Sylphella puccoon gen. n., sp n. and two additional new species of aquatic oligochaetes (Lumbriculidae, Clitellata) from poorly-known lotic habitats in North Carolina (USA)

Three new species of Lumbriculidae were collected from floodplain seeps and small streams in southeastern North America. Some of these habitats are naturally acidic. Sylphella puccoon gen. n., sp. n. has prosoporous male ducts in X-XI, and spermathecae in XII-XIII. Muscular, spherical atrial ampullae and acuminate penial sheaths distinguish this monotypic new genus from other lumbriculid genera having similar arrangements of reproductive organs. Cookidrilus pocosinus sp. n. resembles its two subterranean, Palearctic congeners in the arrangement of reproductive organs, but is easily distinguished by the position of the spermathecal pores in front of the chaetae in X-XIII. Stylodrilus coreyi sp. n. differs from congeners having simple-pointed chaetae and elongate atria primarily by the structure of the male duct and the large clusters of prostate cells. Streams and wetlands of Southeastern USA have a remarkably high diversity of endemic lumbriculids, and these poorly-known invertebrates should be considered in conservation efforts.We are grateful to Dr Akifumi Ohtaka for putting at our disposal Yamaguchi's histological preparations of Lumbriculus japonicus, as well as a specimen of Styloscolex japonicus. We thank Mark Wetzel and Christer Erseus for valuable comments on the manuscript. This work was made possible for the first author thanks to a sabbatical permit of the University of the Basque Country (from October 2010 to September 2011), partially supported by the Basque Government research project GIU10/140, and to Cindy Brown for providing access to laboratory facilities at the US Geological Survey Menlo Park campus (CA, USA) during P. Rodriguez's sabbatical period

Sediment-Water Interactions Affecting Dissolved-Mercury Distributions in Camp Far West Reservoir, California

Field and laboratory studies were conducted in April and November 2002 to provide the first direct measurements of the benthic flux of dissolved (0.2-micrometer filtered) mercury species (total and methylated forms) between the bottom sediment and water column at three sampling locations within Camp Far West Reservoir, California: one near the Bear River inlet to the reservoir, a second at a mid-reservoir site of comparable depth to the inlet site, and the third at the deepest position in the reservoir near the dam (herein referred to as the inlet, midreservoir and near-dam sites, respectively; Background, Fig. 1). Because of interest in the effects of historic hydraulic mining and ore processing in the Sierra Nevada foothills just upstream of the reservoir, dissolved-mercury species and predominant ligands that often control the mercury speciation (represented by dissolved organic carbon, and sulfides) were the solutes of primary interest. Benthic flux, sometimes referred to as internal recycling, represents the transport of dissolved chemical species between the water column and the underlying sediment. Because of the affinity of mercury to adsorb onto particle surfaces and to form insoluble precipitates (particularly with sulfides), the mass transport of mercury in mining-affected watersheds is typically particle dominated. As these enriched particles accumulate at depositional sites such as reservoirs, benthic processes facilitate the repartitioning, transformation, and transport of mercury in dissolved, biologically reactive forms (dissolved methylmercury being the most bioavailable for trophic transfer). These are the forms of mercury examined in this study. In contrast to typical scientific manuscripts, this report is formatted in a pyramid-like structure to serve the needs of diverse groups who may be interested in reviewing or acquiring information at various levels of technical detail (Appendix 1). The report enables quick transitions between the initial summary information (figuratively at the top of the pyramid) and the later details of methods or results (figuratively towards the base of the pyramid) using hyperlinks to supporting figures and tables, and an electronically linked Table of Contents. During two sampling events, two replicate sediment cores (Coring methods; Fig. 2) from each of three reservoir locations (Fig. 1) were used in incubation experiments to provide flux estimates and benthic biological characterizations. Incubation of these cores provided “snapshots” of solute flux across the sediment-water interface in the reservoir, under benthic, environmental conditions representative of the time and place of collection. Ancillary data, including nutrient and ligand fluxes, were gathered to provide a water-quality framework from which to compare the results for mercury

