Morphological comparison of genetically differentiated Polymorphus cf. minutus types

Helminths of the mallardAnas platyrhynchosLinnaeus, 1758 from Austria, with emphasis on the morphological variability ofPolymorphus minutusGoeze, 1782

“…In this study, we also detected considerable variation in some characters, particularly proboscis armature and neck length, in individuals from several of the Austrian mallards. Grabner et al (2020) found similar variations in the proboscis armature of the three genetically distinguished subclades (PspT1, PspT2 and PspT3). We also calculated a lower number of hook rows (12-14; table 3) in the genetically investigated specimens of Austria, while previous descriptions of P. minutus referred to 14-18, usually 16, hook rows (e.g.…”

“…Polymorphus minutus has, however, been previously described as exhibiting a wide range of variability within and between different host species across a broad geographical range (Van Cleave & Starrett, 1940;Zittel et al, 2018;Grabner et al, 2020) as can be seen in table 3. However, the genetic results further implicated the specimens from Austria as belonging to the subclade PspT3, which uses G. pulex and G. roeselii as intermediate hosts (Zittel et al, 2018;Grabner et al, 2020). According to Grabner et al (2020), it can be expected that the subclade was introduced by the invasive gammarid G. roeselii.…”

“…Moreover P. minutus has been described previously as exhibiting a wide range of variability within and between different host species across a broad geographical range (Van Cleave & Starrett, 1940). Three different genetic lineages, each with a different intermediate host, were recently discovered, which probably represent cryptic species (Zittel et al, 2018;Grabner et al, 2020).…”

Unravelling the hidden biodiversity – the establishment of DNA barcodes of fish-parasitizing Acanthocephala Koehlreuther, 1771 in view of taxonomic misidentifications, intraspecific variability and possible cryptic species

“…The genetic p -distance of 2.9% between the two subclades E1 and E2 implies the existence of a phylogeographic structure. Considerable intraspecific variation was observed in some Acanthocephala and were especially investigated in the genus Pomphorhynchus (Dudiňák and Šnábel, 2001; O'Mahony et al ., 2004; Vardić Smrzlić et al ., 2015; Perrot-Minnot et al ., 2018) as well as in Polymorphus minutus sensu lato (Zittel et al ., 2018; Grabner et al ., 2020). Also, intraspecific differences were revealed for species of Echinorhynchus , explained by post-glacial population bottlenecks (Väinölä et al ., 1994).…”

“…Such inconsistencies are often attributed to strain formations in parasitic taxa due to different ecological demands and/or adaptations to host species (e.g. O'Mahony et al ., 2004; Steinauer et al ., 2007; Perrot-Minnot et al ., 2018; Grabner et al ., 2020). However, DNA barcode sequences of acanthocephalans in Europe are so far rare and the standard mitochondrial barcoding marker gene cytochrome c oxidase subunit 1 ( COI ) was rarely applied in the identification of this phylum in Europe.…”