Chilota intercisetus, Csuzdi & Mischis, 2010

Csuzdi, Csaba & Mischis, Catalina C., 2010, Earthworms from Argentinean Patagonia with description of two remarkable new species (Oligochaeta: Acanthodrilidae, Lumbricidae and Megascolecidae), Journal of Natural History 44 (1 - 2), pp. 31-40 : 32-34

Chilota intercisetus sp. nov.

( Figures 1–2 )

Notes: fp, female pore; pp, prostate pore.

Material examined

Holotype. HNHM/5241 , Argentina, Prov. Neuquén, Pehuenia near to Aluminé Lake , 38°53′S; 71°21′W, 1170 m, coll. C. Mischis, 14 January 2008.

Paratype. HNHM/5248 one ex., Argentina, Prov. Neuquén, Pehuenia near to Aluminé Lake , 38°53′S; 71°21′W, 1170 m, coll. C. Mischis, 14 January 2008 .

Derivatio nominis

The species is named after the missing penial setae. The specific epithet is a combination of the words seta and intercido (Latin) = being lost.

Diagnosis

L. 80–95 mm. D. 3–4 mm. No. segments 101–135. Colour dark brown-violet on dorsum, pale on ventrum. First dorsal pore in 18/19. Clitellum 1/2 13–17, saddle-shaped. Prostatic pores paired on protruding papillae, in 17, 19. Penial setae lacking. Spermathecal pores 7/8, 8/9 ab. Muscular gizzard in 6, calciferous glands lacking, calciferous lamellae in 14–15. Last pair of hearts in 13. Spermathecae with short and wide duct and a pearshaped ampoule. Diverticulum large, oakleaf-shaped. Penial setae lacking.

External characters

Holotype. L. 80 mm, D. 3 mm, No. segments 101. Paratype. L. 95 mm, D. 4 mm, No. segments 135. Colour dark brown-violet on dorsum rapidly diminishing towards setal line b, pale on ventrum. Prostomium 1/3 epilobous open. The first dorsal pore occurs in the intersegmental furrow 18/19. Setae are closely paired, setal formula after the clitellum aa:ab:bc:cd:dd = 4:1:4:1.2:8. The clitellum extends over segments 1/2 13–17 saddle-shaped, provided with an escutcheon-shaped male field ( Figure 1 ). Prostatic pores paired on protruding papillae in 17, 19. Male pores externally not visible, they are on segment 18, in the seminal groves. Female pores paired on 14, large scissures anterior to setae a-a. Two pairs of spermathecal pores are present in furrows 7/8, 8/9 near to setae b. Nephridiopores aligned in setal line c. Paired porophores on 10, 11, 12, 16 medial to setae a.

Internal characters

Septa 8/9–11/12 somewhat strengthened, others membranous. Oesophageal gizzard of moderate size in 6. Calciferous glands lacking. Oesophagus enlarged in 14–15 bearing small intramural calciferous lamellae. Intestine begins in segment 20. Excretory system holoic, nephridial bladders are biscuit-shaped. Paired hearts are present in segments 10, 11, 12 and 13. Testes are free in 10. Two pairs of seminal vesicles present in 9, 11. Those in 9 are small and tufted, those in 11 are large, somewhat protruding also in 12. A pair of large racemose ovaries pendent from the posterior face of the septum 12/13. Seminal duct somewhat undulated, discharging in segment 18. Two pairs of prostates present in 17, 19. The glands are moderately large occupying one or two segments. The duct is short muscular, somewhat widens before the prostatic pore. Two pairs of spermathecae present in segments 8 and 9. Each consists of a short and wide duct and a pear-shaped ampoule. The ectal part of the duct bears a large, oakleaf-shaped diverticulum ( Figure 2 ).

Remarks

There are three Chilota species characterized by lack of penial setae; Ch. hilgeri (Michaelsen, 1888) , Ch. lossbergi Michaelsen, 1899 and Ch. platei (Michaelsen, 1898) . Ch. intercisetus n. sp. differs from Ch. hilgeri in the shape and position of the clitellum, the shape of spermathecae and lacking of intestinal caecum which is present in the clitellar region at Ch. hilgeri . The new species differs from Ch. lossbergi by the structure of the spermathecae, the position of the last pairs of hearts and the shape of the head. From Ch. platei the new species differs in the position of the clitellum, the shape of spermathecae and the position of the last pair of hearts.

Figures

Figures 1–2. Chilota intercisetus sp. nov. (1) Ventral view of the clitellar region; (2) spermatheca.