Pheretima vergrandis, 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 : 429-431

Pheretima vergrandis n. sp.

( Fig. 8 A,B, Table 4)

Material examined. Holotype: adult (NMA 4521) Brgy Sibucal, Oroquieta City, Misamis Occidental Province, Mt. Malindang Range (8º19'31"N, 123º38'02"E), 900 m asl., Mindanao Island, Philippines, coll. Nonillon Aspe, Nolan Aspe, M. Lluch, and J. Adeva, Feb. 18–25, 2004. Paratypes: four adults (NMA 4541), same collection data as for holotype. Other material: four adults ( ZRC.ANN.0023), 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 name is from the Latin 'vergrandis' (small, tiny), referring to the small size of individuals of this species.

Diagnosis. Very small, light-brown worm reaching 35–75 mm in adult length; single mid-ventral spermathecal pore on 7/8; single male pore mid-ventral on xviii; first dorsal pore at 13/14; spermatheca with irregularly rounded ampulla, bulbous muscular duct expanding ectally with single stalked diverticulum attached to middle of duct; hearts from x to xiii; elongate racemose prostates in xvi to xxi; columnar copulatory bursae in xviii to xx; caeca extending from xxvii to xxiv.

Description. Living animals with very light-brown dorsum; no stripes; clitellum pale; body cylindrical in cross-section, tail narrowing gradually to sharp point. Length 35–75 mm (n= 10 adults); diameter 2.3–3.0 mm at x; 2.3–2.7 mm. at xx; 85–99 segments. First dorsal pore 13/14; single mid-ventral spermathecal pore with wide white lips at 7/8; female pore single in xiv; openings of copulatory bursae united mid-ventrally in xviii. Clitellum annular, extending from xiv to xvi. Setae unevenly distributed, 37–42 setae on vii, 50–54 setae on xx, dorsal and ventral gaps present.

Anterior septa all delicate, 8/9/10 absent. Dense tufts of nephridia on anterior faces of 5/6 and 6/7; nephridia of intestinal segments located on body wall at septum/body wall junction and on anterior and posterior faces of septa. Large gizzard extends from viii to x; esophagus with villous-pebbly lining extends from x to xiii; intestinal origin in xv; caeca originate in xxvii, extend forward to xxiv; typhlosole a simple fold of about 1/5 lumen diameter, originating at 27/28; intestinal wall with 24–28 longitudinal blood vessels.

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

Ovaries and funnels free in xiii; single spermatheca preseptal in vii, with nephridia on ducts; spermatheca with irregularly rounded ampulla, bulbous muscular duct expanding ectally; duct internally corrugated, with two large internal ridges on anterior side; single stalked diverticulum attached to middle of duct, terminating in spherical receptacle; stalk short. Spermatophores spherical, with short, narrow tail. Male sexual system holandric; testes and funnels enclosed in paired sacs in x and xi; seminal vesicles in xi and xii, each with long dorsal lobe; vasa deferentia slender, free from body wall en route to ental end of prostatic ducts; prostates in xvi to xxi; each racemose, wrapped around dorsolateral margin of copulatory bursa; muscular duct partially attached to and entering posterior face of copulatory bursa. Copulatory bursae in xviii to xx; columnar with rounded apex, attached to body wall at end; oriented towards common opening through body wall. Coelomic surface of copulatory bursae muscular; secretory diverticula lacking; roof with slender, tapering penis.

