Fimoscolex elkeae Dudas, James, Brown & Bartz, 2025

Dudas, Rafaela Tavares, James, Samuel Wooster, Bartz, Marie L. C. & Brown, George Gardner, 2025, New earthworm species of Glossoscolex Leuckart, 1835 and Fimoscolex Michaelsen, 1900 (Clitellata: Glossoscolecidae) from southeastern Brazil, Zootaxa 5589 (1), pp. 321-345 : 336-337

Fimoscolex elkeae Dudas, James, Brown & Bartz sp. nov.

( Figure 13 )

Holotype. Brazil, one adult, São Paulo, Bananal Ecological Research Station , in forest soil, in the soil; latitude, longitude: 22°47”53.34’S, 44°21”36.22’W, elevation: 1,212 m asl; February 2009; S.W. James, G.G. Brown, M.L.C. Bartz, S.K. Davidson coll. Sample ID: COFM BRSP0926 .

Paratype. Brazil, one adult, same collection details as holotype. Sample ID: MZUSP 6440 (former COFMBRSP0927) .

Other materials. Brazil, three adults and one juvenile, same collection details as holotype. Sample ID: COFM BRSP0936 .

Etymology. The species is named for Dr. Elke Jurandy Bran Nogueira Cardoso†, former professor of the Soils Department at the Escola Superior de Agricultura Luis de Queiroz (ESALQ) of the University of São Paulo, for her long-term support to soil fauna research (over 20 years) at the university, including the supervision of several graduate students who collected new species of earthworms.

External morphology. Holotype: body length 63 mm, body mass 0.15 g after ethanol fixation. Diameter pre clitellar (X) 2 mm, at clitellum ( XV) 2.2 mm, and post clitellar ( XXX) 1.5 mm. Number of segments 248. Paratype: length 92 mm, body mass 0.2 g after fixation. Diameter at X 2.6 mm, at XV 2.4 mm, and at XXX 2.2 mm. Number of segments 248. Body shape cylindrical. Body pigmentation absent. Prostomium proepilobic. Setae beginning in XIII and very small throughout body. Setal arrangement at XXX-L aa:ab:bc:cd = 30:1:8:1. Clitellum annular in XV– XXI ( Figure 13A ). Genital markings absent. One male pore in XVII, narrow slit on low area, not an elevated porophore ( Figure 13A ). Female pore in XIV at the nephropore level. Nephridial pores on b level.

Internal anatomy. Septa 5/6 is very thin, but muscular on 6/7–10/11 ( Figure 13B ). Gizzard in VI, 0.6 in width by 0.4 mm in length. One pair of calciferous glands are dorsally in XII, composite tubular structure, blood vessels on dorsal ventral, in XII. Esophagus-intestine transition origin in XV. Typhlosole origin in XV, zigzag to laminar, in XX–XXXV cupped folds, becoming smaller. The final pair of hearts is in XI, with lateral vessels originating in VII–IX. These vessels exhibit a whitish coloration and appear to circumnavigate the body. Nephridia in XI in normal form, but on XII–XVI they morph into big iridescent sperm sacs ( Figure 13B ), with pre and post septal parts per segment. Testis sac in XI large, single and bulging into XII. Seminal vesicles narrow tubes within XII, back ventral below esophagus to segments LXX. Spermathecae absent. One singular copulatory bulb disc-shaped, over XVI–XVIII ( Figure 13C ).

Remarks. The vas deferens clearly emerges from the testis sac in XI but the seminal vesicle extends from the poterior end of the sac in XII and there is no clear delimitation between what is only in XI and what is in XII, other than the vas deferens and the beginning of the seminal vesicles. The sac could be morphologically in XI but it is not possible to determine if it is extending into XII at the posterior boundary. F. elkeae sp. nov. is the only Fimoscolex species with annular clitellum from XV–XXII, as the other species with clitellum in this range all have saddle-shaped clitella. It exhibits considerable external and internal similarity to F. cunhai sp. nov., but this latter species clitellum is shorter (XV–XXI) and the tubular seminal vesicle runs above the intestine, while in F. elkeae sp. nov. it is under the intestine.

Figures

FIGURE 13. Fimoscolex elkeae sp. nov. Holotype. A. External ventral view with clitellum and male pore in XVII in the middle of segment. B. Internal view with emphasis in the thin part of the septa (Sp) and iridescent nephridia (Np). C. Copulatory bulb (CB) in XVI–XVII.