Martiodrilus (Maipure) huitoto, 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 : 28-32

Martiodrilus (Maipure) huitoto , sp. nov.

( Figs. 1–3 C)

Material. Holotype: Clitellate specimen. Locality: Belém de los Andaquíes, rural community of Agua Dulce, 01º20’39.6’’N, 75º49’12’’W, altitude: 280 m above sea level. 25 June 2008. Collectors: A. Feijoo, L. Celis. Paratypes: 1 adult, four subadults, 19 juveniles. Locality: Municipality of Florencia, rural community of Balcanes (01°25’33.9”N, 75°30’26.9”W), altitude: 284 and 264 m above sea level. Dates: 18 and 20 June 2008. Locality: Municipality of Belén de Los Andaquíes, rural community of Agua Dulce (01°20’29.7” N, 75°48’38.7” W; 01°20’25.2” N, 75°48’48.6”W), altitude: 273 and 294 m above sea level. Dates: 23 and 25 June 2008. Collectors: A. Feijoo, L. Celis.

Etymology. The new species was named in recognition of and homage to the Huitoto indigenous people who live in the departments of Caquetá and Putumayo, Colombia.

Description. Epigeic species, with brown-colored dorsum and milky white ventrum, cylindrical body in the preclitellar region and flattened in the postclitellar region. The length of the conserved holotype is 69 mm, with 113 segments. Its diameter is 3.5 mm in the preclitellar region (segment 8), 3.0 mm in the clitellum, and 2.9 mm in the mid-posterior region. Paratype: 60 mm long and 2.1 mm wide. Number of segments 108.The prostomium is long, thin, and ends in a milky white lobe measuring 0.3 mm. The whitish saddle-shaped clitellum is located in segments 14, 15–28 (=15 segments); tubercula pubertatis are between segments ½ 19–½ 26, with six pairs of genital tumescence in segments 16, 17, 18, 22, 23, 24 ( Figure 1). Eight rows of closely paired setae are visible (a, b, c, d) as of segment 4. The distance between setae in the mid-body region (segments 40–50) was aa:ab:bc:cd:dd = 3.8:0.4:7.5:0.2:11.2. The genital setae are slightly sigmoid with four deep rectangular markings that alternate with a protruding empty space on each groove line, ending in the shape of a lance in the distal region ( Figure 2 A; Figure 2 B). The male pores are located in segment 21/22 and female pores are microscopic and, as a result, were not recognized. The nephropores are aligned with setae c. Four pairs of spermathecal pores were observed on intersegments 5/6, 6/7, 7/8, 8/9.

Species Length Seg- Setae arrangement Diameter Position of Male genital field Position of (mm) ments aa:ab:bc:cd:dd (mm) clitellum male pores (no.)

M. (Mp.) huitoto 69 113 3.8: 0.4: 7.5: 0.2: 3 14, 15-28 A pair of tubercula 21/22

11.2 pubertatis between ½ 19–½ 26

Internal anatomy. The anterior septa are very fragile and only tiny membranous threads representing the septa between segments 6 and 14 are observed. The round muscular gizzard and thick musculature are found in the cavity of segment 6. Seven pairs of small extramural calciferous glands open into the dorsoventral region of the esophagus in segments 7–13. These appear in the form of tubules and are of similar size from the anterior to posterior region, with a small appendage in the distal region highly irrigated with blood. Gland structure is composite–tubular type, made up of short parietal tubes that flow into each other once ( Figure 3 A). In the center, the lumen joins the tubules from where they branch out toward the tip of the gland; the lumen narrows in the submedial region and tubules close irregularly.

The esophagus–intestine transition begins in segment 17 and the typhlosole begins in segment 27 and ends in segment 88. This thick S-shaped lamella occupies 2/3 of the intestinal space, beginning in the mid-gut limiting the dorsal blood vessel on the outside. There is no caecum.

Three pairs of thin lateral hearts are differentiated in segments 7–9, separating the calciferous glands, as well as two pairs of voluminous intestinal hearts located in segments 10 and 11. There is one pair of holonephridia per segment and the nephridiopores are located just above the line of setae c ( Figure 3 B).

Two pairs of large hypoesophageal testis sacs are located in segments 10 and 11, and two pairs of seminal vesicles push forward in segments 11 and 12, covering the esophagus, the calciferous glands, and the lateral hearts from segment 7 to 13, with the posterior pair longer than the anterior. Ovaries were not observed in the ventral region of segment 13. Spermathecae can be observed from segments 6, 7, 8, 9, near setae c; the sperm duct is short and contains a tongue-shaped ampulla with abundant sperm cells ( Figure 3 C).

Remarks. Martiodrilus (Maipure) huitoto is a species closely related to M. (Mp.) ecuadoriensis , M. (Mp.) grandis , M. (Mp.) palmirus , and M. (Mp.) savanicola , because of the presence of seven pairs of calciferous glands in segments 7–13 or 8–14. However, it differs in the distance of the setae aa:ab:bc:cd:dd, the placement and number of segments of the clitellum, locations of tubercula pubertatis, the extent of seminal vesicles, shape of spermathecae, and intestine origin ( Table 1).

Figures

FIGURE 3. Martiodrilus (Mp.) huitoto. A: calciferous gland from segment 9 showing the external shape; B: nephridium of segment 16; C: spermathecae of segments 5 / 6, 6 / 7, 7 / 8, 8 / 9.