Andiorrhinus (Turedrilus) yukuna, M, Alexander Feijoo & Celis, Liliana V., 2012

M, Alexander Feijoo & Celis, Liliana V., 2012, New species of earthworms (Oligochaeta: Glossoscolecidae) in the Amazon region of Colombia, Zootaxa 3458, pp. 103-119 : 108-110

Andiorrhinus (Turedrilus) yukuna sp. nov.

( Figs. 4, 5 A,B, 6, 7, Table 2 )

Material examined. Holotype: Clitellate specimen (CA-0015). Locality: Municipality of Belén de los Andaquíes, rural community of Agua Dulce (01º20’39.6’’N, 75º49’12’’W), altitude: 280 m above sea level. Collection date: 25 June 2008. Collectors: A. Feijoo, L. Celis. Paratypes: 6 adults (CA-0016), two subadults, 36 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 (1 adult, 6 juveniles). Collection dates: 18 June 2008. Locality: Municipality of Florencia, rural community of Alto Canelos (01°28’15.4”N, 75° 32’49.7”W), altitude: 272 m above sea level (1 adult, 5 juveniles). Collection date: 20 June 2008. Locality: Municipality of Belén de Los Andaquíes, rural community of Agua Dulce (01°19’51.9”N, 75° 48’43.5”W), altitude: 290 m above sea level (4 adult, 2 subadults, 25 juveniles). Collection date: 23 June 2008. Collectors: A. Feijoo, L. Celis.

Etymology. The new species is named in recognition of and homage to the Yukunas indigenous people who live in the departments of Caquetá, Colombia. Noun in apposition.

Description. Endogeic species, with brown-colored dorsum, milky white belly, and cylindrical body. The length of the conserved holotype is 78 mm, with 134 segments. Its diameter is 3.0 mm in the preclitellar region, 3.1 mm in the clitellum, and 2.9 mm in the mid-posterior region. Paratype: 74.5 mm long and 2.9 mm wide. Number of segments: 131. The prostomium is long, thin, and ends in a milky white lobe measuring 3.0 mm. The clitellum is saddle-shaped and lies in segments 16–1/2 24, 24 (= 8.5, 9 segments). In the ventral region of the clitellum there are two genital markings, the first flatter in segments 20/21 and the second transverse oval shaped in segment 22 ( Fig. 4 ). 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) is aa:ab:bc:cd:dd = 12.0:1.0:12.8:1.0:38.4. The setae present a pronounced curvature, thickening in 2/3 to finally form a hook ( Fig. 5 A). Genital setae are found in segments 17–22, measure 0.9 mm, and have a straight form, presenting alternating semi-lunar grooves that leave deep spaces where the grooves meet, all through the distal apex to end in the form of a triangular tip ( Fig. 5 B). The male pores are located in segment 19 and the female pores in segment 14. The nephropores are aligned with setae c, d. One pair of spermathecal pores was observed on intersegments 8/9, aligned with seta b.

Internal anatomy. The anterior septa are fragile and only tiny membranous threads separate the septa between segments 6 and 14. The round muscular gizzard and thick musculature are found in the cavity of segment 6. Three pairs of extramural calciferous glands, with a garlic clove shape in segments 7–9. The structure is lamellar, presenting 13–16 parallel lamellae in the mid cross-section.

The esophagus-intestine transition begins in segment 24 and the typhlosole begins in segment 27. This thick structure, shaped like a bent tube, occupies most of the intestinal lumen. There are no intestinal caeca.

Three pairs of thin lateral hearts are differentiated in segments 7–9, separating the calciferous glands. Two pairs of voluminous intestinal hearts are located in segments 10 and 11. There is one pair of holonephridia per segment ( Fig. 6 ), and the nephridiopores are located just above the line of setae c.

Two pairs of large hypoesophageal testis sacs are located in segments 10 and 11, and two pairs of seminal vesicles are located in segments 11 and 12. The deferent ducts open toward the intraparietal region from segments 10 and 11, merging to form a single duct that flows into segment 19 into a structure similar to a prostatic gland, shaped as a seminal vesicle in 19 and measuring 2.1 mm length x 1.7 mm width. Ovaries are in segment 13 and elongated spermathecae can be observed in segment 9, without differentiation of the ampulla. Abundant sperm cells are also observed at the base and in the duct ( Fig. 7 ).

Remarks. Andiorrhinus (Turedrilus) yukuna sp. nov. is closely related to A. (T.) acaciascensis Feijoo, 2008 , A. (T.) brunneus Michaelsen, 1892 , and A. (T.) samuelensis Righi, 1986 because of the number of segments of the clitellum. However, it differs from the aforementioned species in the position of tubercula pubertatis, the distance of the setae aa:ab:bc:cd:dd, the extension of tubercula pubertatis, and the type of septa, which are thick, heavy, and muscular in the three abovementioned species as compared with those of A. (T.) yukuna , which are fragile and membrane-like. A. (T.) yukuna also presents only a single pair of spermathecae in segment 9 ( Table 2 ).

Figures

FIGURES 4 - 7. Andiorrhinus (Turedrilus) yukuna sp. nov. 4. Ventral view of segments 16 – 24. 5 A. C ommon seta. 5 B. Genital seta, distal part. 6. Nephridium of segment 12. 7. Spermatheca of 8 / 9.