The California Transition Zone is a long area of coast from near Point Conception to San Diego, with specific phylogeographic breaks near Los Angeles and Monterey Bay. Point Conception provides a significant barrier to Oregonian and California faunas. Twenty-one species of Gastropoda, barnacles, and algae have their range limits at Point Conception. A later survey and summarization of forty-one coastal marine animals for phylogeographic patterns found twenty-four species with phylogeographic structure below the species level. Many California taxa have a close taxonomic relationship with Oregon taxa. Phylogeographic breaks are present along the coast for marine taxa particularly those that are poor dispersers. Drier, more seasonal climate about 14–11 Ma led to development of estuaries that were seasonally closed and led to low nucleotide and high haplotype diversity that reflect a rapid expansion of range. Life-history factors are important in phylogeographic patterns for species with low dispersers having strong genetic signatures.
Keywords: fish; colonization; freshwater fish; marine fish
Chapter. 4794 words. Illustrated.
Subjects: Conservation of the Environment (Social Science)
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