Gastrocopta contracta

Gastrocopta (Albinula) contracta (Say, 1822)
Bottleneck Snaggletooth

  • Pupa contracta Say 1822: 374.
  • Pupa deltostoma “Charpentier” Küster 1855 in 1841–1855: 181.
  • Bifidaria contracta climeana Vanatta 1912: 525, figs 1–3.
  • Gastrocopta (Albinula) contracta f. peninsularis Pilsbry 1916 in 1916–1918: 24, pl. 2, fig. 8.
  • Gastrocopta proarmifera A.B. Leonard 1946: 21, pl. 3, figs 3–5.
Gastrocopta contracta, Bruce Peninsula National Park, Ontario
Gastrocopta contracta, Bruce Peninsula National Park, Ontario.

Identification. Shell conic-ovate. Spire tall, conical, strongly tapering, sides slightly convex. Last whorl pinched at base; its last half straightened. Adult aperture rather small, triangular-subovate, crowded with folds. Apertural dentition parietal plica large, arched, not clearly bifid; columellar plica deeply placed, rather vertical, its upper end curving forward (a callus ridge in front); 2 palatal plicae with lower plica much larger and more deeply placed than upper, tubercular plica). Outer lip thin-edged, expanded, with a low rounded ridge behind. Umbilicus rimate. Protoconch smooth. Teleoconch sculpture irregular microscopic incremental, wrinkle-like threads, with a silky sheen. Colour translucent, waxy whitish (but often encrusted with debris). Height to 2.5 mm (higher than wide).

Recognized by the strongly conic spire and subtriangular aperture crowded with lamellae.

Habitat. Moist, shaded deciduous forests, alvars, rocky outcrops, sandy woods. In leaf litter, under dead wood, in crevices of rocks. Usually associated with limestone.

Canadian range. Southern Manitoba, through southern Ontario and north to Lake Nipissing; southwestern Quebec: Gatineau hills.

Etymology. Latin, contractus, “contracted”.

Remarks. Pilsbry (1948) recognized a southern subspecies, G. contracta climeana (Vanatta, 1912) but also noted that there are intermediates between it and typical G. contracta. Hubricht (1985) treated G. contracta climeana as a synonym although without explanation. No subspecies are currently recognized or used.

  • Hubricht L (1985) The distributions of the native land mollusks of the eastern United States. Fieldiana, Zoology (New Series) 24: i–viii, 1–191.
  • Küster HC (1841–1855) Die Gattungen Pupa, Megaspira, Balea und Tornatellina. Abbildungen nach der Natur mit Beschreibungen Systematisches Conchylien-Cabinet von Martini und Chemnitz (Ed. 2). Bauer & Raspe, Nürnberg, 194 pp., 121 pls.
  • Leonard AB (1946) Three new pupillids from the Lower Pleistocene of central and southwestern Kansas. The Nautilus 60: 20–24, pl. 23.
  • Pilsbry HA (1916–1918) Pupillidæ (Gastrocoptinæ). Manual of Conchology, Structural and Systematic with Illustrations of the Species. Second Series: Pulmonata 24: 1–112, pls 1–13 [1916]; 113–176, pls 14–29 [1917]; 177–256, pls 30–38 [1917]; 257–380, pls 39–49 [1918].
  • 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 (1822) Description of univalve terrestrial and fluviatile shells of the United States. Journal of the Academy of Natural Sciences of Philadelphia 2: 370–381.
  • Vanatta EG (1912) Mollusca of Arkansas, Louisiana and Mississippi. Proceedings of the Academy of Natural Sciences of Philadelphia 63: 525–532.