Category Archives: Mollusca

An invasive semi-slug

Not a Canadian species, Parmarion martinsi Simroth, 1893 is an invasive semi-slug in Hawaii. I photographed these individuals in January on the undersides of woody debris at Puu Kukae (a cinder-cone hill) in Puna District, Hawaii Co., Hawaii.

Parmarion martinsi, Puu Kukae, Puna District, Hawaii Co., Hawaii, USA. 30 January 2017.

This semi-slug (that is, midway in body form between a slug and a snail) is likely native to Southeast Asia, according to a paper that I found on the internet (Hollingsworth et al. 2007). First noticed on Oahu in 1996, it was found the Puna District in 2005. Apparently it is also in Kailua-Kona.

Parmarion martinsi is also a vector for Rat Lung Worm (more here).

Reference:

  • Hollingsworth, R.G., R. Kaneta, J.J. Sullivan, H.S. Bishop, Y. Qvarnstrom, A.J. da Silva & D.G. Robinson. Distribution of Parmarion cf. martensi (Pulmonata: Helicarionidae), a new semi-slug pest on Hawai‘i island, and Its potential as a vector for human Angiostrongyliasis. 2007. Pacific Science 61(4): 457–467.

Gastrocopta contracta

Gastrocopta contracta, Bruce Peninsula National Park, Ontario

Gastrocopta contracta, Bruce Peninsula National Park, Ontario. Shell 2.7 mm.

I have to admit a fasciation with the Gastrocopta, a.k.a. “Snaggletooths”. The genus seems so foreign to me, and in a way it is. Here in British Columbia, there seems to be just one species, G. holzingeri, and it is rare! The pattern in Canada is that Ontario has the most Gastrocopta species (seconded by Quebec), with decreasing numbers of species east and west of Central Canada.

Seen here is Gastrocopta contracta, the Bottleneck Snaggletooth, known from Manitoba to at least western Quebec. Insofar as Gastrocopta go, this species is very distinctive. The conical spire and narrowed last whorl that is produced into a projecting, vaguely triangular aperture are diagnostic. The “folds” (aka, plicae, lamellae, denticles, etc. … whatever terminology you use) within the aperture give the appearance of almost blocking the opening, and hence the name.

The pale colour of Gastrocopta shells is so not widespread in Canadian micro-snails (in older literature: having the colour of “spermaceti” — a waxy substance in the head of whales according to Wikipedia),*  But, shells of this and other species often are plastered with dirt and debris, making them almost unrecognizable as snails, such as the well-camouflaged G. tappaniana in a photo in a previous post.

*This is a case where old descriptions use terminology that no longer has as much meaning as it once did, since when was the time you came across a jar (did it come in jars?) of spermaceti to compare with snails’ colour?

Oxychilus draparnaudi

Dark-bodied Glass-snail

Oxychilus draparnaudi, Ottawa, 2016

Oxychilus draparnaudi, Ottawa, 2016.

The somewhat unimaginatively named Dark-bodied Glass-snail — “Inky Blue Glass-snail” might have been better — is one of three species of terrestrial snail belonging to the genus Oxychilus in Canada. (Oxychilus alliarius and O. cellarius are the others.) Among these three species, this one is perhaps the most widely distributed, having been reported from Atlantic and Central Canada, as well as British Columbia. Many unpublished records exist in collections.

This photo was taken in an urban “wasteland” ravine in Ottawa in 2016.

Previous photos of this species are here  and here.