ISSN 10630740, Russian Journal of Marine Biology, 2013, Vol. 39, No. 6, pp. 420–428. © Pleiades Publishing, Ltd., 2013.
Original Russian Text © Nguyen Vu Thanh, V.G. Gagarin, 2013, published in Biologiya Morya.
When studying the fauna of marine freeliving
nematodes in the shallow nearshore waters of Viet
nam in the South China Sea (called East Sea in Viet
nam), in 2010–2011, we found three nematode spe
cies of the order Enoplida new to science:
Oncholaimidae). Descriptions and pictures of these
species are provided below.
The family Thoracostomopsidae Filipjev, 1927
comprises 14 genera of nematodes, whose species are
oxyphilic and inhabit rocky and sandy bottoms of seas
. Until now, species of this family have not been
recorded from Vietnamese coastal waters.
sp. n. is the first finding of this family in Vietnam.
The family Oncholaimidae Filipjev, 1916 includes
41 genera; species of the genus
live in fresh
and brackish bodies of water. The seven following spe
cies of four genera have been found in Vietnamese
Gagarin, Nguyen Vu
Gagarin, Nguyen Vu
Gagarin, Nguyen Vu Thanh,
Nguyen Vu Thanh, 2007, and
Thanh, 2008 [1–3, 7, 8].
MATERIALS AND METHODS
In 2010–2011, the fauna of freeliving nematodes
in shallow nearshore waters of the South China Sea
was studied off the northern Vietnam coast, Gulf of
Tonkin, within the area 21
E. Samples were taken with
a Ponar grab sampler; meiobenthos samples were
taken with a 3.5 cm wide and 10 cm long elastic cylin
der. Samples were fixed in a hot (60–70
C) 4% form
aldehyde solution. After decantation, a sample was
placed into a 200ml plastic bottle, a Ludox–TM 50
solution (1 : 1) was added, mixed intensively, and then
the upper layer of the solution with nematodes was
poured off; the procedure was repeated five times.
Nematodes were transferred in pure glycerin, then
placed onto a microscope slide in a small drop of glyc
erin, and sealed with a ring of beeswax. An MBB1A
light microscope was used for measurements and
identification of the worms, as well as for making their
The symbols that were used in the text and tables,
are as follows:
is the body length/maximum body
is the body length/esophagus length;
body length/tail length;
' is the tail length/anal body
is the distance from the anterior body end
to vulva/body length, %.
Three New Species of Nematodes (Nematoda: Enoplida)
from Coastal Waters of Vietnam
Nguyen Vu Thanh
and V. G. Gagarin
Department of Nematology, Institute of Ecology and Biological Resources, Vietnam Academy of Sciences and Technology,
18 Hoang Quoc Viet Rd. Hanoi, Vietnam
Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok, 152742 Russia
Received March 28, 2013
—Three new species of freeliving nematodes of the order Enoplida from coastal shallow waters of
northern Vietnam are described and illustrated.
sp. n. is morphologically
Vitiello, 1971, and
Warwick, 1970; however,
it differs in lacking subcephalic setae and in having articulate cephalic setae in the males.
sp. n. is morphologically similar to
Kreis, 1929 but differs in having a shorter body and a shorter and
thicker tail in the females.
is distinguished from
(Ditlevsen, 1928) by its shorter
body, longer cephalic setae, more slender tail, and the position of the vulva.
can be distinguished from
Gagarin, Nguyen Vu Thanh, 2007 by its thinner body, longer
and more slender tail, and shorter and narrower stoma. In contrast to
, it has short spicules and lacks
vesiclelike cells between the gut and the longitudinal chords.
freeliving marine nematodes, new species, Enoplida,