Eclipidrilus fontanus Wassell 1984

Eclipidrilus fontanus Wassell, 1984 MATERIAL EXAMINED: Pennsylvania: Somerset Co.: Forbes State Forest, Wildcat Spring, 22.VII. 1978, collected by J.T. Wassell. Paratypes, USNM 68643, 6 whole mounts. USNM 68645, sagittally sectioned worm. Supplementary description Ventral wall of pharynx much thinner than dorsal at least to III. One or two pairs of lateral vessels present in posterior segments, not obviously branched, but difficult to see. First nephridia single or paired on 6 / 7. Male pores on small papillae formed by tips of atrial ducts, within shallow sacs, surrounded by accessory glands. Ectal ends of atrial ducts with thin lining of more or less cuboidal cells. Vasa deferentia very thin, as narrow as 5 µm. Atrial ampulla muscle fibers nearly transverse entally and nearly longitudinal ectally, but apparently not divided into distinct layers. Middle layers appear crosshatched, with opposing spirals (possibly not clear due to poor fixation). Epithelium of atrial ampullae very thin, about 2–3 µm. Prostatic cells in small bundles; prostate glands appear sparse compared with other Eclipidrilus species. Spermathecal pores surrounded by a ring of petiolate accessory glands; ectal ducts of spermathecae cylindrical, slightly expanded at the ectal end, but without distinct vestibules. Spermathecal ampullae with sperm; cells in ental part may be slightly larger and vacuolated compared with those in ectal part.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 page 26, DOI: 10.5281/zenodo.17127

Eclipidrilus lacustris Verrill

Eclipidrilus lacustris (Verrill) (Figures 13–14) MATERIAL EXAMINED: Canada: Ontario: Lake Superior, Saint Ignace Island, south side, 1871. USNM 17947, paralectotypes: 3 whole mounted worms on one slide, labeled O­ 104; 2 sagittally sectioned worms, series labeled O­ 12 and O­ 480; 1 transversely sectioned, series labeled O­ 11. United Kingdom: Wales: Bala Lake, collected by D. Cook, R. Brinkhurst collection. 2 longitudinally sectioned worms (1 sagittal, 1 horizontal). USA: Montana: Granite Co.: Ranch Creek, 22.VI. 1997. 1 dissected. Missoula Co.: Bitterroot River at Maclay Flats, 46 º 50 ’ 16 ”N, 114 º06’01”W, 11.XI. 2001. 1 mature and 2 partially mature, dissected. Clearwater River below Seeley Lake, 47 º 10 ’ 13 ”N, 113 º 28 ’ 50 ”W, 12.IV. 1997. 2 dissected, partially mature. Swan River, 47 º 25 ’ 24 ”N, 113 º 40 ’05”W, 26.VI. 1999. 2 whole mounts, 9 dissected, 1 sagittally sectioned, 1 transversely sectioned. Ravalli Co.: North Burnt Fork Creek, 46 º 31 ’09”N, 114 º03’ 49 ”W, 10.III. 1997. 1 dissected. All Montana specimens collected by D. L. Gustafson. Oregon: Jackson Co: Rogue River near Grants Pass, 42 º 24 ’ 45 ”N, 123 º07’ 36 ”W, collected by S. Fend, 1.VI. 2003. 7 dissected. Rogue River at Gold Hill, 42 º 25 ’ 50 ”N, 123 º02’ 45 ”W, collected by S. Fend, 28.IV. 2004. 5 whole mounts. Supplementary description Pharynx thickened dorsally from middle of I and ventrally from mid­II or 2 / 3; ventral wall nearly as thick as dorsal (Fig. 14 B). One pair of long, convoluted commissural blood vessels in preclitellar segments; their insertion in the ventral vessel usually 1 segment posterior to insertion in the dorsal vessel. Anterior end of each segment from XIII to about XX or XXII with one pair of thick, lateral blood vessels which join perivisceral sinus at lower side of gut; these vessels usually unbranched or with few short branches. Posterior segments usually have two pairs of thinner lateral vessels, with numerous, short, blind branches or caecae in at least the posterior 1 / 2 of the body. Nephridial arrangement and morphology as described for E. pacificus (see above). Testes in IX smaller than those in X. Sperm sacs and male funnels without mature sperm, but some apparent morulae may be present in both anterior and posterior sacs. Mature eggs present. Anterior male funnels small but ciliated and convoluted; posterior funnel much larger and highly convoluted. Vasa deferentia 10–17 µm in diameter. Male pore within a short (40–100 µm tall by 115–140 µm wide) collar of elongate epidermal cells; a small papilla may be present, but most specimens without penes or other duct modifications (Fig. 13 C). Collar may be retracted into the body, forming a shallow pit. Cells of collar interspersed with ducts from petiolate accessory glands. Ectal duct of atrium mostly cylindrical, but tapered in the ectal 1 / 3; a thin layer of muscle with nearly transverse fibers in opposing spirals is surrounded by loosely­packed longitudinal muscle. Epithelial cells of the ectal duct are cuboidal to somewhat columnar. Musculature of atrial ampulla in 2 main layers (Fig. 13 A–B). Outer layer 4–11 µm thick; fibers arranged longitudinally (parallel to long axis of atrium). Inner layer 32–80 µm thick; fibers arranged diagonally in opposing spirals at a 60–70 º angle from the longitudinal axis (Fig. 13 A), but may be nearly transverse in innermost part. In sagittal sections the inner layer appears as many thin (2–3 µm thick) lamellae having alternating orientation, but in surface view they appear as a crosshatched pattern (Fig. 13 A). Atrial epithelium very thin and often indistinct. Lumen of ampulla 90–180 µm wide, or 0.4–0.7 times atrium diameter. Prostate glands petiolate, usually numerous over entire atrial ampulla (Fig. 13 B); 50–90 µm tall in Montana specimens, to 120 µm in Oregon specimens, and over 200 µm in some Lake Superior and Lake Bala specimens. Spermathecal duct cylindrical, terminating abruptly in a narrow sphincter of transverse­circular muscle (Fig. 13 D). Spermathecal pore midventral, slightly behind chaetae in IX, within a small pad of slightly thickened epidermis, surrounded by a cluster of petiolate accessory glands. Spermathecal ampulla ovate to pear­shaped with narrowed ental end. Ampulla has thin (12 µm), cuboidal epithelium in about the ectal 1 / 3; an amorphous mass of undetermined material is contained within this portion (Fig. 13 E). Epithelium in the ental 2 / 3 with thick (30–50 µm), vacuolated cells. Vacuoles contain substance staining with eosin Y in the Montana specimens, and with an unknown stain in the Lake Superior and Lake Bala specimens. One Lake Superior specimen has a second spermatheca with the pore in the anterior half of IX. Remarks All specimens of this widely distributed species were morphologically similar. The Lake Superior specimens are from the series described by Smith (1919) and redescribed by Brinkhurst (1998); material from Lake Bala (presumably introduced) was apparently from a series described by Cook (1967). The blood vessels, pharyngeal glands, atrial musculature and vasa deferentia of the new material correspond to earlier descriptions by Smith (1919) and Cook (1967). Cook described the prostate glands as a “diffuse layer”, but the present material has distinct prostatic cell bundles. Cook also described (without illustration) a “small, protrusible” penis. Brinkhurst (1998, Fig. 5 B,E) described and illustrated a small papilla within a shallow penial sac, surrounded by “lips” (= the “collar” in the present account), and implied that the end of the atrial duct may be protrusible. The new material generally resembles the latter description, but there is no evidence of a distinct penis: most specimens lacked an ectal papilla, and neither duct nor lining cells was extruded in any of the specimens. The ectal duct extends vertically within the body, with no evidence of a stiffening or retracting structure, and the lining is not detached from the muscle layer. Many specimens had well­developed testes, ovaries, and clitellum, and mature eggs within the egg sacs, but neither the new material nor the museum specimens had mature sperm in sperm sacs, on male funnels, or in spermathecae. The amorphous contents of the spermathecal ampullae and the darkly staining material in the epithelial cells suggest a secretory function (M. Ferraguti, personal communication). It is unlikely that all individuals were at a post­mature state on the multiple sampling dates; consequently, it appears that the examined populations are parthenogenetic. As this condition was not reported in previous descriptions, this may not be the general case for the 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 22-25, DOI: 10.5281/zenodo.17127

