Phreatogammarus Fragilis
P. fragilis was the first species to be described, when Charles Chilton named it Gammarus fragilis in 1882; it was moved to the genus Phreatogammarus by T. R. R. Stebbing in 1899, becoming the type species for the group. It lives in wells and groundwater, mainly in Canterbury and Nelson, and is not known to occur on the North Island.
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