Eclipidrilus ithys Brinkhurst, 1998

Steven & Fend, V., 2005, A review of the genus Eclipidrilus (Annelida: Clitellata: Lumbriculidae), with description of a new species from western North America, Zootaxa 969, pp. 1-42 : 26

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 60–70º 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.

Figures

FIGURE 13. Eclipidrilus lacustris, from Swan River, Montana (A­E); E. ithys, from Spicket River, Massachusetts (F). A—muscle layers of atrial ampulla, sagittal section: fibers of inner, transversediagonal layer appear crosshatched in center, and as alternating layers in sagittally sectioned wall; thin outer layer has longitudinal fibers. B—transverse section of atrial ampulla and prostate glands; a vas deferens is embedded between the thin longitudinal muscle layer and the thick inner layer. C—male pore, showing ectal end of atrial duct and the collar of thickened epidermis; from a transverse section. D—spermathecal pore, showing end of duct with narrow, terminal sphincter, sagittal section. E—spermathecal ampulla and part of duct; thin­walled ectal part of ampulla is to the left, thick­walled ental part to the right; sagittal section. F—ectal part of atrial duct, showing undifferentiated lining cells. Abbreviations: ag—accessory gland; ep—epithelium; lm—longitudinal muscle; muPmuscle; sa—spermathecal ampulla; sd—spermathecal duct; sp—spermathecal pore; tmtransverse­diagonal muscle. Scale bars 50 µm.