Eclipidrilus daneus Cook 1966

Eclipidrilus daneus Cook, 1966 MATERIAL EXAMINED: Louisiana: undetermined locality, 1.VI. 1916, Paratypes, USNM 32908: the better material in 2 atrial dissections, 4 sagittally sectioned worms and 2 transversely sectioned. Mississippi: Hancock Co., Bay St. Louis, VI. 1996. 1 mature, dissected; 3 whole mounts of immature specimens, from the R. Brinkhurst collection. South Carolina: Aiken Co., Savannah River Plant Site, Fourmile Branch, 13.III. 2002, collected by J. Epler. 1 dissected. Montana: Swamp near Polson, 7.VII. 1914, USNM 26301: 1 sagittal and 1 transversely sectioned worm. Supplementary description Pharynx thicker dorsally than ventrally. Usually two pairs of lateral blood vessels in segments behind XII, with many short branches posterior to XV. In the posterior half of the body, short branches have distended ends and appear to be associated with the body wall muscles. In middle segments, at least, one branch appears to join the perivisceral sinus, but others end in the coelom. Nephridia as described for E. pacificus (see above). Male pores medial to chaetae, about halfway between chaetae and midventral line. Penes as described for E. palustris (see above); may be coiled within the penial sacs. In the Bay St. Louis specimen, the inner sacs of the penial structures are up to 1880 µm long; the protruded part of one penis extends an additional 1100 µm. Atrial ampulla with muscle wall 12–23 µm thick; a thin ental layer of circular muscle is surrounded by a thicker outer layer having muscle fibers arranged in an unopposed spiral, up to 50 º from the longitudinal axis, but often nearly parallel in ectal part of ampulla. Atrial lumen 0.66–0.73 times total diameter of atrial muscle tube. Prostate glands may be large, to 180 µm long (Brinkhurst [1998, Figure 4 E]). Vasa deferentia 11–26 µm thick, joining atria near ectal end of ampulla. Spermathecal pores about halfway between chaetae and midventral line. Spermathecal ducts terminate in a vestibule as described for E. palustris (see above). Remarks The distinction between this species and E. palustris is slight, and Cook (1971) suggested that future study might invalidate E. daneus. In the original daneus description, Cook (1966) stated that the two species differed mainly in thickness of the atrial musculature, and possibly as a consequence, in the degree of atrial curvature. E. palustris was distinguished as having an atrial lumen: total atrial diameter ratio of 0.3, as opposed to a ratio of 0.6–0.9 in E. daneus. Cook (1971) gave ranges of atrial muscle thickness from 60–100 µm in E. palustris, and 6–20 µm in E. daneus. Wassell (1984) confirmed these ranges after examining new material from several sites in Florida (E. palustris) and Louisiana (E. daneus), although values presented in Brinkhurst (1998) implied greater variation for E. daneus. Cook (1966) also described E. daneus as having thinner and less muscular penial structures than E. palustris, but this character also varied considerably within populations considered to be E. palustris. Brinkhurst (1998) suggested that some E. daneus specimens with thin or crumpled penial structures were in a post­reproductive state, implying that that some of the observed differences may relate to reproductive maturity of individual specimens. Two additional characters not emphasized in earlier descriptions may be of use in distinguishing these species. The internal, ventral pads of cells in X of E. palustris were not apparent in the E. daneus material (cf. Brinkhurst [1998, Fig. 4 A]). Prostate glands were generally larger in specimens identified as E. daneus, but there was considerable intraspecific variation in that character. The new specimens from Florida and Alabama generally appeared closer to E. palustris than to E. daneus, consistent with prior distributional records. However, the atrial muscle thickness and lumen: atrium ratios were quite variable within populations, and were often intermediate between published values for the two species. One exceptional specimen from Rock Springs Run had thin­walled, folded atrial ampullae, resembling the description of E. daneus. Nevertheless, the small prostates and well­developed ventral pad of that specimen, plus its collection from a population of normal palustris, suggested that it was an aberrant E. palustris. As in the case of the penial structures, some of the variation in atrial morphology may be attributable to reproductive maturity. Additionally, the range in contraction of observed worm specimens implied variability in fixation methods. This sort of variation may also occur in other species. The lumen and tissue layers in the atrial ampulla varied either intraspecifically or with reproductive maturity in E. pacificus: ratios ranged from 0.1 to 0.6 in mated specimens from the type locality, and greater differences occurred among populations. As in the case of the E. pacificus variants, future collections from intermediate localities may determine whether differences among geographic forms of E. (Premnodrilus) represent distinctive species or clinal variation.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 31-32, DOI: 10.5281/zenodo.17127

