Drawida alishanensis Shen & Chang
, sp. nov.
( Figure 1
View FIGURE 1
)
Holotype: Clitellate (mature) specimen (50 mm in total length, dissected), Zhuqi, from roadside ditches around a parking lot at south end of a hiking trail in Longyun Farm, 23°28'57.87''N, 120°42'00.62''E, 1486 m asl, 28 April 2014, H.-T. Fang (TESRI-O-H-51; Ali046).
Paratypes: 5 clitellates [one amputated (Ali010) and one dissected (Ali009, PCR failed)], Alishan, from roadside slopes and ditches around Dinghu, 23°29'25.28''N, 120°43'16.77''E, 1661 m asl, 25 July 2013, H.-T. Fang (TESRI-O-P-46).
Other material. 1 clitellate, same collection data as holotype (TESRI-O- 2014-8-7).
Diagnosis. Small, length 35–50 mm, weight 0.08–0.14 g in 95% ethanol, diameter 2.3–2.6 mm. Segments numbering 85–95. Prostomium prolobous. Dorsal pores absent. Setae lumbricine, short and closely paired. Clitellum in X–XIII, swollen, paler than rest of the body. Spermathecal pores one pair in 7/8. Penes usually wholly concealed or slightly visible externally. Secondary male aperture not visible or slit-like in 10/11. Female pores minute, hardly visible, one pair on anterior-most border of XII, each pore in line with seta b. Genital markings absent. Gizzards two in XII–XIII. Testis sacs one pair, large, each suspended on septum 9/10. Sperm duct short, slightly curved. Male atrium follicular, cotton-like, transversely elongated oval-shaped. Spermathecae one pair. Ampulla small, oval-shaped, with slender, coiled duct. Spermathecal atrium small, oval-shaped. Accessory glands absent.
Description. External: Length 35–50 mm (amputated specimen not included), weight 0.08–0.14 g in 95% ethanol, diameter 2.3–2.6 mm. Segments numbering 85–95. Prostomium prolobous. Dorsal pores absent. Setae lumbricine (eight setae per segment), short and closely paired, ab = cd, aa = bc, aa Ề 6 ab, dd greater than 0.5 body circumference. Clitellum in X–XIII, swollen, paler than rest of the body. Spermathecal pores one pair in 7/8, each pore small, slit-like, edge slightly wrinkled, medial to seta c. Penes usually wholly concealed in retracted condition ( Fig. 1A
View FIGURE 1
) or slightly visible externally ( Fig. 1B
View FIGURE 1
). Secondary male aperture not visible or slit-like in 10/11. Female pores minute, hardly visible, one pair on anterior-most border of XII, each pore in line with seta b. Genital markings absent. Preserved specimens grayish or pale gray, and paler or pink around clitellum.
Internal: Septa 5/6–8/9 thick and muscular, 9/10 thin. Gizzards two in XII–XIII, round, white, muscular and shining. Hearts four pairs in VI–IX. Nephridia holoic. Testis sacs one pair, large, white or yellowish white, elongated oval-shaped, each suspended on septum 9/10, 0.9–1.5 mm in length and 1.16–1.45 mm in width. Sperm duct short, slightly curved, entirely confined to segment X, entering the upper right side of the male atrium ( Fig. 1D
View FIGURE 1
). Male atrium white, follicular, cotton-like, transversely elongated oval-shaped, about 0.35 mm in length and 0.55–0.75 mm in width. Ovarian chamber formed by septa 10/11 and 11/12, meeting in front of the gizzard on dorsal side. One pair of follicular, yellowish ovisacs dorso-lateral on both sides of the digestive tract, occupying the entire compartment of segment XII. Spermathecae one pair, ampulla posterior while spermathecal atrium anterior to septum 7/8. Ampulla small, oval-shaped, 0.62–0.75 mm long and about 0.5 mm wide, its duct long, slender, with two coils and a loop and then becoming straight to join the spermathecal atrium ( Fig. 1C
View FIGURE 1
). Atrium small, ovalshaped, about 0.3 mm long. Accessory glands absent.
DNA barcodes. GenBank accession numbers
MH 051135
View Materials
(Ali046, holotype) and
MH 051134
View Materials
(Ali010, paratype).
Etymology. The name
alishanensis
is given to this species with reference to its type locality in the Alishan area, Chiayi, southwestern Taiwan.
