Pheretima ascensa, Aspe & Manasan & Manlavi & Patiluna & Sebido & Obusan & Simbahan & James, 2021

Aspe, Nonillon M., Manasan, Rafael Ethan, Manlavi, Albert B., Patiluna, Ma. Lotus E., Sebido, Maria Asela B., Obusan, Marie Christine M., Simbahan, Jessica F. & James, Samuel W., 2021, The earthworm fauna of Palawan, Philippines with description of nineteen new pheretimoid species (Clitellata: Megascolecidae), Journal of Natural History 55 (11 - 12), pp. 733-797 : 748-750

Pheretima ascensa sp. nov.

( Figure 5 )

Material examined

Holotype: adult ( MSUN-A005 ), arboreal, on the ridge of Mt. Mantalingahan in Brgy. Marinana , municipality of Brooke’s Point, (8.750°N, 117.683°E), 930 m asl, Palawan Province, Philippines, coll. S. James, D. Flores, 25 October 2003 . Paratype: one adult ( MSUN-A 006), same collection data as for holotype.

Etymology

The word ‘ascensa’ is Latin and means arboreal or climber, referring to the arboreal habit of the species.

Diagnosis

Brown worm with adult length 129–145 mm, diameter 4.2–5 mm; 94–117 segments; four pairs of spermathecal pores at 5/6–8/9; 38 setae on vii, 42 setae on xx; 8 setae between male pores; spermathecal pores 0.26 circumference apart ventrally; male openings 0.27 circumference apart ventrally; genital markings lacking; prostates small in xv–xviii; penis lacking.

Description

Brown, equators pigmented. Length 129–145 mm (n = 2 adults); diameter 5 mm at x, 4.2–4.5 mm at xx; body circular in cross section, tail tapering; 94–117 segments. First dorsal pore at 12/13, four pairs of spermathecal pores at 5/6–8/9, spermathecal pores 2.9–3 mm (0.26 circumference apart ventrally). Female pore single in xiv, openings of copulatory bursae paired in xviii, distance between openings 3.5–3.9 mm (0.26–0.27 circumference apart ventrally), 8 setae between openings. Clitellum annular, from xiv to xvi. Setae unevenly distributed around equators in some segments; 38 setae on vii, 42 setae on xx, dorsal setal gaps present, ventral setal gaps lacking. Genital markings lacking.

Septa 4/5–7/8 muscular, 10/11–13/14 thin, 8/9/10 lacking. Dense tufts of nephridia on anterior faces of 5/6 and 6/7; nephridia in intestinal segments located mainly on body near septum/body wall junction. Large gizzard in ix–xi, oesophagus with low vertical lamellae x–xiii, intestinal origin in xv; caeca simple, originating in xxvi, extending forward to xxii. Hearts in x–xiii, oesophageal; commissural vessels in vi, vii and ix lateral.

Ovaries and funnels free in xiii. Spermathecae four pairs in vi–ix, with nephridia on ducts. Each spermatheca with obpyriform ampulla; short, bulbous, muscular duct; single stalked diverticulum attached to the ental portion of the right face of duct of right spermatheca, and on left face of duct of left spermatheca; stalk short, terminating in ovate receptacle. Male sexual system holandric; testes and funnels enclosed in paired sacs in x, xi; seminal vesicles xi, xii, each with digitate dorsal lobe; vesicles of xi enclosed in testes sac; vasa deferentia slender, free from body wall on way to ental end of prostatic ducts; prostates in xv–xviii; each prostate a single, dense, racemose mass; short muscular duct entering copulatory bursa. Copulatory bursae round, small in xviii; coelomic surfaces muscular, secretory diverticula lacking; penis lacking.

Remarks

Pheretima ascensa sp. nov. belongs to the Ph. darnleiensis species group of Sims and Easton (1972). Among the members of the Ph. darnleiensis group, the new species is relatively close in length to Ph. darnleiensis (75–170 mm), Ph. margaritata (85–148 mm), Ph. pugnatoris (75–125 mm), Ph. adevai (110–131 mm), Ph. lluchi (104–135 mm), Ph. palawanensis sp. nov. (76–112 mm) and Ph. atongensis sp. nov. (148–150 mm) ( Table 1). Similar to Ph. palawanensis sp. nov. and Ph. atongensis sp. nov., Ph. ascensa sp. nov. has its first dorsal pore in 12/13, has more or less the same number of setae between male pores (8–9) and lacks a penis, in contrast to the other species. It has more segments (94–117) than Ph. margaritata (83–96), Ph. pugnatoris (61–102), Ph. adevai (83–99) and Ph. lluchi (71–104). Also, the spermathecal pores and the male pores, respectively, are closer in Ph. darnleiensis (0.2, 0.2 circumference apart ventrally), Ph. adevai (0.25, 0.16 circumference apart ventrally), Ph. lluchi (0.2, 0.2 circumference apart ventrally), Ph. palawanensis sp. nov. (0.2–0.24, 0.19–0.24 circumference apart ventrally) and Ph. atongensis sp. nov. (0.19–0.2, 0.18–0.25 circumference apart ventrally) than in Ph. ascensa sp. nov. (0.26, 0.26 circumference apart ventrally). In addition, the new species differs from the other species in the relative length of the caeca (xxvi–xxii in Ph. ascensa vs xxvii–xxiv in Ph. darnleiensis , Ph. pugnatoris and Ph. lluchi , xxvii–xxv in Ph. margaritata and Ph. atongensis , xxvii–xxiii in Ph. adevai , and xxvii–xxiii in Ph. palawanensis ) and the prostate gland (xv–xviii in Ph. ascensa vs xviii–xix in Ph. darleiensis , xvii–xviii in Ph. margaritata and Ph. atongensis , xvii–xix in Ph. pugnatoris and Ph. adevai , xviii–xx in Ph. lluchi , and xvi–xviii in Ph. palawanensis ).

Figures

Figure 5. Pheretima ascensa sp. nov. (a) External ventral view. (b) Internal dorsal view. (c) Spermathecae. Abbreviations: c, caecum; cb, copulatory bursa; fp, female pores; mp, male pores; p, prostate gland; s, spermathecae; sp, spermathecal pores; sv, seminal vesicles.