Glossoscolex (Glososscolex) maschio, Feijoo & Brown, 2018

Feijoo, Alexander & Brown, George G., 2018, New species of Glossoscolex and Fimoscolex earthworms (Oligochaeta: Glossoscolecidae) from Embrapa Forestry, Paraná, Brazil, Zootaxa 4496 (1), pp. 492-502 : 496-498

Glossoscolex (Glososscolex) maschio sp. nov.

( Figure 2 )

Etymology. Named in honor of Wilson Maschio & Wagner Maschio, father and son, for their contributions to the study of earthworms in southern Brazil. Noun in apposition.

Holotype. COFM BRPR0433 , one clitellate specimen found crawling on the surface of the road after rainfall next to mixed ombrophylous forest ( Araucaria forest) at Embrapa Florestas , Colombo municipality, state of Paraná, Brazil; 25°18'56.88"S, 49°9'31.21"W, 950 masl, 18-04-2012, Wagner Maschio, coll.

Paratype. COFM BRPR0191 , 1 adult, same location as holotype, 10-02-2011, Wagner Maschio, coll.

Other material examined. COFM BRPR0190 , 1 adult, same location as holotype, 8-10-2008, Wilson Maschio, coll.

Description. Epiendogeic species with cylindrical body and brown color dorsally and light brown ventrally and dark brown in the clitellum (color Nos. 701, 698 and 694, respectively according to Seguy, 1936). Holotype: length of preserved holotype 250.2 mm, diameter 7.99 mm in the preclitellar region, 9.03 mm in the clitellum, and 6.27 mm in the postclitellar region. Number of segments: 343. Paratype: length 177.1 mm long and widths of 6.39 mm (segment 10), 7.38 mm (segment 20) and 4.78 mm (segment 38). Number of segments: 345. Prolobic prostomium with first segment invaginated. Eight rows of closely paired setae a, b, c, d, visible from segment 12 on. The distance between the setae in segment 40 is aa:ab:bc:cd:dd = 12.2:1:4.7:0.4:24. The first 12 segments have transverse grooves; from segment five on, secondary annulations are present. The saddle-shaped clitellum lies in segments 15–24 (=10), with tubercula pubertatis in segments 19– 2/3 20, 21 (=1 2/3, 2 1/2) ( Fig. 2A ). The male pores are located in segment 18/19 and female pores in segment 14. The nephropores are above the line of b setae. Spermathecal pores absent.

Internal anatomy. Septa of segments 6/7–10/11 are thick, conical and interpenetrated. Large, strong heartshaped gizzard in segment 6. One pair elongated calciferous glands 4.1 mm long in segment 12, with composite tubular structure (Kompositenschlauchtaschen), and lumen greatly irrigated with blood vessels that completely fill the interior spaces of the gland. Oesophagus-intestine transition in segment 14 and typhlosole beginning in segment 15, with an S-shaped folded dorsal lamina that occupies 2/3 of the intestinal lumen. The first part of the intestine, from the transition between the oesophagus up to segment 43 was empty and thereafter abundant quantities or organic matter and small wood pieces were observed in all three dissected specimens. Intestinal caeca absent. Five pairs of lateral-oesphageal hearts in segments 7–11. One pair of preseptal holonephridia per segment. Testes and funnels in single midventral subesophageal sac in segment 11. Ovaries and ovarian funnels in segment 13. One pair of whitish lobulated large seminal vesicles restricted to segment 12. Spermathecae absent. Male sexual system metandric, with vas deferens beginning in segment 11, extending backwards along c–d setae line, penetrating the copulatory chambers and exiting at the male pore in segment 18/19. Cylindrical-shaped copulatory chamber in segments 18–19 ( Fig. 2B ).

Remarks. The subgenus Glossoscolex (Glossoscolex) has 48 species/subspecies, but only 16 of them have male pores in segments 18 and 19 or 19, and are therefore part of the giganteus group according to Righi & Lobo (1979) (see discussion), which now includes G. maschio sp. nov. However, of these only eight species have clitellum ranging from 15–23 ( G. umijae Righi & Lobo, 1979 ; G. (G.) paulistus Michaelsen, 1925 ; G. (G.) facchini Righi, 1971 ; G. (G.) gordurensis Michaelsen, 1918 ; G. (G.) fasold Michaelsen, 1918 ; G. (G.) montagneri Righi, 1972 and G. (G.) mrazi Černosvitov, 1934 ), but only one of these has seminal vesicles restricted to 11 and 12 ( G. paulistus ). All other species have vesicles extending further back, from 13 ( G. fasold ), to 15 ( G. mrazi , G. facchini ) and beyond (other species). Although Righi (1978) states that seminal vesicle extension by itself is not a good enough character to define species differences, because it varies with maturation stage of the earthworm, all individuals evaluated were clearly adult, collected at different dates and had their seminal vesicles restricted to segment 12. Furthermore, when aided by other somatic characters such as clitellum position, size and shape of copulatory pouch and setal arrangements, it can be of use. The copulatory chamber of G. paulistus is large and reniform (kidney-shaped), occupying segments 17/18–23, while that of G. maschio sp. nov. is cylindrical and occupies only segments 18–19. Furthermore, seminal vesicles of G. maschio are short and restricted to segment 12, while those of G. paulistus are irregularly shaped and occupy segments 11 and 12. The setal arrangements of G. paulistus (21.8:1:5:0.8:23.8) is different from that of G. maschio (12.2:1:4.7:0.4:24). G. fasold , the only other species close enough to G. maschio by extension of its seminal vesicles is a very large earthworm (about 1 m long), with setal arrangements quite different from G. maschio (5:1:1.7:1:6.9), but for which we do not have exact details on copulatory chamber shape or placement. However, Michaelsen (1918) considered this species close to G. wiengreeni Michaelsen, 1897 and G. giganteus , both of which are quite different from G. maschio , particularly in their copulatory chamber placement (segments 18–22 and 18–20, respectively) and clitellum position (segments 15–24/25 and 15–24, respectively).

Figures

FIGURE 2. Glossoscolex (Glossoscolex) maschio sp. nov., holotype. A. Ventral external view of anterior body (preserved), showing tubercula pubertatis in segments 19– 2/3 20, 21. B. Internal anatomy of anterior segments, dorsal view. CC= cylindrical-shaped copulatory chamber in segments 18–19.