105 — Spotted whelk, Cominella maculosa

Cominella maculosa, low tide at Devonport,
Auckland 2015.

Cominella maculosa, Sumner, Christchurch, 1993.

The spotted whelk, Cominella maculosa * is another small to middle-sized snail (~45mm) endemic to New Zealand. It's very similar to it's near relative the speckled whelk (C. adspersa). However, spotted whelks have a slightly different distribution, tending to occur in shallower, more sheltered waters and harder substrates. They are found throughout North Island and down to at least Christchurch in the south. South Island forms are smaller and more compact than those from the north.

These two Cominella species are thought to be predator/scavengers and can often be found around carrion. Graham (1941) reported C. maculosa as feeding on the rock oyster **  and cockle *** in Manukau Harbour. However, those observations were published before the advent of the Pacific oyster #, which now dominates much of that habitat. It would be interesting to find out if C. maculosa preys on the Pacific oyster.


* (Martyn, 1784)
** Saccostraea glomerata (Gould, 1850)
*** Austrovenus stutchburyi (Wood, 1828)
# Crassostraea gigas (Thunberg, 1793)



More info:

http://www.mollusca.co.nz/speciesdetail.php?speciesid=1088&species=Cominella%20maculosa

Donald K. M. , Winter, D. J., Ashcroft, A. L., Spencer, H. G. 2015. Phylogeography of the whelk genus Cominella (Gastropoda: Buccinidae) suggests long-distance counter-current dispersal of a direct developer. Biological Journal of the Linnean Society, 115, 315–332.

Graham DH 1942. Breeding habits of twenty-two species of marine Mollusca. Transactions and Proceedings of the Royal Society of New Zealand, 71, 152–159.