Eclipidrilus frigidus Eisen 1881

Eclipidrilus frigidus Eisen, 1881 (Figures 11–12) MATERIAL EXAMINED: California: Amador Co.: Mokelumne River near Tiger Creek afterbay, collected by W. C. Fields, 8.VIII. 1999. 1 dissected. Calaveras Co.: small spring near Calaveras Big Trees State Park, 10.XI. 1996. 2 whole mounts. Plumas Co.: Upper Butt Valley Creek, collected by W. C. Fields. 1 whole mount, 6 dissected. Sierra Co.: Big Spring near Bassets, at North Yuba River, 39 º 35 ’ 47 ”N, 120 º 36 ’ 38 ”W, 9.VIII. 1996. 1 dissected, 6 sagittally sectioned, 1 transversely sectioned. 4.XI. 2002. 6 dissected. Trinity Co.: small creek, east side of Clair Engle Lake, 13.V. 2001. 1 dissected. Tuolumne Co.: North Fork Stanislaus River, 4.XII. 1996, collected by B. Quelvog. 2 dissected. Yuba Co.: Jackass Creek at Deadwood Creek, tributary to North Yuba River, 39 º 32 ’ 48 ”N, 121 º05’ 34 ”W, 26.IX. 2000. 10 dissected, 5 sagittally sectioned, all partially mature. Deadwood Creek, 5.X. 1999, collected by W. C. Fields. 1 dissected, 1 whole mount. Idaho: Boise Co.: Little Gallagher Creek, tributary to South Fork Payette River, 30.V. 1996. 1 dissected, 1 sagittally sectioned. Idaho Co.: Crooked River, 45 º 47 ’ 29 ”N, 115 º 32 ’ 47 ”W, 1.VII. 2002, collected by D. L. Gustafson. 2 dissected. O'Hara Creek at Selway River, 46 º05’06”N, 115 º 31 ’03”W, 3.IV. 2001, collected by D. L. Gustafson. 2 dissected. Rainy Day Creek at mouth, 45 º 48 ’ 10 ”N, 115 º 41 ’ 38 ”W, 1.VII. 2002, collected by D. L. Gustafson. 2 dissected. Snake Creek at mouth, 45 º 51 ’00”N, 114 º 44 ’ 24 ”W, 7.X. 2001, collected by D. L. Gustafson. 1 dissected. Worms collected by S. Fend unless otherwise noted. Supplementary description Dorsal wall of pharynx much thicker than ventral wall anterior to IV; esophagus begins near 4 / 5. Some specimens with branched lateral blood vessels in posterior 1 / 3 of body, as described by Eisen (1885); other specimens with very short, blind lateral vessels that do not appear to be branched, and others with no apparent lateral vessels in posterior segments. Nephridial arrangement and morphology as described for E. pacificus (see above). Specimens from Idaho have small, external papillae posterolateral to the male pores (Fig. 11 A). Penial structures very long (1000–1700 µm) and cylindrical, covered with a longitudinal muscle layer and a very thin, inner circular muscle layer. The muscle tube surrounds a thick layer of narrow epithelial cells, with basal nuclei. In the ectal 1 / 2 to 2 / 3 of the structure, these cells are very elongate and appear fibrous, similar to muscle tissue (Fig. 12 C), and the lumen is narrow and possibly cuticular. The lumen is variably coiled in most specimens (Fig. 11 C,F), but may straighten when the penis is extruded (Fig. 11 B). The lumen gradually widens and becomes ciliated in the ental portion of the penial structure. Penial structures terminate on short papillae (or “collars” as termed by Eisen 1895), contained within small sacs (Figs. 11 F, 12 A; see also Brinkhurst [1998, Fig. 1 B]); ectally, the sacs terminate in small folds in the epidermis, which form the external male pores (Fig. 11 F). Small retractor muscles join the sacs to the body wall, dorsally at 10 / 11. In most mated specimens, fibrous extensions of lining cells are extruded through the terminal papillae to some extent, forming the actual penes. The extruded penes form a loose spiral, and may be contained within the penial sac (Figs. 11 F, 12 A) or extruded beyond the body wall (Figs. 11 B–C). Male pores without distinct accessory glands. Atrial ampullae 450–1450 µm long; nearly cylindrical but tapered ectally. Musculature of atrial ampulla with outer layer 7–24 (12) µm thick, of variably spiral muscle, with fibers in thin, radiating lamellae (Fig. 12 E) usually arranged at an angle about 20 º to the long axis (Fig. 12 D), but ranging from parallel in some specimens to about 50 º in one Idaho specimen. Inner, transverse­circular muscle layer 1–5 µm thick, orthogonal to the long axis of the atrium (Fig. 12 E). Thickness of both muscle layers decreases with distension of atrium. Vasa deferentia narrow, diameter about 12 µm. Anterior male funnels with or without sperm, slightly smaller and thinner than posterior pair; testes in IX usually smaller than those in X. Numerous prostate glands are petiolate bundles of less than 