Andiorrhinus (Amazonidrilus) karinae, Feijoo & Brown & James, 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 : 57-59

Andiorrhinus (Amazonidrilus) karinae sp. nov.

( Figure 1A,B )

Material examined. Holotype: Clitellate specimen ( COFM BRMT0009 ). Locality : Brazil, state of Mato Grosso, municipality of Campo Verde, private farm (15°43'14.30"S, 55°20'43.27"W). Type of vegetation: vereda (swampy grassland), between maize/soybean crops and ‘cerradão' (semi-deciduous forest). Altitude : 735 m a.s.l. Depth : 0– 10 cm. Collection date: 9 May 2012. Collector: Karina Peña. Paratypes: One subadult ( COFM BRMT0008 ). Locality : Brazil, state of Mato Grosso, municipality of Primavera do Leste, private farm (15°30'12.84"S, 54°4'3.20"W). Type of vegetation: Cerrado sensu stricto. Altitude : 635 m a.s.l. Depth: 0–10 cm. Collection date: 18 April 2012. Collector: Karina Peña.

Etymology. The new species was named in honor of Karina Peña Peña , biologist and PhD student.

Description. Epigeic species, with variegated blue-colored dorsum, clitellum and ventral region, corresponding to the respective color code numbers 519, 522, and 510 ( Seguy 1936), and cylindrical body that decreases in diameter after segment 35. Holotype: The length of the holotype fixed and preserved in 95% alcohol is 140 mm, with a diameter of 3.05 mm in the preclitellar region, 3.2 mm in the clitellum, and 2.2 mm in the postclitellar region. Number of segments: 163. Paratype: 140 mm long with widths of 4.4 mm (segment 9), 4.0 mm (segment 21), and 3.4 mm (segment 40). Number of segments: 175. The first segment is invaginated and the prostomium is small, measuring 1.2 mm, lobular in shape with a rounded tip. Eight rows of closely paired setae are visible as of segment 5. The hook-shaped common setae measure 0.43 mm and present a strong curvature in the upper end, widening in 2/3 and then decreasing ( Fig. 1A ). Several incomplete lines are observed, alternating with the ornamentation of the setae. The distance between setae in segment 30 is aa:ab:bc:cd:dd = 10.0:1.0:15.0:1.0:65.0 and, in the posterior region in segment 110, 5.7:1.0:7.0:0.7:20. Setae a,b of segments 7, 8, 9 and 16–19 are modified as genital setae, measuring 2.4 mm and contained in long follicles. These setae are rectilinear and present U-shaped grooves that appear irregularly along the edges ( Fig. 1B ). The clitellum measures 11 mm and lies in segments 17–24 (=8), with rectangular-shaped tubercula pubertatis located between segments 19–22 (=4). The male pores are located in intersegment 20/21; no female pores were observed. The nephropores are located between setae c and d. Three pairs of spermathecal pores were observed in intersegments 6/7, 7/8, 8/9 aligned with setae c, d.

Internal anatomy. Septum 6/7 is thick, while the others are thin, resembling fine membranes. The round muscular gizzard and thick musculature are located in the cavity of segment 6. Three pairs of sac-shaped calciferous glands, with no appendage and with a lamellar internal structure, are present in segments 7–9, each with 28 parallel lamellae. Glands contain abundant calcium carbonate. The esophagus-intestine transition begins in segment 20/21 and the typhlosole begins in segment 22. There are no intestinal caeca. Three pairs of lateral hearts are in segments 7–9 and four pairs of intestinal hearts in segments 10–13, with those of segments 12 and 13 larger. Both supraesophageal and subesophageal vessels are present. There is one pair of holonephridia per segment.

Two pairs of testis sacs are located in segments 10 and 11, and two pairs of seminal vesicles in segments 11 and 12. The two pairs of deferent ducts open towards the male pore in intersegment 20/21. One pair of ovaries is found in the cavity of segment 13; the female pore is unrecognizable. Three pairs of spermathecae of almost the same size are present in segments 7, 8 and 9, located close to three glandular masses. Spermathecae are adiverticulate and no duct is observed because the base contains seminal chambers from which the oblong ampulla emerges.

Remarks. Andiorrhinus (Amazonidrilus) karinae sp. nov. is closely related to A. (A.) duidanus Michaelsen, 1936 , A. (A.) planaria Michaelsen, 1934 , and A. (A.) motto Righi & Araujo, 1999 due to the presence of three pairs of spermathecae in 6/7–8/9 (Table 1). The new species is distinguished by the extension of the clitellum, tubercula pubertatis (Table 1), the shape of the spermathecae, as well as the shape and size of the normal setae and ornamentation of the genital setae.

Figures

FIGURE 1. Andiorrhinus (Amazonidrilus) karinae sp. nov., holotype. A. Common seta, segment 35. B. Genital seta a, segment 8.