On the use of integumentary characters in bird phylogeny: the case of Tinamus osgoodi (Palaeognathae: Tinamidae) and plumage character coding

Abstract

Integumentary characters have rarely been included in Systematic Ornithology in spite of the fact that most characters used to differentiate species are of plumage, ramphoteca (corneous sheath of the bill and nares) and podoteca (horny scales of the legs), and many such characters contribute to higher-order groupings of traditional diagnosis. Several recent studies have used integumentary characters in a cladistic context, particularly a comprehensive phylogeny of tinamous that included the 9 genera, all 47 currently recognized species, and some distinct subspecies. Here we re-evaluate the position in that phylogeny of the uniformly dark species Tinamus osgoodi. This forest tinamou was recovered in the previous analysis as closely related to species of Crypturellus that also exhibited dark plumage coloration. All these species are possibly melanic, or alternatively, exhibit a plumage coloration pattern af fecting many pterylae at once. We discuss the nonindependence of some plumage characters of tinamous, and re-analize the integumentary data set by re-coding these characters for the dark species. Using implied-weights for phylogeny reconstruction, we recover most of the expected groupings, including Tinamus osgoodi as one member of its genus. Interestingly this position did not influence the dark Crypturellus species, which could have been affected by the same coding scheme but instead grouped together with their congeners, indicating that interaction with other characters played a crucial role in the recovery of these taxa in their respective genera. Finally, we comment on the usefulness of integumentary characters and the incidence of their coding in Systematic Ornithology.