Martiodrilus (Martiodrilus) alegrei, Feijoo & Lavelle, 2023

Feijoo, Alexander & Lavelle, Patrick, 2023, New species and records of earthworms (Annelida, Oligochaeta: Crassiclitellata) in small holder farming systems in the Peruvian Amazon, Zootaxa 5255 (1), pp. 157-170 : 164-165

Martiodrilus (Martiodrilus) alegrei sp. nov.

( Fig. 4A–E )

Etymology. The name of the species was given as a tribute to Dr. Julio Alegre, Professor at La Molina University, who has dedicated his research to the design and experimentation of agroforestry systems in the Yurimaguas region and has always been very supportive to research in soil biology.

Holotype. Clitellate specimen (CNLT-UTP-0360). Locality: Perú, Department of Loreto, Santa Rosa Farm (5°53'56'' S 76°10'34'' O). Type of vegetation: Purma. Altitude: 168 m. a.s.l. Sampling depth: 20 cm. Collection dates: 16 October 2016. Collectors: Obed Carrascal Torres.

Paratypes. Four adults, five juveniles (CNLT-UTP-0361). Same collection data as holotype .

Description. Endoanecic species with a violet to gray colored dorsum, milky white ventral, and cylindrical body. Holotype: length (preserved) 278.6 mm, diameter 13.1 mm in preclitellar region (segment 8), 11.43 mm at clitellum, 10.4 (segment 82) mm in mid-posterior region. Number of segments: 192. Paratypes (four adults): Adult 1: 250.3 mm long, diameter 11.3 mm in preclitellar region, 10.2 mm at clitellum, 9.9 mm in mid-posterior region, number of segments: 188. Adult 2: 189.9 mm long, diameter 9.4 mm in preclitellar region, 9.8 mm at clitellum, 9.5 mm in mid-posterior region; number of segments: 96. Adult 3: 342 mm long, diameter 11.5 mm in preclitellar region, 10.1 mm at clitellum, 9.5 mm in mid-posterior region, number of segments: 231. Fragmented adult 4: 178.3 mm long, diameter 13.2 mm in preclitellar region, 12.2 mm at clitellum, 10.9 mm in mid-posterior region. The first two segments are invaginated. The prostomium is a big structure that occupies 2/3 of the peristomium, with four divisions that present multiple roughnesses and four nephribuccal furrows. Eight rows of closely paired setae are visible (a, b,) as of segment 7, and the other pair (c, d) from 11. The common setae are sigmoid with a pronounced central nodule and slight curvature, after the nodule, it shows some marks ( Fig. 4A ). Setal arrangement in mid-body region (segments 40–50); aa: ab: bc: cd: dd = 12.5:1:12:0.5:37. Genital setae are found between segments 16-24 and, the one segment 18 is 1.5 mm long; it has a slight curvature in the proximal region and from ½ onwards pronounced ornamentations are observed with 14 compartments homogeneous in size, then in the distal region it ends in a lanceshaped point ( Fig. 4B ). Clitellum whitish (preserved), violet (just fixed) on the ventral region the color changes to light yellow. Saddle-shaped, in segments 15–26, 27 (=12, 13 segments); tubercula pubertatis between segments 20–1/3 26 ( Fig. 4C ). Male pores in segment 20/21, female pores in segment 14/15. Nephridiopores aligned with setae c. One pair of spermathecal pores observed in intersegment 5/6 near line c.

Internal anatomy. Anterior septa are strong, thick and shaped like interpenetrating cones, observed between segments 5/6 and 13/14. Gizzard rounded, in segment 6. Eight pairs of extramural calciferous glands, moon-shaped in the crescent phase, opening into lateral region of esophagus in segments 7–14. All glands of similar size, with a small-elongated appendix with a widened end in the distal region; gland structure of composite-tubular type, consisting of short parietal tubules that flow into each other. In the center, the tubules merge in the lumen from where they branch out toward the tip of the calciferous gland ( Fig. 4D ). Esophagus–intestine transition at 17/18, typhlosole beginning in segments 29. No caecum. Three pairs of thin lateral hearts in segments 7–9, separating the calciferous glands, and two pairs of voluminous intestinal hearts in segments 10 and 11. One pair of holonephridia per segment without rosette like nephrostome, nephridiopores located just above the line of setae c. Two pairs of large hypoesophageal testis sacs in segments 10 and 11, two pairs of seminal vesicles extending forward in segments 11 and 12. One pair of ovaries in segment 13. One pair of spermathecae in segment 6. Each spermatheca has a duct and a very big ampulla; duct seems to roll on itself, it differs from the chamber; in both, there are numerous seminal chambers ( Fig. 4E ).

Remarks. Martiodrilus (Martiodrilus) alegrei sp. nov. has affinities with M. (M.) cosanganensis ( Zicsi, 2000) (Napo, Ecuador), by the presence of saddle-shaped clitellum in segments 15-26, 27 and eight pairs of calciferous glands in segments 7–14. However, it differs by the extension of tubercula pubertatis, 20–1/3 26 (vs. 21-26). It also differs in the number and shape of spermathecae, one pair in 6, bag-shaped without distinction between duct and ampulla (vs. three pairs in 7-9, very long, thin duct with a spoon-like ampulla), and the position of male pores in 20/21 (vs. 21/22). M. (M.) alegrei is the only species of the genus that presents a single pair of spermathecae in 6, while all the remaining species have two pairs in 7-8 (M. (M.) devriesi Zicsi, 1988 (Tandajapa, Pichincha / Colombia); M. (M.) psikakao Righi, 1995 (Puerto Caldas, Risaralda / Colombia, Puerto Tejada, Cauca / Colombia); M. (M.) robustus chilesensis Zicsi, 2000) (Carchi / Ecuador); M. (M.) robustus robustus Zicsi, 2000 (Carchi / Ecuador), or three pairs in 7-9 (all others).

Figures

FIGURE 4. Martiodrilus (Martiodrilus) alegrei sp. nov. Holotype. A. Common seta, segment 32. B. Genital setae a, segment 17. C. External, ventral view of clitellum and tubercula pubertatis, segments 15 - 27. D. Calciferous glands of segment 8. E. Spermathecae of 6.