26 — Margin shells, Serrata fasciata

Serrata fasciata, Mt. Maunganui, 1980's.

These are margin shells (Family: Marginellidae). They are quite commonly found in the north of the north island, at and below low tide (down to ~20m) under rocks on moderately exposed shores. Even though they are common, they don’t often get seen because they’re only about 7mm in size. This particular species was, for many years called Marginella (Haloginella) mustelina, but recently it was found that its identity was unclear.

It turns out that there are two similar species, one endemic to Australia and the other New Zealand. For most of the last century the New Zealand species had been confused with the Australian one and as such they’d been called the same thing. The New Zealand species was called the same name as the Australian one—not sure if it was another piece of Australian cultural appropriation...

Anyway, in 2004 it was recognised (see the paper linked below) that these were in fact two separate species and the New Zealand one was given a new name: Serrata fasciata (Sowerby, 1846). By new name, it’s really an old name that wasn’t being used for anything anymore (it’s actually a wee bit more complicated than that). See the link below if you’d like to know more about the arcane ways in which animals get their their names changed. It's all to do with who did what first...


More info:

Marshall, B. A. (2004). New names for four common Marginellidae (Mollusca: Gastropoda) from northern New Zealand. Molluscan Research, 24, 7–20.

For more pictures: http://www.mollusca.co.nz/speciesdetail.php?speciesid=1221&species=Serrata%20fasciata