Pheretima palawanensis, 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 : 744-746

Pheretima palawanensis sp. nov.

( Figure 3 )

Material examined

Holotype: adult ( WPU-A006 ), Brgy. Irawan, Puerto Princesa City, (9.783°N, 118.650°E), 200 m asl, Palawan Province, Philippines, coll. S. James, 25 September 2005 . Paratypes: two adults ( WPU-A 007), same collection data as for holotype.

Etymology

The species is named after the Province of Palawan.

Diagnosis

Unpigmented worm with adult length 76–112 mm, diameter 3–5 mm; 68–104 segments; four pairs of spermathecal pores at 5/6–8/9; 48–51 setae on vii, 50–55 setae on xx; 8–10 setae between male pores; spermathecal pores 0.2–0.24 circumference apart ventrally; male openings 0.19–0.24 circumference apart ventrally; genital markings lacking; prostates small in xvi–xviii; penis lacking.

Description

Dorsal unpigmented, equators unpigmented. Length 76–112 mm (n = 3 adults); diameter 3–4 mm at x, 4–5 mm at xx; body circular in cross section, tail tapering; 68–104 segments. First dorsal pore at 12/13, four pairs of spermathecal pores at 5/6–8/9, spermathecal pores 2.3–2.5 mm (0.2–0.24 circumference apart ventrally). Female pore single in xiv, openings of copulatory bursae paired in xviii, distance between male openings 2.4–3.8 mm (0.19–- 0.24 circumference apart ventrally), 8–10 setae between openings. Clitellum annular, from xiv to xvi. Setae unevenly distributed around equators in some segments; 48–51 setae on vii, 50–55 setae on xx, dorsal and ventral setal gaps present. Genital markings lacking.

Septa 4/5–7/8 and 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 viii–x, oesophagus with low vertical lamellae x–xiii, intestinal origin in xiv; caeca simple, originating in xxvii, extending forward to xxiii. 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 many nephridia on ducts. Each spermatheca with obpyriform shape; thick, robust, 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 small, in xvi–xviii; each prostate a single, dense, round, racemose mass; short muscular duct to copulatory bursa. Copulatory bursae round, small in xviii; coelomic surfaces muscular, secretory diverticula lacking; penis lacking.

Remarks

Pheretima palawanensis 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 similar to Ph. darnleiensis Fletcher, 1886 (74–170 mm), Ph. pugnatoris Hong and James, 2010 (72–125 × 4.5–5 mm), Ph. tabukensis Hong and James, 2010 (65–74 × 3.5–4 mm), Ph. margaritata Hong and James, 2011b (85–148 × 3–3.7 mm), Ph. thaii Hong and James, 2011b (60 × 2.1–2.3 mm), Ph. adevai Aspe and James, 2014 (110–131 × 4–5 mm), Ph. lluchi Aspe and James, 2014 (104–135 × 4–4.5 mm) and Ph. potonganensis Aspe and James, 2014 (63–89 × 4 mm) in size ( Table 1). However, the new species lacks a penis while the other species have one. Pheretima palawanensis sp. nov. has its first dorsal pore in 12/13, similar to Ph. adevai and Ph. potonganensis , but the other species have their first dorsal pore either in 11/12 (in Ph. darnleiensis , Ph. pugnatoris and Ph. tabukensis ), 9/10 (in Ph. margaritata ) or 13/14 (in Ph. lluchi ). The spermathecal pores are more widely spaced in Ph. pugnatoris (0.26–0.29 circumference apart ventrally) and Ph. margaritata (0.25–0.28 circumference apart ventrally) compared with the new species (0.2–0.24 circumference apart ventrally). Also, the male pores are more widely spaced in Ph. margaritata (0.26 circumference apart ventrally), Ph. thaii (0.5 circumference apart ventrally) and Ph. adevai (0.25 circumference apart ventrally) and are closer in Ph. pugnatoris (0.17–0.18 circumference apart ventrally) compared with the new species (0.19–0.24 circumference apart ventrally). The new species has more setae on vii and xx (48–51, 50–55) 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 ; and 32–34, 28– 44 in Ph. potonganensis ). In addition, Ph. palawanensis sp. nov. has 8–10 setae between the male pores whereas the other species have fewer (5–7 in Ph. pugnatoris , 6 in Ph. tabukensis , 4 in Ph. margaritata , 3 in Ph. thaii , 3–7 in Ph. adevai , 5–6 in Ph. lluchi and 4 in Ph. potonganensis ), except Ph. darnleiensis which has 12.

Pheretima palawanensis sp. nov. was coded as Pheretima sp. Palawan 1 in the molecular phylogenetic and biogeographic distribution analysis of pheretimoid earthworms of the Philippine archipelago ( Aspe and James 2018). The genes 16S, 28S and 12S were sequenced and deposited in the DNA Data Bank of Japan ( DDBS) under Accession Nos . LC259261 , LC259226 and LC259164 , respectively .

Figures

Figure 3. Pheretima palawanensis 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.