Urogonimus macrostomus (Rudolphi, 1803) (Digenea): its taxonomy and morphology as revealed by light and scanning electron microscopy

The surface microtopography of adult Urogonimus macrostomus (Rudolphi) recorded in Sturnus vulgaris L. from southwest Norway is revealed by scanning electron microscopy and compared with Norwegian specimens of Leucochloridium variae McIntosh. The morphometric information from U. macrostomus in Norwegian starlings is compared with similar data on other U. macrostomus identified samples (U. macrostomus (sensu Witenberg) (= U. witenbergiella Kagan), U. macrostomus (sensu Schmidt), U. macrostomus (sensu Rutkowska)), and the present knowledge of morphological total range of the species is given. This result is further compared with other Urogonimus-related species, and the following species are regarded to be synonymous with U. macrostomus: U. cordis (Yamaguti), U. dryobatae (McIntosh), U. icteri (McIntosh), U. mniotiltae (McIntosh), and U. tetrastae (Oliger). The following are regarded as species inquirendae: U. mesostomus (Rudolphi), Urogonimus sp. (Lutz), Urogonimus sp. (Witenberg) (= L. witenbergi Skrjabin), U. seiuri (McIntosh), and U. vireonis (McIntosh). Four species are regarded from the present knowledge of their morphological variability, and that of U. macrostomus, as separate species within genus Urogonimus Monticelli: U. macrostomus (type species), U. caryocatactis (Zeder) (= D. caudale Rudolphi and D. caudale sensu Mueller), U. certhiae (McIntosh), and U. indicum (Singh).