Pheretima aquila, Aspe & James, 2017

Aspe, Nonillon M. & James, Samuel W., 2017, Pheretimoid earthworms (Clitellata: Megascolecidae) from Mt. Apo, Mindanao Island, Philippines with description of eight new species, Raffles Bulletin of Zoology 65, pp. 357-372 : 365

Pheretima aquila , new species

( Fig. 2A )

Material examined. Holotype: adult ( NMP 4620 ), Brgy Baracatan , Davao City , Mt. Apo National Park (7°00′04″N, 125°21′55″E), 1,524 m asl, Mindanao Island, Philippines, coll. N. Aspe, A. Solis, D. Flores, R. Librado, 11–14 December 2003 . Paratype: one adult, amputee ( ZRC. ANN 0073 ), same collection data as for holotype .

Etymology. The species is the Latin word for ‘eagle’. Mt. Apo is known as home of the majestic but critically endangered Philippine eagle Pithecophaga jefferyi .

Diagnosis. Dimension 165 mm × 5–5.2 mm; body reddish brown, appearing striped due to its non-pigmented segmental equators; one pair of spermathecal pores at 5/6; distance between spermathecal pores and male pores 0.22 and 0.21 circumference apart ventrally, respectively; intestinal origin in xv; spermatheca with an elongated ampulla and a very large bulbous, muscular duct; prostates extending from xvi–xviii; penis lacking.

Description. Reddish brown dorsum, lighter ventrum, equators non-pigmented making it appear striped. Length 165 mm (n= 1 adult); diameter 5 mm at x, 5.2 mm at xx; body cylindrical in cross-section, tail tapering; 94 segments. First dorsal pore 12/13. One pair of spermathecal pores at 5/6, distance between spermathecal pores 3.5 mm (0.22 circumference ventrally apart). Female pore single in xiv. Openings of copulatory bursae paired in xviii, distance between openings 3.5 mm (0.21 circumference apart ventrally); 7 setae between openings. Clitellum annular, from xiv to xvi. Setae unevenly distributed around equators in some segments; 39–42 setae on vii, 44 setae on xx, dorsal setal gaps present, no ventral gaps. Genital markings lacking.

Septa 5/6, 7/8, 10/11/12 muscular, 6/7, 8/9, 12/13/14 thin, 9/10 lacking. Dense tufts of nephridia on anterior faces of 5/6 and 6/7; nephridia of intestinal segments located mainly on body near septum/body wall junction. Large gizzard in viii–x, esophagus with low vertical lamellae x–xiii. Intestinal origin in xv, caeca simple originating in xxvii, extending forward to xxiii. Typhlosole very low originating in xxvii, Intestinal wall with 29 longitudinal blood vessels. Hearts in x to xiii, esophageal; commissural vessels in vi, vii, and ix lateral; those in viii extending to gizzard.

Ovaries and funnels free in xiii. Spermathecae paired, postseptal in vi, with nephridia on ducts; each spermatheca with an elongated ampulla and a very large bulbous, muscular duct, diverticulum attached to the ectal portion of the left face of the right spermathecal duct, and to right face of the left spermathecal duct, stalks long, bent, terminating in sausage-shaped receptacles. Male sexual system holandric, testes and funnels enclosed in paired sacs in x, xi; seminal vesicles in xi, xii, each with a digitate dorsal lobe; vesicles of xi enclosed in testis sacs; vasa deferentia slender, free from body wall en route to ental end of prostatic ducts; prostates in xvi to xviii; each prostate a single, dense, racemose mass, with three lobes; short, muscular duct entering central area of copulatory bursa. Copulatory bursae ovate in xvii–xviii; coelomic surfaces muscular, secretory diverticula lacking; two pads present on roof, one pad present floor; penis lacking.

Remarks. Pheretima aquila , new species belongs to the P. urceolata group of Sims & Easton (1972) characterised by having spermathecal pores opening only at 5/6. To date, there are 24 species members of the P. urceolata group, including the new species described here. According to Aspe et al. (2016), the phylogeny of the P. urceolata group formed a weakly-supported clade. However, we do not support any conclusion as to the monophyly of this group and we recommended in future studies to include more data to resolve the relationship among its members.

Among the members of the P. urceolata group, P. aquila is relatively similar to P. libradoi , new species (185 mm × 7.3–8 mm), P. buhiensis ( Hong & James, 2009) (120–221 mm × 4.0– 7.5 mm), and P. gorasi ( Hong & James, 2009) (155–177 m × 6.2–7 mm) in body size. But the latter three have more body segmentations (112–119), have much closer distance between spermathecal pores (0.04–0.1 circumference apart) and between male pores (0.07–0.12 circumference apart), and have no setae between male pores. In addition, P. buhiensis and P. gorasi have penes while the new species has none. Pheretima aquila is relatively close to P. heaneyi James, 2004 and P. baletei James, 2004 in the spacing between spermathecal pores with 0.19–0.22 circumference apart for the former and 0.25 circumference apart for the latter. However, the latter two have relative smaller body size (83–116 mm × 3.9–5.4 mm for P. heaneyi and> 78 mm × 4.3–4.5 mm for P. baletei ). Pheretima baletei has faint pink colouration. We observed that the spermathecal diverticula for members of the P. urceolata group, at least for the Mindanao Island species (these morphological features were not observed or described in other Pheretima species of Luzon Island), are located on the left face of the duct of the left spermathecae and on the right face of the duct of the right spermathecae. In contrast, the spermathecal diverticula for members of the P. sangirensis group are located on the left face of the duct of the right spermathecae and on the right face of the duct of the left spermathecae. Pheretima aquila is different from the other members of the P. urceolata group of Mindanao Island as its spermathecal diverticula are located on the left face of the duct of the right spermathecae and on the right face of the duct of the left spermathecae. No other species in the P. urceolata group closely resemble P. aquila .

Figures

Fig. 2. Schematic drawings of the internal morphology in dorsal view. A, Pheretima aquila, new species; B, P. gamay, new species; C, P. libradoi, new species; D, P. davaoensis, new species. Abbreviations: s, spermatheca; h, heart; p, prostate gland; cb, copulatory bursa; c, caecum. Scale bars = 5 mm.