Striatura milium

Striatura (Striatura) milium (Morse, 1859)
Fine-ribbed Striate

  • Helix milium Morse 1859: 28.

Striatura milium, Prince Edward Island.

Identification. Shell subdiscoidal, with low, domed spire. Whorls ca 3, convex. Suture deep. Periphery medial, rounded. Aperture subrotund, edentulous. Lip thin, simple. Whorls ca 2½, last slightly descending in adults. Periphery rounded, medial. Width of last whorl ca 2× penultimate whorl. Protoconch initially smooth, then with close, weak, microscopic spiral threads. Teleoconch with round-topped, close colabral riblets (spaces between riblets about equal to width of riblets), weak spiral threads throughout, including on base. Umbilicus ca ⅓ of shell width. Shell thin, glossy, pale yellow-grey. Shell width to 1.5 mm (wider than high).

Animal white, with head and tentacles darker.

Habitat. In forests; in moist leaf litter and under woody debris.

Global range. North-eastern USA from Maine to Minnesota and South Dakota in the west, and south to Louisiana (Hubricht 1985, Anderson 2005, NatureServe 2021); southern Canada from Manitoba east.

Canadian range. Manitoba to Newfoundland. In Ontario, north to Thunder Bay and Cochrane Districts (Oughton 1948).

Etymology. Latin, milium, millet. Likely a reference to the small size.

References

  • Anderson TK (2005) Land snail diversity in Wind Cave National Park, South Dakota. Western North American Naturalist 65: 186–195.
  • Hubricht L (1985) The distributions of the native land mollusks of the eastern United States. Fieldiana, Zoology (New Series) 24: i–viii, 1–191.
  • Morse ES (1859) Helix milium Morse. Proceedings of the Boston Society of Natural History 6: 28–29.
  • Oughton J (1948) A zoogeographical study of the land snails of Ontario. University of Toronto Studies, Biological Series 57: xii + 126 + [5] pp.