Pheretima gamay, Aspe & James, 2017

Aspe, Nonillon M. & James, Samuel W., 2017, Pheretimoid earthworms (Clitellata: Megascolecidae) from Mt. Apo, Mindanao Island, Philippines with description of eight new species, Raffles Bulletin of Zoology 65, pp. 357-372 : 367

Pheretima gamay , new species

( Fig. 2B )

Material examined. Holotype: adult ( NMP 4621 ), Brgy Baracatan , Davao City , Mt. Apo National Park (7°00′04″N, 125°21′55″E), 1,524 m asl, Mindanao Island, Philippines, coll. N. Aspe, A. Solis, D. Flores, R. Librado, 11–14 December 2003 . Paratype: one adult ( ZRC. ANN 0074 ), same collection data as for holotype .

Etymology. The species name ‘gamay’ is a word which means ‘small’ in Bisaya, a dialect used by most people of Mindanao.

Diagnosis. Very small worm with adult length 38–51 mm; dorsum purplish brown, ventrum pale; one pair of spermathecal pores at 5/6; distance between spermathecal pores and male pores 0.19 and 0.13 circumference apart ventrally, respectively; intestinal origin in xvii; spermatheca with an ovate ampulla and a very large bulbous, short, muscular duct; racemose prostates extending from xvii–xx; penis lacking.

Description. In living animals, purplish brown dorsum, lighter ventrum, equators pigmented. Length 38–51 mm (n= 2 adults); diameter 1.5–2 mm at x, 2 mm at xx; body cylindrical in cross-section, tail tapering; 63–87 segments. First dorsal pore 12/13. One pair of spermathecal pores at 5/6, 0.9 mm apart (0.19 circumference apart ventrally). Female pore single in xiv. Openings of copulatory bursae paired in xviii, distance between openings 0.8 mm (0.13 circumference apart ventrally); 1–5 setae between openings. Clitellum annular, from xiv to xvi. Setae unevenly distributed around equators in some segments; 38–40 setae on vii, 36–45 setae on xx, dorsal setal gaps present, no ventral gaps. Genital markings lacking.

Septa 5/6–9/10 thin, 10/11–13/14 muscular. Dense tufts of nephridia on anterior faces of 5/6 and 6/7; nephridia of intestinal segments located mainly on body near septum/ body wall junction. Large gizzard in viii–x, esophagus with low vertical lamellae x–xiii. Intestinal origin in xvii, caeca, typhlosole and longitudinal blood vessels were not observed due to damage of the intestine around the area in both holotype and paratype. Hearts in x to xiii, esophageal; commissural vessels in vi, vii, and ix lateral; those in viii extending to gizzard.

Ovaries and funnels free in xiii. Spermathecae paired, postseptal in vi, with nephridia on ducts; each spermatheca with an ovate ampulla and a short, very large bulbous, muscular duct, diverticulum attached to the ental portion of the right face of the right spermathecal duct, and to the left face of the left spermathecal duct, stalks short, terminating in small, ovate receptacles. Male sexual system holandric, testes and funnels enclosed in paired sacs in x, xi; seminal vesicles in xi, xii, each with a digitate dorsal lobe; vesicles of xi enclosed in testes sac; vasa deferentia slender, free from body wall en route to ental end of prostatic ducts; prostates in xvii to xx, one individual has asymmetrical prostates, with the right prostate in xvi to xx; each prostate a single, dense, racemose mass, with three lobes; short, muscular duct entering posterior margin of copulatory bursa. Copulatory bursae ovate in xvii–xix; coelomic surfaces muscular, secretory diverticula lacking; roof with two pads, floor pads lacking; penis lacking.

Remarks. Pheretima gamay belongs to the P. urceolata group of Sims & Easton (1972). It is relatively similar to P. acia ( Aspe & James, 2016) (33–47 mm × 1–1.2 mm), P. dinagatensis ( Aspe & James, 2016) (65 mm × 2.5–3 mm), P. abiadai ( Hong & James, 2008b) (33–60 mm × 2.2–3 mm), P. nagaensis ( Hong & James, 2008b) (36–53 mm × 2.4–3 mm), P. viracensis ( Hong & James, 2009) (38–61 mm × 1.9–2.6 mm), P. doriae ( Hong & James, 2009) (34–45 mm × 2–2.4 mm), P. batoensis ( Hong & James, 2009) (45–65 mm × 2.4–3.2 mm), and P. camarinensis ( Hong & James, 2009) (54–61 mm × 2.2–3.5 mm) in body size. However, the other species have wider distance between spermathecal pores (0.21–0.36 circumference apart) except in P. camarinensis (0.18–0.19 circumference apart), and between male pores (0.15–32 circumference apart), have more setae between male pores (5–14) except in P. acia (3), have intestinal origin in xiv–xvi, and have penes. The other species also have unpigmented setal rings except P. batoensis and P. dinagatensis , which are striped, and P. viracensis , which has pigmented setal rings. Pheretima gamay also differs from P. acia by the latter having very small prostate, and the muscular duct connecting the prostate and the copulatory bursa at the anterior margin of the bursa. No other species in the P. urceolata group closely resemble P. gamay .

Figures

Fig. 2. Schematic drawings of the internal morphology in dorsal view. A, Pheretima aquila, new species; B, P. gamay, new species; C, P. libradoi, new species; D, P. davaoensis, new species. Abbreviations: s, spermatheca; h, heart; p, prostate gland; cb, copulatory bursa; c, caecum. Scale bars = 5 mm.