Erichsonius parcus (Horn, 1884)

Brunke, Adam J. & Marshall, Stephen A., 2011, Contributions to the faunistics and bionomics of Staphylinidae (Coleoptera) in northeastern North America: discoveries made through study of the University of Guelph Insect Collection, Ontario, Canada, ZooKeys 75, pp. 29-68 : 44

Erichsonius parcus (Horn, 1884)

Materials.

CANADA: ON: Kent Co., Rondeau Prov. Pk., spicebush trail, Carolinian forest, yellow pans, 25-V-2003, M. Buck and S. Paiero (1); Rondeau Prov. Pk., spicebush trail, Carolinian forest, yellow pans, 16 to 17-VI-2003, Buck and Carscadden (1); Wainfleet bog, 8km S of Welland, DIE pt. 1 -north ditch (control), 10 to 24-V-1988, A. Stirling (1); 7 to 13-VI-1988, all collected by A. Stirling: D2H pt. 2 - '1962 zone’ (1), D4H pt. 4 - '1980 zone’ (1), D5H pt. 5 - '1985 zone’ (1), D5E pt. 5 - '1985 zone’ (1).

Diagnosis.

Erichsonius parcus can be easily distinguished from other northeastern species of the genus with a sparsely punctate forebody, with the exception of Erichsonius pusio , by its small size (<3.6mm from clypeus to abdominal apex). Frank (1975) stated that Erichsonius parcus could be separated from Erichsonius pusio by the paler coloration, the smaller eyes and the head broader behind the eyes. Head shape was found to be highly variable in both males and females of Erichsonius parcus and this character should not be used to identify this species. However, the length of the pronotum appears to be a reliable character and is subequal to that of the elytra in Erichsonius parcus (Fig. 9) and clearly shorter in Erichsonius pusio . It should also be noted that the parameres of the aedeagus in Erichsonius parcus possess characteristic short, stout setae (Fig. 19) which were not illustrated by Frank (1975) but mentioned later in Frank (1981a). Erichsonius pusio lacks these setae on the parameres.

This species was previously known from Florida (Frank 1981), District of Columbia, Massachusetts, Louisiana, Virginia ( Frank 1975), and New Hampshire ( Chandler 2001). Herein we record it as new from Canada (Ontario) based on eight specimens, all collected in the Carolinian region of southern Ontario (Map 23). Erichsonius parcus has previously been collected by ‘sifting’, in ‘drift’ ( Frank 1975) and at lights ( Frank 1981a); all Canadian specimens were collected in wet habitats with abundant moss (bog, slough forest). In a survey of southern Ontario peatlands, Blades and Marshall (1994) reported Erichsonius pusio from Wainfleet bog based on a series of specimens found by the first author to be misidentified Erichsonius parcus . To our knowledge, no true Erichsonius pusio have been found in southern Ontario peatlands.