed and elongate. The variants may correspond to geographic regions. Typical E. pacificus have been collected only in coastal drainages of Washington, with most records from the Olympic Peninsula. Variant 1 is relatively widespread, with several records from the Coast Ranges of Oregon, two from small tributaries to Puget Sound in northern Washington, and two from northern Idaho. The wide but disjunct distribution of Variant 1 records precludes morphometric analysis that could rule out clinal variation in characters. An additional problem is that specimens from some sites were not well fixed, leading to possible artifacts. Given the persistent ambiguity in species limits between E. palustris and Eclipidrilus daneus Cook, 1966 (see below), it seems best at this point to consider all E. pacificus populations as representatives of a single, variable species.Published as part of Steven & Fend, V., 2005, A review of the genus Eclipidrilus (Annelida: Clitellata: Lumbriculidae), with description of a new species from western North America, pp. 1-42 in Zootaxa 969 on pages 3-17, DOI: 10.5281/zenodo.17127
Eremidrilus humboldti Fend & Rodriguez 2020, n. sp.
No full textEremidrilus humboldti n. sp. (Figures 3, 4, 11C)Holotype. USNM 1618760. Whole worm, incomplete (tail segments missing), with sperm in anterior spermathecae, and mature egg, slide-mounted in Canada balsam. Type Locality. USA, Idaho, Blaine Co., Corral Creek at Trail Creek, 1 Jun 2008 (Site 11, Table 1), coll. S. Fend. Paratypes. MNCN 16.03 /3111, from the type locality (Site 11), 1 Jun 2008, 1 whole-mount. USNM 1618762Trail Creek at Trail Creek Road (Site 10), 30 Jun 2000, DG, 1 dissected. USNM 1618761Site 10, 5 Sep 2004, DG, 1 whole-mount. USNM 1618763, Corral Creek1 km above Trail Creek (Site 12), 1 Jun 2016, PR and SF, 1 wholemount, DNA voucher (C. Erséus pers. com.)MNCN 16.03 /3112, Site 10, 5 Sep 2004, DG, 1 dissected. All slidemounted in Canada balsam. Other material. From the type locality (Site 11), SF, 1 Jun 2008, 1 whole-mount and 1 dissected. Site 10, 5 Sep 2004, DG, 1 mature and 3 immature whole mounts; 15 Apr 2002, SF, 6 partially-mature whole mounts. Site 12, 1 Jun 2016, PR and SF, 3 whole-mounted DNA vouchers; 26 Sep 2019, SF, 3 whole mounts, all unmated. Site 13, 26 Sep 2019, SF, 8 whole mounts and 5 whole-mounted DNA vouchers. All slide-mounted in Canada balsam. Collectors: DG = Daniel L. Gustafson, PR = Pilar Rodriguez, SF = Steven Fend. Etymology. Named for the great biologist and naturalist Alexander von Humboldt, who emphasized the relationships between species diversity and their distribution, forming the basis of biogeography, and inspiring many generations of zoologists and botanists. Description. Length 12–26 mm; 54–74 segments; diameter in X 0.4–0.7 mm. Prostomium with proboscis, the latter 300–600 µm long, diameter about 80 µm at middle. Secondary segmentation well marked from IV–IX, weak in postclitellar segments (Fig. 3A). Chaetae moderately sigmoid, with nodulus slightly distal to midpoint (0.35–0.45 the distance from the tip); in anterior bundles 113–204 µm long, shorter in II, dorsals similar in length to ventrals; in mid body segments 120–216 µm long (Fig. 3B). Genital pores all on the longitudinal lines of ventral chaetae. Male pores on prominent dome-shaped porophores (26–84 µm high, 64–120 µm wide) in X, midway between chaetae and septum X/XI (Figs. 3D,E, 4A). Two pairs simple spermathecal pores in XI and XII; those in XI midway between chaetae and posterior septum; those in XII very close to posterior septum (12/13) (Fig. 3 C–E). Female pores on 11/12. Epidermis 9–24 µm thick in anterior segments, up to 40 µm in clitellum. Clitellum in X–XIII (XIV), not greatly thickened in most specimens. Pharyngeal glands in IV–VI (VII). First nephridium at 12/13 or 13/14; pores anterior to ventral chaetae, nephridial duct tubular at pore, without forming a vesicle.Sperm sacs extend anteriorly to VIII or VII, posteriorly to XIII–XIX; egg sacs extend 1–2 segments beyond. Male funnels on 9/10 and 10/11. Vasa deferentia 18–24 µm diameter, about 250–400 µm long; posterior vasa loop into XI; both vasa join the atrium near mid-length and enter the muscle layer, opening to atrial lumen near the (ental) apical end (Figs. 3 C–E, 4C). Atria short, 172–310 µm long, entirely in X, club-shaped, ampulla gradually narrows towards the pore, not clearly separated from the ectal duct; atrium length 0.3–0.5 times body width at segment X, and 2–3 times the porophore width (Fig. 4A,B). Maximum atrium diameter 38–69 µm; epithelial cells 5–10 µm thick; atrial muscle layer thin (3–6 µm); prostate glands 10–22 µm high, usually appearing as a continuous layer over most of the atrium, but in some specimens they can be seen as distinct clusters (Fig. 4C). No obvious glands at the ectal pore.Spermathecal ampullae oval or sac-like, the first pair about 150–700 µm long, the second pair similar or slightly smaller, 170–480 µm long, sometimes without sperm (Fig. 3D). Spermathecal ducts 40–85 µm long, 25–35 µm maximum diameter, tapered to the pore (Figs. 3 C–E; 4D–F); duct epithelium with columnar cells, usually with a gradual transition to the thinner epithelium of the ampulla (Figs. 3E, 4E).Remarks.Eremidrilus humboldtin. sp. resembles the Pacific Coastal E. ritocsi Fend & Rodriguez, 2003 in the size of the atrium relative to the body diameter, and the male porophore is also similar. However, E. ritocsi has only one spermathecal segment, and the spermathecal pores are near the lateral line. Spermathecal morphology also differs: ampullae are more globular in E. ritocsi, with a characteristic sperm arrangement, and ducts are longer and more tubular (Fend & Rodriguez 2003). As in other inland species described here, E. humboldtin. sp. has two spermathecal segments; spermathecae have short, tapered ducts, spermathecal pores are in line with ventral chaetal bundles, and the pores of the second pair are close to intersegment 12/13. It is distinguished from other species of the region by its small atrium (Table 2) and by the broadly rounded male porophore, with a simple pore (Fig. 4A).Published as part of Fend, Steven & Rodriguez, Pilar, 2020, New Eremidrilus species (Clitellata: Lumbriculidae) from western North America Part 1, species with two spermathecal segments, pp. 111-131 in Zootaxa 4809 (1) on pages 116-118, DOI: 10.11646/zootaxa.4809.1.6, http://zenodo.org/record/393398
Eremidrilus artzaini Fend & Rodriguez 2020, n. sp.
No full textEremidrilus artzaini n. sp. (Figures 1, 2, 11B)Holotype. USNM 1618756. Whole worm, incomplete (tail segments missing), mated with sperm in anterior spermathecae, slide-mounted in Canada balsam. Type Locality: USA, Idaho, Custer Co., East Fork Big Lost River above Willow Creek (Site 4 in Table 1), 1 Jul 2000, DG. Paratypes. USNM 1618757, from type locality (Site 4), 1 Jul 2000, DG, 1 dissected. USNM 1618758, Site 4, 1 Jul 2000, transverse histological sections. USNM 1618759, Site 6, 27 Sep 2019, SF, 1 whole-mounted anterior end, DNA voucher (C. Erséus pers. com.). MNCN 16.03 /3108, Site 1, 30 Jun 2000, DG, sagittal sections, and MNCN 16.03 /3109, Site 1, 30 Jun 2000, DG, one dissected. MNCN 16.03 /3110, Site 4, 1 Jul 2000, DG, 1 whole-mount. All slide-mounted in Canada balsam. Other material. several sites in the Big Lost River Basin, Idaho (Table 1): Site 1, 30 Jun 2000, DG, 1 wholemount and 6 dissected. Site 2, 5 Sep 2004, DG, 1 whole-mount. Site 3, 1 Jul 2000, DG, 3 dissected and 3 wholemounts; 27 Sep 2019, SF, 6 whole-mounted DNA vouchers. Site 4, 1 Jul 2000, DG, 1 sagittally sectioned, 6 dissected and 2 whole mounts. Site 5, 14 Sep 2003, DG, 3 dissected and 7 whole-mounts. Site 6, 13 Sep 03, DG, 4 dissected; 27 Sep 2019, SF, 6 whole-mounted DNA vouchers. Site 7, 5 Jun 1999, DG, 1 dissected, 1 whole-mount; 1 Jun 2008, SF, 1 dissected. Site 8, 14 Sep 2003, DG, 1 dissected. Site 9, 30 Apr 2000, DG, 1 dissected. All slidemounted in Canada balsam. Collectors: DG = Daniel L. Gustafson, SF = Steven Fend. Etymology. From "artzain", shepherd in the Basque language. The species is named for the many Basques who migrated to Idaho to work as shepherds in remote valleys. Description (based on populations from the Big Lost River Basin, Idaho). Length of preserved worms 11–19 mm; 56–75 segments; diameter in X 0.4–0.7 mm. Prostomium with proboscis, the latter 240–530 µm long, about 65 µm diameter at middle (Fig. 1A). Segmentation distinct in anterior segments; anterior secondary annulus about ¼ segment