Pheretima maculodorsalis, Aspe, Nonillon M. & James, Samuel W., 2014

Aspe, Nonillon M. & James, Samuel W., 2014, New species of Pheretima (Oligochaeta: Megascolecidae) from the Mt. Malindang Range, Mindanao Island, Philippines, Zootaxa 3881 (5), pp. 401-439 : 406-408

Pheretima maculodorsalis n. sp.

( Figs 2 A, 3A,B, Table 2)

Material examined. Holotype: adult (NMA 4505), Brgy Lake Duminagat, municipality of Don Victoriano, Misamis Occidental Province, Mt. Malindang Range (8º17'55"N, 123º37'01"E), 1500 m asl., Mindanao Island, Philippines, coll. Nonillon Aspe, Nolan Aspe, J. Adeva, Oct. 9–15, 2003. Paratypes: two juveniles (NMA 4531), same collection data as for holotype.

Etymology. The species name is derived from the Latin 'macula' (spot) and 'dorsalis' (pertaining to the back) and refers to the oval spots along the dorsal midline.

Diagnosis. Large worm, adult length 226–235 mm; dark red stripes in dorsal intersegmental furrows in head region, replaced by oval dots in post-clitellar segments; one pair of spermathecal pores closely spaced at intersegment 7/8; spermatheca with irregularly rounded ampulla, stout muscular duct, stalked diverticulum with 2–3 lobed receptacle; very long caeca extending from xxvii to xxi.

Description. In living animals, head segments striped dark red in intersegments, non-pigmented equators; in post-clitellar segments, stripes replaced by dorsal oval dots, which are also of dark red coloration. Length 226–235 mm (n= 3 adults, including non-type material); diameter 11–13 mm at x, 9 mm at xx; body cylindrical in crosssection, tail narrowing abruptly in last 8 segments; 115–122 segments. First dorsal pore at 12/13; spermathecal pores one pair at 7/8, 0.09 circumference apart ventrally, with small thickened lips, ventral surface of 1/ 2 vii–viii thickened. Female pore single in xiv, openings of copulatory bursae paired in xviii, 0.13 circumference apart ventrally, 2–4 setae between openings. Clitellum annular, from xiv to xvi. Setae evenly distributed around segmental equators; 73–74 setae on vii, 63–75 setae on xx, dorsal setal gaps present, no ventral gaps.

Septa 5/6–7/8 and 10/11–13/14 muscular, 8/9 membranous, 9/10 lacking. 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 extending from viii to x, esophagus with low vertical lamellae x–xiii, intestinal origin xvii, caeca originating in xxvii, extending forward to xxi, ventral margins slightly incised; typhlosole originates in xxvii, simple fold slightly less than dorsal vessel diameter; intestinal wall with 50–54 longitudinal blood vessels.

Hearts in x to xiii, esophageal; commissural vessels in vi, vii, and ix, lateral; those in viii extend to gizzard; supra-esophageal vessel extends from x to xiii; extra-esophageal vessel joins ventral esophageal wall in xi, receives efferent parieto-esophageal vessel in xiii.

Ovaries and funnels free in xiii. Spermathecae paired, postseptal in viii, with nephridia on ducts; each spermatheca with irregularly rounded ampulla, stout muscular duct, stalked diverticulum attached to duct near ampulla, terminating in 2–3 lobed receptacles, stalks short. Spermathecae contain small, ovate spermatophores with very slender tails about half length of spermatophore body. 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 en route to ental end of prostatic ducts; prostates in xvii to xx, each a single, dense, racemose mass; short straight muscular duct entering posterior margin of copulatory bursa; paired large copulatory bursae extend from xviii to xxi; coelomic surfaces of paired hemispheric copulatory bursae muscular, secretory diverticula lacking; roof of copulatory bursae with two pads, posterior pad bifurcate, both pads with small lumen within glandular tissue; small penis between pads; penial sheaths in copulatory bursae absent. Bursal floor has thick wrinkles, no other projections.

