Martiodrilus (Maipure) yurimaguensis, 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 : 161

Martiodrilus (Maipure) yurimaguensis sp. nov.

( Fig. 2A–F )

Etymology. The name of the species was given as a tribute to a city in the North of Peru, “close to the collecting site”, capital of the Alto Amazonas province in the department of Loreto, Perú.

Holotype. Clitellate specimen (CNLT-UTP-0356). Locality: Perú, Department of Loreto, Santa Rosa Fundo (5°53'56'' S, 76°10'34'' O). Type of vegetation: Purma. Altitude: 168 m. a.s.l. Sampling depth: 0-10 cm. Collection dates: 16 October 2016. Collectors: Obed Carrascal Torres.

Paratypes. Four adults, five juveniles (CNLT-UTP-0357).Same collection data as holotype .

Description. Epigeic species. Individuals preserved in 70 % alcohol are depigmented and the color cannot be specified. Holotype: length 120 mm, diameter 4.9 mm in preclitellar region (segment 8), 5.7 mm at clitellum, 5.1 mm in mid-posterior region. Number of segments: 84. Paratypes (Four adults): Adult 1: 81.3 mm long, diameter 3.4 mm in preclitellar region, 4.1 mm at clitellum, 3.1 mm in mid-posterior region, number of segments: 106. Adult 2: decapitate. The first segment invaginated. Short and lobe-shaped prostomium. Eight rows of closely paired setae are visible (a, b, c, d) as of segment 4. Common setae measure 0.3 mm. After 1/3 proximal, a nodule is observed, from which it becomes thicker and then presents a strong hook-shaped curve that ends in a point ( Fig. 2A ). Setal arrangement at the middle of the body (segments 40–50); aa: ab: bc: cd: dd = 9:1:14:0.9:38. Setae a and b between segments 15 to 24 and 6 to 9 modified into genital setae, measure 1.7 mm, elongated with a slight bend in the proximal third and then in the following 2/3, it presents semilunar excavations alternate, ending in a spearhead ( Fig. 2B ). Clitellum saddle-shaped, in segments 14–1/4 25 (=12 segments); tubercula pubertatis between segments 1/318 – 1/2 25 ( Fig. 2C ). Male pores in segment 20/21, female pores in segment 14/15. Nephropores aligned with setae c. Four pairs of spermathecal pores observed in intersegments 5/6, 6/7, 7/8, 8/9. Between segments 15 and 26, a pair of circular areas around setae a and b are observed.

Internal anatomy. Anterior septa are very fragile and they change their shape from 10/11 to 16/17, in which they appear in the form of delicate membranes. The gizzard is in segment 6, it is slightly elongated. Between segments 7 and 14 there are eight pairs of calciferous glands ( Fig. 2D ). The first three pairs differ in shape and structure. The glands are kidney-shaped with a very large distal appendix that projects with a curve to one side of the gland. The 7-9 pairs structure is made up of parallel compound tubules projecting from the center outward, with a central tube dividing the tubules from the start of the appendix. In those of 10-14, the central tube is absent, the tubules have a lower density, and their spaces are wider ( Fig. 2E ). Esophagus-intestine transition at 17/18, typhlosole beginning in segment 24. No caeca. 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, nephridiopores located just above the line of setae c and d. Two pairs of large hypo-esophageal testis sacs in segments 10 and 11, two pairs of seminal vesicles extending forward in segments 11 and 12. Two pairs of vas deferens project backward and are lost in the parietal musculature between segments 15 and 17, then become visible again at 18 and empty into the male pores between 20/21. One pair of ovaries in segment 13. Four pairs of spermathecae that increase in size, 9>8>7>6, those of segments 8 and 9 are 0.3 mm, in line with setae c and d. In each spermathecae the duct is long, the ampulla shaped like a tree; no seminal chambers ( Fig. 2F ).

Remarks. Martiodrilus (Maipure) yurimaguensis , sp. nov. is a species related to Martiodrilus (M.) ophioides (Cognetti, 1904) (Valle del río Santiago/ Ecuador),because of clitellum position in 14, 15, 16-25, and the presence of eight pairs of calciferous glands in segments 7-14. However, this species differs from the new species in the following characteristics: M. (M.) ophioides presents tubercula pubertatis in segments 20-26 (vs. 1/3 18 – 1/2 25), and it also differs in number and shape of spermathecae (3 pairs and, sessile sac shape) vs. 4, and shaped like a tree).

Figures

FIGURE 2. Martiodrilus (Maipure) yurimaguensis sp. nov. Holotype. A. Common seta, segment 56. B. Genital setae a, segment 17. C. External, ventral view of clitellum and tubercula pubertatis, segments 14–1/4 25. D. Calciferous glands segment 8. E. Calciferous glands segment 11. F. Spermathecae of 6, 7, 8, 9.