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Variability and phylogenetic significance of detachable nodes in feathers of tinamous, galliforms and turacos
Author(s) -
Brom Tim G.
Publication year - 1991
Publication title -
journal of zoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.915
H-Index - 96
eISSN - 1469-7998
pISSN - 0952-8369
DOI - 10.1111/j.1469-7998.1991.tb04327.x
Subject(s) - synapomorphy , biology , feather , phylogenetic tree , evolutionary biology , zoology , clade , genetics , gene
The occurrence of detachable nodal structures in the downy barbules of many birds was studied with light‐ and scanning electron microscopy. Anuli are the only type of nodal structure that may break loose and slide along the barbules to form dual or multiple nodes. Considerable variation exists in the occurrence of this feature. Multiple nodes are more frequently present in tail‐coverts than in breast feathers. This is the first report of the presence of detachable anuli in feathers of Cracidae, Numididae and Musophagidae. The suggestion by earlier workers that these structures are characteristic for all galliforms is not confirmed, since megapodes never show detached nodes. The downy barbules of Afropavo resemble those of other phasianids in all respects, while those of Opisthocomus are strikingly different from both galliforms and cuckoos. Outgroup comparison indicates that multiple nodes may be synapomorphic for Tinamidae, Cracidae, Tetraonidae, Phasianidae, Numididae, Meleagridae and Musophagidae together, but, considering the incongruence of this hypothesis with recently proposed phylogenies, alternative explanations for the structural similarities between the downy barbules of tinamous, turacos and galliforms are discussed.