Lumbricus rubellus Hoffmeister, 1843

Carrera-Martínez, Roberto & Callaham, Mac A., 2018, Observations on an epilobic Lumbricus rubellus (Oligochaeta, Lumbricidae) from the Great Smoky Mountains National Park, Tennessee, USA, Zootaxa 4496 (1), pp. 411-413 : 411-412

Lumbricus rubellus Hoffmeister, 1843

For a list of synonyms see Blakemore (2002).

One adult (SI.0086, collection of M.A. Callaham, Jr., USDA Forest Service ), Great Smoky Mountains National Park , Tennessee, USA (35.5538N, 83.9943W), close to Abrams Creek Shoals , coll. H. Ikeda & M.A. Callaham, Jr; 27 JULY 2011.

Length at least 30 mm (posterior amputation), width at x 3.1 mm, at clitellum 4.5 mm. Prostomium epilobic ( Fig. 1). Number of segments more than 45. First dorsal pore in 5/6, small and hidden by overlapping segments. Color of preserved specimen purple, with a pale ventrum and dark-yellowish clitellum. Setae lumbricine, closely paired. At x aa:ab:bc:cd = 10:4:13:3, dd = 1/2 of body circumference. Spermathecal pores in 9/10 and 10/11, inconspicuous and level with d. Female pores in xiv, lateral to b. Male pores in xv, lateral to b. Clitellum in xxvii– xxxii, saddle-shaped. Tubercula pubertatis in xxviii–xxxi in the ventral margin of clitellum, not well developed or differentiated. Nephridiopores anterior in each segment not forming regular rows, level with or dorsal to b.

Septa 6/7– 11/12 and 18/19 –20/21 slightly muscular, 17/18 extremely thin and delicate. Pharynx well developed, ends in v. Calciferous glands paired in xi and xii, sacks in x, and oesophagous with calciferous lamellae in xiii. Crop in xv–xvi. Gizzard in xvii–xviii, without definite boundary from the crop. Intestinal origin in xxi. Typhlosole well developed and filiform with wrinkles oriented dorsoventrally, about 3/4 of the lumen diameter, starting abruptly in xxii. Spermathecae paired in ix and x, without diverticula. Ampulla globular, with a short duct connecting with the intersegmental furrows. Seminal vesicles in ix, xi and xii, size increasing posteriorly. Those in xii extending to xiii, passing through the 12/13 septum. Testes in x and xi. Ovaries in xiii. Meganephridia tubular and coiled. Bladder J-shaped.

The internal characters of this specimen follow the diagnosis of the genus Lumbricus as defined by Fender (1985), and by Sims and Gerard (1999). Externally, the specimen follows the description of L. rubellus with the exception of its prostomium. Following the key of Schwert (1990), the epilobic L. rubellus will key to Eisenoides lonnbergi (Michaelsen) and/or Eiseniella tetraedra (Savigny) . However, it can be easily distinguished from these by the location of the clitellum, tubercula pubertatis and number of spermathecae and the spermathecal pores location relative to the setal lines. Furthermore, Eisenoides does not have calciferous sacks in x and has U-shaped nephridial bladders ( Gates 1972), whereas Lumbricus has calciferous sacks in x and J-shaped nephridia ( Fender 1985; Sims & Gerard 1999). The epilobic specimen of L. rubellus can be distinguished from El. tetraedra by the position of its clitellum in xxii, xxiii–xxvi, xxvii, tubercula pubertatis in xxiii–xxv, xxvi. Additionally, El. tetraedra usually has a smaller size of less than 60mm body length and a distinctly quadratic or trapezoid shape in cross section posteriorly ( Schwert 1990, Sims & Gerard 1999).