10 cells each; length 25–50 µm (Fig. 12 E). Spermathecal ducts complex. Ectal end of duct apparently an epidermal fold up to 200 µm deep; this section surrounded by a distinct transverse­circular muscle layer under a thinner longitudinal layer (Figs. 11 G–I, 12 F). In middle portion, each spermathecal duct widens into a globular expansion, 110–200 µm wide; elongate lining cells form irregular, transverse lamellae extending into the lumen (Figs. 11 G–I, 12 F). Epithelium of spermathecal ampullae similar throughout or up to twice as thick entally versus ectally; cells are never highly vacuolated. Ampullae may be irregularly ovate (Fig. 11 H), or rounded ectally, with a narrowed ental “diverticulum” (Fig. 11 G). Sperm loosely packed throughout ampullae in all mated worms. Remarks Earlier descriptions of E. frigidus copulatory structures have been somewhat contradictory, due to limitations in the available material. Wassell (1984) stated that the penis was “formed from tissue lining anterior inside of atrium”, but also made the confusing statement that it was “continuous with the body wall muscles anteriorly”. Brinkhurst (1998) noted that in some lumbriculids the penis is composed of elongated lining cells, and Figure 1 B of that paper showed a retracted E. frigidus penis with what appear to be elongate, fibrous lining cells, as in the new material. Nevertheless, he suggested that the penis of E. frigidus was eversible because the lining at the ectal end appeared detached from the muscle in a lectotype. The lining did not appear detached in the new material (Fig. 12 C), suggesting that the appearance of the lectotype specimen was an artifact of fixation. Material examined by the above authors apparently did not include specimens with extended penes, but several of the new specimens have extended penes that appear to be formed of extruded (elongated) atrial lining cells. Gradual modification of the atrial duct lining was observed in partially mature worms (Figs. 11 D–F and 12 A–B); this derivation of the penial structure contrasts with the development of pendant penes in E. palustris (see below, Fig. 15 C). Coiling of the lumen in fully mature E. frigidus may be caused by contraction of a cuticular lining within the retracted penis, which further implies that the penis is extended by elongation rather than eversion. Other than the short papilla or collar within the ectal sac, there is no obvious pendant penis at any stage of development. Therefore, the primary mechanism appears to be extrusion of the duct lining. Although none of the new specimens had everted penial sacs, Brinkhurst (1998, Fig. 1 B) indicated that the sac is eversible, and may also contribute to penial extension. The musculature of the atrial ampulla was not discussed in detail by Brinkhurst (1998), although it was described as “spiral” in one specimen. Eisen (1895) described a thin circular layer and an exterior “spirally wound layer of longitudinal muscles” covering the penial structure, and implied that the same layers also covered the ampulla. The degree of spiraling in the new material, here indicated by divergence of the muscle fibers from the longitudinal axis, varies considerably within and among specimens, but is usually less than in the E. (Premnodrilus) or E. (Leptodrilus) species. Neither muscle layer has the crosshatched pattern seen in the inner muscle layer of E. lacustris (see below). Somatic characters of the new material generally agree with the original description (Eisen, 1895), except that the branching of lateral blood vessels in posterior segments is usually not pronounced. However, the lateral vessels were often difficult to see, especially in worms with gut contents. Eisen described nephridia as occurring in several preclitellar segments, as far forward as 3 / 4, but the most anterior nephridia in the new material were always on 6 / 7, and the next on 12 / 13. Eclipidrilus frigidus has only been confirmed from California and Idaho. Mature Idaho specimens have small, external lobes, possibly functioning as claspers, posterolateral to the male pores on 10 / 11; these were not seen in the California material. Despite the apparent geographic range disjunction, there is little else to distinguish specimens from these two regions.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 17-22, DOI: 10.5281/zenodo.17127

