Andiorrhinus (Meridrilus), 2017

Feijoo, Alexander, Brown, George G. & James, Samuel W., 2017, New species of Andiorrhinus Cognetti, 1908 (Oligochaeta: Rhinodrilidae) from Venezuela and Brazil, Zootaxa 4363 (1), pp. 55-78 : 70

Andiorrhinus (Meridrilus) sp. 1

( Figure 7A,B ; Table 2)

Material examined. One incomplete adult ( MZUSP 01476 ). Locality : Venezuela, state of Mérida, Mount Zerpa (08°37' N, 71°09'W). Altitude : 1800–2200 m a.s.l. Collection date: 20 July 1996. Collectors: Pedro Durant and E.J. Arellano.

Description. Epiendogeic species, with brown-colored dorsum and belly and red clitellum, which correspond to the respective color code numbers 693 and 117 ( Seguy 1936), and cylindrical body. The length of the specimen is 35 mm up to segment 33, with a diameter of 2.9 mm in the preclitellar region, 3.5 mm in the clitellum, and 2.21 mm in the postclitellar region. Number of segments: Incomplete specimen.The first and second segments are visible and the long, tentacular-shaped prostomium measures 3.1 mm. Four pairs of closely paired setae are visible as of segment 4. The hook-shaped common setae measure 0.46 mm, with no ornamentations. The distance between the setae in segment 32 is aa:ab.bc:cd:dd = 5.0:1.0:6.0:0.5:16.0. The setae of segments 7, 8, 9, and 17–22 are transformed as genital setae, which are contained in long follicles that are longer than the body cavity diameter, and are internally located close to five pairs of genital setal gland masses in segments 17–22. Genital setae measure 2.36 mm, are rectilinear and, in the apical half, present 16 U-shaped ornamentations that end in a spear-shaped tip.

The saddle-shaped clitellum measures 9.4 mm and lies in segments 15–24 (=10), with the tubercula pubertatis located between segments ½18 and ½23 (=5) ( Fig. 7A ). The male pores are located in intersegment 19/20, close to the row of setae ab, and female pores are located in segment 16/17, in the center away from the row of setae b and c. The nephropores are aligned with setae c and d. Five pairs of spermathecal pores were observed in intersegments 5/6, 6/7, 7/8, 8/9, and 9/10, close to the row of setae c and d.

Internal anatomy. The septa of segments 6/7–11/12 are very fine, while those of segments 12/13–16/17 are slightly stronger without being thick, also conic-shaped and nested. The round muscular gizzard and round thick musculature are present in segment 6. Three pairs of large, digitiform calciferous glands of lamellar structure are present in segments 7– 9, with no lobulate appendage in the ectal region The transverse cut of the gland shows between 20–22 parallel lamellae. The esophagus-intestine transition begins in intersegment 22 and the S-shaped typhlosole begins in segment 24, occupying 1/3 of the intestinal lumen. There are no intestinal caeca. Intestinal content consisted mostly of very fine organic matter with absence of small stones. Three pairs of lateral hearts are located in segments 7–9, covering the calciferous glands, and two voluminous intestinal hearts are present in segments 12 and 13. Both supraesophageal and subesophageal vessels are present. There is one pair of holonephridia per segment.

Two pairs of peri-esophageal testis sacs are located in segments 10 and 11, and two pairs of seminal vesicles are present in segments 11 and 12. The two pairs of deferent ducts open towards the male pore in intersegment 19/ 20, close to the row of setae b. One pair of ovaries is present in the cavity of segment 13; the female pore is located in segment 16/17. Five pairs of very small spermathecae, measuring 0.6 x 0.3 mm, 0.7 x 0.4 mm, 1.0 x 0.4 mm, 1.2 x 0.42 mm, 1.2 x 0.42 mm (length x width), are present in segments 6, 7, 8, 9, and 10, respectively ( Fig. 7B ). The oblong spermathecal duct is short and strong, with numerous seminal chambers, while the ampulla is slightly oblong. A group of larger-sized bifurcated genital setal gland masses are located at the base of each spermatheca, giving it a quadrangular shape.

Remarks. Andiorrhinus (Meridrilus) sp. 1 is closely related to A. (M.) timotocuica sp. nov. and A. (Meridrilus) boconius Righi,1989 because of the position of the clitellum and the location of male pores in 19/20. This specimen is distinctive because of the extension of the clitellum, the tubercula pubertatis, the number of pairs of spermathecae ( Table 2), the number of lamellae in the calciferous glands, the shape of the spermathecae, shape and size of the normal setae, and ornamentation of the genital setae. However, more material is needed to confirm its taxonomic status as belonging to a new species.

Figures

FIGURE 7. Andiorrhinus (Meridrilus) sp.1. A. External, ventral view of clitellum.B. spermathecae of 8, 9.