width, beginning segment IV and extending throughout body length except for clitellum. Chaetae (Figs. 1B, 2A) with nodulus median to slightly distal (about 0.4–0.5 from distal end), similar in anterior and posterior segments; within each pair, the inner chaeta is slightly longer, with a more proximal nodulus; ventral chaetae in preclitellar segments 122–192 µm, shorter in II (102–115 µm); in middle and posterior segments 127–192 µm long; dorsal chaetae 122–175 µm in anterior segments, and 120–175 µm in postclitellar segments. One pair of male pores in X, midway between chaetae and posterior septum (Fig. 1A,E,F), on short papillae (ca. 30–40 μm long) within broad, concave, ring-shaped porophores (Figs. 1C,F, 2G); porophore width 94–134 µm, height 30–72 µm; in some unmated specimens the atrial duct opens in a simple pore without a porophore. Two pairs of simple spermathecal pores, well behind ventral chaetae, on or slightly lateral to the ventral chaetal lines in XI and XII (Fig. 1A,D); those in XII very close to the posterior septum (12/13). Female pores on 11/12. Epidermis 16–28 µm thick in anterior segments, longitudinal muscles 26–44 µm thick. Clitellum (IX) X to XII, up to 36 µm thick. Pharynx mostly in II–IV, without a prominent dorsal pad; pharyngeal glands in IV–VI (VII). First nephridium on 12/13, nephridial duct without vesicle at pore.Paired testes in IX and X, ovaries in XI. Sperm sacs extend anteriorly to VIII, posteriorly to XIII or XIV; egg sacs to XV. Male funnels on 9/10 and 10/11, of similar size. Free portion of both anterior and posterior vasa deferentia 14–25 µm wide and about 320–600 µm long. Posterior vas forms a short loop in XI before entering X; both join basal part of atrial ampulla, run along outer surface a short distance, then under the muscle layer to enter atrial lumen near midpoint of the ampulla (Figs. 1E,F, 2E). Atrium petiolate, entirely in X, total length 440–720 μm; atrial duct narrow (180–300 µm long, diameter 18–30 µm), gradually widening into the elongate ampulla, and widening slightly near the ectal pore (Figs. 1C,E,F, 2B). Atrial ampulla covered by a layer of prostate cells, 10–24 µm high; layer may appear continuous (Fig. 2D), or as small, tightly-packed multicellular clusters (Fig. 2C); maximum atrium diameter in ental part of ampulla 127–205 µm; epithelial cells cuboidal, not glandular, forming a narrow layer, 3–10 µm high; atrial musculature very thick in ampulla (14–42 µm); muscle fibers arranged in an irregular, somewhat diagonal direction in the median part of the ampulla (Fig. 2 D–F). Atrium length 4–7 times porophore width, and 0.7–1.5 times body diameter in X.Spermathecae paired in XI and XII (Fig. 1E,F), either both with sperm, or only the anterior pair well-developed and filled with sperm. Spermathecal ampullae may extend into adjacent segments; ducts usually in segments XI and XII, but the second pair may extend into XIII, due to the pore location near the posterior intersegment. Ampullae irregular, sac-like, with uniform epithelial layer not glandular, about 8 µm thick; sperm appears unordered within ampulla (Fig. 2H). Spermathecal ducts short and strongly tapered, 40–150 µm long, with gradual transition to ampulla; usually with columnar cells and a narrow lumen; muscle layer thin (ca. 1 µm) (Fig. 2I,J). Ectal pores of spermathecae without glands or distinct epidermal modification.Specimens from other drainages: Two specimens from sites in other drainages (1 each from Muldoon and Hayden Creeks, both within the Snake River catchment) are similar to typical specimens in diagnostic characters, with elongate (but somewhat shorter, 320–595 µm), petiolate atria, with thick muscle layer and thin prostate layer. Male porophores are broad and slightly concave.Remarks. Externally, E. artzainin. sp. is distinguished from other Eremidrilus species by the low, concave (annular) porophore, which surrounds a small papilla terminating in the male pore. Atrial morphology differs from that of all other species in the following combination of characters: large dimensions (Table 2), petiolate form (with elongate, narrow duct), thick and complex muscular layer, very thin epithelium, and thin layer of prostate glands (see the descriptions and Fig. 