Echyridella aucklandica

Echyridella aucklandica is a species of freshwater mussel endemic to New Zealand. E. aucklandica is an aquatic bivalve mollusc in the family Unionidae, the river mussels.

Description

Echyridella aucklandica was first described by John Edward Gray in 1843 and given the name Unio aucklandicus. It was described again by American malacologist Charles Torrey Simpson in 1902, who used the name Diplodon websteri.
Simpson's original text reads as follows:
The length of the shell is 62–81 mm. The height of the shell is 32–39 mm. The width of the shell is 14–20 mm.

Distribution

Echyridella aucklandica is found in two separate locations, Southland and the lower North Island. This broken distribution may have come about due to transportation by Māori. It inhabits lakes and streams.

Ecology

Like other unionids, E. aucklandica has a complex life-cycle characterised by a parasitic larval stage called glochidia that require a fish host to metamorphose into juveniles. Echyridella aucklandica glochidia attach themselves exclusively to the New Zealand smelt, unlike the more common Echyridella menziesii, which generalises to many different host species.