: Updates on egg morphology, host range, and distribution.

During a survey for helminths in reindeer () across the Palearctic region, eggs were found in zoo reindeer feces. These were identified as eggs of based on their morphology, morphometrics, location, and analysis of their partial sequence of ITS rDNA region. Some of the eggs had an appendage, previously unreported. Additionally, adults of were studied. Eggs derived from their uteri were also appendaged. Diagnostic morphological traits of eggs (abopercular appendage, knob, egg shell thickening, and egg shape) are discussed in this article. Three dimensional models of eggs were created to demonstrate the eggs features as best as possible. Since fecal examination remains gold standard in diagnosing fasciolosis in humans and animals worldwide, our findings may contribute to improved diagnostics. This research has also shown that reindeer can be a final host for . We also discuss whether the Novaya Zemlya archipelago might be the northernmost site of fasciolosis.