11 below; see also Fig. 5 in Fend & Rodriguez 2003). Spermathecal pores are close to the posterior septa, and approximately on the ventral chaetal lines, as in other species described here; in contrast, they tend to be more laterally positioned in species having one spermathecal segment (cf. Fig. 7 in Fend & Rodriguez 2003). The posterior spermathecae (in XII) are usually smaller than the anterior pair (in XI), and may not contain sperm.Published as part of Fend, Steven & Rodriguez, Pilar, 2020, New Eremidrilus species (Clitellata: Lumbriculidae) from western North America Part 1, species with two spermathecal segments, pp. 111-131 in Zootaxa 4809 (1) on pages 113-116, DOI: 10.11646/zootaxa.4809.1.6, http://zenodo.org/record/393398
Pararhynchelmis Fend & Lenat, 2010, n. gen.
No full text<i>Pararhynchelmis</i> n. gen. <p> <b>Included species:</b> <i>Pararhynchelmis murdocki</i> <b>n. sp.</b></p> <p> <b>Diagnosis.</b> Small worms with rounded prostomium. Lateral blood vessels in middle and posterior segments unbranched. Preclitellar nephridia on 6/7. Pharynx without a distinct dorsal pad. Male pores in X, behind and slightly medial to chaetae; spermathecal pores inconspicuous, paired in VIII and IX, behind and slightly medial to chaetae; female pores on chaetal line, intersegmental on 11/12. Testes in IX and X, ovaries in XI. Spermathecae simple, roughly cylindrical; without ampulla or diverticula, connected to the gut entally. Atria petiolate, with thin duct, and club-shaped ampulla covered with multicellular prostate glands. Very short, retractable penes. Semiprosoporous; each atrium with two thin vasa deferentia; both anterior and posterior male funnels functional; posterior vasa deferentia do not form a loop in the postatrial segment or penetrate septum 10/11.</p> <p> <b>Etymology.</b> From Latin <i>para</i>, “beside”, indicating its possible close relationship to <i>Rhynchelmis</i>.</p> <p> <b>Remarks.</b> The single known <i>Pararhynchelmis</i> species, described herein, has male pores in X and spermathecal pores paired in both VIII and IX, distinguishing it from all other lumbriculids except for two Palearctic <i>Rhynchelmis</i> species (<i>Rhynchelmis tetratheca</i> Michaelsen and <i>Rhynchelmis granuensis</i> Hrabĕ). Four described genera (<i>Rhynchelmis</i>, <i>Pseudorhynchelmis</i> Hrabĕ, <i>Secubelmis</i> Fend & Gustafson 2001, and <i>Tatriella</i> Hrabĕ), plus two undescribed southeastern Nearctic species (S. Fend & D. Lenat, unpublished) have the first spermathecae located two segments anterior to the atria. Of these, only <i>Rhynchelmis</i> includes species in which the spermathecae connect to the gut (Martin & Kaygorodova 2008). Almost all described <i>Rhynchelmis</i> species have a long, filiform proboscis. The few species or subspecies without a proboscis (<i>Rhynchelmis brachycephala brachycephala</i> Michaelsen, <i>Rhynchelmis komareki brevirostra</i> Hrabĕ, and an undescribed Nearctic species [S. Fend, unpublished]) closely resemble proboscis-bearing species: they are all large worms, usually found in profundal lake habitats. The petiolate atria of <i>Pararhynchelmis</i> do not resemble those of any described <i>Rhynchelmis</i> species, and the very short, duct-like spermathecae are unique within the family. Other distinguishing characters are evaluated below, in the Discussion.</p> <p> <i>Pararhynchelmis</i> has a narrower geographic range than any of the <i>Rhynchelmis</i> subgenera or species groups. The single known species has been collected only within a single spring system in the southern Appalachian Mountains, USA.</p>Published as part of <i>Fend, Steven V. & Lenat, David R., 2010, New southeastern Nearctic Rhynchelmis (Rhynchelmoides) species and the description of Pararhynchelmis n. gen. (Annelida: Clitellata: Lumbriculidae), pp. 1-22 in Zootaxa 2554</i> on page 14, DOI: <a href="http://zenodo.org/record/196882">10.5281/zenodo.196882</a>
Rhynchelmis aleutensis n. sp. (Clitellata: Lumbriculidae) from Adak Island, Alaska
No full textFend, Steven V. (2005): Rhynchelmis aleutensis n. sp. (Clitellata: Lumbriculidae) from Adak Island, Alaska. Zootaxa 1093 (1): 45-53, DOI: 10.11646/zootaxa.1093.1.4, URL: https://biotaxa.org/Zootaxa/article/view/zootaxa.1093.1.
