Penion chathamensis

Penion chathamensis is a species of very large predatory sea snail or whelk, a marine gastropod mollusc in the family Austrosiphonidae.^[2]

Penion chathamensis
A shell of Penion chathamensis
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Caenogastropoda
Order:	Neogastropoda
Family:	Austrosiphonidae
Genus:	Penion
Species:	P. chathamensis
Binomial name
Penion chathamensis (Powell, 1938)
Synonyms
Penion fairfieldae (Powell, 1947)[1]

Description

Penion chathamensis is a very large species of Penion siphon whelk.^[3] Although P. chathamensis has separate sexes, the species does not appear to exhibit secondary sexual dimorphism in shell shape or size.^[4]

A separate species, Penion fairfieldae was formerly recognised, but recent genetic data has demonstrated that the species is indistinguishable from Penion chathamensis.^[1] Shells originally recognised as P. fairfieldae can be distinguished from P. chathamensis using shell size, but not using shell shape.^[1]

Distribution

Penion chathamensis is endemic to New Zealand.^[3][4][5] The species is distributed off of the west coast of the South Island, and occurs on Chatham Rise and in waters surrounding the Chatham Islands^[3][4][5] The latter location is the type locality, giving rise to the binomial name of the species.^[3]