Nearctic Region

Nearctic Region

 

a zoogeographic region of dry land that is considered by many zoogeographers to be a division of the Holarctic region. The Nearctic Region covers the continent of North America, including the Mexican Plateau, as well as the Aleutian Islands, the Canadian Arctic Archipelago, Greenland, and Newfoundland. The fauna in the northernmost parts is similar to that of the Palearctic division of the Holarctic region. This similarity may be explained by the repeated, prolonged unions of North America and Northeastern Asia in the region of what is now the Bering Sea, which made possible a broad exchange of species.

The Nearctic Region is divided into four subregions: the Arctic, Circumboreal, Western American, and Eastern American. The first two are common to the Palearctic; the last two are often united in the Sonoran subregion. The American portion of the Circumboreal subregion is sometimes regarded as the independent Canadian subregion.

References in periodicals archive ?
A catalogue of the blood-sucking fly family Tabanidae (horseflies and deerflies) of the Nearctic region north of Mexico.
Alarie Y and Roughley RE: Predaceous diving beetles (Coleoptera: Dytiscidae) of the Nearctic Region, with emphasis on the fauna of Canada and Alaska.
Predaceous diving beetles (Coleoptera: Dydscidae of the Nearctic region, with emphasis on the fauna of Canada and Alaska (D.
230-232, in Predaceous diving beetles (Coleoptera: Dytiscidae) of the Nearctic region, with emphasis on the fauna of Canada and Alaska (D.
occur in the Nearctic region (Cokendolpher 1989) and show a great karyotypic uniformity in relation to diploid number (2n = 15), metacentric chromosome morphology, and X/XX sex determination chromosome system type.
The distribution pattern suggests five derivations of taxa in the Nearctic Region and five derivations of taxa in the Palearctic Region.
Larson DL, Alarie Y and Roughley RE: Predaceous diving beetles (Coleoptera: Dytiscidae) of the Nearctic Region, with emphasis on the fauna of Canada and Alaska.
The Nearctic Region taxa were listed by Griffiths (1991) and the Palaearctic species by Dely-Draskovits (1993).
Larson DL, Alarie Y, and Roughley RE: Predaceous diving beetles (Coleoptera: Dytiscidae) of the Nearctic Region, with emphasis on the fauna of Canada and Alaska.
The genus Apostenus is newly recorded from the Nearctic region and a new species, Apostenus californicus, is described from California.