Comparative Parasitology 67(2) 2000 - Peru State College

HASEGAWA ET AL.—LIFE HISTORY OF SPIROXYS HANZAKl 227
Table 1. Measurements of third-stage larvae of Spiroxys hanzaki collected from experimentally-infected
copepods, naturally infected fish, and salamanders (measurements in micrometers unless stated otherwise).
No. measured
Body length, mm
Maximum width
Nerve ringt
Excretory poret
Deiridst
Esophagus length, mm
Esophagus width
Genital primordium, mm:|:
Tail length
* Advanced third-stage larvae.
t Distance from cephalic extremity.
+ Distance from caudal extremity.
Mesocyclops
dissimilis and
Macrocyclops
albidus
2
1.39-1.80
61-80
140-198
175-219
220-296
0.50-0.70
32-34
0.46-0.47
45-56
18—19 at posterior esophagus level, nerve ring
69—72 from anterior extremity and esophagus
115-143 long (n = 2). On day 15, length 345,
maximum width 18, nerve ring 75 from anterior
extremity and esophagus 148 long (n =1).
MORPHOLOGY OF THE THIRD-STAGE LARVAE
COLLECTED FROM THE INFECTED COPEPODS: Body
slender. Cuticle with fine transverse striations.
Lateral alae absent. Anterior extremity with lateral
pseudolabia with trilobed internal sclerotized
structure of which dorsal and ventral lobes
much smaller than median lobe, directed anteriorly
(Figs. 6, 17). Large submedian papillae
and amphidial pore present (Fig. 17). Esophagus
club-shaped. Intestinal Wall densely packed with
brown granules. Genital primordium with elongated
2 branches extending anteriorly and posteriorly
(Fig. 7). Tail conical, with prominent
phasmidial pores and blunt extremity (Fig. 8).
Measurements are presented in Table 1.
Natural infection of fish with Spiroxys larva
A total of 83 individuals of 7 fish species belonging
to 3 families was examined during the
Misgtirnus
anguillicaudatus and
Cobitis biwae
3
1.33-2.01
46-56
118-144
149-205
226-304
0.41-0.58
28-38
0.43-0.77
56-69
Andrias
japonicus
2
1.76-2.00
56-90
176-143
214-190
293-296
0.57-0.65
28-32
0.54-0.65
54-64
Andrias
japonicus
5~'~
6.70-9.00
208-286
384-455
462-539
666-813
1.83-2.16
78-102
2.36-3.02
150-183
period from May to November 1998. Only 1 M.
anguillicaudatus and 2 sand loach, Cobitis biwae
(Jordan et Snyder, 1901), were found to be
infected each with 1 larva of Spiroxys. Two of
the larvae were found encysted on the stomach
wall and liver surface, whereas the remaining
larva was recovered by artificial digestion. The
morphology was identical with that of the larvae
recovered from the experimentally infected copepods
(Figs. 9, 10, 18). Measurements are also
comparable with those of the third-stage larvae
from the experimentally infected copepods as
shown in Table 1.
The third-stage larva of S. hanzaki is readily
distinguished from that of S. japonica, because
the latter has inwardly curved dorsal and ventral
lobes of the internal sclerotized structure in the
pseudolabium (Figs. 11, 19).
Morphology of 5. hanzaki larvae and
immature adults vomited from A. japonicus
THIRD-STAGE LARVAE (Figs. 12-14): Morphology
comparable with those from the exper-
Figure 11. Third-stage larva of Spiroxys japonica collected from pond loach, Misgurnus anguillicaudatus
from Hachiro-gata, Akita Prefecture, Japan, lateral view, showing inwardly bent dorsal and ventral
lobes of the sclerotized structure in pseudolabium (scale bar = 50 |xm).
Figures 12-14. Smallest third-stage larva of S. hanzaki collected from Andrias japonicus, lateral view
(scale bars = 50 jxm). 12. Anterior portion. 13. Genital primordium (arrow). 14. Posterior portion.
Figures 15, 16. Advanced third-stage larva vomited by A. japonicus, lateral view (scale bars = 50 |xm).
15. Anterior extremity. 16. Posterior extremity.
Copyright © 2011, The Helminthological Society of Washington