The utility of chemical signals as phylogenetic characters: an example from the Felidae

Chemical secretions that are explicitly tied to species recognition may potentially be informative for phylogenetic reconstruction, especially when traditional morphological or molecular characters lack resolution. Anal sac secretions from 16 species within the family Felidae (order Carnivora) were chemically analysed and their utility as phylogenetic characters was assessed. Results were generally consistent across the different chemical data types (e.g. glycolipids, neutral lipids, or phospholipids). Two major clades were indicated, falling out according to body size: one for species greater than 30 kg (Panthera, Uncia, and Puma) and another for those less than 12 kg (remaining species). The primary solutions agreed with respect to the species pairs Prionailurus + Leptailurus, Caracal + Lynx, Oncifelis + Leopardus, Otocolobus + Felis, Panthera leo + P. pardus, and P. tigris + Uncia. The only area of disagreement between chemical types was the positioning of the mountain lion (Puma concolor); however, this species appears to cluster with the cheetah (Acinonyx jubatus) in the 'big cat' clade. Although our solutions differ from six previously proposed hypotheses of felid phylogeny (morphological and molecular), the previous estimates all differ strongly amongst themselves reflecting the historical uncertainty regarding felid systematics. Phylogenies derived from the lipid data were very robust and decisive. Few equally most parsimonious trees were obtained, consistency indices were much higher than their expected values, and bootstrap and Bremer support values were also high. Thus, our findings illustrate the species-specific nature of chemical signals and their usefulness as phylogenetic characters. (C) 2001 The Linnean Society of London.