Rhynchelmis aleutensis n. sp. (Clitellata: Lumbriculidae) from Adak Island, Alaska

Fend, 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.

Eclipidrilus palustris Smith 1900

Eclipidrilus palustris (Smith, 1900) (Figures 15–16) MATERIAL EXAMINED: Alabama: Cleburne Co.: stream in Talladega National Forest, near Coleman Lake, collected by K. Fritz, 1 mature and 2 nearly mature, unmated worms, dissected. Florida: Polk Co.: “in a decayed stump in a marsh”, III. 1897, collected by A. Hempel, from the collection of F. Smith; Paratypes, USNM 0 25509. 1 sagittally sectioned, 1 transversely sectioned, 1 dissected atrium and spermatheca. Columbia Co.: Suwannee River at SR 6, near Benton, 6.XI. 2002, collected by J. Epler. 2 dissected. Hamilton Co.: Roaring Creek, 23.X. 1996, collected by J. Epler. 1 dissected. Hogan’s Branch, north of White Springs, 25.X. 1997, collected by J. Epler. 2 dissected. Orange Co.: Rock Springs Run, 1 / 2 km upstream of Wekiwa Springs, in shallow, sandy riffle, 3.XII. 2002, collected by S. Fend. 3 dissected, 1 transversely sectioned, 1 sagittally sectioned. Small tributary to Rock Springs Run, near source, in leaf deposits, 3.III. 2005, collected by S. Fend. 12 dissected. Tootoosahatchee Creek near Christmas, in shallow, sandy riffle, 6.XII. 2002, collected by S. Fend. 4 dissected, 1 sectioned, all partially mature; 1 sectioned, nearly mature. Supplementary description Pharynx II–IV; much thinner ventrally than dorsally or laterally. Anterior segments with a single pair of highly convoluted commissural blood vessels. Each segment posterior to about X with two pairs of variably branched lateral vessels; they are highly branched in posterior segments. In middle segments, at least, one branch of the lateral vessels joins the perivisceral sinus, but others end in the coelom. Nephridia paired, single or absent on 6 / 7; the next on or posterior to 12 / 13. Ventral chaetal bundles in IX and X slightly medial to those in other segments; ventral chaetae in X often smaller than those in adjacent segments. Male pores distinctly medial to chaetae in X, and spermathecal pores slightly medial to ventral chaetae in IX (Fig. 15 A). Female pores in line with ventral chaetae at 11 / 12. Mature and partially mature worms with testes in X only. Anterior male funnels (on 9 / 10) smaller than posterior male funnels; vasa deferentia to 16 µm in diameter. Internal pads of cells up to 150 µm thick cover much of the ventral body wall of X, anterior to male pores (Fig. 16 A). In some specimens the ventral pads appear glandular, interspersed with muscle fibers, but in others they appear predominantly muscular. Anteriorly, some muscle fibers coalesce into a band extending to dorsolateral wall of body near 9 / 10 (Fig. 16 A). Posteriorly, some muscle fibers join 10 / 11. Each male pore within a shallow fold of thin epidermis subtending a short (60–70 µm), conical papilla, which forms a sheath surrounding the penis when protruded (Figs. 15 B, 16 B). Ental to the papillae, deep penial sacs typically extend posteriorly into XIII. The penial sacs are not greatly contracted when the penes are protruded: the sacs were the same length (1130 µm) in one specimen with one penis extended 850 µm beyond body wall and the other retracted; in another worm one sac was 1040 µm long, with the penis extending 980 µm. In some specimens the sacs were much shorter (about 600 µm, extending into XI), with retracted penes. Each penial sac surrounded by a very thin, transversecircular inner muscle layer (often indistinct), and a 15–50 µm longitudinal to somewhat spiral outer layer (Fig. 16 C; see also Brinkhurst [1998, Fig. 2 C–D]). Ental end of sac bulblike, connected to a muscle band which usually joins the dorsal body wall musculature in XIV. Sac epithelium continuous with outer wall of the penis (Brinkhurst [1998, Fig. 3 A]). Outer and inner epithelial layers of penis joined by sparse, oblique fibers of apparent muscle tissue, particularly in ental half (Brinkhurst [1998 Fig. 2 D, 3 A]). Outer wall of penis is a thin layer of flattened cells (Brinkhurst [1998, Fig. 2 D]). Lumen of penis is variably twisted in ectal part (Fig. 15 B). Penes may be folded or coiled within the sacs when retracted. Penial structures of worms from other sites may be much smaller than those from the type locality, but morphology otherwise similar. Inner epithelium of penis continuous with epithelium of