Intercontinental disjunctions between eastern Asia and western North America in vascular plants highlight the biogeographic importance of the Bering land bridge from late Cretaceous to Neogene

2016 ◽  
Vol 54 (5) ◽  
pp. 469-490 ◽  
Author(s):  
Jun Wen ◽  
Ze-Long Nie ◽  
Stefanie M. Ickert-Bond
1982 ◽  
Vol 60 (7) ◽  
pp. 1517-1527 ◽  
Author(s):  
Stewart B. Peck

Leptinus beetles are facultative ectoparasites known to occur on 18 species of small mammals in North America. Leptinus americanus is restricted to the central United States, west of the Mississippi River. Its hosts and seasonality are unknown. Leptinus orientamericanus n.sp. is widespread east of the Mississippi River. It occurs on seven hosts, most frequently on Blarina brevicauda and Scalopus aquaticus and during fall and winter months. Leptinus occidentamericanus n.sp. has a range in western North America from California to Alaska and the Yukon. It occurs on 11 hosts, most frequently on Sorex trowbridgii, and during spring and fall months. A hypothesis of evolution is given for all nine species in the genus. It suggests a Palaearctic origin for the family and genus and an early Tertiary entry to North America by a Bering land bridge.


Zootaxa ◽  
2009 ◽  
Vol 2166 (1) ◽  
pp. 57-68 ◽  
Author(s):  
HIROMI NIITSUMA ◽  
CHARLES N. WATSON JR.

The genus Bilyjomyia is erected for Apsectrotanypus algens (Coquillett, 1902) from western North America and B. fontana n. sp. from Japan. A generic diagnosis and a description are given for all life stages. Bilyjomyia algens is redescribed. All life stages of Bilyjomyia fontana are described and figured. The new genus shows affinities to Macropelopia Thienemann and Bethbilbeckia Fittkau et Murray in the immature stages. Bilyjomyia can be distinguished from all other known Macropelopiini by the following features: the reduced setation of T.IX and the restriction of these setae to the tergal posterior edge in the adult male; the aeropyles of the thoracic horn in the pupa; the labral sclerite and the position and form of the ventral cephalic setae in the larva. The distribution of Bilyjomyia indicates dispersal across the Bering Land Bridge, a pattern known in some other genera of Chironomidae and other orders of insects.


2018 ◽  
Author(s):  
S. Augusta Maccracken ◽  
◽  
Ian M. Miller ◽  
Conrad C. Labandeira

1964 ◽  
Vol 29 (3) ◽  
pp. 338-344 ◽  
Author(s):  
Edwin N. Wilmsen

AbstractTwo sites, Kogruk (at the summit of Anaktuvuk Pass, Alaska) and Engigstciak (at the head of the Firth River delta, Yukon Territory, Canada), have recently yielded flake-tool assemblages which show striking resemblances to a Eurasiatic flake-blade tradition based on a Levallois-Mousterian stone-chipping technique, and to the Clovis flake-blade tradition of America which appears to be based on a similar chipping technique. It is suggested that these traditions are historically related and that the Arctic sites provide a possible link between the two. The presence of incipient fluting in Siberia and at Engigstciak may prove significant. Dating is discussed in terms of the ecology and geology of the sites and is correlated with the probable periods of availability of the Bering land bridge. An upland-foothills zone is seen to be essentially continuous from central Asia to central North America. It is suggested that this zone provided the only environmentally compatible link between the two continents, and that it was therefore the most probable route of early hunting peoples into the New World.


1974 ◽  
Vol 106 (11) ◽  
pp. 1121-1131 ◽  
Author(s):  
Horne R. Wong

AbstractThis study identifies and presents a key to five strains of the larch sawfly, Pristiphora erichsonii (Hartig), which are designated Aweme, Fernie, Ambleside, Thirlmire, and Salzburg.Aweme and Fernie strains occur only in North America and Salzburg strain is confined to Eurasia. Two Eurasian strains, Ambleside and Thirlmire, were accidentally introduced into Canada from England by 1913 among cocoons shipped for the release of the parasite Mesoleius tenthredinis Morley. It is postulated that the ancestors of Aweme-Salzburg strains Fernie–Thirlmire strains dispersed across the Bering Land Bridge into North America some time in the Miocene. These phyletic lines evolved into distinct Eurasian and North American strains. Early infestations in North America apparently consisted of North American strains, while later outbreaks have consisted primarily of the recently introduced Eurasian strains.


1976 ◽  
Vol 54 (16) ◽  
pp. 1911-1925 ◽  
Author(s):  
C. Puff

By using morphology, karyology, pollen size, leaf flavonoids, ecological observations, and modification experiments, a new classification of the Galium trifidum group is proposed. Nine taxa in five species are recognized: (1) G. tinctorium, with ssp. tinctorium and sap. floridanum (new comb.) in eastern North America; (2) G. brevipes, a rare species centered in the Great Lakes region; (3) G. trifidum, with ssp. trifidum in northern North America. Asia, and Europe, ssp. columbianum (new comb.) in (north)western North America and (north)eastern Asia, and ssp. subbiflorum (new comb.) and ssp. halophilum (new comb.) in northern North America; (4) G. innocuum in southeastern Asia; (5) G. karakulense in central Asia.New chromosome counts of n = 12 and 2n = 24 are reported for G. tinctorium ssp. tinctorium and ssp. floridanum; and G. trifidum ssp. trifidum, ssp. columbianum, and ssp. subbiflorum.


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