Onychochaeta windlei, Beddard, 1890

Hernández-García, Luis Manuel, Sousa, Sandriel Costa, Pereira, Natália Jovita, Rousseau, Guillaume Xavier & Ferreira, Carmen, 2023, Additions to earthworms (Annelida, Crassiclitellata) from Aragua and Miranda states, Venezuela, Zootaxa 5255 (1), pp. 171-182 : 173-174

Onychochaeta windlei, Beddard, 1890 ( Figs. 2 A-G)

Material. MBUCV-XIII 0307 five adults, complete, Rodríguez Farm, La Cortada settlement, Urdaneta county , Miranda, Venezuela, 66°57'0.25"W, 10°2'25.29"N, 600 masl. June 2010. Hernández-García, L.M. & Rodriguez, L.N. colls .

Description. Dimensions: length 83–110 mm; width 4.5–5.5 mm at X; 5.5–7.2 mm at clitellum, and 4.5–6.5 mm at XXX; 191–290 segments. Body cylindrical, unpigmented. Setae ab and cd commence on IV, regular throughout the body at preclitellar region. Setae a become irregular in clitellar segments while setae bd are irregular from XXIV. Setae c become irregular from segment LXX–LXXVI; quincunx at tail. Prostomium slightly tentacular retracted; peristomium longitudinally grooved. Clitellum in (1/2) XIV–XXIII, slightly annular in XV–XIX, saddle shape in XX–XXIII, light beige color after preservation. Tubercula pubertatis paired, band-shaped, projected laterally on XX–XXII in BC line ( Fig. 2A ). Intra-clitellar genital markings are absent. Protruding markings (different from genital markings) also related to setae in XXIV–XXXIV only on AB line ( Fig. 2A ). Post-clitellar common setae smooth and slightly curved at the apical region, while those of XXX measured 320–350 μ m in length. At tail, common setae became sigmoidal hook-shaped, 850–950 μ m in length ( Fig. 2B ). Intra-clitellar setae ab of XVIII -XXIII transformed to genital setae, straight at the apical part, genital setae with length of 1200–1400 μ m. At the sub-apical part of those complete genital setae, there are four longitudinal series each with 12 to 13 paired semilunar excavations ( Fig. 2C ). Microscopic ovipores and male pores not recognized externally. Sphincteric nephropores in C line, just near the anterior segment limit. First nephropore visible in XIII–XIV. Spermathecal pores open in 6/7, 7/8, and 8/ 9 in C line.

Conical septa highly muscular in 6/7, 7/8, 8/9, 9/10. Septa 10/11 and 11/12 slightly muscular, then intra-clitellar and further septa membranous. Gizzard in VI, 2.5 mm in width and 3.3 mm in length, highly muscular; esophagus in XII-XIV internally with parallel folds; intestinal origin in XIX. Lamellar typhlosole starting at XXIII, then sigmoidshaped in XXV and extended until CXLI, occupying approximately 80% of the intestinal diameter. There are three pairs of calciferous glands in VII–IX, the most frequent form is shell-shaped ( Fig. 2D ), lateroventral connection, and tubular structure ( Fig. 2E ). The tubes are simple but some of them became dichotomous and wider in the middle region. Holoic, postclitellar nephridia with a short duct opening in a membranous bladder ( Fig. 2F ). Nephridial loops were not observed in our samples. Vascular system with a ventral trunk, one pair of blood vessels in IX, those of VII, VIII as a very tiny membrane or poor development, and two pairs of large lateroesophageal hearts in X–XI. Large blood vessel is dorsally in XIV–XVII, reduced in XVIII-XXII and then transformed into a tiny vessel.

One pair of ovaries in XIII, ovules recognized only as a tiny line. Ovary funnels in 13/14 with ducts opening at posterior limit of segment XIV near A line. Three pairs of spermathecae in VII-IX. The ampulla, sac-shaped and 400 μ m in length, is gradually transitions to the duct, which is approximately 500 μm in length ( Fig. 2G ). Two pairs of testes in X and XI. Testicular sacs absent. Two pairs of short and lobulated seminal vesicles are present in segments XI and XII. Deferent ducts follow B line and open on 19/20 just at the tubercula pubertatis edge.

Remarks. O. windlei is one of the most widely distributed earthworms in the Americas and, as in P. (P). corethrurus , phenotypic variation could be expected from one locality to another. Differences are present in our specimens compared with previous descriptions ( Beddard, 1890; Righi, 1989). We contrasted our description with the most recent and complete description of Righi (1989) based on samples collected in Trujillo state, Venezuela. The common setae in Righi (1989) were 270 μ m in length, compared with 320 to 350 μ m in the current study. The maximum length of posterior setae in Righi (1989) was 662 μ m, while in our specimens it was 850–950 μ m. The genital setae characteristics also change with 7–10 excavation per series and 836 μ m in length in Righi (1989) vs. 12–13 excavation per series and 1200–1400 μ m in this study. The clitellum is in XIV–XXV (Righi 1989) vs. XIV– XXIII in our samples. Nephridial loops were present in Righi (1989) but it was lacking or possibly not recognized in our samples. The male pore in our samples was seen in 19/20 while Righi (1989) reported it in 20/21. We added some other parameters used currently for functional traits, such as a more detailed gizzard dimension and intestinal typhlosole extension.

Figures

FIGURE 2. Onychochaeta windlei. A. Ventral view of anterior region. B. Posterior a setae of the segment CC. C. Right genital b seta of XVIII. D. Cross-section of the right calciferous gland of IX. E. Dorsal view of transversal cut of the right calciferous gland of IX. F. View in cross-section of right post-clitellar nephridium. G. Dorsal view of right spermathecae of IX.