Four new earthworm species of the genus Amynthas (Megascolecidae: Oligochaeta) from southwestern Taiwan with re-description of Amynthas tungpuensis Tsai, Shen and Tsai, 1999
Author
Shen, Huei-Ping
Author
Chang, Chih-Han
Author
Chih, Wen-Jay
text
Journal of Natural History
2016
2016-06-21
50
29 - 30
1889
1910
http://dx.doi.org/10.1080/00222933.2016.1180721
journal article
10.1080/00222933.2016.1180721
7304bf51-5acc-4cdf-bc2e-4f8e36fb6dc8
1464-5262
269053
Amynthas douliouensis
Shen and Chang, sp. nov.
(
Figure
3
)
Type
material
Holotype
.
Clitellate (mature) specimen (
78 mm
in length, dissected) collected
11
December
2007
from roadside slope along the Fongshuhu South Creek (elevation
150
–
210 m
) near the borders of Douliou and Linnei, Yunlin by C.H. Chang, T.J. Lin and Y.P. Li (TESRI-O-H-
48
) (voucher number: WH
3
P
12
).
Paratype
.
One clitellate (same collection data as
holotype
, TESRI-O-P-
43
).
Other material
Six clitellates (voucher number of specimen used for
DNA
barcoding analyses: WH
3
P
3
) and an aclitellate collected
12
June
2007
from roadside slope along Waihu Creek (elevation
230 m
) near the borders of Douliou and Linnei, Yunlin by M.H. Chen (coll. no.
2007
–
24
); two clitellates collected
27
June
2007
from
type
locality by S.T. Chang and Y.P. Li (coll. no.
2007
–
27
); five clitellates (voucher number of specimen used for
DNA
barcoding analyses: WH
3
P
14
) and an aclitellate collected
18
July
2007
from
type
locality by C.H. Chang, T.J. Lin and Y.H. Lin (coll. no.
2007
–
45
); two clitellates collected
16
August
2007
from
type
locality by C.H. Chang, Y.H. Lin and Y.P. Li (coll. no.
2007
–
65
; voucher number of specimen used for
DNA
barcoding analyses: WH
3
P
13
); one clitellate collected
13
September
2007
from
type
locality by T.J. Lin, Y.P. Li, L.H. Chen and H.I. Tsai (coll. no.
2007
–
85
) (voucher number: WH
3
P
11
); one clitellate collected
30
October
2007
from
type
locality by C.H. Chang, T.J. Lin and Y.P. Li (coll. no.
2007
–
105
).
Diagnosis
Small to medium; length (clitellates)
78
–
120 mm
. Segments numbering
82
–
99
. Setae
40
–
45 in
VII,
48
–
57 in
XX,
9
–
14
between male pores. Clitellum XIV
–
XVI. First dorsal pore in
11
/
12
or
12
/
13
. Spermathecal pores three pairs in
6
/
7
–
8
/
9
,
0.29
body circumference ventrally apart. Male pores
0.25
body circumference ventrally apart in XVIII, each on a round porophore surrounded by three or four circular or diamond-shaped folds. Genital papillae widely paired in presetal VIII and IX, and absent, single or closely paired immediately anterior to setal line in the mid-ventral position in IX and X, number variable. Spermathecae three pairs in VII
–
IX. Accessory glands stalked, each corresponding to external genital papilla. Seminal vesicles small, two pairs in XI and XII. Prostate glands large in XVI
–
XX. Prostatic duct long, U-shaped in XVII
–
XVIII.
Figure 3.
Amynthas
douliouensis
sp. nov.
Holotype (TESRI-O-H-48) (voucher number: WH3P12). (a) Ventral view of spermathecal pore region (gp, genital papilla; sp, spermathecal porophore). (b) Ventral view of male pore region (mp, male porophore). (c) Dorsal view of right spermathecae (amp, ampulla; dv, diverticulum; ag, accessory gland). (d) Dorsal view of right prostate gland (pd, prostatic duct). Scale bar 1 mm.
Description
External characters.
