Martiodrilus (Cordilleroscolex) mirania, Alexander Feijoo, M. & Celis, Liliana V., 2012

Alexander Feijoo, M. & Celis, Liliana V., 2012, Earthworms (Oligochaeta: Glossoscolecidae) of the Amazon region of Colombia, Zootaxa 3201, pp. 27-44 : 33-36

Martiodrilus (Cordilleroscolex) mirania , sp. nov.

( Figs. 4–6 B)

Material. Holotype: Clitellate specimen. Locality: Belém de los Andaquíes, La Mono, Víctor Hernando Cabrera plantation, plains area of the Pescador river (01°20’41” N, 75°49’23” W), altitude: 290 m above sea level. 13 January 1989. Collectors: Alberto Escobar, A. Feijoo. Paratypes: 1 adult, 3 juveniles. Locality: Belém de los Andaquíes, La Mono; altitude, locality, date: Similar to the holotype. Collectors: A. Escobar, A. Feijoo.

Etymology. The new species was named in recognition of and in homage to the Miraña indigenous people who live in central and southern Caquetá and Putumayo ( Colombia).

Description. Round, brown-colored endogeic species. The length of the conserved holotype is 131 mm and it has 84 segments. The diameter of the preclitellar region is 11 mm (segment 8); that of the clitellum, 15 mm; and that of the mid-posterior region, 11 mm. Paratype: 122 mm long and 1.8 mm wide. Number of segments 106. The peristomium is corrugated with large folds and segments 1, 2, 3 are invaginated. The girdle-shaped prostomium passed through the preoral cavity, forming a type of partition. The saddle-shaped clitellum is located in segments 14–27 (=14 segments). Tubercula pubertatis are located segments 21–½27 ( Figure 4). Setae a and b start in segment 8, whereas c and d are present starting from segment 14. The distance between setae in the mid-body region (segments 40 to 50) was aa:ab:bc:cd:dd = 2.8:0.5:3.0:0.5:11. Normal setae are slightly sigmoid with a medial node, with several transversal markings up through the distal region where it ends in a sharp point ( Figure 5 A). Genital setae are slightly curved and then straightened in the distal part, which has numerous deep indentations that give them the shape of a drill with strong irregular contours ( Figure 5 B). The male pores are located in segment 21/22 and the female pores are microscopic and, as a result, are not recognized. The nephropores are aligned with setae d. No spermathecal pores were observed.

Internal anatomy. Septa 5/6–9/10 are very strong, thick, with a branch-like structure beginning in the male and female reproductive system and pushing forward in the form of funnels. Each septum is joined to the ventral body wall by a ventral muscular fiber originating from the mid-ventral region. Septa are weaker between segments 10/11 and 13/14, and are transversely joined to the body wall and, from here on, take on the shape of membranes and are more fragile. The gizzard, located in the cavity of segment 6, is strong, round, and measures 10 mm. Septa 5/6–9/10 are located on the back and cover structures such as the nephridia, hearts, and calciferous glands.

Eight pairs of calciferous glands with composite tubular structure are located in the ventrolateral region of segments 7–14 ( Figure 6 A).

The esophagus–intestine transition starts in segment 18 and the heavily striated S-shaped typhlosole begins in segment 27, occupying 1/5 of the dorsal intestinal space. There is no caecum. The intestine is moniliform, with pronounced segmental constrictions. The species has three pairs of lateral hearts in segments 7–9 and two pairs of intestinal hearts in 10 and 11. The hearts of segment 10 are large and thick, while those of segment 11 open into two bifurcations in the mid-heart region before rejoining in the dorsal side of the esophagus. Each segment has a pair of holonephridia, which consist of a preseptal funnel and a postseptal duct. The duct dilated before the nephridiopore forming the nephridial bladder and the nephridial bladder opens to the exterior through the nephropore ( Figure 6 B). The periesophageal testis sacs are located in segments 10 and 11. Nephridia encircle the testis sacs of segment 11, covering the hearts and calciferous glands in this segment. Two pairs of seminal vesicles are found in segments 11 and 12. A pair of deferent vessels run along each side of the intraparietal region of the body wall and open into the male pores in intersegment 21/22, close to where the tubercula pubertatis begin. Ovaries are observed in the ventral region of segment 13, next to the following septum. There are no spermathecae.

Remarks. Martiodrilus (Maipure) mirania is not closely related to the other species of the subgenus because of the absence of spermathecae. The remaining 20 species have three or four pairs of spermathecae located between segments 5–10. It also differs from other species in the extension of the number of segments of the clitellum, and in the location of tubercula pubertatis.

Figures

FIGURE 6. Martiodrilus (C.) mirania. A: calciferous gland from segments 3, 12, 13, 14; B: nephridium of segment 9.