Pheretima abiadai, Hong & James, 2008

Hong, Yong & James, Samuel W., 2008, Two new earthworms of the genus Pheretima (Oligochaeta: Megascolecidae) from Mt. Isarog, Luzon Island, Philippines, Journal of Natural History 42 (23 - 24), pp. 1565-1571 : 1566-1567

Pheretima abiadai sp. nov.

( Figure 1 )

Type material

Holotype

Clitellate specimen (NMA 004194): Philippines, Camarines Sur Province, Mt. Isarog, ‘‘ Camp 3’’ (13 ° 39.799N, 123 ° 21.799E), 1360 m, mossy montane forest transition, arboreal, 13 May 2001, S.W. James, M. Levi, P. Nillos, and J. ffitch colls. Three paratypes: one clitellate (NMA 004199), one clitellate ( NIBR): same data as for holotype.

Other material

Three clitellates, three aclitellates.

Etymology

The species is named after Rene Abiada, one of our guides on Mt. Isarog.

Diagnosis

One pair of spermathecal pores deep in 5/6 at eighth setal lines, spermathecal pores 0.25 mm circumference apart; copulatory bursae with two lateral, two medial sucker-like pads on internal roof of copulatory bursae, pads with associated glandular tissue in copulatory bursae walls, openings paired in xviii at ninth setal lines, openings 0.18–0.26 mm circumference apart.

Description

Dark violet-red dorsal, light red ventral i–xiii, setal zones unpigmented (ventrally) or lighter pigment (dorsally). Light to medium brown dorsal pigment in post-clitellar segments. Dimensions 33–60 mm by 2.5–3.0 mm at segment x, 2.2–3.0 mm at xxx, 2.3–2.8 mm at clitellum, segments 74–78; body circular in cross-section. Setae numbering 34–42 at vii, 42–47 at xx; 6–9 between male pores, size regular, dorsal setal spacing wider, setal formula AA:AB:YZ:ZZ52:2:3:4 at xiii. Clitellum annular xiv–xvi; setae invisible externally.

First dorsal pores 12/13. One pair of spermathecal pores deep in 5/6 at eighth setal lines, laterally placed, 0.25 circumference between spermathecal pores, 0.4– 0.5 mm openings of copulatory bursae, paired in xviii at ninth setal lines, slightly crescentic concave anteriorly, ventro-laterally placed, 0.18–0.20 mm circumference between openings. Female pore single in xiv 0.4 mm on light coloured circle. Genital markings lacking.

Septa 5/6–7/8 thick, 8/9, 9/10 absent, 10/11–13/14 thin. Gizzard in viii–x, intestine begins in xvi, simple paired lymph glands from xxvii along dorsal vessel; intestinal caeca simple originating in xxvii, and extending anteriorly about to xxiv, fingershaped sac; typhlosole vestigial from xxvii. Hearts xi–xiii oesophageal, x absent.

Ovaries and funnels in xiii, spermathecae in vi, with nephridia on ducts; spermathecae with large globular ampulla, bulbous weakly muscular duct shorter than ampulla; diverticulum with chili-shaped, iridescent chamber with thick stalk shorter than chamber. Male sexual system holandric, testes and funnels in ventral paired sacs in x–xi. Seminal vesicles two pairs in xi–xii, small triangular dorsal lobes apically attached, prostates in xvii–xix; two lobes, one anterior, one posterior to copulatory bursae, long muscular ducts from anterior lobe along lateral side of copulatory bursae, turning 90 ° medially to centre of copulatory bursae without stalked glands; copulatory bursae with two lateral, two medial sucker-like pads on internal roof of copulatory bursae, these each with a glandular tissue mass in bursa wall; pads surround central cylindrical penis with apical male pore.

Remarks

Pheretima abiadai sp. nov. keys to the urceolata group in Sims and Easton (1972), which is composed of eight species, P. urceolata ( Horst, 1893) , P. baweanensis ( Michaelsen, 1924) , P. baletei James, 2004 , P. bukidnonensis James, 2004 , P. heaneyi James, 2004 , P. kitangladensis James, 2004 , P. monotheca James, 2004 and P. simsi James and Hong, 2004 . Gates (1961) synonymized P. baweanensis , P. ditheca and P.urceolata ; for further discussion of this decision see James (2004b). However, Sims and Easton (1972) placed P. ditheca in Metaphire , because nephridia were not recorded from the spermathecal ducts.

Table 1 summarizes the differences among the species of the urceolata group. Pheretima abiadai sp. nov. is most similar to the other new species described from Mt. Isarog, Pheretima nagaensis sp. nov., with which it shares the same array of hearts, missing septa and segment of intestinal origin. This combination of characters differentiates these two species from other group members. However it differs from Pheretima nagaensis sp. nov. in having a narrower separation between spermathecal pores and male pores (0.26 vs 0.29, 0.19 vs. 0.25, respectively, in fractions of body circumference). Other differences are the arrangement of pads in the copulatory bursae and the shape of the penes. The two species were found in different habitats, one arboreal and the other in soil. Pheretima abiadai sp. nov. is distinguished from the rest of the species group by its smaller size, the missing septa, and its unique copulatory bursal pads ( Table 1).

Figures

Figure 1. Pheretima abiadai sp. nov. (A) Ventral view; (B) spermathecae. Scale bars52.5 mm (A), 2 mm (B).