14 — Jeaking's siphon whelk, Penion cuvierianus jeakingsi

Penion cuvierianus jeakingsi, Nelson area, 1960's.
The shell is about 150 mm.

Penion cuvierianus jeakingsi, Nelson area, 1960's.
The wee holes in the shell are caused by burrowing
tube worms.

Penion cuvierianus jeakingsi (Powell, 1947) is another seashell endemic to offshore New Zealand (and one not often seen). Virtually nothing is known about the ecology of this form. It is the southern sub species of P. cuvierianus, although there is some argument to whether this is in fact different enough from the northern species to warrant being called something else. However, there are some points that suggest a separation might be justified.

Penions (Family: Buccindae) are direct developers—they lay eggs and a small snail hatches out and crawls away. So, since there isn’t a pelagic larval dispersal phase it is possible for populations to become isolated and genetically separated over time. The type locality for P. c. jeakingsi is the Nelson area, which is a long way from where the typical species is found. This suggests that there is already a discontinuity in their relative distributions (allopatry). Another supporting point is that major New Zealand oceanic currents also separate these two forms.

Genetic analysis will be the key here and I believe scientists at the Museum of New Zealand Te Papa Tongarewa in Wellington are currently undertaking research on this family. It may turn out to be that these two populations have been separated long enough for them to be different species.

More info:

http://www.mollusca.co.nz/speciesdetail.php?speciesid=1122&species=Penion%20cuvierianus%20jeakingsi