Wednesday 31 August 2016

9 — Cuvier's siphon whelk, Penion cuvierianus

The same shell as above (~150mm).
Cuvier's siphon whelk, Penion cuvierianus (Powell, 1927) is a large gastropod whelk (up to 235mm) endemic to northeastern New Zealand. They are found from just offshore to the edge of the continental shelf (>180m). The shallow water forms can look very similar to another, more common species: Penion sulcatus (Lamarck, 1816), and can be difficult to distinguish from it. Of the species in this genus, Penion sulcatus is the species that people find washed up on beaches, as it has a distribution from the intertidal down to about 100m. The genus Penion is quite old and dates back in the fossil record almost to the Cretaceous period (Beu & Maxwell, 1990).

Penion cuvierianus, trawled, Bay of Plenty ~1960s.
These whelks are vulnerable to the bottom trawling activities of commercial fishing. Very little is known regarding their distribution, numbers, or how long they take to grow to maturity. It's important to know these basic biological data, as they are quite large shells and could be depleted before they are reproductively mature. Not that much is known about their ecology either, and for the most part this has been extrapolated from closely related shallow water species; it is assumed that they are predators/scavengers.



More info:

http://www.mollusca.co.nz/speciesdetail.php?speciesid=1121&species=Penion%20cuvierianus

Some 3d scans http://www.nzfauna.ac.nz/penionc

This fossil guide is available free online:

Beu AG, Maxwell PA 1990. Cenozoic Mollusca of New Zealand. New Zealand Geological Survey Paleontological Bulletin 58, 1990 ISSN 0114-2283

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