Remarks. Pheretima maculodorsalis n. sp. belongs to the P. sangirensis species group in Sims & Easton (1972), characterized by spermathecal pore(s) opening only in 7/8 and absence of penial sheaths in the copulatory bursae. Members of this group may have no septa in either intersegments 8/9 or 9/10 or both; the caeca are either simple or have short pockets on the ventral margins; the male system is holandric, with paired testis sacs; and the copulatory bursae are simple, with short conical penes. In Sims & Easton (1972), the P. sangirensis group was composed of P. sangirensis , P. ceramensis Cognetti, 1922 , and P. crassicystis Michaelsen, 1896 . Michaelsen (1900) reassigned P. crassicystis as a subspecies of P. sangirensis . Blakemore (2007) acknowledged Michaelsen's (1900) reassignment of P. sangirensis subspecies: P. s. sangirensis , P. s. crassicystis , and P. s. chica Michaelsen, 1896. The subspecies vary in size (140 mm x 3.5–4.5 mm in P. s. sangirensis ; 240 mm x 8 mm in P. s. crassicystis ; and 54–120 mm in P. s. c h i c a) and color (dark purple brown in P. s. sangirensis ; purplish gray in P. s. crassicystis ; and purple in P. s. chi ca). Also, the first dorsal pore in P. s. sangirensis is located in 11/12 while it is in 12/ 13 in P. s. crassicystis and P. s. c h i c a. Another species, P. unicystis Lee, 1981 from Vanua Tu, was added to the species group, but P. unicystis differs from the other members in the group by having the clitellum located in 1/2 xiv– 1/2 xvi and in consistently having only one spermatheca located on the right side of 7/8. Blakemore (2007) considered P. unicystis to be a possible junior synonym of P. montana Kinberg, 1867 . Pheretima maculodorsalis differs markedly from P. sangirensis (and subspecies; see Table 2 for comparison) and P. ceramensis in pigmentation pattern (pigmented over the entire dorsum in P. ce r a m e n s i s), the distance between male pores and spermathecal pores (about 0.2 circumference apart and slightly closer set, respectively in P. ceramensis ) (James, 2004), the origin of the intestine (xv in P. ceramensis ), and the number of intestinal vessels (36 in P. ceramensis ), among other characters. Pheretima maculodorsalis is similar to P. s. crassicystis in size (240 mm) and the location of the dorsal pore, but the latter is entirely pigmented, has no septum in 8/9, has caeca extending from xxvii–xxii, and has the prostate extending from xvii–xix.

James (2004) reviewed the P. sangirensis group and added to this group 10 new species ( P. quincunxia , P. diesmosi , P. monoporata , P. vicinipora , P. baungonensis , P. paucisetosa , P. alba , P. v i rg at a, P. rubida and P. asurgo Blakemore, 2006 (a replacement name for P. rugosa James, 2004 to avoid homonymy with P. houlleti rugosa Gates, 1926 ) from the Mt. Kitanglad range in Mindanao. Hong & James (2008b) added another two species ( P. lagunaensis and P. m a r i a e) to this group from Mt. Makiling on Luzon Island. Pheretima maculodorsalis n. sp. is a large worm, and among the species at Mt. Kitanglad is most similar in size to P. virgata , which reaches 290 mm. The two species differ in the intestinal origin (xvi in P. v i rga t a), the pigmentation pattern (stripes in P. v i rga t a), the number of intestinal vessels (42 in P. v i rg at a), and the number and shape of pads in the copulatory bursae. Other large worms on Mt. Malindang are P. tigris n. sp., P. i m m an i s n. sp., and P. l ag o n. sp. Pheretima maculodorsalis differs from them ( Table 2) in pigmentation pattern; the length of the caeca; the shape, size and position of prostate glands and copulatory bursae; and the spermathecal pores, which are closer together. Pheretima maculodorsalis is the only species of the sangirensis group at Mt. Malindang that has the intestinal origin in xvii.

Occurrence. We found P. maculodorsalis in primary and disturbed forest at two of five forest sites in Brgy Lake Duminagat, at elevations of 1479–2027 m asl. It occurred in soil and rotting logs (Table 1).

Figures

FIGURE 2. Photographs of living Pheretima worms in dorsal view, showing coloration. (A) P. maculodorsalis n. sp.; (B) P. tigris n. sp.; (C) P. immanis n. sp.; (D) P. longigula n. sp.; (E) P. malindangensis n. sp. Scale bars: A – D, 5 cm; E, 3 cm.