Redescription of four species of Hatschekia (Copepoda: Siphonostomatoida: Hatschekiidae) parasitic on tetraodontiform fishes from Japan
Author
Uyeno, Daisuke
Author
Nagasawa, Kazuya
text
Zootaxa
2009
2110
1
21
journal article
10.5281/zenodo.187869
81bf112d-edb5-42c8-b765-a9f8aea414f7
1175-5326
187869
Hatschekia ostracii
Yamaguti, 1953
(
Figs 25–37
)
Hatschekia ostracii
:
Yamaguti 1953
: 228
;
Jones 1985
: 256
;
Kim 1998
: 739
.
Material examined.
7Ψ (NSMT-Cr 20332), ex
Ostracion immaculatus
Temminck & Schlegel, Tatsukushi
(32°47΄N, 132°51΄E),
Kochi
, North Pacific Ocean,
Japan
,
9 May
, 2006; 1Ψ (NSMT-Cr 20333), ex
Ostracion cubicus
L., Ama (26°13΄N, 127°17΄E), Kerama Islands, Okinawa, East
China
Sea,
Japan
,
26 May
, 2007; 1Ψ (NSMT-Cr 20334), ex
O
.
cubicus
L., Sakimotobu (26°38΄N, 127°52΄E), Okinawa, East
China
Sea,
Japan
,
25 July
, 2007.
Description of female.
Body (
Fig. 25
) 0.66–1.02 (0.87 ± 0.10) long, excluding caudal rami (n = 9). Cephalothorax suborbicular, longer than wide [0.30–0.46 (0.37 ± 0.04) × 0.28–0.39 (0.35 ± 0.04)], with dorsal, T-shaped chitinous frame. Trunk longer than wide [0.41–0.69 (0.57 ± 0.09) × 0.21–0.39 (0.32 ± 0.06)], with pair of posterior lobes. Abdomen (
Fig. 26
) length 0.07–0.11 (0.10 ± 0.01); width 0.06–0.09 (0.08 ± 0.01). Caudal ramus (
Fig. 26
) longer than wide [0.03–0.04 (0.03 ± 0) × 0.01–0.02 (0.01 ± 0)] and bears 5 naked setae.
Rostrum with 1 ovoid process on each posterolateral corner (
Fig. 27
). Antennule (
Fig. 27
) 5-segmented, 0.17–0.25 (0.21 ± 0.02) long; armature formula: 9, 5, 4, 1, 13 + 1 aesthetasc. Antenna (
Fig. 28
) 3-segmented; proximal segment (coxa) unarmed; middle segment (basis) covered with surface pits; terminal segment clawlike, unarmed; proximal segment length 0.06–0.11 (0.08 ± 0.02); middle segment length 0.20–0.28 (0.24 ± 0.03); terminal segment length 0.06–0.07 (0.06 ± 0.01); total length 0.32–0.43 (0.38 ± 0.04). Parabasal papilla (
Fig. 29
) thumb-shaped, ventrally-directed. Oral cone robust. Mandible (
Fig. 30
) slender, with 4 sharp apical teeth. Maxillule (
Fig. 31
) bilobate; inner lobe sclerotized, bears 1 proximal and 1 apical elements; outer lobe with 2 attenuate elements. Maxilla (
Fig. 32
) 4-segmented; proximal segment unarmed; second segment rodlike, with 1 basal seta; third segment elongate, with 1 distal seta; terminal segment small, with 1 small seta and bifid claw. Maxilliped absent.
FIGURES 25–31.
Hatschekia ostracii
Yamaguti, 1953
, female. 25, habitus, dorsal. 26, abdomen and caudal rami, dorsal. 27, antennule, ventral. 28, antenna, ventral. 29, antenna and parabasal papilla, medial. 30, mandible, ventral. 31, maxillule, ventral. Scale bars: 25, 0.2 mm; 26–27, 0.04 mm; 28, 0.05 mm; 29, 0.1 mm; 30–31, 20 μm.
Legs 1 and 2 (
Figs 33–34
) biramous, with incompletely bimerous exopod and 2-segmented endopod; leg armature formula as follows (armature on terminal segment of rami represented by the mode followed by the range in parentheses):
| Protopod |
Exopod |
Endopod |
| Leg 1 |
1–1 |
1–0; 5 (4–6) |
0–0; 4 (3–5) |
| Leg 2 |
1–0 |
1–0; 5 (4–5) |
0–0; 3 (2–4) |
FIGURES 32–37.
Hatschekia ostracii
Yamaguti, 1953
, female. 32, maxilla, ventral. 33, leg 1, ventral. 34, leg 2, ventral. 35, intercoxal sclerite of leg 1 and 2, ventral. 36, leg 3, ventral. 37, leg 4, ventral. Scale bars: 32–34, 36–37, 20 μm; 35, 0.05 mm.
Intercoxal sclerite of legs 1 and 2 (
Fig. 35
) bears 2 short and 2 long processes. Protopods bear row of blunt spinules along distal margin and semicircular wrinkles on anterior surface (it is uncertain whether these wrinkles consist of spinules or not). Rami bear small, spinulate, hyaline sculptures on anterior surface. Leg 1 (
Fig. 33
) 0.14–0.16 (0.15 ± 0.01) long; protopod length 0.06–0.08 (0.07 ± 0.01); exopod length [0.07–0.08 (0.08 ± 0.01)] exceeding endopod length [0.02–0.03 (0.02 ± 0)]. Leg 2 (
Fig. 34
) length 0.10–0.17 (0.13 ± 0.02); protopod length 0.05–0.09 (0.07 ± 0.01); exopod length 0.05–0.07 (0.06 ± 0.01); endopod length 0.03–0.04 (0.03 ± 0).
Leg 3 (
Figs 25
,
36
) represented by 2 simple setae on mid-lateral surface of trunk. Leg 4 (
Figs 25
,
37
) represented by 1 simple lateral seta on posterior ½ of trunk.
Attachment site.
Gill filaments.
Remarks.
Hatschekia ostracii
was described originally by
Yamaguti (1953)
based on several gravid female specimens collected from
Ostracion cubicus
captured in Komatsushima (as Komatusima), Tokushima,
Japan
. This species was later redescribed by
Kim (1998)
from female specimens removed from
O
.
immaculatus
collected in
Korea
.
Hatschekia ostracii
has 4 processes on the intercoxal sclerite of legs 1 and
2 in
common with
H
.
balistae
Nuñes-Ruivo, 1954
and
H
.
monacanthi
Yamaguti, 1939
. However,
H
.
balistae
is distinguishable from
H
.
ostracii
by the presence of an anteromedian pointed apex on the cephalothorax and absence of posterior lobes on the trunk.
Hatschekia ostracii
differs from
H
.
monacanthi
by lacking a chitinous ring on the cephalothorax and having a significantly longer exopod relative to the endopod in leg 1 [L1ExL/ L1EnL ratio 3.24 ± 0.36 vs. 2.22 ± 0.30 (U-test;
p
<0.01),
Table 1
] and a considerably longer abdomen relative to the body length [AbL/BL ratio 0.12 ± 0.01 vs. 0.03 ± 0.01 (U-test;
p
<0.001),
Table 1
].