The first survey of caryophyllidean tapeworms parasitising catostomid and cyprinid fish in Mexico is provided, including new host and geographical records.
Isoglaridacris brevicollis
n. sp. is described from the Nazas sucker,
Catostomus nebuliferus
Garman (type host), in Durango,
C. bernardini
Girard in Sonora, and
Moxostoma austrinum
Bean (Cypriniformes: Catostomidae) in Jalisco. The new species differs from congeners mainly in the shape of the scolex, which is rounded, and by the absence of a defined neck (distinct, often long in other congeners).
Pseudoglaridacris confusa
found in
Ictiobus meridionalis
(also a member of the family Catostomidae) from Oaxaca and Veracruz represents the southern-most report of species of this Nearctic genus. Three morphotypes of the holarctic
Archigetes
Leuckart, 1878 were found in two leuciscid fishes (
Notropis caliensis
and
N. nazas
) and in silverside
Chirostoma
sp. (Atherinidae). It is the first record of any caryophyllidean in atheriniform fish. The first record of
Khawia japonensis
(Yamaguti, 1934) (syn.
K. iowensis
Calentine et Ulmer, 1961), a parasite of common carp (
Cyprinus carpio
L.), in Mexico represents another evidence of its invasive potential. The caryophyllidean fauna of Mexican freshwater fish is depauperate compared to that in the United States and Canada, which seems to be related to a much lower number of species of suckers (Catostomidae) occurring in Mexico, possibly also to the lower number of fish in the population.