Grammia nevadensis nevadensis ( Grote & Robinson, 1866 )

Ferguson, Douglas C. & Schmidt, Christian, 2007, Taxonomic review of the Grammia nevadensis species group (Lepidoptera: Arctiidae) with descriptions of`two new species, Zootaxa 1405, pp. 39-49 : 40-41

Grammia nevadensis nevadensis ( Grote & Robinson, 1866)

( Fig. 1 a)

Grammia nevadensis was described from Nevada, and the accompanying illustration in the original description ( Grote & Robinson 1866) shows the phenotype typical of the Great Basin region of the western United States, the thorax being entirely dark and with reduced marginal and submarginal hindwing markings. Subspecies nevadensis is generally smaller and paler than other G. nevadensis subspecies, with a whitish­pink hindwing and often with entirely dark­brown thoracic vestiture. It occurs throughout the Great Basin region, from southeastern Oregon and southern Idaho through Nevada and Utah to southern California. We have not seen specimens from northwestern Arizona, but it almost certainly occurs there, with the nearest records from Kanab, Utah. Some populations from north­central Oregon (Madras, Umatilla, John Day River) exhibit variation from superba to nevadensis phenotypes, and populations in northwestern Colorado (Moffat Co.) exhibit similar variation from nevadensis to superba and gibsoni phenotypes, including individuals intermediate between all­dark and striped thoracic vestiture, wherein the whithish stripes are darkened considerably. We interpret this variation as gradation into subspecies superba and gibsoni , respectively.

Grammia nevadensis superba (Stretch, 1874) revised status ( Figs. 1 b, 3)

Although true G. nevadensis superba occurs primarily in the Pacific Northwest (Type locality: Vancouver Island, British Columbia; type in AMNH), superba or superba ­like phenotypes occur in an extremely variable population of G. nevadensis in Moffat Co., northwestern Colorado. Two such males from Echo Park, Dinosaur National Monument, Moffat Co., taken 18 August 1993, were initially thought to be bowmani ; rather, it is evident from a long series taken in Moffat Co. by Andrew Warren (9 mi. north of junction of County Rd. 10 & Hwy. 318, 31 Aug–1 Sept. 1991) that specimens range from those with narrow forewing bands and saturated hindwing colours (superba) to the broad­banded forms with pinkish­white, washed­out hindwings typical of the Great Basin ( G. n. nevadensis ). This may represent the southern end of superba’s distribution, which extends irregularly northward in suitable habitats through western Montana (Polson, Missoula), Idaho, northeast Oregon and Washington to central British Columbia and western Alberta. Specimens from central and north­central Oregon (Madras, Umatilla, John Day River) are on average intermediate between superba and nevadensis . Populations in the Yukon appear to be an undescribed, disjunct species or subspecies, superficially most similar to G. n. superba (reported as Grammia geneura in Lafontaine & Wood 1997).

Figures

FIGURE 1. Adult males of the Grammia nevadensis species group, a) G. n. nevadensis (Winnemuca, Humboldt Co., NV); b) G. n. superba (Victoria, Vancouver Is., BC); c) G. n. geneura (Estes Park, Larimer Co., CO); d) G. n. gibsoni (Burstall dunes, SK); e) G. behrii (Eight Dollar Mtn., Josephine Co., OR); f) G. i n c o r r u p t a (Comanche Natl. Grassland, Baca Co., CO); g) G. williamsii (Jenner, AB); h) G. eureka (HOLOTYPE, Eureka, Juab Co., UT); i) G. bowmani (PARATYPE, Black Ridge, Mesa Co., CO).