Echinococcus canadensis, E. borealis, and E. intermedius. What's in a name?

Phylogenetic Pattern, Evolutionary Processes and Species Delimitation in the Genus Echinococcus

“…Although the metacestode of G6 is often found in camels, while that of G7 is often found in pigs, there is overlap in life cycles, as well as similarity in morphological traits and close genetic similarity in mtDNA and nuclear DNA sequences (Nakao et al, 2007(Nakao et al, , 2013bLymbery et al, 2015;Romig et al, 2015). These data are all consistent with ecological exchangeability between the G6 and G7 genotypes (and hence conspecific status), although, as pointed out by Romig et al (2015), there remains the possibility of biologically important variation between these groups.…”

“…If the genotypes of E. canadensis are not monophyletic, they clearly cannot be regarded as a single evolutionary species, but if we accept the mtDNA phylogeny as a true reconstruction of evolutionary history, then they may be. Nakao et al (2007;2013b,c) proposed the unification of the G6, G7, G10 and G8 genotypes into the species E. canadensis, while Lymbery et al (2015) suggested that there were three different evolutionary lineages within this group; G6/G7 as one species, G10 as a second and G8 as a third.…”

“…The G6 and G7 genotypes are largely allopatric, making it difficult to establish the presence or absence of genetic exchangeability (Lymbery et al, 2015). Although the metacestode of G6 is often found in camels, while that of G7 is often found in pigs, there is overlap in life cycles, as well as similarity in morphological traits and close genetic similarity in mtDNA and nuclear DNA sequences (Nakao et al, 2007(Nakao et al, , 2013bLymbery et al, 2015;Romig et al, 2015).…”

“…Genetically differentiated populations within described species may at some stage warrant further taxonomic revision. For example, Lymbery et al (2015) suggested that E. canadensis may consist of three separate species, based on differences in mtDNA sequences, morphology and life history of (apparently) sympatric populations. Substantial genetic diversity has been found among geographically separated populations of E. multilocularis ), E. vogeli (Santos et al, 2012) and E. oligarthra (Soares et al, 2013); at present there is no basis for taxonomic recognition of these differences, but that may change with further studies.…”

“…Officially, Canada is considered endemic for E. granulosus and import requirements for dogs into Canada do not require treatment with an anthelmintic. Such treatment could prevent the introduction of E. granulosus s.s., a species of far more economic and public health significance than E. canadensis (Lymbery et al, 2015).…”