Comparative Parasitology 68(2) 2001 - Peru State College

KUZMIN ET AL.—RHABD1AS AMBYSTOMAE SP. N. 231
Table 2. Measurements of Rhabdias ambystomae sp. n. subadult specimens (n = 15) (measurement in
micrometers unless otherwise noted).
Character
Body length (mm)
Body width
Buccal capsule depth
Buccal capsule width
Width of esophagus, anterior end
Width of esophagus, muscular region
Minimum width of esophagus, glandular region
Esophageal bulb width
Distance, anterior end of esophagus to nerve ring
Distance, anterior end of esophagus to nerve ring (as % of esophagus length)
Esophagus length
Esophagus length (as % of body length)
Distance from anterior end to vulva (mm)
Distance from anterior end to vulva (as % of body length)
Tail length
Tail length (as % of body length)
completely developed, but eggs absent. Proximal
regions of gonads overlap level of vulva. Each gonad
forms a single loop as it bends. Uteri narrow,
lacking eggs.
Taxonomic summary
TYPE HOST: Spotted salamander Arnbystoma
maculatum (Shaw, 1802).
TYPE LOCALITY: Roadside wetland near Pigeon
Lake, Bayfield County, Wisconsin, U.S.A.;
46°20'84"N, 91°20'58"W.
SITES OF INFECTION: Lungs, body cavity.
TYPE SPECIMENS: The type series consists of
the gravid specimens only. Holotype: U.S. National
Parasite Collection, Beltsville, Maryland,
U.S.A., USNPC 90869. Paratypes: USNPC
90870 (9 specimens); Department of Parasitology,
Institute of Zoology, Kiev, Ukraine, Vial N
847 (8 specimens).
ETYMOLOGY: The new species is named in
reference to the generic name of its type host.
PREVALENCE AND INTENSITY: Two of 4 specimens
of spotted salamander; 20-116 specimens
of R. ambystomae (5-21 adult nematodes in
lungs and 15-95 subadults in body cavity).
Remarks and Discussion
Rhabdias ambystomae sp. n. is most similar
morphologically to R. bermani and R. tokyoensis,
the only other species of Rhabdias described
from salamanders. The 3 species are similar in
body size and shape and in egg size (Table 3).
Rhabdias ambystomae sp. n. differs from R. ber-
Mean
4.2
11 1
12
17
37
39
42
57
149
34.4
432
10.5
2.4
57.4
171
4.1
Minimum
3.3
100
10
15
35
35
37
50
110
26.8
400
8.8
1.9
54.4
150
3.5
Maximum
4.9
120
12
17
40
42
47
60
170
37.8
460
12.0
2.8
61.8
190
5.0
mani in the absence of a lancet-like cuticular
swelling of the posterior extremity characteristic
of the latter species. In R. bermani, the circumoral
lips are arranged in 2 lateral groups; in each
group, the lateral lip is situated closer to the oral
opening than are the submedian lips (Rausch et
al., 1984). In contrast, the lateral lips of R. ambystomae
sp. n. are situated farther from the oral
opening than are the submedian lips, a character
more prominent in subadult worms than in
adults (Figs. 3, 7). Additionally, the vulva of R.
ambystomae sp. n. is usually postequatorial,
whereas it is equatorial in R. bermani (Rausch
et al., 1984). The most apparent differences between
R. ambystomae sp. n. and R. tokyoensis
are the markedly smaller buccal capsule and narrower
esophagus of R. ambystomae (Table 3).
Rhabdias ambystomae sp. n. can be distinguished
readily from 2 Rhabdias species common
in North American amphibians, R. atnericanus
and R. ranae, by the absence of lateral
pseudolabia on the cephalic end. The presence
and shape of pseudolabia in R. americanus and
R. ranae were well documented by Baker (1978)
and confirmed by examination of specimens collected
as part of the present study. In addition,
R. americanus has a more elongated tail (cf.
Baker, 1978, fig. 3) compared with that of R.
ambystomae sp. n.
Parasitic nematodes of the genus Rhabdias
have been reported in several species of salamanders
from the midwestern U.S.A. Price and
St. John (1980) reported finding an undeter-
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