New Nearctic Eremidrilus species (Clitellata: Lumbriculidae). Part 2, western species with one spermathecal segment
No full textRodriguez, Pilar, Fend, Steven V. (2022): New Nearctic Eremidrilus species (Clitellata: Lumbriculidae). Part 2, western species with one spermathecal segment. Zootaxa 5159 (2): 245-264, DOI: 10.11646/zootaxa.5159.2.
New species of Rhyacodrilus (Annelida: Clitellata: Rhyacodrilinae) of North America, with re-description of R. sodalis (Eisen, 1879)
No full textRodriguez, Pilar, Fend, Steven V. (2013): New species of Rhyacodrilus (Annelida: Clitellata: Rhyacodrilinae) of North America, with re-description of R. sodalis (Eisen, 1879). Zootaxa 3664 (1): 1-44, DOI: 10.11646/zootaxa.3664.1.
Eremidrilus owyhee Rodriguez & Fend 2022, n. sp.
No full text3.4. Eremidrilus owyhee n. sp. (Figs. 2C, F; 3J–M; 6) Holotype. USNM 1593361, whole-mounted worm, slide-mounted in Canada balsam. Type Locality. Nevada, Elko Co., Bruneau River at Fawn Gulch, N 41.7594, W 115.5744, 1440 m altitude (3 June 2008). S. V. Fend coll. Paratypes. USNM 1593362–1593366, from the type locality, same collection data, 2 whole-mounted, 3 dissected on slides. CASIZ 233664–233666, 2 whole-mounted, 1 dissected on slide. USNM 1593367, Owyhee River at Beaver Creek, 27 April 2004, coll. D.L. Gustafson. MNCN 16.03 /3151, 1 transversely sectioned from Owyhee River, at Beaver Creek, 27 April 2004, coll. D.L. Gustafson. MNCN 16.03 /3152, 1 dissected and MNCN 16.03 /3153–16.03/3154, 4 whole mounts from type locality, 3 June 2008, S. V. Fend coll. Etymology. Named for the Owyhee River. The name was given to the river and the region in memory of three Hawaiian explorers lost in the region in 1819–20, during Mackenzie‘s Snake expedition (en.wikipedia.org/wiki/Owyhee_County,_ Idaho, last edited on 15 December 2021). Other material. Nevada, Elko Co., several localities, in authors’ collections. Bruneau River at Fawn Gulch (type locality), 3 June 2008, S. Fend coll., 2 dissected, 21 whole mounts. Bruneau River at Cottonwood Creek, N 41.7737, W 115.5823, 1768 m altitude, 15 July 2004, 2 whole-mounted. Owyhee River at Beaver Creek, 27 April 2004, one whole-mounted, 3 dissected, 1 transversely sectioned. Owyhee River below Wildhorse Reservoir, N 41.7259 W 115.896, 1828 m altitude, 27 March 2003, one dissected. Idaho, Camas Co., Big Smoky Creek N 43.6076, W 114.8995, 22 August 2005, 3 whole mounts. All collected by D. L. Gustafson unless otherwise indicated. Description (from type locality population). Segments 55–90. Length of fixed worms 10–19 mm, body diameter in X, 0.31–0.58 mm. Proboscis (100) 250−425 µm long, 40−64 µm diameter at middle. Segmentation distinct, with secondary annulus well marked from III to postclitellar segments (XIII−XIV) (Fig. 2C). All chaetae simplepointed and sigmoid; in anterior part of the body 100–147 µm long, those in ventral bundles usually slightly longer than dorsals, short in II 72−96 µm, and gradually longer to VII or VIII, nodulus at 0.3–0.4 chaetal length from the tip, sometimes about median in segment II. Chaetae in middle and posterior segments of similar length (112−149 µm), with nodulus distal (at 0.3–0.4 from distal end), dorsals and ventrals about equal in length (Fig. 2F). Epidermis smooth, 6–18 µm high, slightly thicker at the clitellum (14–26 µm), which extends from X to anterior part of XIII, and is formed by irregularly organized epidermal glands. Pharyngeal glands dorsal and ventral to the gut in segments (IV)V−VII; ventral lobes may be present in VIII. Nephridia with the ectal duct usually ending in a short, expanded vesicle (40–62 µm long, 25–35 µm wide) (Fig. 6H); nephridia absent in preclitellar segments. Male pores slightly lateral to ventral chaetal lines, in the posterior part of segment X, at about midway between ventral chaetae and posterior septum, opening on conical to almost cylindrical porophores of variable size (Figs. 