Metaphire yuanpoaea, Chang & Chen, 2005

Chang, Chih-Han & Chen, Jiun-Hong, 2005, Three new species of octothecate pheretimoid earthworms from Taiwan, with discussion on the biogeography of related species, Journal of Natural History 39 (18), pp. 1469-1482 : 1470-1473

Metaphire yuanpoaea sp. nov.

( Figure 2 )

Type material

Holotype: a mature (clitellate) specimen (dissected) collected 1 August 1999 from Wulia, Taipei County, north-west of the Shei-Shan Mountain Range , in the north region of Taiwan ( Figure 1 ) by S. P. Wu (coll. no. 14-02577) . Paratype: a mature (clitellate) specimen (dissected) collected 9 June 2000 from same collection site of holotype by C. E. Li (coll. no. 14-02576), and a mature (clitellate) specimen (dissected) collected 18 March 1995 from Pinglin, Taipei County by H. T. Shih (coll. no. 14-00015) .

Other material

A mature (clitellate) specimen collected 15 June 1999 from Wulia, Taipei County by J. H. Wu (coll. no. 14-00125); and a mature (clitellate) specimen collected 17 November 2000 from Shindian, Taipei County by S. P. Wu (coll. no. 14-02571) .

External characters

Length (mature) 215–425 mm, clitellum width 13.9–15.6 mm, segment number 129–189. Number of annulets (secondary segmentation) per segment three in 5–9, five in 10–13, and three in body segments behind 17. Prostomium epilobous. Setae 114–122 in 7, 126– 162 in 20, 30–35 between male pores. First dorsal pore in 12/13. Clitellum 14–16, smooth, saddle-shaped, length 9.8–14.1 mm, dorsal pore absent, setae absent. Spermathecal pores four pairs in 5/6–8/9, lateral, distance between the paired pores about 0.5 body circumference ventrally apart. No genital papillae in the spermathecal region. Female pore single, situated on the medio-ventral in 14. Male pore paired, situated on setal line close to lateral border of 18. Each male pore area is C-shaped, with the opening of the C facing the ventral setal line, bordered by a thick skin wall, which has several folds on its lateral side. The male pore area is enlarged, with length about twice the length of 18, extending to the setal line of 17 and 19. The male aperture is situated on the end of the ventral setal line, with one oval pad on each side. The two oval pads are linked by a vertical bar-shaped structure extending from the male aperture. These structures are sometimes partially covered by the skin wall bordering the male pore area. Genital papillae absent in the male pore area.

Live specimens bluish brown or dark purplish grey with metallic lustre on dorsum, reddish brown on ventral. Preserved specimens purplish brown on dorsum, light greyish brown on ventral.

Internal characters

Septa 5/6–7/8 thickened, 8/9 thin, 9/10 absent, 10/11–13/14 greatly thickened. Gizzard in 8–10. Intestine enlarged from 15. Intestinal caeca paired in 27, simple, extending anteriorly to 23. Lateral hearts enlarged in 10–13.

Spermathecae four pairs in 6–9. Ampulla large, about 3.5–6.2 mm in length, with a stalk about 0.5–1.3 mm in length. The spermathecal diverticulum is short, beyond the middle of spermathecae, with a small oval seminal chamber on the tip. Nephridia tufted, attached to the post-segmental septa, surrounding the segmental chambers anterior to the 6/7 septum. Ovaries paired in 13, medio-ventral, close to the 12/13 septum.

Testis sacs paired in 10 and 11, the anterior pair oval, smooth, medio-ventral in front of 10/11, the posterior pair is much larger than the anterior one, filling the space between septa. Sperm ducts meeting in 12. Seminal vesicles paired in 11 and 12, the anterior pair included in the posterior testis sac, both pairs moderate in size. Prostate glands paired in 18, large, lobular, extending to 17.

