Zoogenetes harpa (Say, 1824)
Boreal Top
- Helix harpa Say 1824: 256, pl. 15, fig. 1.
- Pupa costulata Mighels 1844: 187.
Identification. Shell conic-ovate. Spire raised, conical. Whorls c. 4, convex. Suture deep. Periphery rounded. Aperture subrotund, edentulous. Lip thin, simple. Protoconch microscopically granular. Teleoconch with rather evenly, widely spaced, lamellar (periostracal) colabral ribs and irregular incremental striae. Ribs sometimes in part obsolete or unequal. Umbilicus tiny. Shell semitranslucent, with a silky lustre; brown. Height to 3.4 mm (higher than wide).
Animal grey with darker ocular tentacles and pale foot; mantle dark grey, speckled with white. Foot prominently crenulated. Large labial lobes present. Sensory tentacles nearly obsolete (Pilsbry 1948).
Habitat. Dry to mesic forests generally. Often on acidic soils. Sometimes in somewhat disturbed places such as roadsides, and rarely in drier parts of marshes. Often occurring in sporadic, discreet colonies but usually abundant within each colony. In leaf litter and under rocks and dead wood, including fallen branches and logs. During cool, wet weather, climbing vegetation and tree trunks.
Global range. Northern Europe through northern Asia. In North America, much of Canada and the northern USA south along the Rockies to Colorado.
Canadian range. Widespread across most of Canada: known from every province and territory except Nunavut. In British Columbia, absent along the coast. Seemingly rare in south-eastern BC, but rather common in the north-central interior. In Ontario, almost entirely absent from areas along the Great Lakes, but known south as far as the Bruce Peninsula, where it may be rare.
Remarks. Zoogenetes harpa is ovoviviparous; that is, the young hatch from their egg within the parent and emerge as fully developed snails. At birth, the young are as large as the aperture of the adult shell (Pilsbry 1895 [1893–1895]).
- Mighels H (1844) [Some specimens of shells, with descriptions]. Proceedings of the Boston Society of Natural History 1: 187–189.
- Pilsbry HA (1948) Land Mollusca of North America (north of Mexico), 2(2). The Academy of Natural Sciences of Philadelphia, Monographs 3: i–xlvii + 521–1113 pp.
- Say T (1824) Appendix. Part I. — Natural history. §1. In: Keating WH (Ed.) Narrative of an expedition to the Source of St Peter’s River, Lake Winnepeek, Lake of the Woods, &c &c performed in the year 1823, by order of the Hon JC Calhoun, Secretary of War, under the command of Stephen H Long, Major USTE Compiled from the notes of Major Long, Messrs Say, Keating, and Colhoun. H.C. Carey & I. Lea, Philadelphia, 253–378.