Amynthas huangi, James & Shih & Chang, 2005

James, Samuel W., Shih, Hsi-Te & Chang, Hsueh-Wen, 2005, Seven new species of Amynthas (Clitellata: Megascolecidae) and new earthworm records from Taiwan, Journal of Natural History 39 (14), pp. 1007-1028 : 1014-1015

Amynthas huangi sp. nov.

( Figure 2E, F )

Holotype: adult collected at Shihwen , Pingtung County, Taiwan, 22 ° 219530N, 120 ° 399450E; 391 m, 18 August 1999 by Chung-Chi Huang and Jin-Kuan Yang, NMNS 4054-011 .

Etymology

This species is named after Mr. Chung-Chi Huang who helped the collection work extensively.

Description

Dimensions 70 mm by 3.5 mm at segment x, 3.1 mm at xxx, 3.2 mm at clitellum; body cylindrical throughout, segments 101. Setae regularly distributed around segmental equators, numbering 38 at vii, 48 at xxv; size and distance regular; no dorsal gaps, ventral gap AA:AB54:3 at xxv. Female pores paired in xiv. Prostomium epilobic, with tongue open. Pale brown dorsal pigmentation, formalin preservation. First dorsal pore 12/13. Clitellum annular xiv–xvi; setae invisible externally.

Male pores on small knobs visible under hoods covering male pore openings; 10 setae between male pores. Spermathecal pores lateral, deep slits in 6/7/8/9. Genital markings not visible externally ( Figure 2E ).

Septa 6/7/8 thinly muscular, 8/9, 9/10 absent, 10/11–13/14 thinly muscular; gizzard viii– x. Intestinal origin xv, typhlosole simple fold one-quarter lumen diameter from xxvii. Intestinal caeca simple, originating in xxvii, extending anteriorly to xxiv. Oesophageal hearts four pairs in x–xiii; commissural vessels vii, right ix lateral, viii to gizzard; extraoesophageal vessels to ventral oesophageal wall in x.

Male sexual system holandric, testes, funnels in ventral paired sacs in x, xi. Seminal vesicles small in xi, xii, without dorsal lobe. Prostates large xviii, deeply lobed; ducts thick, muscular, short; vasa deferentia join duct at duct–glandular portion junction; vasa deferentia non-muscular; prostatic duct flanked by large sessile glandular masses on body wall.

Ovaries in xiii. Paired spermathecae in vii–ix; ampulla ovoid, large; diverticulum large flat ovate mass composed of tightly folded tubular chamber, short slender straight stalk ( Figure 2F ); no nephridia on spermathecal ducts; genital marking glands with long stalks meeting body wall in vi–viii next to spermathecal ducts.

Remarks

The male pores are clearly not within intra-coelomic copulatory pouches, such as characterize Pheretima s.s. and perhaps Metaphire . In the present case, and in some species described below, the male pores are within slight folds of the body wall. In the absence of additional evidence supporting transfer to Metaphire , we assign this species to Amynthas . Sims and Easton (1972) stated that in the absence of spermathecae, it is not possible to distinguish a Pheretima from a Metaphire . In light of the fact that Pheretima all have intracoelomic copulatory pouches appearing as domes of tissue (usually muscular in appearance) partially separable from the body wall, this must also be a characteristic of Metaphire , or Sims and Easton (1972) were wrong. We are open to both possibilities, but to date no one has adequately addressed this question. In our experience, there exist species with large intramural copulatory pouches within a thickened body wall of xviii, and these consistently fall in Metaphire . Such structures appear to us not homologous to the intracoelomic pouches of Pheretima , but we could be mistaken. Based on this we prefer to restrict Metaphire to those species with well-characterized copulatory pouches and no nephridia on the spermathecal ducts ( Sims and Easton 1972), excluding those whose pores lie within wrinkles or seminal grooves, under small flaps, or within shallow indentations.

Amynthas huangi belongs to the aelianus species group, in which it is most similar to A. taipeiensis ( Tsai, 1964) . However, the differences are many: smaller size than A. taipeiensis , fewer setae, no setal enlargement ventro-anteriorly, male pore area different, hood or flap over male pores present, colour different, intestinal origin in xvi not xv, seminal vesicles lack dorsal lobes, prostatic ducts short and straight, not coiled or bent, diverticulum chamber coiled with straight stalk versus stalk kinked in A. taipeiensis , and no genital marking glands in A. taipeiensis . Note that genital marking glands are present in xviii even though no externally visible genital markings are present. This suggests that the genital markings are hidden under the hoods partially obscuring the male pores. Furthermore, the spermathecal segment genital markings must be deep in the pore slits or even within the pores themselves, out of view.

Figures

Figure 2. (A) Ventral view of Amynthas nanrenensis holotype, with detail of the male pore; (B) spermatheca of Amynthas nanrenensis; (C) ventral view of Amynthas monsoonus holotype; (D) spermatheca of Amynthas monsoonus; (E) ventral view of Amynthas huangi holotype; (F) spermatheca of Amynthas huangi; (G) left lateral view of segments i–ix and ventral view of xiv–xix of Amynthas hengchunensis, with detail of male pore; (H) spermatheca of Amynthas hengchunensis.