Pheretima paucisetosa, James, 2004

James, Samuel W., 2004, New Species Of Amynthas, Pheretima And Pleionogaster (Clitellata: Megascolecidae) Of The Mt. Kitanglad Range, Mindanao Island, Philippines, Raffles Bulletin of Zoology 52 (2), pp. 289-313 : 303-304

Pheretima paucisetosa , new species

( Figs.3E, F )

Material examined. – Syntypes - 2 adults ( NMA 003984 ), Philippines, Mindanao Island, Bukidnon Province, Mt. Kitanglad Range , 16.5 km S, 4 km. E of Camp Philips, 8 10.5' N, 124 51' E, 1900 m. elevation, coll. L. Heaney, 22 Mar.1993 .

Etymology. – The species name refers to the low numbers of setae compared to its congeners.

Description. – Unpigmented, body 115 x 5.0 mm (vii), 5.5 (x), 6.0 mm (xxv), 89 segments; body cylindrical in crosssection. First dorsal pore 11/12, spermathecal pores paired in 7/8, 0.16 circumference apart, female pore single in xiv, openings of copulatory bursae paired in xviii, 0.13 circumference apart in 5 th setal line, 2 setae between openings. Setae more crowded ventrally; 22 setae on vii, 28 setae on xx; in vii ZZ: YZ = 1.8, in xx ZZ: YZ = 1.9, no ventral gaps; setae of ii-ix larger than those following. Clitellum annular xiv-xvi; no genital markings ( Fig. 3E ).

Septa 4/5-6/7 thin, 7/8 muscular, 9/10 thin, adherent to 10/ 11 at ectal edges, 10/11-13/14 muscular. Dense tufts of nephridia on anterior faces of 5/6, 6/7; nephridia of intestinal segments located at septum-body wall junction on anterior and posterior faces of septa, primarily on posterior faces.

Large gizzard in viii, esophagus with vertical lamellae xixiii, intestinal origin 1/2xvi, full size xvii, simple caeca originating in xxvii, extending forward to xxv, ventral margins smooth; typhlosole xxvii-xlii, mere wrinkle; intestinal wall with 34 longitudinal blood vessels xxxi-xxxix.

Hearts x-xiii esophageal, commissural vessels vi, vii, ix lateral; viii to gizzard; supra-esophageal vessel x-xiv; extraesophageal vessel to esophageal wall in x; efferent parietoesophageal vessel from body wall to ventral esophagus in xiii.

Ovaries and funnels free in xiii, spermathecae paired, preseptal in vii with nephridia on ducts; each spermatheca with large rounded ampulla, stalked diverticulum terminating in sausage-shaped receptacle, stalks long, kinked with one or two loops closely adherent to spermathecal duct ( Fig. 3F ). Male sexual system holandric, testes and funnels enclosed in separate paired sacs in x, xi; seminal vesicles xi, xii with digitate dorsal lobe; vasa deferentia free from body wall en route to ental end of prostatic ducts; each prostate racemose, occupying xvii-xix, bilobed, stout muscular duct entering posterior side of copulatory bursa in xviii; coelomic and exterior surfaces of paired copulatory bursae lacking glandular or other projections; floor of copulatory bursae with three pads, one medial as long as bursal chamber, two lateral half as long, together forming a T-shaped intersection over the opening of bursa; penis present.

Remarks. – Pheretima paucisetosa has relatively few setae per segment, though not much different in this respect from P. quincunxia , and setae of the head segments are larger than the rest. However the setae of P. paucisetosa are regularly arranged rather than irregular to offset. Among species described here and other members of the sangirensis group, it is unique in having the combination of an intestinal origin in xvi, no typhlosole, spermathecae in vii, lack of pigment, regular setal arrangement and three large pads on the copulatory bursae floors. It most closely resembles P. alba but differs in body size, number of intestinal blood vessels, the number and sizes of anterior setae, and the lack of a typhlosole.

Figures

Fig. 3. Spermathecae, and ventral views showing spermathecal pores, female pores, and male pores of P. vicinipora (A, B), P. baungonensis (C, D), Pheretima paucisetosa (E, F), P. alba (G, H), P. rubida (I, J), and P. virgata (K, L, plus M, spermatophore). Symbols: fp, female pore(s); mp, male pores; sp, spermathecal pores.