Vertigo andrusiana

Vertigo (Boreovertigo) andrusiana Pilsbry, 1899
Columbian Vertigo

  • Vertigo columbiana Sterki 1892b: 5, nomen nudum.
  • Pupa columbiana “Sterki” Pilsbry 1898 (1897–1898): 119, nomen nudum.
  • Vertigo andrusiana Pilsbry 1899: 315, fig. 3.
  • Vertigo columbiana Pilsbry & Vanatta 1900: 602, pl. 23, fig. 11.
Vertigo andrusiana; Willow Lake, Bulkley Ranges, Hazelton Mountains, BC (RGF 10.100.3258).

Identification. Shell minute, subovate-cylindrical. Suture shallow. Surface relatively smooth, or with colabral striae scattered, blunt, and irregular. Aperture subovate, slightly more flared below, with 4 (occasionally 5) lamellae in adults: 1 long parietal, sometimes a weak angular, 1 peg-like columellar, 2 palatals, sometimes a weak basal. Palatal lip slightly expanded, with without indentation but flattened. Palatal callus none, rarely weakly developed. Palatal depression weak to modest. Sinulus absent to weak. Crest weakly to strongly developed. Shell straw-yellow-brown or reddish-brown, shiny to glassy. Height to 1.7–2.4 mm.

Habitat. In forests or in swamp forests and willow-dominated wetlands (Nekola et al. 2018). In leaf litter, on dead wood, and sometimes climbing vegetation, such as Sword Ferns (Polystichum munitum) .

Canadian range. British Columbia: along the whole coast, but also in the Interior Wet Belt of south-eastern BC.

Etymology. Named after Fred Andrus, an early Oregon conchologist and naturalist (Pilsbry 1948).

Remarks. Nekola et al. (2018) synonymized V. columbiana and V. andrusiana but used V. columbiana Sterki, 1892 for this species’ name. However, V. columbiana Sterki (1892) and Pupa columbiana Pilsbry (1898 [1897–1898]) are nomina nuda and columbiana was only made available by Pilsbry & Vanatta (1900). The earliest available name is V. andrusiana Pilsbry, 1899, which has precedence over V. columbiana Pilsbry & Vanatta, 1900.

In addition to the nominotypical subspecies, Pilsbry (1948) recognized V. andrusiana sanbernardinensis Pilsbry, 1919. Roth & Sadeghian (2003) continued to recognize this taxon as a subspecies, but Nekola et al. (2018) considered it to be small or immature Vertigo occidentalis Sterki, 1907. Thus, no subspecies are recognized here, as occidentalis represents another species altogether and andrusiana and columbiana ecological variants, with the andrusiana form from wetter habitats (Nekola et al. 2018).