Pheretima misamisensis, 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 : 418-419

Pheretima misamisensis n. sp.

( Fig. 5 B, Table 2)

Material examined. Holotype: adult (NMA 4516) Brgy Sibucal, Oroquieta City, Misamis Occidental Province, Mt. Malindang Range (8º19'31"N, 123º38'02"E), 991 m asl., Mindanao Island, Philippines, coll. Nonillon Aspe, Nolan Aspe, M. Lluch, and J. Adeva, Feb. 18–25, 2004. Paratypes: two adults (NMA 4537); two adults ( ZRC.ANN.0021), Brgy Lake Duminagat, municipality of Don Victoriano, Misamis Occidental Province, Mt. Malindang Range (8º17'55"N, 123º37'01"E), 1500 m asl., coll. Nonillon Aspe and J. Adeva, Oct. 9–15, 2003.

Etymology. The species is named after Misamis Occidental Province, where this species was collected.

Diagnosis. Small, brown worm, reaching 55–65 mm in adult length; one pair of spermathecal pores widely spaced at 7/8; intestinal origin in xv; elongate prostate glands extending from xvi to xxii; low, circular copulatory bursae in xvii to xix; short caeca extending from xxvii to xxv.

Description. In living animals, dorsum very dark red-brown to black anteriorly, medium red-brown posteriorly; equators non-pigmented; ventral side non-pigmented; clitellum dark. Length 55–65 mm, diameter 3.5 mm at x (n= 5 adults), 3–4 mm at xx; 90–103 segments; body cylindrical in cross-section, tail blunt. First dorsal pore 12/13; paired spermathecal pores sublateral on 7/8; 0.3 circumference apart ventrally; female pore single in xiv, openings of copulatory bursae paired in xviii, 0.23 circumference apart ventrally, 6 or 7 setae between openings. Clitellum annular, extending from xiv to xvi. Setae on ventrum more closely spaced compared with that of the dorsum, 42–51 setae on vii, 43–48 setae on xx, dorsal gap present, ventral gap absent.

Septa 5/6/7/8 and 10/11–13/14 slightly muscular, 8/9 very thin, 9/10 partial. Dense tufts of nephridia on anterior faces of 5/6 and 6/7; nephridia of intestinal segments located mainly on body wall at anterior and posterior faces of septa, at septum/body wall junction. Large gizzard in viii to x; esophagus with circumferential lamellae from xi to xii, digitiform internal texture from xiii to xiv; intestinal origin in xv; caeca originating in xxvii, extending forward to xxv; typhlosole rudimentary; intestinal wall with 32 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 to between x and xiii; extra-esophageal vessels join ventral esophageal wall in x, receive efferent parieto-esophageal vessels in xiv.

Ovaries and funnels free in xiii; paired spermathecae preseptal in vii, with nephridia on ducts. Each spermatheca consists of blunt reniform ampulla; equally long, stout duct; and single stalked diverticulum attached to duct near body wall, terminating in blunt ovate receptacle; stalks longer than spermathecal duct. Male sexual system holandric; testes and funnels enclosed in paired ventral sacs in x and xi, but funnels of x extend into xi; seminal vesicles in xi and xii, each with short, acinous dorsal lobe; vasa deferentia slender, free from body wall, passing over anterior lateral face of copulatory bursae en route to ental end of prostatic ducts; prostates in xvi to xxii, each racemose, 5- or 6-lobed, wrapped around lateral margin of copulatory bursa; muscular duct enters posterior dorsal face of copulatory bursa. Ductlets from anterior prostatic lobes join vas deferens; posterior ductlets join anterior ductlets at junction with muscular prostatic duct. Copulatory bursae low circular domes extending from xvii to xix. Coelomic surface of copulatory bursa muscular, secretory diverticula lacking; walls consist of outer muscular layer, inner glandular layer; floors of bursae with one large anterior pad, inner posterior dorsal face with very short, conical penis; penial sheaths in copulatory bursae absent.

Remarks. Pheretima misamisensis n. sp. belongs to the P. sangirensis group of Sims & Easton (1972). It is similar to P.s. chica ( Michaelsen, 1896) in size (54–120 mm) but differs in color (purple in P.s. ch i c a); the spacing of the spermathecal pores and male pores (0.25 and 0.2 circumference apart, respectively, in P.s. c h i c a); and in the number of setae in the post-clitellar region (> 60 in P.s. c hi c a). Pheretima misamisensis is most similar to P. wati n. sp. in size, the origins of the gizzard and intestine, and the number of hearts ( Table 2). However, in P. misamisensis the spermathecal and male pores are widely spaced, whereas they are more closely spaced in P. wati ; in P. misamisensis , septa 9/10 is absent, whereas in P. wati septa 8/9 is absent. These two species also differ in the number of setae on vii; shape of the spermathecae; size and position of the prostates and copulatory bursae; and length of the caeca. Pheretima misamisensis is similar in length to P. quincunxia , P. asurgo , and P. rubida at Mt. Kitanglad (James, 2004), but differs from the latter three in the spacing between spermathecal pores (0.13 circumference apart in P. quincunxia , 0.15 circumference apart in P. asurgo , and 0.12 circumference apart in P. rubida ), the origin of the intestine (xvi in P. quincunxia and P. rubida ; xvii in P. asurgo ), the absence of septa in 9/ 10, and the length of the prostate (xvii–xix in P. quincunxia ; xvi–xx in P. asurgo and P. r ub i da). Pheretima misamisensis also differs from P. rubida and P. asurgo in the location of the first dorsal pore, which is in 11/12, and from P. quincunxia in pigmentation (the latter is unpigmented).

Occurrence. Pheretima misamisensis was not found on any of the sampling plots, but was detected in haphazard samples at four of the five sites listed in Table 1; it occurred at elevations above ~ 900 m in Brgys Sibucal, Small Potongan, and Lake Duminag, but was not found at 238–271 m in Brgy Toliyok. We found it in soil and rotting logs (Table 1).

Figures

FIGURE 5. Schematic drawings of the internal morphology of Philippine Pheretima species, in dorsal view: (A) P. malindangensis n. sp.; (B) P. misamisensis n. sp.; (C) P. w at i n. sp.; Abbreviations: s, spermatheca; h, heart; p, prostate gland; cb, copulatory bursa; c, caecum. Scale bars: 5 mm.