Two new species of Helobdella Blanchard 1896 (Hirudinida: Rhynchobdellida: Glossiphoniidae) from Taiwan, with a checklist of hirudinea fauna of the island
Author
Lai, Yi-Te
Author
Chang, Chih-Han
Author
Chen, Jiun-Hong
text
Zootaxa
2009
2068
27
46
journal article
10.5281/zenodo.187040
0b4370bc-e62a-4959-a0f7-afe68488c4bc
1175-5326
187040
5F854ED1-197A-44F4-A867-5C152C85AA4B
Helobdella europaea
Kutschera, 1987
new record
(
Fig.5
&
Fig. 6
)
Helobdella striata
Kutschera, 1985
Helobdella europaea
Kutschera, 1987
Helobdella papillornata
Govedich et Davies, 1998
Helobdella europaea
Kutschera, 2004
Helobdella europaea
Siddall et Budinoff, 2005
Material exmined:
L00048, L00051, L00058, L00068, L00069,
L00095
-A, and mounted specimen SLD0016L&R, SLD0017L, SLD0022L&R, SLD0023L&R. Deposited in the Invertebrate Zoology and Cell Biology Lab, Department of Life Science in National
Taiwan
University, Taipei. Underneath submerged stone in Guandu Plain, Taipei,
Taiwan
, collected by Yi-Te Lai from
Mar 2003
to date.
Diagnosis:
Externally,
H. europaea
can be easily recognized with the five rows of distinct black-tipped papillae of the dorsum. Dorsal pigmentation arranged in numerous longitudinal dark gray stripes is an important character of
H. europaea
as well. No nuchal scute present.
Form:
Body length
10–25 mm
, maximum body width
4–7 mm
, anterior sucker diameter 0.8–
1 mm
, posterior sucker diameter
1–2 mm
. Body ovate-lanceolate, moderately flattened, posterior half body much wider than tapering cephalic end. Dorsum arched; venter flat or slightly indented. Cephalic sucker triangular, proboscis pore in anterior part of cavity. Posterior sucker circular, diameter almost equal to half of maximum body width, venter flat, directed ventrally.
FIGURE 5.
External morphology of
Helobdella europaea
.
The scale indicates 1 mm.
FIGURE 6.
Internal morphology of
Helobdella europaea
. Roman numerals of X and XX indicate the orders of the ganglia. an. Anus; atr. Atrium; br. Brain; cr. Crop and crop caeca; ejc. Ejaculatory duct; g. Ganglion; int. Intestine and intestine caeca; mth. Mouth; ov. Ovary; prb. Proboscis; rt. Rectum; salg. Salivary gland; te. Testisacs.
Color and pattern:
Dorsum fawn; pigmentation arranged in numerous longitudinal light and dark gray lines and stripes; the two median lines most conspicuous and close together, from segment II–III till posterior sucker; whereas the submarginal and marginal lines more inconspicuous. White spots appeared regularly and interrupted the straight lines, hence the two median lines presented as a chain in particular. Venter without any dots or spots.
Eyes:
One pair of punctiform to triangular eyes in III (3rd annulus).
Annulation:
Body totally 67 annuli. I and II fused together as one annulate. III uniannulate. IV biannulate. V–XXIV midbody somite, triannulate with a2>a1&a3. XXV and XXVI biannulate with (a1a2)>a3. XXVII uniannulate. Anus on the somite XXVII (67th annulus).
Papillation:
Dorsum with five rows of conical, black-tipped papillae; one median row and two rows on each side submarginally. The middle row of papillae from VII–XXV; while the submarginal and marginal rows of papillae from IX–XXIV and XVII–XXII respectively. Dorsum of posterior sucker with few scattered flattened papillae. Venter smooth.
Gonopores:
Gonopores separated by one annulus, male gonopore in the groove between somite XI a2/a3 (24th/25th annulus), female gonopore in the groove between somite XI a3 and XII a1 (25th/26th annulus).
Digestive system:
Pharyngeal proboscis long, with diffuse salivary glands distributed aside the root of the pharynx in XI and backward to XVI. Crop in XV–XIX, with five pairs of slightly complex and branched caeca; each pair of caeca larger, more complex and lobate than the former one; all caeca stretched more or less backward, especially the last pair of caeca stretched and elongated backward to XXIII. Four pairs of large and conspicuous intestinal caeca in XX–XXIII.
Hind
gut saccate, rectum oblique and tapered towards anus.
Male reproduction system:
Five pairs of testisacs intersegmentally arranged at XIV/XV–XVIII/XIX; vas deferens enters sperm duct in XIII, expands into seminal vesicle with S-shaped loop. Ejaculatory duct almost straight, with the same wide and proceeds obliquely outward and forward up to XI/XII. Terminal end of ejaculatory duct turning inwards towards atrial cornu at XI/XII, Cornua muscular, strongly divergent, nearlyovate in dorsal view. Atrium short and indistinct.
Female reproduction system:
one pair of long, thick, and straight ovisacs directed caudally. Oviducts joined into short and indistinct atrium in XII.
Habitat:
H. europaea
was only recorded in slow streams, irrigation ditches, drainage ditches and polluted open sewers in the Guandu Plain in Taipei. They were found attached underneath submerged or semisubmerged objects, including stones, woodblocks, and plastic rubbish. They could also be found on the concrete walls of ditches. Occasionally
H. europaea
were collected from the surface of shells and mantle cavity of apple snails,
P. canaliculata
.
Prey or host
: aquatic snails.
Remarks:
H. europaea
is similar to
H. triserialis
and
H. cordobensis
, and has been recognized as a member of the
H. triserialis
complex with the latter two species because of the resemblance in their external and internal characters (Siddall & Budinoff 2005). The use of DNA barcoding for identifying
H. europaea
has been variously documented (
Siddall & Borda 2003
; Kutschera 2004;
Pfeiffer
et al.
2004
; Siddall & Budinoff 2005;
Bely & Weisblat 2006
), and this technique may be the best way to identify this species.
It is the first time that
H. europaea
was recorded in the Sino-Japanese region and also in
Taiwan
. Because of the conspicuous conical and black-tipped papillae, the misidentification of
H. europaea
as another species is hardly possible. Because
H. europaea
was found in an easily accessible habitat, such as rice paddies and irrigation ditches, it should have been recorded before. Since leeches with strong and black-tipped papillae have never been recorded in
Taiwan
(
Oka 1910
,
1923
,
1925
,
1928
a–
c
,
1929 a
–
c
,
1930
,
1931
,
1934
;
Takahashi 1931
,
1933
,
1934 a
–
b
,
1935
),
H. europaea
likely invaded the island in these decades.