A New Record Earthworm Amynthas masatakae
(Beddard) (Megascolecidae: Oligochaeta) from
Taiwan
Shu-Chun Chuang1 and Jiun-Hong Chen2 *
Depa rtment o f Zoolog y, National Taiwan Univ ersity, Taipei, Taiwan, ROC
AB STRACT
This pap er reports one new record of a megascolecid earthworm from Taiwan: Amynthas
mas atak ae (Beddard, 1892), which w as collect ed from D ong-Yan M t . P revious ly, A. masatakae was only known from Japan. To now in T aiwan, this species has only been
recorded in a small area of Dong-Yan M t. in northern Taiwan, so lit tle is known about its ecological data here. The external and internal characters of A. masatakea are described in this paper.
Key words: new record eart hworm, Taiwan, Amynthas
*Corresponding author: Department of Zoology, National Taiwan University, No. 1 Roosevelt Road, Section 4,
Taipei 106, Taiwan, R.O.C.; Tel: 886-2-23630231ext.2354; Fax::886-2-23658912; E-mail:chenjh@ccms.ntu.edu.tw
INTRODUCTION
Taiwan is located in both tropical and subtropi-ca l re gio ns o f t he west ern edg e o f th e Pacific Oce an. The t opography of Taiwan is c omplex, including mountains, hills, and plains. Due to the complex topography and geomorphology, terres-trial an imals, such as e arthworms, prese nt great diversity.
The earthworm fauna of Taiwan has not been extensively studied. Before the 1970s (Tsai, 1964; Shinet al., 1999), only 24 sp ecies of earthworms we re rep orte d he re . Durin g th e 1970s to t he 1990s, the re was a ce ssa tion of earthwo rm re-sea rch in Taiwan. Some rela ted s tudie s on the earthworm fauna of Taiwan were again initiated after 1990. To the present, 44 nominal species of earthworms in Taiwa n have been repo rted. All
of them are megadrile earthworms (Oligochaeta: Anne lida) (Kobayash i, 1938; Gates, 1959; Tsai, 1964; Ch en and Sh in , 1996; Shih et a l., 1999; Tsai et al., 1999; Shen and Tsai, 2002; She n e t al. 2002; Tsai et a l., 2000a, b, c, 2002; Tsai e t al., 2000).
The family Me gascolec idae is dominant and consis ts of 38 sp ecies in Ta iwan. Among them, the ge nera Amynt has an d Metap hire are do mi-n ami-n t a mi-nd c o mi-ns is t o f 33 sp e cies . The ge mi-nu s Amynthas is d ivided from the ge nus Phere tima (Phe re timoid-gro up ). Be fo re 1972, the g en us Pheretima in t he Megasc olecidae was the larg-est genus in the animal kingdom, with more than 700 n ominal sp ecies (Sims a nd Eas ton , 1972). This genus is also t he larg est and the most im-p orta nt g ro uim-p in Taiwa n. In 1972, Sims an d Easton divided the genus Phere tima in to eight
ne w ge ne ra (Sims a nd Eas ton , 1972; Eas to n, 1979), b ecaus e Ph ere tima was t oo large to be effective ly st udied. Amy ntha s is on e of the se eight genera. Its morphology is similar to that of the genus Metaphire, but Amynthas species lack copulatory pouches. This paper describes a new re co rd of Amyn th as from Taiwa n, Amy nt ha s masatak ae.
Amynthas masatak ae was first d escribe d by Be dd ard (1892), and was on ly re co rd ed from Jap an. This is the firs t rep ort o f A. masatak ae ou ts ide o f Jap an (Bedd ard, 1892; Kaminh ira, 1973). It has neve r bee n re porte d fro m Taiwan in the past (Go to a nd Hatai, 1898; Koba yash i, 1938; Tsa i, 1964). In this paper, the ext ernal and internal characters of A. masatak ae are described, and we also compare these characte rs with the origina l ma terial.
MATERIALS AND METHODS
The co llected ea rthworms were anesth etized in a 10% ethy l-alc ohol s olution, fixed in a 10% formalin wat er solution, and preserved in a 70% ethyl-alcohol solution. Specimens were collected on 2 De cemb er 2001 and 16 November 2002 at an elevation of around 1000 m at Dong-Yan Mt., n orth e rn Taiwan (25°53’N, 121°21’E). Th eir habitat consists of bushes and fallen leaves. The soil chara cterist ics is humic with mu ch org anic mat eria ls.
RESULTS
Amynthas masatak ae (Be ddard) 1892 Amynthas masatak ae (Beddard) Zool. Jb. Syst. (1892) 6: 755-766. The following description was bas ed on 12 prese rved matu re sp ecime ns with well-developed clitella and reproductive organs. To tal len gth 105-138 mm, clitellum wid th 4. 0-7.5 mm, se gmen t n umbe r 96-138. Pro tomium ep ilob ous. set ae 34-41 in VII, 41-49 in XX, 13-15 b etween male p ores. First d orsal p ore in XI/
XII. Clit e llu m XIV-XVI, le n g t h 3-4.5 mm, smooth, setae and dorsal pore absent.
Sp erma the cal pore s 2 pairs in VII/VIII-VIII/ IX, vent ro-lateral. Dist ance between pores 0.31-0.38 o f body circu mference apa rt. Pores visible, each in a depressed furrow with a tiny projection. Ge nit al pap illae in VII-VIII, 1 lo ca ted immed i-ately anteriorly to spermathecal pore and the other pos teriorly to spermath ecal pore. Some of t he papillae are partially embedded in the pore. Each pa pilla is circu lar and flat with a s lig htly co n-cave center.
