Pheretima atongensis, 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 : 746-748

Pheretima atongensis sp. nov.

( Figure 4 )

Material examined

Holotype: adult ( MSUN-A003 ), lower montane forest around Lake Atong in Victoria Peak area, municipality of Narra (9.300°N, 118.216°E), 700 m asl, Palawan Province, Philippines, coll. S. James, D. Flores, 31 October 2003 . Paratype: one adult ( MSUN-A 004), same collection data as for holotype.

Etymology

The species is named after Lake Atong in Victoria Peak in the municipality of Narra, Palawan, where the species was collected.

Diagnosis

Brown worm with adult length 148–150 mm, diameter 7–7.5 mm; 111–113 segments; four pairs of spermathecal pores at 5/6–8/9; 58–60 setae on vii, 60–62 setae on xx; 9 setae between male pores; spermathecal pores 0.19–0.2 circumference apart ventrally; male openings 0.18–0.25 circumference apart ventrally; genital markings lacking; prostates small in xvi–xviii; penis lacking.

Description

Dorsal brown, equators pigmented. Length 148–150 mm (n = 2 adults); diameter 7.5 mm at x, 7 mm at xx; body circular in cross section, tail tapering; 111–113 segments. First dorsal pore at 12/13, four pairs of spermathecal pores at 5/6–8/9, spermathecal pores 4.1 mm (0.19–0.2 circumference apart ventrally). Female pore single in xiv, openings of copulatory bursae paired in xviii, distance between openings 4.1–5.5 mm (0.18–0.25 circumference apart ventrally), 9 setae between openings. Clitellum annular, from xiv to xvi. Setae unevenly distributed around equators in some segments; 58–60 setae on vii, 60–62 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 xiv; caeca simple, originating in xxvii, extending forward to xxv. 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 irregular round ampulla; short, bulbous, muscular duct; single stalked diverticulum attached to the ectal 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 small, in xvii–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 atongensis sp. nov. belongs to the Ph. darnleiensis species group of Sims and Easton (1972). Although the new species overlaps in length with Ph. darnleiensis , the latter has its first dorsal pore at 11/12, has more setae between male pores (12) and has penis ( Table 1). The new species has a significantly thicker body (7–7.5 mm) compared with Ph. pugnatoris (4.5–5 mm), Ph. tabukensis (3.5–4 mm), Ph. margaritata (3–3.7 mm), Ph. thaii (2.1–2.3 mm), Ph. adevai (4–5 mm), Ph. lluchi (4–4.5 mm), Ph. potonganensis (4 mm) and Ph. palawanensis sp. nov. (4.5–5 mm). Similar to Ph. palawanensis sp. nov., Ph. atongensis 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. Pheretima atongensis sp. nov. also has more segments (111–113) compared with the other species (61–102 in Ph. pugnatoris , 65–103 in Ph. tabukensis , 83–96 in Ph. margaritata , 81 in Ph. thaii , 83–99 in Ph. adevai , 71–104 in Ph. lluchi , 69–96 in Ph. potonganensis and 68–104 in Ph. palawanensis sp. nov.). In addition, Ph. atongensis sp. nov. has more setae on vii and xx (58–60, 60–62) compared with the other species (12–35, 38– 45 in Ph. darnleiensis ; 16–19, 34– 35 in Ph. pugnatoris ; 19–20, 23– 36 in Ph. tabukensis ; 24, 30 in Ph. margaritata ; 16, 24 in Ph. thaii ; 32–37, 36– 39 in Ph. adevai ; 29–30, 39– 45 in Ph. lluchi ; 32–34, 28– 44 in Ph. potonganensis ; and 48–51, 50– 55 in Ph. palawanensis sp. nov.).

Pheretima atongensis sp. nov. was coded as Pheretima sp. Palawan 3 in the molecular phylogenetic and biogeographic distribution analysis of pheretimoid earthworms of the Philippine archipelago ( Aspe and James 2018). The genes 16S, COI and 12S were sequenced and deposited in the DNA Data Bank of Japan ( DDBS) under Accession Nos . LC259273 , LC268859 and LC259166 , respectively .

Figures

Figure 4. Pheretima atongensis 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.