Guide to the Parasites of Fishes of Canada Part V: Nematoda
Author
Arai, Hisao P.
Author
Smith, John W.
text
Zootaxa
2016
4185
1
1
274
journal article
10.11646/zootaxa.4185.1.1
11620862-ddcf-4c01-b0d9-32867e03d74b
1175-5326
165530
0D054EDD-9CDC-4D16-A8B2-F1EBBDAD6E09
Ascarophis
sp.
Sites: intestinal lumen, stomach
Hosts:
Coregonus nasus
(8);
Cottus aleuticus
(5);
Gadus macrocephalus
(5);
Gadus morhua
(9);
Hexagrammos decagrammus
(1, 5);
Mallotus villosus
(6);
Nautichthys oculofasciatus
(5);
Oncorhynchus gorbuscha
(2, 4);
Reinhardtius hippoglossoides
(7)
Distribution: Atlantic,
British Columbia
, Newfoundland,
Northwest Territories
, Pacific
Records: 1. Margolis 1977 (PA); 2. Anon. 1981 (BC); 3.
Sankurathri
et al.
1983
(PA); 4.
Anon. 1984
(BC); 5.
Ko 1986
(BC, PA); 6.
Arthur
et al.
1995
(AT); 7.
Boje
et al.
1997
(AT); 8.
Choudhury & Dick 1997
(NT): 9.
Khan
et al
. 2011
(NF)
Comments: Five
Ascarophis
species are known currently from Canadian fishes.
Appy (1981)
provided good
descriptions and illustrations for
A. arctica
,
A. extalicola
and
A. filiformis
; the original descriptions of
A. morrhuae
and
A. sebastodis
are relatively poor. Taxonomic problems concern morphology of the head of both sexes, and the
tails of males. Regarding the head, the pseudolabia of
A. extalicola
have a blunt knob rather than the prominent conical apex of
A. arctica
and
A. filiformis
, so Appy (
op. cit.
) and
Ko (1986)
suggested that
A. extalicola
might be related to “
Cystidicoloides
” [species of which have been transferred to
Salmonema
; see page 100]. Regarding male tails, an
area rugosa
, narrow caudal alae, six pairs of post-cloacal papillae, and paired phasmids behind the 6th pair of papillae appear to be diagnostic. Appy (
op. cit.
) pointed out that papillae of the 5th pair are relatively small and ventral to the 6th pair, so earlier workers might have overlooked them. Indeed,
Figure 55
B illustrates an
A. morrhuae
male, redrawn from
Berland (1961)
, apparently with only five pairs of post-cloacal papillae, and structures that are [
sic
] “possibly the phasmids”. The description of neither
A. morrhuae
nor
A
.
sebastodis
mentions an
area rugosa
; there is no reference to paired phasmids for
A. sebastodis
; and caudal alae are not mentioned in the descriptions for either species, although
Figure 55
B illustrates them for
A. morrhuae
. Both
A. morrhuae
and
A. sebastodis
should be redescribed and illustrated with special attention to the morphology of heads and tails.