Fimoscolex schmelzi 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 : 331-332

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

( Figures 8 , 9 )

Holotype. Brazil, one adult, Resende, Rio de Janeiro, Abrigo Rebouças, Itatiaia National Park , high plateau grassland near the Abrigo Rebouças , in the soil; latitude, longitude: 22°23”5.58’S, 44°40”45.24’W; elevation: 2.380 m asl; 12 February 2009; S.W. James, M.L.C. Bartz, G.G. Brown and S.K. Davidson coll. Sample ID: COFM BRRJ0051 .

Paratype. Brazil, five adults, same collection data as holotype. Sample ID: MZUSP 6447 (former COFMBRRJ0052) .

Other materials. Brazil, one adult, same collection data as holotype. Sample ID: COFM BRRJ0057 . Two adults and two juveniles, same collection data as holotype. Sample ID: COFM BRRJ0058 .

Etymology. The species is named for Dr. Rüdiger Schmelz, from the University of A Coruña, Spain, in acknowledgement for his long-standing contributions to Annelid taxonomy, particularly of enchytraeids in Brazil and elsewhere in the world.

External morphology. Holotype: body length 45 mm, body mass 0.09 g after ethanol fixation. Diameter pre clitellar (X) 2.4 mm, at the clitellum ( XIV) 2.5 mm and post clitellar ( XXX) 2.4 mm. Number of segments 163 ( Figure 8A, B ). Paratype: length 53 mm, body mass 0.11 g after fixation. Diameter at X 2 mm, at XIV 2 mm and at XXX 1.7 mm. Number of segments 172. Body shape cylindrical. Body pigmentation absent. Prostomium prolobic. Setae begins no later than XXII, with slight irregularities in spacing in different portions of the body. Setal arrangement aa:ab:bc:cd:dd = 5.5:1.5:2:1:5.5 at around XXX. Clitellum in ⅓ XI –XXIII ( Figure 9A ). Genital markings absent. One male pore in XVII, on conical elevated porophore ( Figure 9A ). Female pores on XIV, medial level of sperm ducts and b setae. Nephridial pores approximately on b line.

Internal anatomy. Septa 5/6 on anterior curve of gizzard, slightly muscular, 6/7–10/11 muscular, 11/12 thin, 12/13–20/21 thick with white covering ( Figure 9B ). Gizzard in VI, with an average size (width x length) of 0.9 x 0.6 mm. Calciferous glands one pair, of tubular composite structure, rounded with lateral triangles, separated in XII, dorsal position to blood vessels on top of glands ( Figure 9C ). Esophagus-intestine transition origin in XV. Typhlosole origin in XV, simple blade except segments XXII–XXV, slightly cupped folds. Hearts in XX–XI with lateral vessels in VII–IX. The excretory apparatus comprises one pair of nephridia, each possessing a blind sac and an elongated structure oriented dorsally. Normal nephridia from V–XI. Others, from XII to XXII, are modified, enclosed by septa/joined to acinous masses per segment. Testis sac in XI is substantial and suspended in XI–XII, while vas deferens are located approximately in the copulatory bulb in XIV–XVII. Seminal vesicles long tubes dorsally to LVIII–LIX, terminating in very narrow tubes (Figura 9B). Spermathecae absent. One copulatory bulb, oval-shaped ( Figure 9C ) separate from the body wall.

Remarks. F. schmelzi sp. nov. is a small-sized Fimoscolex species, similar to F. bartzi , F. nivae , F. feijooi sp. nov. and F. pereirai sp. nov. although its annular-shaped clitellum is longer than any other Fimoscolex species (>12 segments) except F. elodieae sp. nov. (15 segments), and begins the most anteriorly (in segment XI). The new species also has an unpaired testis sac, found in F. nivae , F. ohausi , F. cunhai sp. nov., F. barettai sp. nov., F. elodieae sp. nov., F. elkeae sp. nov., and F. angai minor . The copulatory bulb is relatively small, occupying only segment XVII, a feature shared only with F. elodiae . Furthermore, this species has irregularity in setal spacing, which is different from the other species described here, and a feature only shared with F. sporadochaetus ( James and Brown, 2010) , which has its single copulatory bulb within the body wall.

Figures

FIGURE 8. A. Recently collected Fimoscolex schmelzi sp. nov. (left) and Fimoscolex feijooi n.sp (right) being prepared for dissection. B. Close-up of Fimoscolex schmelzi specimens.

FIGURE 9. Fimoscolex schmelzi sp. nov. Holotype. A. External lateral view showing the male pore (MP) in the middle of segment XVII. B. Internal view with emphasis on the smooth and thin septa (Sp). C. Round shaped copulatory bulb (CB) and pair of calciferous glands (CG).