Pontoscolex (Mesoscolex) Borges and Moreno, 1992

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 : 177-178

Subgenus Pontoscolex (Mesoscolex) Borges and Moreno, 1992

Type species. Pontoscolex (Mesoscolex) cynthiae Borges and Moreno, 1992

Diagnosis. Tubercula pubertatis extend over 6–1/n7 segments in the region of segments 1/nXXVI, XXVII– XXXII. Posterior setae are arranged in irregular rows.Anterior septa present conventional parietal insertion. Number of species: 2.

Distribution: Puerto Rico (1), México (1), Cuba (1) and Venezuela (1),

Pontoscolex (Mesoscolex) juanae Hernandez-Garcia & Sousa , n. sp.

Diagnosis: Setae arranged irregularly in part. One gizzard in VI. Esophagus with very small extramural calciferous glands in segment VII-IX, simple tubular structure. Sexual system metandric, testes and funnels enclosed in sacs, and metagynous. Holonephridial excretory system. Last hearts in XI. Spermathecae are present in VI-IX.

Pontoscolex (Mesoscolex) juanae, Hernandez-Garcia & Sousa , n. sp.

( Figs. 4 A-F)

Holotype. MBUCV-XIII 0305 one adult, complete, bean crop, Santa María settlement, San Casimiro County, Aragua, Venezuela, 10°2’15.56’’S, 67°2’15.09’’W, 950 masl. June 2010. Hernández-Garcia, L.M. and García, J. D. colls.

Paratypes. MBUCV-XIII 0309 four adults, same locality as holotype. June 2010. Hernández-Garcia, L.M. and García, J. D. colls .

Etymology. The species name is in honor of Juana Dolores García who collected the samples.

Description. Dimensions: holotype 235 mm in length by 3.5 mm in width at X; 5.0 mm at clitellum, 4.1 mm at XXX, 447 segments; complete paratypes 190-230 mm in length, by 3.5–5.5 mm in width at X; 4.7–6.5 mm at clitellum and 4.0– 5.5 mm at XXX; 380–420 segments. Body cylindrical, unpigmented. Setae ab and cd commence on III, only A line is regular, whereas the B and CD lines are irregular throughout the body from IV to pygidium. Prostomium prolobic. Clitellum, annular, in XVIII–XXXIII. Tubercula pubertatis, band-shaped, are present in XXVI–XXXII limited to BC line ( Fig. 4A ). Post-clitellar common setae slightly sigmoidal, 310–320 μ m in length, jagged-shaped at the apical part ( Fig. 4B ). Genital setae associated with genital markings at AB line, straight, 720 to 750 μ m in length, the concave sub-apical part ornamented with many excavations, irregularly arranged, cuneiform ( Fig. 4C ). Genital markings as protruding papillae present surrounding setae a, b in XI or XI, XIII, and XXIII, XXIV–XXVII; some paratypes present incomplete patterns (or poor development) lacking genital setae. Microscopical male and female pores are not recognized externally. Three pairs of spermathecal pores marks are present near the intersegmental lines 6/7-8/ 9 in C line. Sphincteric nephropores just at the anterior part of segments near the intersegmental limit and aligned with C line, first nephropore visible in VI.

Septa highly muscular in 6/7/8/9/10/11, septa slightly muscular in 11/12, 12/13, intraclitellar and further septa membranous. Gizzard in segment VI, 3.3 mm in width and 2.1 mm in length, highly muscular; intestinal origin in XVIII. Typhlosole, lamellar-shaped at XXXII, extends to CCCXXIX, is poorly developed occupies approximately 10% of the intestinal diameter. Three pairs of tiny tube-shaped calciferous glands are present in VII–IX, lateral connection and oriented parallel to the esophagus to anterior region. The glands are 0.2–0.3 mm in width and 1.0– 1.1 mm in length, with a simple tubular structure ( Fig. 4D ). Holonephridial system, postclitellar nephridia with a small nephrostome connected to a short tube (first loop) which extends no more than a quarter of the bladder length. A second loop extends nearly three-quarters of the bladder length and continues to connect with a sigmoidal rough thick tube that opens into the bladder ( Fig. 4E ). The vascular system with ventral trunk, single dorsal trunk, and three pairs of commissures in VII–IX. Two pairs of large lateroesophageal hearts, kidney-shaped, in X–XI. Large vessel runs over the dorsal side of esophagus, thicker in XVI–XXVIII.

One pair of ovaries, similar to bunch grapes, in XIII. Female pores not recognized. Three pairs of long spermathecae in VI–VIII: the duct measures 0.10 to 0.20 mm in width and 1.3-1.5 mm in length, the saccular ampulla width 0.7 to 0.85 mm and length 3.0 to 3.5 mm ( Fig. 4F ). Spermathecal pores open near the intersegmental limits 6/7, 7/8, 8/ 9 in CD line, just at the posterior part of the segments; seminal chambers are absent. A pair of large testicular sacs in XI. A pair of long seminal vesicles are in XII, extending to segment CL. Deferent ducts go through B line and open on 26/27.

Remarks. Pontoscolex Mesoscolex juanae , n. sp. is similar to Pontoscolex (Mesoscolex) cynthiae Borges & Moreno, 1992 on account of the extension of the tubercula pubertatis (6 segments). The main difference is the calciferous gland structure (simple tubular) and size, being minuscule (<400 µm in diameter) in our specimens, vs. tubular-dichotomous in P. (Mesoscolex) cynthiae Borges & Moreno, 1992 . Another difference is the position of spermathecae, which is in VI-VIII in our specimens, vs. VII-IX in P. (M.) cynthiae Borges & Moreno, 1992 .

Figures

FIGURE 4. Pontoscolex Mesoscolex juanae n. sp. A. Ventral view of anterior region. B. Right common seta a of segment XXX. C. Right genital b seta of XXVI. D. Dorsal view of transversal cut of the right calciferous gland of IX. E. Cross-section view of right post-clitellar nephridium. F. Dorsal view of right spermathecae of VIII. npt: nephrostome. np: nephropore.