atrial duct. Entally, the atrial duct widens into the ampulla; ampulla has thin (about 3 µm) epithelium, surrounded by two muscle layers (Fig. 16 F; see also Brinkhurst [1998 Fig. 2 C]). Inner atrial muscle layer thin (2–7 µm) and transverse­circular; outer longitudinal­spiral layer thick: about 80 µm in the type series; 36–100 µm in worms from other sites, with fibers arranged at 30–60 º from longitudinal axis of ampulla (Fig. 16 G). Ratio of maximum lumen width to atrial muscle tube diameter about 0.3 in 3 specimens from the type locality. In most Rock Springs Run specimens, the ratio varied from 0.27–0.55 (median 0.37). One exceptional specimen from that site had thin­walled, folded atrial ampullae (27 µm muscle layer and ratio 0.76); the small prostates and thick pad anterior to the male pores resembled other members of the population. Outer muscle layer fibers may be nearly parallel to longitudinal axis of ampulla in ectal part (Fig. 16 H). Prostatic cells in small, petiolate clusters 50–120 µm long cover most of ampulla (Fig. 16 F,G). Spermathecal ducts terminate in narrow vestibules, 100–250 µm deep, filled with irregular, transverse lamellae composed of elongate epithelial cells (Fig. 16 E). Epithelium of spermathecal ampulla thin (14–24 µm) in about the ectal 1 / 3 – 1 / 4; most sperm is in this area, unordered but densely packed. Remainder of ampulla with thick epithelium (about 35 µm), having basal nuclei (Brinkhurst [1998, Fig. 2 A]). In partially mature specimens, penial sacs extend only into XI, and retractor muscles appear to join the body wall musculature in XII. Penes conical, 1 / 3 to 2 / 3 the length of penial sacs (Figs. 15 C, 16 D), appearing as simple folds of sac lining and containing attenuated ectal ends of atrial ducts. Outer penial folds and glandular pads not present, but a mass of cells extends forward from base of penial structure at male pore. Atrial ampulla weakly differentiated from duct, with thick epithelium (ca. 16 µm), a thin layer of muscle, and an outer layer of loosely packed cells, some of which are in weak clusters. In a nearly mature specimen, penial structures extend to 12 / 13, the retractor muscle to 13 / 14, and elongate penes extend to near the male pore. The small epidermal fold is partially formed; the pads of cells anterior to the male pores have thin cell extensions extending through the body wall musculature to the epidermis. Spermathecal vestibule similar to that of mature worm, but ampulla small, ovoid, with cuboidal epithelium. Remarks The elongate, highly modified penes of mature worms develop from simple extensions of the atrial ducts, contained within folds in the penial sacs. The penes of partially developed E. palustris resemble fully developed penes of some other lumbriculids, such as Rhynchelmis rostrata Eisen (cf. Fend and Brinkhurst [2000, Fig. 57]). The highly modified cell types of the mature worms develop gradually as the penes lengthen within the sacs. The small epidermal folds, which resemble the penial sacs of some other lumbriculids, appear late in the development. The length and diameter of the penial structure in mature worms is quite variable, but does not appear strongly related to penial extension. Therefore, the extensive musculature surrounding the sac, including the ental “retractors” (or “retainers”, as suggested by Brinkhurst [1998]), appears to provide structural rigidity rather than directly extending the penis by contracting the sac. Protrusion thus appears to result at least in part from lengthening the penis itself. Brinkhurst (1998) suggested that the E. (Premnodrilus) penis is everted during extension, but the observation that the sinuate lumen straightens during extension suggests lengthening of the surrounding tissue. A possible mechanism would be contraction of the thin muscle strands within the penis, which may increase turgor as the expanded base is contracted. The “cuticularized penis sheath” mentioned by Wassell (1984) was not prominent or rigid in material examined in the present study, and penes were usually somewhat coiled or even folded back within the sacs in this species as well as in E. daneus. The small epidermal folds were often seen in an everted state, with the short papillae visible externally (Fig. 15 B); this may be controlled by action of the retractor muscles.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 27-31, DOI: 10.5281/zenodo.17127

