Amynthas apongensis, 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 : 358

Amynthas apongensis , new species

( Fig. 1A, B )

Material examined. Holotype: adult ( NMP 4628 ), 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, 11–14 December 2003.

Etymology. The species is named after Apong, a nobleman of whom the name of Mt. Apo was said to have derived from.

Diagnosis. Reddish brown worm with body dimension 61 mm × 4–4.7 mm; one pair of spermathecal pores at 7/8; pairs of genital markings in viii and in ix, those in viii closely positioned to the spermathecal pores; pairs of genital markings in xviii and xix, those in xviii presetal, medial to male pores, those in xix mid-ventral on setal line; male sexual system proandric; spermatheca with a small and round ampulla; single, dense, racemose prostates in xvii to xviii.

Description. Reddish brown dorsum, lighter ventrum, equators pigmented. Length 61 mm (n= 1 adult); diameter 4 mm at x, 4.7 mm at xx; body cylindrical in cross-section, tail tapering; 77 segments. First dorsal pore 12/13. One pair of spermathecal pores at 7/8, distance between spermathecal pores 1.7 mm (0.13 circumference ventrally apart). Female pore single in xiv, male pore openings paired in xviii, distance between pores 1.8 mm (0.12 circumference apart ventrally), seven setae between male pores. Clitellum annular, from xiv to xvi. Setae unevenly distributed around equators in some segments; 44 setae on vii, 52 setae on xx, dorsal and ventral setal gaps present. Pairs of genital markings in viii and in ix, those in viii closely positioned to the spermathecal pores; pairs of genital markings in xviii and xix, those in xviii presetal, medial to male pores, those in xix mid-ventral on setal line.

Septa 4/5–8/9, 10/11–13/14 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 xxv. Typhlosole originating in xxvii, simple fold, 1/3 lumen diameter. Intestinal wall with 32 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 viii, nephridia on ducts lacking; each spermatheca with a small, round ampulla and a long, slender duct, diverticulum attached ectally to the left face of the right spermathecal duct, and to the right face of the left spermathecal duct, terminating in an elongated receptacle, stalk longer than ampulla. Male sexual system proandric, testes and funnels enclosed in paired sacs in x; seminal vesicles in xi, each with a digitate dorsal lobe, enclosed in testis sacs; vasa deferentia slender, free from body wall en route to ental end of prostatic ducts; prostates in xvii to xviii; each prostate a single, dense, racemose mass; stout muscular duct widened towards body wall, then slightly narrowed just before body wall. Copulatory bursae lacking.

Remarks. Currently, there is a total of 17 species of Amynthas in the Philippines, including Amynthas apongensis , new species. While Amynthas species vary in the number of pairs of spermathecae (one to five pairs except A. dinagatensis [ Aspe & James, 2016], which is athecate), A. apongensis is similar to A. philippinensis ( Hong & James, 2004) , A. heaneyi (James, 2004) and A. cagdianaoensis ( Aspe & James, 2016) in having only one pair. However, A. philippinensis has its pair of spermathecal pores at 4/5 while A. cagdianaoensis has its pair at 8/9. Amynthas apongensis is most similar to A. heaneyi in the location of the spermathecal pores, in the shape of the spermathecae and in having a proandric male sexual system. However, A. heaneyi is larger (84–111 mm × 4.6–5.7 mm), has dark gray to black pigmentation, has wider distance between the male pores (0.14–0.16 circumference apart), and has a different pattern of genital markings (James, 2004).

Figures

Fig. 1. A, Diagrammatic ventral view of Amynthas apongensis, new species showing the spermathecal pores (sp), clitellum (cl), male pores (m), and the pattern of the genital markings (gm). Schematic drawings of the internal morphology in dorsal view: B, A. apongensis, new species; C, Pheretima floresi, new species; D, P. baracatanensis, new species; E, P. solisi, new species. Abbreviations: s, spermatheca; h, heart; p, prostate gland; cb, copulatory bursa; c, caecum. Scale bars = 5 mm.