Total length (clitellates)
78
–
120 mm
. Weight
0.62
–
1.29 g
. Segments numbering
82
–
99
. Clitellum XIV
–
XVI, setae and dorsal pores absent, length
2.60
–
3.98 mm
and width
3.16
–
4.55 mm
. Prostomium epilobous. Setal number
40
–
45 in
VII,
48
–
57 in
XX, and
9
–
14
between male pores in XVIII. First dorsal pore in
11
/
12
or
12
/
13
. Spermathecal pores three pairs in intersegmental furrows of
6
/
7
–
8
/
9
, distance between paired pores about
0.29
body circumference ventrally apart (
Figure
3
a). Genital papilla presetal, usually widely paired in presetal VIII and IX, and absent, single or closely paired immediately anterior to setal line in the mid-ventral position in IX and X, number variable. For
20
specimens
examined, in VIII, two (widely paired) in
12
specimens
, one on right in three specimens, absent in five specimens; in IX, four (widely and closely paired) in
11
specimens
, three (widely paired and single median) in four specimens, two (widely paired) in four specimens, two (single median and one on left) in one specimen; in X, two (closely paired) in nine specimens, single median in three specimens, absent in eight specimens. Each papilla round, about
0.3 mm
in diameter. Female pore single, mid-ventral in XIV.
Male pores simple, paired in XVIII, about
0.25
body circumference ventrally apart, each on a small, round porophore surrounded by three or four circular or diamondshaped folds (
Figure
3
b). Genital papillae usually absent in the postclitellar region, one tiny papilla anteromedial to right male porophore in one specimen and two tiny papillae anteromedial to left male porophore in one specimen.
Preserved specimens reddish brown on dorsum and preclitellar region with orange brown clitellum and greyish brown ventrum.
Internal characters.
Septa
5
/
6
–
7
/
8
thick,
8
/
9
/
10
absent,
10
/
11
membranous,
11
/
12
–
13
/
14
muscular. Nephridial tufts on anterior faces of
5
/
6
/
7
. Gizzard large in VIII
–
X. Intestine enlarged from XVI. Intestinal caeca long, simple, paired in XXVII and extending anteriorly to XXI. Oesophageal hearts in XI
–
XIII.
Spermathecae three pairs in VII
–
IX, varied in size and shape (
Figure
3
c). Each ampulla round, peach-shaped or elongated oval-shaped, surface wrinkled,
1.05
–
1.23 mm
long and
0.65
–
0.97 mm
wide, with a short, stout spermathecal stalk about
0.2 mm
in length. Diverticulum with an iridescent, oval-shaped seminal chamber of
0.45
–
0.60 mm
long and a slender stalk of
0.60
–
0.77 mm
in length. Accessory glands stalked,
0.70
–
0.80 mm
in total length, each corresponding to external genital papilla (
Figure
3
c).
Holandry: testes oval, two pairs in ventrally joined sacs in X and XI. Seminal vesicles small or normal, two pairs in XI and XII, occupying one-third to nearly full segmental compartment. Pseudovesicle absent or present in XIII. Prostate glands in XVI
–
XX, large, smooth, lobed (
Figure
3
d). Prostatic duct long, U-shaped in XVII
–
XVIII, stouter toward distal end. Accessory glands absent.
DNA
barcodes
GenBank accession numbers
KU
232822
(WH
3
P
12
,
holotype
),
KU
232825
,
KU
232821
,
KU
232823
and
KU
232824
(WH
3
P3, 11,
13
and
14
, respectively).
Etymology
The name
douliouensis
is given to this species with reference to its
type
locality in Douliou, Yunlin, southwestern
Taiwan
.
Remarks
Amynthas douliouensis
sp. nov.
is only known from its
type
locality and the
type
locality of
A. quadriorbis
in the foothills near Douliou, Yunlin, southwestern
Taiwan
. The two
type
localities are only
1 km
away from each other in areas where natural habitats have mostly been transformed into farmlands, and so
A. douliouensis
may also be considered as an endangered species like
A. quadriorbis
.
Amynthas douliouensis
is sexthecate with three pairs of spermathecae in VII
–
IX and belongs to the
sieboldi
species-group of the genus
Amynthas
(
Sims and Easton
1972
)
. It is most similar to
A. tungpuensis
, an endemic earthworm widely distributed in western
Taiwan
, based on the characters of setal numbers, simple male pore structure, stalked accessory glands and three pairs of spermathecae in VII
–
IX. The presence of stalked accessory glands in
A. tungpuensis
was neglected in the original description of
Tsai et al. (
1999
)
. Despite these similarities,
A. tungpuensis
is morphologically separable from
A. douliouensis
because it has distinctive violet brown colouration with white setal rings and generally two transverse rows of papillae in presetal VIII and IX (
Tsai et al.
1999
). Molecular analyses also show that
A. douliouensis
is distinguishable specifically from
A. tungpuensis
(
Figure
1
).
Amynthas douliouensis
differs from the other members of the
sieboldi
-group primarily by its combined characters of simple male pore and unique papilla arrangements.