Comparative Parasitology 67(1) 2000 - Peru State College

increase in the number of cuticular ridges, (2) rotation
of the axis of orientation, and (3) lengthening
of the genital cone. This line was divided
into 3 genera: Carolinensis in the Palearctic Region,
Hassalstrongylus in the Nearctic Region,
and Stilestrongylus in the Neotropical Region.
But evolution being gradual, the generic separations
are necessarily arbitrary, and the geographic
localities overlap in the Americas. Carolinensis is
also present in North America, and Hassalstrongylus
is present in South America.
The phyletic position of the new species is
interesting since it possesses some characteristics
of the genus Hassalstrongylus: a high number
of cuticular ridges (13-16 in Carolinensis vs
19-25 in Hassalstrongylus), disappearance of
the gradient of size of the cuticular ridges, which
tends to an equalization of their size and the appearance
of a new symmetry in relation to the
axis of orientation, and a relatively developed
genital cone. According to Durette-Desset
(1974), Hassalstrongylus musculi (Dikmans,
1935) was an example of an intermediary species
between the genera Hassalstrongylus and
Stile strongylus. Carolinensis tuffi seems to be an
intermediary between the genera Carolinensis
and Hassalstrongylus.
The species Boreostrongylus romerolagi Gibbons
and Kumar (1980) was described from a
Mexican lagomorph, Romerolagus diazi (Ferrari
Arez, 1893), and was automatically transferred
to the genus Carolinensis, since Boreostrongylus
was considered a synonym of Carolinensis by
Durette-Desset (1983). However, this species is
very different from the other species of the genus
and can be classified in the genus Paraheligmonella
Durette-Desset, 1971, particularly
because of its synlophe: the left and right ridges
are hypertrophied; a lateromedial gradient in the
size of the ridges is present; and the axis of orientation
is inclined 45° to the sagittal axis (Gibbons
and Kumar, 1980). We thus propose a new
combination: Paraheligmonella romerolagi
(Gibbons and Kumar, 1980) comb. n. (=Boreostrongylus
romerolagi Gibbons and Kumar,
DURETTE-DESSET AND SANTOS—CAROLINENSIS TUFF/ SP. N. 69
1980; = Carolinensis romerolagi (Gibbons and
Kumar, 1980), Durette-Desset, 1982).
Acknowledgments
We wish to thank Drs. D.W. Tuff, J.T. Baccus,
and J.M. Kinsella for their advice during the
course of this study and comments on the manuscript.
Additional thanks are due to Dr. Baccus
for obtaining permission from the Texas Parks
and Wildlife Department for use of the study
site, obtaining the scientific collecting permit,
and securing funding for the collection of the
specimens. Thanks are due to Kevin Schwausch,
T Wayne Schwertner, and Todd Pilcik for assistance
in trapping and handling rodents and to
the staff of Colorado Bend State Park, especially
Robert Basse.
Literature Cited
Dikmans, G. 1935. New nematodes of the genus Longistriata
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. 1985. Trichostrongyloid nematodes and their
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Figures 1-8. Carolinensis tuffi sp. n. in Peromyscus pectoralis from Texas, drawings based on paratypes.
1. Male, anterior extremity, right lateral view. 2. Female, head, apical view. 3. Female tail, disappearance
of cuticular ridges. 4. Female, posterior extremity, left lateral view. 5. Male synlophe at mid body. 6.
Female synlophe at mid body. 7. Male, genital cone and membrane, ventral view. 8. Male, caudal bursa,
ventral view. V = ventral side; R = right side. Scales in micrometers.
Copyright © 2011, The Helminthological Society of Washington