Metaphire nanaoensis, 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 : 1473-1475

Metaphire nanaoensis sp. nov.

( Figure 3 )

Type material

Holotype: a mature (clitellate) specimen (dissected) collected 11 August 2002 from Nanao , Ilan County, north-east of the Central Mountain Range in the north region of Taiwan ( Figure 1 ) by Y. H. Chen and C. H. Chang (coll. no. 14-04354) . Paratypes: a mature (clitellate) specimen (dissected) with the same collection data as holotype (coll. no. 14- 04355), and a mature (clitellate) specimen (dissected) collected 20 November 2002 from Nanao , Ilan County by Y. H. Chen (coll. no. 14-05024) .

Other material

Three mature (clitellate) specimens collected 20 November 2002 from Nanao, Ilan County by Y. H. Chen (coll. no. 14-05423, 14-05426, 14-05427).

External characters

Length (mature) 335–429 mm, clitellum width 10.1–14.9 mm, segment number 132–177. Number of annulets (secondary segmentation) per segment three in 5–9, five in 10–13, and three in body segments behind 17. Prostomium prolobous. Setae 103–114 in 7, 120– 131 in 20, 19–23 between male pores. First dorsal pore in 12/13. Clitellum 14–16, smooth, saddleshaped, length 13.8–14.4 mm, dorsal pore absent, setae absent. Spermathecal pores four pairs in 5/6–8/9, ventral, distance between the paired pores about 0.4 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, partially covered by the skin wall bordering the male pore area. The region covered by the skin wall is swollen, forming a smooth appearance. A very small pad presents on the posterior end of 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 3.5–5.5 mm in length, with a stalk about 0.5–1.4 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, oval, smooth, medio-ventral in front of 10/11. Seminal vesicles paired in 11, filling the space between septa. Some specimens have a pair of very small vestiges of seminal vesicles in 12. Prostate glands paired in 18, large, lobular, extending to 17.

Habitat and behaυiour

This species lives in the mountains below the altitude of 1500 m, where the vegetation is evergreen broadleaf forest or deciduous broadleaf forest. 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 during the day. When resting, it is usually found more than 30 cm deep below the ground.

Remarks

The male pore area of M. nanaoensis is C-shaped, and with respect to body size, colour, number of spermathecae, and position and shape of prostate gland and intestinal ceaca, M. nanaoensis resembles M. yuanpoaea , M. paiaeanna and M. bununa . However, the male pore area of M. yuanpoaea has an oval pad on each side of the male aperture, and the width between the paired spermathecal pores of M. yuanpoaea , which is about 0.5 body circumference apart, is wider than that of M. nanaoensis . The major difference between the two species is that M. yuanpoaea is holandric, while M. nanaoensis is protandric. Metaphire paiaeanna and M. bununa are also protandric species, but the male pore areas of these two species are different from that of M. nanaoensis . The male pore area of M. paiaeanna and M. bununa has an 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). These differences are easily seen under a dissection microscope, or even with the naked eye.

The species name ‘‘ nanaoensis ’’ is given referring to Nanao in Ilan County in Taiwan, where the species was first collected.

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 3. Metaphire nanaoensis. (A) Male pore region (sw, skin wall; sp, small pad); (B) caecum; (C) spermathecae (dv, diverticulum; amp, ampulla); (D) testis sacs and seminal vesicles (ts, testis sacs; sv, seminal vesicles); (E) prostate gland.