Abstract
In March and April 2018, we carried out a survey of myxosporean parasites in coastal fishes collected from Nha Trang Bay in Vietnam’s East Sea. Of the 159 fish specimens, 18 fish species were represented, belonging to 10 families. In 8 host species, 7 myxosporean species were found, representing the genera
Kudoa
and
Unicapsula
. Two of these species were new to science:
Kudoa igori
n. sp. from the gallbladder of Longarm mullet
Osteomugil cunnesius
(Valenciennes, 1836) (prevalence 10%) and
Kudoa borimiri
n. sp. from skeletal muscles of Longarm mullet and Longfinned mullet
Osteomugil perusii
(Valenciennes, 1836) (prevalence 30% and 60%, respectively). Vegetative stages were not found. Spores of
K. igori
n. sp. were small, orbicular to quadrate in apical view, and with four equal valves. In lateral view, spores were shallowly ovoid with a slightly protruding anterior pole. The 4 polar capsules were slightly unequal sizes and were oriented toward the apex of the spore. Dimensions were as follows: spore length 4.56 ± 0.22 (4.18–4.56), thickness 4.42 ± 0.39 (3.55–5.13), width 5.74 ± 0.46 (4.66–6.50), length of biggest polar capsule 1.38 ± 0.14 (1.1–1.65), middle 1.28 ± 0.12 (1.03–1.53), smallest 1.13 ± 0.11 (0.94–1.30), width of biggest polar capsule 1.03 ± 0.14 (0.83–1.4), middle 0.92 ± 0.12 (0.76–1.08), smallest 0.74 ± 0.12 (0.55–0.94). Spores of
K. borimiri
n. sp. had four equal valves with slightly rounded ends and were quadrate in apical view. In lateral view, spores were broadly deltoid. Four equal-sized polar capsules opened at the apex of the spore. In
O. cunnesius
, spore dimensions were as follows: length 3.51 ± 0.15 (3.34–3.92), thickness 3.65 ± 0.38 (2.79–4.21), width 4.97 ± 0.37 (4.13–5.97), length of the polar capsules 1.23 ± 0.18 (0.99–1.57), width 0.88 ± 0.07 (0.70–1.00). Overlapping dimensions for
K. borimiri
n. sp. spores were also found in
O. perusii
. Other known myxozoan species we encountered were
Kudoa thyrsites
and
Kudoa whippsi
, which had not previously been reported from the East Sea and Vietnam
.
We also encountered
Kudoa monodactyli
, which had not previously been reported from Nha Trang Bay. In addition, we report 2 additional species, a
Kudoa
sp
.
and a
Unicapsula
sp., that were not attributable to previously described myxozoans and need further investigation to completely characterize.