| The mitochondrial DNA cytochrome b gene (1,045 bp) and ATPase 6 gene (600 bp) were sequenced to characterize molecular evolution and phylogenetic relationships among 22 species of calidridine sandpipers. The evolution of cytochrome b in sandpipers is comparable to that in other birds, and both transitions and transversions are potentially phylogenetically informative. For the faster-evolving ATPase 6 sequences, however, transitions in particular are more prone to saturation, and thus phylogenetic analyses were restricted to transversions only.;Phylogenetic relationships among species were estimated on the combined sequences using maximum likelihood and using weighted (5:1) parsimony to accentuate the phylogenetic information in transversions relative to transitions. The highest likelihood value was obtained for a tree in which rates of evolution at each of the three codon positions was specified, and this was the preferred maximum likelihood tree. Weighted parsimony analyses were performed with the two species of turnstones as outgroups, as they were shown to be sister species to the calidridines. The weighted parsimony and maximum likelihood trees contain the same basic phylogenetic relationships, and establish that the sandpipers are monophyletic. The major differences between the trees involve the relationships of T. subruficollis, C. alba, C. melanotos and C. bairdii with the other species. Under the proposed phylogenetic classification, all species in this monophyletic group should be merged as Calidris.;The phylogenetic comparative method was used to examine the evolution of mating systems and parental care in sandpipers by optimizing characters on the preferred molecular trees. Most mating systems have evolved independently several times. In sandpipers, uniparental care was derived from biparental care. An increase in female parental care provided the opportunity for a loss of male parental care, and may be critical in the evolution of polygynous and promiscuous mating systems. |
