Pheretima adevai, 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 : 424-425

Pheretima adevai n. sp.

( Fig. 7 A,B, Table 3 )

Material examined. Holotype: (NMA 4524) Brgy Small Potongan, municipality of Concepcion, Misamis Occidental Province, Mt. Malindang Range, 8º24'04" N, 123º36'47" E, 900 m asl, Mindanao Island, Philippines, coll. Nonillon Aspe, Nolan Aspe, M. Lluch and J. Adeva, Feb. 18–25, 2004. Paratypes: three adults (NMA 4543), same collection data as for holotype. Other material: two adults ( ZRC.ANN.0025), 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 Julius Adeva, who assisted in the fieldwork.

Diagnosis. Slender brown worm reaching 110–131 mm in adult length; four pairs of spermathecal pores in 5/ 6–8/9; space between spermathecal pores wider than space between male pores; first dorsal pore at 12/13; intestinal origin in mid-xv; prostates in xviii to xix; caeca extending from xxvii to xxiii.

Description. In living animals, dorsum brown, darker anteriorly; equators pigmented. Length 110–131 mm (n= 6 adults); diameter 5 mm at x, 4 mm at xx; body cylindrical in cross-section; 83–99 segments. First dorsal pore at 12/13; spermathecal pores at 5/6/7/8/9, 0.25 circumference apart ventrally; female pore single in xiv; openings of copulatory bursae paired in xviii, 0.16 circumference apart ventrally, 3–7 setae between openings. Clitellum annular, extending from xiv to xvi. Setae unevenly distributed, 32–37 setae on vii, 36–39 setae on xx, no dorsal or ventral gaps.

Septa 5/6/7/8 and 10/11–13/14 muscular, 8/9 present ventrally, 9/10 absent. 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 ix to x; esophagus with low vertical lamellae extending from x to xiii; intestine originates in mid-xv; caeca originate in xxvii, extend forward to xxiii, with smooth, simple ventral margin; typhlosole rudimentary; intestinal wall with 34–38 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 xv; extra-esophageal vessels join ventral esophageal wall in x, receive efferent parieto-esophageal vessels in xiii.

Ovaries and funnels free in xiii; spermathecae paired in vi to ix, with many nephridia on ducts; each spermatheca with ovate, spherical, or pyriform ampulla, short thick non-muscular duct, stalked diverticulum attached to anterior face of duct near ampulla, terminating in short, oblong receptacle containing 2 or 3 rounded masses of sperm; stalk short. No spermatophores were observed in spermathecal ampullae. Male sexual system holandric; testes and funnels enclosed in paired sacs in x and xi; seminal vesicles in xi and xii, each with long, narrow dorsal lobe; vasa deferentia slender, free from body wall en route to ental end of prostatic ducts; prostates in xviii to xix, each racemose and bilobed in shape of butterfly wings; short muscular duct enters apex of copulatory bursa in xviii. Coelomic surface of copulatory bursa muscular, secretory diverticula lacking, walls thin; each bursa ovate-hemispheric, with elongate, conical penis on bursa roof; one spherical pad anterior and one posterior to opening.

Remarks. Pheretima adevai n. sp. belongs to the P. darnleiensis species group of Sims & Easton (1972). Sims & Easton (1972) synonymized 15 species under the name P. darnleiensis Fletcher, 1887 , all characterized by having either 4 or 5 pairs of spermathecal pores, located in 5/6–8/9, with an optional fifth pair in 4/5. Incongruently, Darmawan et al. (2012), described nominal P. darnleiensis from Darmaga, Indonesia, to have 4 pairs of spermathecal pores, from 4/5–7/8. Blakemore et al. (2007) further expanded the synonymy to include very large worms (about 700 mm long) from Mt. Kinabalu and Borneo, and possibly some of the Pheretima dubia group (three pairs of spermathecae vii–ix). After examining several of the species included in the synonymy of P. darnleiensis, Hong & James (2011a) suggested that species-level differences had been ignored, or had been discounted against the large number of spermathecae. They argued that the synonymy was excessive and buried significant morphological and geographical diversity in an increasingly meaningless concept of P. darnleiensis , and concluded that it is not probably useful to place into synonymy morphologically distinguishable taxa of greatly differing sizes. In any case, synonymy decisions in the P. darnleiensis group need to be reviewed, and the issue needs to be addressed with both morphological and molecular data.

Pheretima adevai n. sp., P. lluchi n. sp., and P. potonganensis n. sp. (see below) at Mt. Malindang are the only species in the P. darnleiensis group presently known from Mindanao Island. Pheretima adevai differs from P. darnleiensis in the location of the first dorsal pore, the spacing between the spermathecal pores and between the male pores, and the number of setae between the male pores ( Table 3 ). Pheretima adevai is similar to P. lluchi n. sp. in size and in the origin of the gizzard, but the two differ in the location of the first dorsal pore, the spermathecal and male pore spacings, the origin of the intestine, the number of intestinal vessels, and the extent of the prostates and copulatory bursae ( Table 3 ).

Seven species in the darnleiensis group were recently described from Luzon ( P. cabigati Hong & James, 2008a from Banaue; P. pugnatoris and P. tabukensis Hong & James, 2010 from Kalinga; P. margaritata , P. kalbaryonensis , and P. t h ai i Hong & James, 2011a from Kalbaryo; and P. barligensis Hong & James, 2011b from Mountain. Province), aside from three other species placed synonymy ( Sims & Easton 1972) with P. darnleiensis : Perichaeta belli Rosa, 1898 from Mindoro Island; Perichaeta vaillanti Beddard, 1912 ; and Pheretima benguetensis Beddard, 1912 . Perichaeta belli is 75 mm long, has zebra-like brown bands dorsally, has 48 setae in vii, has 8 setae between the male pores, and has very short caeca in xxvi–xxv. Perichaeta benguetensis is 190 mm in length, has purplish blue pigmentation, has the first dorsal pore in 7/8, and lacks seta in 8/9/10. These features differ markedly from those in P. adevai . Length and other pertinent characters in Pe. vaillanti are unavailable for comparison with the other species. Among recently described species, P. margaritata and P. pugnatoris are most similar to P. adevai in size and in the origin of the intestine (xv), but differ from P. adevai in the location of the first dorsal pore (9/ 10 in P. margaritata ; 11/ 12 in P. pugnatoris ), in the number of setae on vii (24 in P. margaritata ; 16–19 in P. pugnatoris ), in lacking a septum in 8/9, in the origin of the gizzard in viii, and in the length of the caeca (xvii–xxv and xxvii–xxiv in P. margaritata and P. pugnatoris , respectively). In addition, P. adevai has the male pores closer together than in P. margaritata , and a shorter prostate than in P. pugnatoris .

Occurrence. Pheretima adevai was the most abundant species at Malindang, comprising 19.4% of all individuals collected (Table 1). Although we detected it in disturbed habitat in Brgy Small Potongan at 915–1024 m elevation, it was most common in Brgy Lake Duminagat at elevations of 1479–2027 m. It mostly inhabited soil, but some individuals were collected on rotten logs and other substrates above ground (Table 1).

Figures

FIGURE 7. (A) Diagrammatic ventral view of polythecal Pheretima adevai, showing the spermathecal pores (sp), clitellum (cl), and male pores (m). (B – D) Schematic drawings of the internal morphology of Philippine Pheretima species, in dorsal view: (B) P. a de v ai n. sp.; (C) P. lluchi n. sp.; (D) P. potonganensis n. sp. Abbreviations: s, spermatheca; h, heart; p, prostate gland; cb, copulatory bursa; c, caecum. Scale bars: B – D: 5 mm.