Fe ma le p ore s in gle, me dio-ve ntral in XIV. Ma le pore pa ire d in XVIII, v entro-late ral, dis-tance between the pores 0.3-0.33 of body circum-ference (Fig. 1a). Each male po re with 2 pa pillae forming a flat tria ngle: male pore latero -medial, one papilla e vent ro-ante rior to setae , the o ther papillae ventro-posterior to setae, and all of them surro unded by 2 or 3 circular flods (Fig. 1b).
Color o f preserved spec imen s in 70% eth yl a lc oh ol, da rk brown on d ors um a nd a ro un d clit ellum, yello wish o n vent rum.
Septa V/VI-VI/VII thic kened, VIII/IX an d IX/ X absent . X/XI-XIII/XIV greatly thicken ed. Giz-za rd in IX-X, pea ch-shap ed; ye llo wis h whit e. In te st in e en la rg ed from XV. Cae ca p aire d in XXVII, exte n din g 4 s e gme nt s a nt e rio rly t o XXIII, simple, light brown , wrin kled, with s aw-shaped borders (Fig. 1c).
Sp erma th ec ae 2 p airs in VII-VIII, ampu lla ova l-sh aped , abo ut 1.5 mm lo ng, 1.5 mm wide, stout stalk not easily visible. Diverticulum with a lon g white s trip of se minal cha mber abou t 2.5 mm lo ng a nd sle nde r st alk ab out 2.5 mm lo ng (Fig. 1d).
Sperm sac 2 pairs in X and XI, med io-ventral, sma ll, ye llowis h, ova l sha ped, 2 vas d eferen tia on ea ch side jo ining in se gme nt XII. Se min al ves icles 2 p airs in XI and XII, larg e, y ellowish white, with wrinkle d surface (Fig. 1e). Prost ate glan ds abs ent or very s mall, only ap pear p ros-tat ic du ct in XVIII (Fig. 1f).
Table 1. Characters of these collections from Taiwan compa red to t he origin al paper of Amyn thas
masat ak ae(1892)
A. masatakae (1892) A. masatakae in Taiwan
Body length (mm) 134 105-138 No. of segments 90 96-138 First dorsal pore - XI/XII Prostomium epilobous epilobous Setae in VII X XVIII - - - 34-41 41-49 13-15
Spermathecal pore 2 pairs (VII/VIII, VIII/IX) 2 pairs (VII/VIII, VIII/IX) No. of spermathecae 2 pairs (VIII, IX) 2 pairs (VIII, IX)
Sperm sac - X, XI
Seminal vesicle XI, XII XI, XII Prostate absent, only duct absent, only duct Intestine origin XV XV Genital papillae
Preclitellar VIII, IX VII, VIII Postclitellar - XVIII Caeca paired XXVI XXVII- XXIII
Re marks
By comparin g the characters of th ese collec-tions in Taiwan to the original paper on Amynthas masatak ae, such as t he number and lo cation of spermathecal pores, sperm sacs, seminal vesicles, and prostate glands as listed in Table 1, we con-firm that the collection s at Dong-Yan Mt. are A. masata k ae. In particu lar, th e numbe r and loca-tion of spermathecal pores are very important to eart hworm taxono my, be cause they a re related to c opulatio n and re production. In addit ion, in most species of earthworms, the prostate gland is large, but it is absent from A. masatak ae. This is a key character for iden tifying A. masa tak ae. The male pore is ano ther ke y charac ter for
rec-ognizing the s pecies: e ach male pore has along with two p apilla e whic h form a fla t tria ngle. Ex-clusiv e of tho se t wo p apillae , no oth er p apilla exists arou nd th e ma le p ore. This morphology ha s no t be en de sc ribe d fo r oth er e arth wo rm species.
DISCUSSION
The origin al paper (Bed dard, 1892) does not illust rate A. masatak ae. W e confirmed that the collectio ns are A. masatak ae based on a re view pap er pub lishe d by Kaminh ira (1973), in wh ich A. masatak ae showed four taxonomic characters including male pores, prostate glands, caeca, and spermatheca e. Amynt has masat ak ae ha s ne ver
Figure 1. Amynt has masat ak ae: (a-b) male po re region (mp, male opening) (c) right caecae (d) left
sp erma thec ae (dv, div erticulu m; a mp, amp ulla ) (e ) v etra l view o f sp erm sac s (t s) a nd seminal vesicles (sv) (f) right pro state gland.
be en re ported from Ta iwa n before (Got o a nd Hata i, 1898; Koba yashi, 1938; Tsai, 1964). This is the first record.
We thought that they were exotic earthworms, not species native to Taiwan. The reason was very simple. Because this collection was restricted to the area of Dong-Yan Mt. at an elevation of about 1000 m, a n important agricu ltural site fo r te m-perate fruit s such as peaches since the 1980s in northern Taiwan, it is reasonable to suspect that the earthworms might have been transported into the area with those temperate fruits at some time in the past 20 years. This is one possible reason we only found them a round agric ultural farms. So far, we kno w lit tle a bout its e cological d ata from Taiwa n. Beca use exot ic eart hworms may co mpe te wit h n ative spe cie s, we nee d t o p ay gre ater attent ion t o the se exotic specie s in the future.
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莊淑君1,陳俊宏2*
台灣大學動物學研究所
