Comparative Parasitology 68(2) 2001 - Peru State College

Comp. Parasitol.
68(2), 2001, pp. 228-235
Rhabdias ambystomae sp. n. (Nematoda: Rhabdiasidae) from the
North American Spotted Salamander Ambystoma inaculatum
(Amphibia: Ambystomatidae)
YURIY KUZMIN,' VASYL V. TKACH,1-2 AND SCOTT D. SNYDER3'4
1 Department of Parasitology, Institute of Zoology, Ukrainian National Academy of Sciences, 15 Bogdan
Khmelnitsky Street, Kiev-30, MSP, 01601, Ukraine,
2 Institute of Parasitology, Polish Academy of Sciences, Twarda Street 51/55, 00-818, Warsaw, Poland, and
3 Department of Biology and Microbiology, University of Wisconsin Oshkosh, Oshkosh, Wisconsin 54901,
U.S.A. (e-mail: snyder@uwosh.edu)
ABSTRACT: Rhabdias ambystomae sp. n. is described on the basis of specimens found in the lungs and body
cavity of the spotted salamander (Ambystoma maculatum) from northwestern Wisconsin, U.S.A. The new species
differs from Rhabdias bermani in tail shape, arrangement of circumoral lips, and position of vulva, from Rhabdias
tokyoensis in the morphology and size of the buccal capsule and the shape of the esophagus, and from
Rhabdias americanus in the absence of pseudolabia at the cephalic extremity and the shape of the tail. Rhabdias
ambystomae sp. n. is the first species of the genus described from salamanders in North America.
KEY WORDS: Nematoda, Rhabdiasidae, Rhabdias ambystomae sp. n., salamanders, Ambystoma maculatum,
Wisconsin, U.S.A.
Nematodes of the genus Rhabdias Stiles and
Hassall, 1905, are globally distributed lung parasites
of amphibians and reptiles. Among amphibian
hosts, the vast majority of Rhabdias species
have been reported from anurans (frogs and toads),
whereas only 2 species of the genus have been
described from caudatans (salamanders): Rhabdias
bermani Rausch, Rausch, and Atrashkevich, 1984,
from the Siberian newt Salamandrella keyserlingii
Dybowski, 1870, in the eastern Palearctic (Rausch
et al., 1984) and Rhabdias tokyoensis Wilkie,
1930, from Cynops spp. in Japan (Wilkie, 1930).
In North America, Rhabdias spp. previously have
been found in the lungs and body cavities of several
species of salamanders (Lehmann, 1954; Dyer
and Peck, 1975; Price and St. John, 1980; Coggins
and Sajdak, 1982; Muzzall and Schinderle, 1992;
Bolek and Coggins, 1998; Goldberg et al., 1998).
These nematodes were identified as either Rhabdias
sp., Rhabdias ranae Walton, 1929, or Rhabdias
joaquinensis Ingles, 1935, the latter 2 species
normally restricted to anuran amphibians.
In the course of investigations of the helminth
fauna of Wisconsin amphibians, infections by a
species of Rhabdias were detected in the lungs and
body cavities of 2 specimens of the spotted salamander
Ambystoma maculatum (Shaw, 1802).
Morphological examination revealed these worms
Corresponding author.
228
Copyright © 2011, The Helminthological Society of Washington
to represent a new species of the genus Rhabdias.
This species is described herein as Rhabdias ambystomae
sp. n.
Materials and Methods
Amphibians were collected from a roadside wetland
near Pigeon Lake, Bayfield County, Wisconsin, U.S.A. A
total of 26 gravid and 110 subadult nematodes were
found in 2 of 4 A. maculatum. Nematodes were fixed in
hot formalin and postfixed in 70% ethanol. Prior to light
microscopic examination, worms were cleared in glycerol
by gradual evaporation from a 5% solution of glycerol in
70% ethanol. Nematodes to be examined with scanning
electron microscopy (SEM) were postfixed in ethanol, dehydrated
in a graded series of ethanol and acetone, and
critical point dried in a Desk II Critical Point Dryer®
(Denton Vacuum, Inc., Moorestown, New Jersey, U.S.A.)
with CO2 as the transition fluid. The specimens were
mounted on stubs, coated with gold, and examined with
a Hitachi 2460N® scanning electron microscope (Hitachi
USA, Mountain View, California, U.S.A.) at an accelerating
voltage of 10-15 kV
Five specimens of R. bermani from S. keyserlingii collected
in Magadanskaya Region, Russia, 10 specimens of
R. tokyoensis from the brown newt Cynops ensicauda
(Hallowell, 1860) collected on Okinawa Island, Japan, 20
specimens of R. ranae from the northern leopard frog
Rana pipiens (Schreber, 1782) collected in Wisconsin,
U.S.A., and 18 specimens of Rhabdias americanus Baker,
1978, from the American toad Bufo americanus Hoibrook,
1836, collected in Wisconsin, U.S.A. were examined
by light microscopy and measured after being
cleared as above. All measurements are given in micrometers
unless otherwise stated. Measurements are given
for the holotype followed by minimum and maximum
measurements of paratypes in parentheses.