Remarks. Among the few monothecal species placed in Pheretima is P. ambonensis Cognetti, 1913 ( Sims & Easton 1972) . Originally described from Ambon, Indonesia, P. ambonensis has a single spermathecal pore located midventrally in 7/8, with 2 spermathecal diverticula. It is 125 mm long with 98 segments, and has 32–40 setae in the pre-clitellar and 50–60 setae in the post-clitellar areas. Its male pores are 0.2 circumference apart ventrally (James 2004), the intestine originates in xv, and penes are present. Pheretima vergrandis n. sp. differs from P. ambonensis in size, and in having a single diverticulum and a single male pore. Other monothecal species in the Philippines are P. monotheca James, 2004 and P. monoporata James, 2004 , both from Mt. Kitanglad; P. arayatensis James et al., 2004 from Mt. Arayat in Luzon; and P. concepcionensis n. sp. described herein. In contrast to P. vergrandis , these species all have 2 spermathecal diverticula and 2 male pores, like P. ambonensis . In addition, the spermathecal pore is in 5/ 6 in P. monotheca , and in 8/ 9 in P. arayatensis ( Table 4). Individuals of P. vergrandis are among the smallest in Pheretima species recorded in the Philippines. The condition of having a single diverticulum seems to be derived from two spermathecae present ancestrally. A single diverticulum could have resulted from the loss of one spermatheca (in this case, the left, as the one present is consistently offset toward the right side), or it could have resulted from fusion. Likewise, two male openings is the ancestral condition, but the two pores have fused externally in species like P. vergrandis .

Occurrence. Pheretima vergrandis was moderately common (6.9% of all individuals collected on plots) in Brgys Sibucal and Lake Duminagat, at elevations of 902–1662 m. It was not observed in Brgys Small Potongan or Toliyok. The species inhabited soil and rotten logs (Table 1).

Pheretima Pheretima monotheca Pheretima Pheretima Pheretima Pheretima monoporata James, 2004 arayatensis vergrandis concepcionensis n. subanensis Character James, 2004 James et al., 2004 n. sp. sp. n. sp.

Body pigmentation Dorsally Dorsally pigmented Dorsally pigmented Dorsally Dorsally pigmented Dorsally pigmented pigmented all over all over pigmented all over all over all over all over

Length [mm] 60–70 62 88–141 35–75>89 67

Spermathecal pore 7/8 5/6 8/9 7/8 7/8 0

dorsal pore 12/13 (4); 13/14 12 /13 12/13 13 /14 12/13 12 /13

(1)

Setae vii; xx 26–34; 32–36 36; 32 54; 87 37–42; 50–54 40–50; 56–68 36; 45

Setae bet. male pores 0 3 5–6 0 2 5

Male pores spacing 0.05 0.11? 0 0.14 0.21

Setal gaps D; V +; - +; -? +; + +; + +; -

Spermathecal two two two one two 0

diverticulum

Septa in 5/6-13/14 + in 4/5, - in + in 4/5; - in 8/9/10 - in 8/9 - in 8/9/10 - in 8/9/10 - in 8/9/10

13/14 and 13/14

Origin of gizzard viii viii viii viii viii ix

Origin of intestine xvii xviii xv xv xvi xv

Caeca xxvii–xxiii xxvii–xxiii xxvii–xxii xxvii–xxiv xxvii–xxv xxvii–xxiii

Origin of typhlosole xxvii xxvii xxvii xxvii/xviii xxvii xxvii

Intestinal vessels 18–20 26? 24–28 30–35?

Location of hearts x–xiii x–xiii x–xiii x–xiii x–xiii xi–xiii

Prostate glands xvi, xvi–xx xviii (?) xviii xvi–xxi xvii–xix xvii–xx

Copulatory bursae xviii xviii xviii (?) xviii–xx xviii xviii–xix

Penes - + + + + -

Figures

FIGURE 8. (A) Diagrammatic ventral view of monothecal Pheretima vergrandis n. sp. showing the single spermathecal pore (sp), clitellum (cl), and single male pore (m). (B – D) Schematic drawings of the internal morphology of Philippine Pheretima species: (B) P. vergrandis n. sp.; (C) P. concepcionensis n. sp.; (D) athecate Pheretima subanesis n. sp. (E) Diagrammatic ventral view showing the clitellum (cl) and a pair of male pores (m), as in P. concepcionensis and P. subanensis. Abbreviations: s, spermatheca; h, heart; p, prostate gland; cb, copulatory bursa; c, caecum. Scale bars: B – D: 5 mm.