Remarks. In contrast to the long, twisted sperm ducts of
Dr. japonica
,
Dr. koreana
,
Dr. beiganica
and
Dr. dongyinica
reported from Taiwan and Matsu ( Shen et al. 2015), the simple structure of sperm duct of
Drawida alishanensis
sp. nov. distinguishes it from all the above species. In addition, when compared with all 41 species and subspecies of
Drawida
from East Asia listed in Blakemore et al. (2014),
Dr. alishanensis
is fairly similar to
Drawida barwelli ( Beddard, 1886)
,
Drawida nepalensis Michaelsen, 1907
,
Drawida syringa Chen, 1933
,
Drawida keikiensis Kobayashi, 1938
,
Drawida moriokaensis Ohfuchi, 1938
,
Drawida tairaensis Ohfuchi, 1938
,
Drawida omeiana Chen, 1946
, and
Drawida eda Blakemore, 2010
in the small body size and lack of papillae or genital markings. However, sperm ducts of
Dr. barwelli
,
Dr. nepalensis ( Michaelsen 1909)
,
Dr. moriokaensis
,
Dr. tairaensis
,
Dr. omeiana
, and
Dr. eda
are long and coiled. Chen (1933) did not describe the sperm duct of
Dr. syringa
in detail but mentioned a short, broad, warty male atrium with thick glandular layer and very long, conspicuous egg sacs (ovisac) extending over 10–15 segments. These two characters are apparently disparate from those of
Dr. alishanensis
. Besides,
Dr. syringa
is slightly larger than
Dr. alishanensis
with 50–100 mm in length and 2.5–3.0 mm in width and has 124–172 segments ( Chen 1933). The position of the spermathecal atrium of
Dr. syringa
is also different from that of
Dr. alishanensis
with the former posterior to septum 7/8 and the latter anterior to it.
As to
Dr. keikiensis
, its short sperm duct wholly behind septum 9/10 with only a few twists described in Kobayashi (1938) is akin to that of
Dr. alishanensis
. It differs from the new species in the same characters as
Dr. syringa
. In fact, we consider
Dr. keikiensis
to be a junior synonym of
Dr. syringa
. The description of
Dr. keikiensis
was based on two semi-mature specimens from Korea ( Kobayashi 1938). Their body size (40 and 54 mm in length and greatest diameter 2.5 mm), segment number (154 and 138) and number of gizzards (three or four in XIII–XV or XII–XV) are within the species range of
Dr. syringe
of which a total of 68 specimens were collected from Zhejiang (= Chekiang) Province, central China ( Chen 1933). Like
Dr. syringa
,
Dr. keikiensis
also has short penis, short and broad prostate (= male atrium) with a highly warty surface, long ovisacs in XII–XVI (shortest) or XII– XXII (longest), large ampulla, and spermathecal atrium posterior to septum 7/8 ( Kobayashi 1938). Although Kobayashi (1938, p. 110) states in the Remarks that
Dr. keikiensis
differs from
Dr. syringa
“mainly in shape of penis and probably also in the structure of the other parts of the male organs, and in position where the sperm-duct enters into the atrium”, he also indicates that “where the sperm-duct enters into the prostate was not decidedly determined” ( Kobayashi 1938, p. 108). When the structures of penis, spermatheca and male atrium and penis pouch illustrated in Chen (1933, Fig. 7) and Kobayashi (1938, Fig. 4) are compared, it is found that they are not distinguishable. Consequently,
Dr. keikiensis
is considered to be synonymous with
Dr. syringa
. The other four species of
Drawida
listed in Kobayashi (1938),
Dr. japonica
,
Drawida gisti Michaelsen, 1931
,
Drawida nemora Kobayashi, 1936
and
Dr. koreana
, are also species commonly found in China and Korea.
Drawida glabella Chen, 1938
from Hainan Island, China is also small sized with a body length of 52 mm and diameter 2 mm. It has no genital papillae or other markings except the swollen lips around the secondary male apertures ( Chen 1938). Blakemore (2010), Blakemore and Kupriyanova (2010) and Blakemore et al. (2014) synonymized this species with
Dr. barwelli
. Nevertheless, the structures of spermatheca and male organs as shown in Chen (1938, Fig. 1
View FIGURE 1
) and in Blakemore and Kupriyanova (2010, Fig. 1.1) are different. Sizes of the ampulla and the spermathecal atrium in Chen (1938, Fig. 1A
View FIGURE 1
) are almost the same while ampulla is apparently larger than spermathecal atrium in Blakemore and Kupriyanova (2010, Fig. 1.1e). The larger ampulla together with the smaller spermathecal atrium of
Dr. barwelli
is also shown in Shen (2018, Fig. 1E
View FIGURE 1
). The sperm duct in Chen (1938, Fig. 1B
View FIGURE 1
) is with a few loose coils in front of septum 9/10 and rather straight behind to join a roundish and smooth male atrium, whereas in Blakemore and Kupriyanova (2010, Fig. 1.1c), the sperm duct is heavily twisted with a short, straight distal end connecting to a small, follicular prostate (= male atrium) linking to a round, globular copulatory chamber. Fig. 8 of
Drawida
sp. 3 in Shen and Yeo (2005) shows exactly the same structure characteristic of
Dr. barwelli
and thus, the identity of this immature specimen of
Drawida
sp. 3 should be
Dr. barwelli
