Pithemera duminagati, Aspe & James, 2015

Aspe, Nonillon M. & James, Samuel W., 2015, New Polypheretima and Pithemera (Oligochaeta: Megascolecidae) species from the Mt. Malindang Range, Mindanao Island, Philippines, Journal of Natural History 49 (37), pp. 2233-2255 : 2245-2249

Pithemera duminagati sp. nov.

( Figures 2C and 3C )

Etymology

The species is named for Barangay Lake Duminagat , the type locality .

Material examined

Holotype: adult (NMA 4529), Mt. Malindang Range (8.2986°N, 123.6169°E), Barangay Lake Duminagat , municipality of Don Victoriano, Misamis Occidental Province, Mindanao Island, Philippines; 1357 m a.s.l; coll. Aspe et al., 9–15 October 2003 . Paratypes: two adults (NMA 4548), same collection data as for holotype.

Diagnosis

Very small, white worm; adult length 36–37 mm; clitellum from xiv through half of xvi; five pairs of spermathecal pores, 4/5–8/9; distance between male pores 0.13 circumference apart; no genital markings; intestinal origin in xv; prostate glands from xvi–xxi.

Description

White; clitellum grey–brown. Adult length 36–37 mm (n = three adults); diameter 2.5 mm at x, 2 mm at xx; body cylindrical in cross-section, tail blunt; 88–95 segments. First dorsal pore at 12/13; paired spermathecal pores in 4/5/6/7/8/9, inconspicuous; female pores paired in xiv; male pores on paired porophores in xviii, 0.13 circumference apart, zero to three setae between openings. Clitellum annular, extending from xiv to half of xvi. Setae unevenly distributed, 43–48 setae on vii, 31–43 setae on xx; no dorsal or ventral gaps. Genital markings lacking.

Septa 5/6/7/8 slightly muscular, 8/9 absent, 9/10–13/14 thinly muscular. Dense tufts of nephridia on anterior faces of 5/6/7/8; nephridia of intestinal segments located at septum/body wall junction, mainly on body wall near anterior and posterior faces of septa. Gizzard large, extending from viii to ix; oesophagus with lamellar section from xi to xiii; intestinal origin in xv; caeca from xxii to xxi; typhlosole a simple fold of about one-quarter lumen diameter, originating in xix, full size in xxii; intestinal wall lacks longitudinal blood vessels but has two pairs of vertical vessels per segment.

Hearts in x–xii, oesophageal; commissural vessels in vi, vii and ix, lateral; lacking in viii; supra-oesophageal vessel extends from x to xii; extra oesophageal vessels joining ventral oesophageal wall in x, receiving efferent parieto-oesophageal vessels in xiv.

Ovaries and funnels free in xiii; ovisacs in xiv; spermathecae five pairs from v to ix; duct short, slender; small, ovate ampulla; diverticulum stalk short, attached ectally to duct, terminating in short, pyriform receptacle; receptacle a small sphere lacking spermatozoal iridescence. Male sexual system holandric; testes and funnels enclosed in paired ventral sacs in x and xi; seminal vesicles in xi and xii; vasa deferentia slender, free from body wall, joining ental end of prostatic ducts; each prostate racemose, broad, 3- or 4-lobed, present from xvi to xxi; ectal half of duct expands to form muscular spindle; ducts in hairpin loop. Ental portion of duct with two lumens. Copulatory bursae lacking.

Remarks

Pithemera duminagati sp. nov. belongs to the Pi. bicincta group of Sims and Easton (1972). Although Pi. duminagati sp. nov. is similar to Pi. bicincta in some characters, it differs from the latter in size, in lacking genital markings, in the distance between male pores, in the relative size of the prostates and in the origin of the intestine ( Table 3). Pithemera duminagati sp. nov. is similar to Pi. rotunda ( James et al. 2004) , another member of the bicincta group, in size and in being white, in septal arrangement, in intestinal origin and in the length of caeca, but Pi. duminagati sp. nov. has fewer setae between the male pores, lacks genital markings, and has proportionally larger prostate glands. Among the three Pithemera species from Mt. Malindang, Pi. duminagati sp. nov. is more similar to Pi. malindangensis sp. nov. in the extent of the clitellum, number of spermathecae and septal arrangement. Like Pi. donvictorianoi sp. nov., Pi. duminagati sp. nov. is smaller in body size than Pi. malindangensis sp. nov. and has three pairs of dense tufts of nephridia on 5/6/7/8, whereas the latter has only two pairs on 5/6/7.

Occurrence

Pithemera duminagati sp. nov. was found outside the sampling plots at three of five sites: in primary and disturbed forest in Barangay Lake Duminagat and in disturbed forest in Barangay Sibucal, at elevations of 902–2027 m a.s.l. The soil it inhabited was covered with thick leaf litter and roots, bryophytes and lichens. We did not observe it on rotten logs.

Figures

Figure 2. Schematic drawings of the external anterio-ventral area of (A) Polypheretima mindanaoensis sp. nov., (B) Pithemera malindangensis sp. nov., (C) Pithemera duminagati sp. nov. and (D) Pithemera donvictorianoi sp. nov. Abbreviations: fp, female pore; cl, clitellum; mp, male pore; gm, genital markings. Scale bars: 5 mm.

Figure 3. Schematic drawings of the internal morphology of (A) Polypheretima mindanaoensis sp. nov., (B) Pithemera malindangensis sp. nov., (C) Pithemera duminagati sp. nov. and (D) Pithemera donvictorianoi sp. nov. Abbreviations: s, spermatheca; n, dense tufts of nephridia; h, heart; p, prostate gland; c, caecum. Scale bars: 5 mm.