Watershed boundaries and geographic isolation: patterns of diversification in cutthroat trout from western North America

The cutthroat trout, Oncorhynchus clarkii (Richardson, 1836), is one of the most widely distributed species of freshwater fish in western North America. Occupying a diverse range of habitats, they exhibit significant phenotypic variability that is often recognized by intraspecific taxonomy. Recent molecular phylogenies have described phylogenetic diversification across cutthroat trout populations, but no study has provided a range-wide morphological comparison of taxonomic divisions. In this study, we used linear and geometric-based morphometrics to determine if phylogenetic and subspecies divisions correspond to morphological variation in cutthroat trout, using replicate populations from throughout the geographic range of the species. Our data indicate significant morphological divergence of intraspecific categories in some, but not all, cutthroat trout subspecies. We also compare morphological distance measures with distance measures of mtDNA sequence divergence. DNA sequence divergence was positively correlated with morphological distance measures, indicating that morphologically more similar subspecies have lower sequence divergence in comparison to morphologically distant subspecies. Given these results, integrating both approaches to describing intraspecific variation may be necessary for developing a comprehensive conservation plan in wide-ranging species.

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Evolution of archaeocyaths and palaeobiogeography of the Early Cambrian

Geological Magazine ◽

10.1017/s0016756800033471 ◽

1986 ◽

Vol 123 (4) ◽

pp. 377-385 ◽

Cited By ~ 30

Author(s):

Andrey Yu. Zhuravlev

Keyword(s):

North America ◽

North Africa ◽

Siberian Platform ◽

Western Europe ◽

Early Cambrian ◽

Western North America ◽

Geographic Isolation ◽

Taxonomic Rank ◽

Two Peaks

AbstractIn the Early Cambrian, there were two peaks of the increase in number of new archaeocyathan genera. These diversification bursts are, perhaps, related to significant changes in Early Cambrian palaeogeography. The first burst at the beginning of the Atdabanian was, perhaps, connected with the initiation of archaeocyathan expansion beyond the Siberian Platform. During the second half of the Atdabanian, closely related archaeocyathan assemblages were established from North Africa to Australia because neither climate, nor geographic isolation could have affected their differentiation in that time. At the end of the Atdabanian and the beginning of the Botomian the number of archaeocyathan genera again increased sharply, and isolated provinces were established. The American–Koryakiyan province was formed in western North America (from Alaska to Sonora) and included the Koryakiya, while the Afro–Siberian–Antarctic province probably extended from North Africa and Western Europe to Siberia, Australia, and Antarctica. The main difference between the regular archaeocyathan assemblages lies in what skeletal elements filled the intervallum. There was a certain stability in the distribution of skeletal elements of high taxonomic rank and an interchangeability of elements of low taxonomic rank.

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THE RUSTS OF ERIOGONUM, CHORIZANTHE, AND OXYTHECA

Canadian Journal of Botany ◽

10.1139/b66-127 ◽

1966 ◽

Vol 44 (9) ◽

pp. 1151-1170 ◽

Cited By ~ 4

Author(s):

D. B. O. Savile

Keyword(s):

British Columbia ◽

North America ◽

Host Plants ◽

Host Specialization ◽

Western North America ◽

Geographic Isolation ◽

The Past ◽

Species Groups

Uromyces intricatus is broken into six varieties. Var. umbellati and var. major attack montane and lowland species of Eriogonum subgen. Eueriogonum in much of western North America, and the former probably attacks Oxytheca. Vars. intricatus (Oregon, California), parvifolii (California), nivei (interior British Columbia to Arizona), and pluriporosus (mainly Montana, Wyoming, and Colorado) attack various species or species groups in Eriogonum subgen. Oregonium, the variation being partly geographic and partly due to host specialization. Var. intricatus attacks Chorizanthe spp. and Eriogonum subgen. Ganysma in California. This variety has met and intergraded with var. pluriporosus in the past but the link is now broken. Uromyces bisbyi, a microcyclic derivative of var. parvifolii, is described on Eriogonum parvifolium in California. The implications on the evolution of Eriogonum and the problem of realistic nomenclature of rusts derived from both host and geographic isolation are discussed. A table clarifies the nomenclature of reported host plants.

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