. Such a structure of a small, follicular prostate together with a round, globular copulatory chamber typical of
Dr. barwelli
and visible even in an aclitellate specimen like the one depicted in Shen and Yeo (2005) was not presented in Fig. 1B
View FIGURE 1
of Chen (1938). Furthermore, the proportion of the entire sperm duct to the testis sac is almost equal in Blakemore and Kupriyanova (2010, Fig. 1.1c), while this proportion is much smaller as shown in Chen (1938, Fig. 1B
View FIGURE 1
). In addition, other accounts such as body size and presence or absence of dorsal pores also vary between
Dr. barwelli
and
Dr. glabella
. Beddard (1886) described
Dr. barwelli
as a small earthworm not more than 1.5 inch (about 38 mm) in length. Body length of specimens of
Dr. barwelli
recorded from Taiwan is 25–44 mm (Shen 2018) and the specimen from Singapore is 40 mm long ( Shen and Yeo 2005). Therefore,
Dr. glabella
is apparently larger. Regarding the presence or absence of dorsal pores, Beddard (1886) mentioned that “The only apertures that I could detect upon the surface of the body besides the mouth and anus were two oval slit-like orifices with tumid yellowish lips, which are the male generative orifices”. This is consistent with the observation of Easton (1984) and Shen (2018) that dorsal pores are totally absent in
Dr. barwelli
. However, later Beddard (1888; 1891) mistook
Drawida beddardii ( Rosa, 1890)
for
Dr. barwelli
and stated in Beddard (1891) that “Dorsal pores are present” (see Shen 2018). Due to misidentification by Beddard (1888; 1891; 1893; 1895),
Dr. beddardii
has long been wrongly considered synonymous with
Dr. barwelli
(see Shen et al. 2015) which leads to the erroneous conclusion by Blakemore (2010, p. 142) that the presence or absence of dorsal pores is possibly an intermittent character. As to
Dr. glabella
, dorsal pores are evident behind the clitellum ( Chen 1938). Accordingly,
Dr. glabella
is not synonymous with
Dr. barwelli
and should be recognized as a valid species.
Drawida cf. barwelli
found in Korea were based on two immature specimens with a body length of 45–60 mm, moderately-coiled sperm ducts and four gizzards in XV–XVIII ( Blakemore et al. 2014). Beddard (1886) did not mention the number and position of gizzards in
Dr. barwelli
, but Beddard (1893; 1895) mentioned three gizzards in XIII–XV in
Drawida bahamensis ( Beddard, 1893)
, a junior synonym of
Dr. barwelli ( Easton 1984)
. Easton (1984) reported three or four gizzards in XII–XVI in specimens from south-western Pacific islands and Central America while three gizzards in XIV–XVI were found in specimens from Taiwan (Shen 2018). The much larger size, not so heavily coiled sperm ducts and posteriorly placed gizzards of specimens from Korea are morphologically dissimilar to
Dr. barwelli
. Moreover, the DNA barcode tree presented in Blakemore et al. (2014, Fig. 1
View FIGURE 1
) clearly shows that the Korean specimens should be assigned to
Dr. eda
(see also Fig. 3
View FIGURE 3
in this study).
The following species of
Drawida
are, like
Dr. alishanensis
, also small worms without papillae or genital markings:
Dr. beddardii
,
Dr. fluviatilis Stephenson, 1924
,
Dr. delicata Gates, 1962
and
Dr. tenellula Gates, 1962
from Burma,
Dr. affinis Stephenson, 1917
from Bengal, and
Dr. ramnadana Michaelsen, 1907
,
Dr. willsi Michaelsen, 1907
,
Dr. fakir Cognetti, 1911
,
Dr. brunnea Stephenson, 1915
, and
Dr. paradoxa Rao, 1921
from India. Among them,
Dr. fluviatilis
,
Dr. delicata
,
Dr. tenellula
,
Dr. affinis
,
Dr. ramnadana ( Michaelsen 1909)
,
Dr. willsi ( Michaelsen 1909)
,
Dr. brunnea
, and
Dr. paradoxa
can be separated from
Dr. alishanensis
by their coiled sperm ducts.
Dr. beddardii
has rather short, S-shaped sperm ducts ( Rosa 1890; Gates 1972) similar to those of
Dr. alishanensis
, but it has higher segment numbers (145–188), large spermathecal pores and 3–4 gizzards in XII–XIX ( Gates 1972). Gates (1972, p. 246) erroneously synonymized
Dr. fluviatilis
with
Dr. beddardii
; the sperm ducts and spermathecal pores of both species are distinctively different.
Drawida fakir Cognetti, 1911
from south India is slightly larger than
Dr. alishanensis
with a body length of 85 mm and maximum diameter 3 mm. It has a segment number, 98, quite close to that of
Dr. alishanensis
. Both species share the following combination of characters: (1) absence of papillae or genital markings, (2) short and slightly wavy sperm ducts, (3) ovisacs in XII and (4) loosely coiled spermathecal ducts ( Cognetti 1911; Stephenson 1923). However,
Dr. fakir
has four gizzards in XIII–XVI, tubular and closely coiled male atriums, and no spermathecal atrium, while
Dr. alishanensis
has two gizzards in XII–XIII, cotton-like and transversely elongated oval male atrium and small spermathecal atrium anterior to septum 7/8. Characters of all the above-mentioned
Drawida
species with short sperm ducts and without genital markings are summarized in Table 1.