Eclipidrilus ithys Brinkhurst 1998

Eclipidrilus ithys Brinkhurst, 1998 (Figure 13 F) MATERIAL EXAMINED: Massachusetts: Essex Co.: Spicket River, Lawrence, 28.V. 1996, collected by D. Grasso, B. Wamsley and R.D. Kathman. Paratypes, USNM 177000, 2 sagittally sectioned. From R. Brinkhurst collection, 28.V. 1996. 1 whole mount, 4 longitudinally dissected, 2 dissected atria, 2 sagittally sectioned. Supplementary description Dorsal wall of pharynx well developed from II–IV; ventral wall very thin anteriorly, but thickened from mid­III through IV. Blood vessels as described for E. lacustris (see above). Nephridial arrangement as described for E. pacificus (see above); with a continuous, midventral mass of tubules posterior to XIII. Male pores as described for E. lacustris (see above). Ectal part of each male duct slightly thickened and fusiform, but otherwise unmodified, with normal cuboidal epithelium (Fig. 13 F). Atrial ampulla with 10–33 µm thick inner muscle layer having diagonal, crosshatched fibers arranged at 60–70 º to the long axis. A thin (2–3 µm) outer muscle layer is parallel to the longitudinal axis. Lumen of ampulla 80–200 µm wide, or 0.6–0.8 times atrium diameter. Prostate glands small (25–90 µm long) and numerous; atrial duct muscle layers similar to those of ampulla, but thinner. Vasa deferentia thin (8–11 µm). Mature eggs present, but sperm absent from male funnels; sperm sacs with partially developed morulae, but no mature sperm. Spermathecal ducts long and cylindrical, terminating in sphincters with circular muscle as described for E. lacustris; pores in a shallow pit surrounded by petiolate gland masses. Histology of spermathecal ampullae as described for E. lacustris; ental epithelium and lumen contain eosin­staining substance, and sperm absent from lumen.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 page 26, DOI: 10.5281/zenodo.17127