β-Phocacholic Acid in Bile; Biochemical Evidence That the Flamingo Is Related to an Ancient Goose

The biliary bile acid composition of 10 anseriform and three flamingo species was determined using a variety of chromatographic techniques. Some bile samples contained an unusual 23-hydroxylated derivative of chenodeoxycholic acid, (23R)-3α, 7α,23-trihydroxy-5β-cholan-24-oic acid (β-phocacholic acid). The proportion of this unusual bile acid correlated highly with the order of evolutionary appearance. β-Phocacholic acid was found to constitute a major proportion of biliary bile acids in three flamingo species. The bile acid spectra present in these flamingos were similar to those of several ducks from the subfamily Anatinae; those of the Greater Flamingo (Phoenicopterus ruber) were virtually identical to those of the Nene or Hawaiian Goose (Branta sandvicensis). It is suggested that the common presence of a new biochemical character, β-phocacholic acid, in both ducks (Anatinae) and flamingos (Phoenicopteridae) provides evidence for a close evolutionary link between these bird families.