Strobilops affinis

Strobilops (Strobilops) affinis Pilsbry, 1893
Eightfold Pinecone

  • Strobilops affinis Pilsbry 1893: 57.
Strobilops affinis; 0.5 mile east of Nancy Lake, King Township, York County, Ontario; leg. John Oughton, 20 May 1940; diameter 2.8 mm (ROM Invertebrate Zoology M6446).

Identification. Shell conical, with old fashioned beehive-shaped spire with convex sides. Whorls 6. Spire whorls not very convex. Suture shallow Periphery bluntly, weakly angular. Protoconch smooth. Teleoconch with strong, curved colabral riblets, mostly absent on base; weak growth lines on base. Aperture subovate. Spiral lamellae, mostly internal in last whorl: 1 large and 2 smaller parietal lamellae; usually ca 8 basal and palatal lamellae. Lip in adults thickened, expanded. Base rather flattened. Umbilicus small, ca 1/7 of shell width. Shell translucent, brown; lip opaque, pale pinkish brown. Width to 2.9 mm (higher than wide).

Animal presumably like other species of Strobilops.

Habitat. Rich, mature forests. In leaf litter, on dead wood, and under bark of old logs. Sympatric with S. labyrinthicus.

Global range. Ontario and possibly Manitoba; in the USA Massachusetts to Minnesota and Kansas, south to New Jersey, west of the Alleghany Mountains to northern Alabama and Oklahoma (Pilsbry 1948).

Canadian range. Southern Ontario: only known from a few places in a narrow region mostly bordering on the lower Great Lakes, from Essex Count northeast to the Ottawa region. Rare. Records from Fort Francis, Rainy River District and Manitoba (Mozley 1927, 1930) need confirmation.

Etymology. Latin, affinis, “allied” or “related”.