Strobilops aeneus in Canada

New publication on a rare species

In a recent publication in Check List, two new records of the small and rare land snail, Strobilops aeneus we (Mike Oldham and myself) recorded from Ontario. Here’s the background on the circumstances that lead to the publication.

Strobilops aeneus

Strobilops aeneus

In the fall of 2012, I travelled to Ottawa (and Gatineau) to study the Canadian Museum of Nature’s (CMN) mollusc collection, having received a research grant from the Malacological Society of London. I had arranged for 10 days at the CMN, so my time spanned a weekend during which I had no access to the museum. This weekend, as well as some evenings during the week, gave me an excellent opportunity to do some fieldwork around Ottawa, both on the Ontario and Québec sides of the Ottawa River (rivière des Outaouais). Twenty sites were visited, some more extensively collected than others.

Among the groups of snails that were found were Strobilops spp. This genus fascinates me because there is nothing like it out here in the West, and indeed, there’s nothing else like it in the east either. Strobilops belongs to the family Strobilopsidae and is orthurethran (related to such taxa Pupillidae, Valloniidae, and others). Strobilops has remarkably completely formed internal “barriers” inside their shells. What’s different about this group from other small native North American orthurethran land snails is that these barriers are present in immature shells as well. (I can only think of one snail in Canada, Lauria cylindracea, with internal “barriers” in immature shells, but it isn’t native.

Anyway, among the twenty sites visited was Morris Island Conservation Area, on the shore of the Ottawa River, north of Ottawa. There, a single specimen of Strobilops aeneus was found that prompted me to investigate the the species’ occurrence in Canada. My new record, as well as a collection made by Mike Oldham in southwestern Ontario, are the only records for this species from Ontario since 1941!

We also investigated claims that the species was found in Nova Scotia and cave infill in Québec. While we couldn’t confirm the Québec record, we did find that the Nova Scotia record was based on a specimen of Strobilops labyrinthicus.

Further reading …

  • Forsyth, R. G., & M. J. Oldham. 2014. Distribution of Strobilops aeneus Pilsbry, 1926, in Canada, with two new Ontario records (Mollusca: Gastropoda: Strobilopsidae). Check List 10 (2): 397–401. → DOI:

My attempt to find this species again at the site in Ottawa failed. I’ve just looked at my samples of Strobilops collected there in September 2014 and all are S. labyrinthicus.

19 September 2014