2C; 3J–L; 6A–C), probably depending on fixation or the degree of extension (44−120 µm basal and 29–70 µm apical diameter; 80–170 µm long). Spermathecal pores just below the lateral line (Figs. 2C; 3J, M; 6A, D). Female pores in 11/12. Sperm sacs usually extend anteriorly to VIII, posteriorly to XIV−XVI; egg sacs to XV−XVIII. Vasa deferentia 12−19 µm wide and about 220−360 µm long; posterior vas forms a loop in XI (in the space of the secondary annulation of segment XI), and both vasa join the atrial wall at about the apical third of the atrium. Atrium elongated, cylindrical (208–350 µm long), very narrow (22−59 µm diameter), including muscle layer (1–6 µm thick) and lining cells (7−10 µm high). Atrial ampulla usually bent and sparsely covered by discrete clumps of prostatic cells (25−55 µm high) (Figs. 3J–L; 6C). Male duct extends through the porophore, with numerous circular muscle fibres attached to the epithelium of the duct (Figs. 3K; 6C). Large spermathecal ampullae, about 1.5 to 2 times as long as wide (65−275 µm wide; 105−460 µm long), in segment XI or may pass to the segment XII. Spermathecal ducts short (70−170 µm long) and tapered (30−65 µm wide at the middle); long transverse muscles join the spermathecal pore to the dorsal body wall; when contracted, the spermathecal pore opens within a lateral fold of the body wall (Figs. 3J; 6F, G). Sperm in ampulla forms a circular bundle that occupies most of the lumen, and part of the spermatozoids are oriented toward the epithelial cells near the duct (Fig. 6E). (a) diameter of the male porophore measured at the ectal end Remarks. Eremidrilus owyhee n. sp. is easily distinguished from all other congeneric species by the narrow atrium with well-separated prostatic glands, and by the long, protrusible male porophore (Table 2). Unlike other species in the Snake River drainage, E. owyhee n. sp. has one pair of spermathecae (in XI). The spermathecal pores are at the lateral line, resembling the position in the California species E. felini and E. ritocsi (Fend & Rodriguez 2003), but differing from all of the other known species in the genus. When retracted, the spermathecal pore opening within a lateral fold is reminiscent of the spermathecal sac of E. felini, although it is shallower and never forming a porophore-like structure when unretracted. The gut of the examined individuals contains detritus mixed with large sand grains and some diatoms. The Bruneau and Owyhee Rivers are tributaries to the Snake River, both joining it in southwestern Idaho. Most of the E. owyhee records are from upper reaches of these rivers, geographically very close to each other (see below). Both drainages are in an arid plateau region, and channels are in deeply incised canyons, with relatively sparse vegetation. Sampling sites have permanent flow throughout the year. Big Smoky Creek is more distant (approximately 200 km North), and drains to the Boise River, yet another Snake River tributary. The limited specimens appeared similar to those from the type locality, despite their proximity to type localities of two other Eremidrilus species (E. artzaini and E. humboldti) in more upstream Snake tributaries. A single, partially mature specimen resembling E. owyhee was also collected in the nearby Marys River, which drains southward to the endorheic Humboldt River (Nevada). The collection localities are intermediate between the Pacific Coastal drainages (having species with only one spermathecal segment) and the Idaho and eastern sites (having species with two spermathecal segments).Published as part of Rodriguez, Pilar & Fend, Steven V., 2022, New Nearctic Eremidrilus species (Clitellata: Lumbriculidae). Part 2, western species with one spermathecal segment, pp. 245-264 in Zootaxa 5159 (2) on pages 255-259, DOI: 10.11646/zootaxa.5159.2.4, http://zenodo.org/record/677713
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