Identification problems with species in the Echinoparyphium recurvatum complex from physid snails in the USA

Abstract

This study was done to help us answer numerous requests that we get about the identity of 45-collar-spined echinostomes in the genus Echinoparyphium. We examined 45-collar-spined cercariae from physid snails collected in Europe and the USA. Morphological observations of these cercariae showed considerable similarities in most of the characteristics we examined in these cercariae. Similar findings were made of adults obtained from natural and experimentally infected avian hosts in Europe and the USA. We suggest that these echinostomes be considered as species in the Echinoparyphium recurvatum complex, until further morphological and molecular studies be done on this group.

Morphological and molecular analyses of larval and adult stages of Echinoparyphium recurvatum von Linstow 1873 (Digenea: Echinostomatidae) from central Mexico

“…End-group spines were larger than other head-collar spines. Other features of adults, including suckers, prepharynx, oesophagus and caecae, testes, cirrus sac, ovary and vitelline glands were identical to those described previously for E. recurvatum by other authors (Lee et al , 1990; Sohn, 1998; Kanev et al , 2008) (table 2).…”

“…Comparative morphometrics (in mm) of adult worms of Echinoparyphium recurvatum obtained in the present study with those of Sohn (1998), Lee et al (1990) and Kanev et al (2008); length (L), width (W) and mean values given in parentheses after ranges.…”

“…The first and second intermediate hosts include the freshwater snails Lymnaea peregra , L. ovata and Planorbis planorbis from Europe; Radix auricularia coreana from Korea; and Physa gyrina , P. heterostropha , P. parkeri, Physa sp. and Stangicola emarginata from the United States (Sohn, 1998; Kanev et al , 2008).…”

Echinoparyphium limosorum n. sp. (Trematoda: Echinostomatidae) from Black-tailed Godwit, Limosa limosa (Aves, Charadriiformes) in Slovakia

“…In Black-tailed Godwit, several Echinoparyphium species were found in Central Europe (Hudec, Šťastný et al, 2005 Kanev et al, 2008); 2) morphology of vitelline fieds in the post-testicular region which may be confluent in A. limosorum but not in E. recurvatum. Regarding E. mordwilkoi, Kanev et al (2008) considered this species belonging to the E. recurvatum species complex.…”

“…In Black-tailed Godwit, several Echinoparyphium species were found in Central Europe (Hudec, Šťastný et al, 2005 Kanev et al, 2008); 2) morphology of vitelline fieds in the post-testicular region which may be confluent in A. limosorum but not in E. recurvatum. Regarding E. mordwilkoi, Kanev et al (2008) considered this species belonging to the E. recurvatum species complex. Except of the difference in the number of spines (45 versus 48 -51 in the new species), E. mordwilkoi has the smaller body size (up to 2.8 x 0.54 mm versus 3.8 -4.9 x 0.6 -0.7 mm in the new species) and the relatively long post-testicular part T % = 31.4, as counted from the drawing of E. mordwilkoi published by Skrjabin and Bashkirova (1956), versus T % = 20.3 in the new species.…”