Habitat and behaυiour

This species lives in the mountains below the altitude of 2000 m, where the vegetation is evergreen broadleaf forest, deciduous broadleaf forest or mixed coniferous–broadleaf forest, according to the altitude. Because it can be found both in virgin forest and secondary forest, it might tolerate low levels of human activity. This species is an anecic species, having permanent vertical burrows. It is active around the upper layer of soil or on the ground at night. Although it is occasionally active after rain, it usually stays in the soil at day. When resting, it is usually found more than 30 cm deep below the ground, and the deepest case we found this species is in 80 cm.

Remarks

Metaphire yuanpoaea is a common species in the mountain area of northern Taiwan. It is usually found moving across the road at night, or at early morning after rain. This species resembles the other two sympatric species, Amynthas aspergillum and A. formosae , in body size, shape and colour, but it is easily distinguished by external characters in the field. The male pore area of M. yuanpoaea is enlarged, with an obvious oval pad on each side of the male pore, while the other two species do not have these characters. The spermathecal pores of A. formosae are medio-dorsal in 5/6–8/9, and the pores are evident with the naked eye through the lighter colour of the pore borders ( Michaelsen 1922). Amynthas aspergillum has many papillae on the male pore area. Furthermore, A. aspergillum was recognized as a peregrine species in Taiwan ( Tsai CF et al. 2000a) and is usually found in cultivated soil, especially in the grassland of public parks (personal observation), while M. yuanpoaea and A. formosae are often found on the mountain slope, where the soil is less disturbed.

Metaphire yuanpoaea shares most of its characters with M. paiaeanna and M. bununa , including body size, colour, number of spermathecae, and the position and morphology of prostate gland and intestinal caeca ( Tsai CF et al. 2000c). However, the male pore area of M. paiaeanna and M. bununa has only one oval pad between the male aperture and the anterior end of the male pore area, and the male pore area of M. paiaeanna also has a horizontal ridge ( Tsai CF et al. 2000c). Moreover, M. yuanpoaea has testis sacs paired in 10 and 11, while both M. paiaeanna and M. bununa have testis sacs paired only in 10.

Except for number of spermathecae, M. yuanpoaea is similar to M. trutina , which has only three pairs of spermathecae ( Tsai et al. 2003) and belongs to the houlleti -group in the genus Metaphire ( Sims and Easton 1972) . It is not yet known if the two species are distantly related due to the difference in the number of spermathecae or closely related due to the similarity of other characters. According to our field survey, M. yuanpoaea is restricted to the west edge of the Shei-Shan Mountain Range, but M. trutina is found only in the east edge of the Shei-Shan Mountain Range. Although they seem to be allopatric, the detailed distribution pattern of the two species is still unknown. A comparative study based on cytochrome c oxidase subunit I gene sequence is now underway to unravel the phylogenetic relationship of these two species.

The species name ‘‘ yuanpoaea ’’ is given to describe the male pore area of this species. The male pore area of this species is like the Chinese ‘‘yuanpau’’, which is a kind of currency in the past in China.

Figures

Figure 1. The map of Taiwan and surrounding areas. (A) The location of Taiwan in East Asia. (B) The map of the major mountain ranges and the distributions of the earthworm species discussed in this paper in Taiwan. Shei- Shan Mountain Range (a), Ali-Shan Mountain Range (b), Yu-Shan Mountain Range (c), Central Mountain Range (d), and Coastal Mountain Range (e) are the five major mountain ranges in Taiwan. Earthworm species, Amynthas formosae (solid circle), Metaphire bununa (open triangle), Metaphire paiaeanna (open star), Metaphire yuanpoaea (open circle), Metaphire nanaoensis (open square), Metaphire taiaeanensis (solid triangle), and Metaphire tahanmonta (solid star), showed different distributions in Taiwan.

Figure 2. Metaphire yuanpoaea. (A) Male pore region (op, oval pad; sw, skin wall); (B) caecum; (C) spermathecae (dv, diverticulum; amp, ampulla); (D) testis sacs and seminal vesicles (ts, testis sacs; sv, seminal vesicles); (E) prostate gland.