. Bulletin of the British Ornithologists' Club. Birds. R. M. Zink 103 Bull. 1997 117(2) P. unalaschcensis. P. schistacea P. megarhyncha Figure 1. Approximate breeding distribution of four phylogenetic species of the Fox Sparrow Passerella iliaca. Phylogenetic tree derived from pattern of restriction sites (Zink 1994). distributions ( gene genealogies) results in more, not less, inclusive groupings of individuals. The mistaken belief that advocates of a phylogenetic species concept rely on single characters to delimit species has misled several authors ( Amadon & Short 1992).
. Bulletin of the British Ornithologists' Club. Birds. R. M. Zink 103 Bull. 1997 117(2) P. unalaschcensis. P. schistacea P. megarhyncha Figure 1. Approximate breeding distribution of four phylogenetic species of the Fox Sparrow Passerella iliaca. Phylogenetic tree derived from pattern of restriction sites (Zink 1994). distributions ( gene genealogies) results in more, not less, inclusive groupings of individuals. The mistaken belief that advocates of a phylogenetic species concept rely on single characters to delimit species has misled several authors ( Amadon & Short 1992). Put another way, a problem with avian subspecies is that they are often based on single characters, and analysis of other characters can suggest different subspecific limits (see below). No taxonomic category, species or otherwise, will likely be based on single characters (Barrowclough 1982). Differences between biological and phylogenetic species concepts are illustrated by studies of the Fox Sparrow Passerella iliaca. In North America, Fox Sparrows range over the taiga, northwest coast, and mountainous regions of the west (Fig. 1). There is considerable phenotypic variation, partitioned by taxonomists into 18 subspecies. However, four basic groups exist: iliaca, unalaschcensis, megarhyncha, and schistacea. Each of the four groups was originally recognized as a separate species. The Fox Sparrow is currently considered a single biological species because each group is known to hybridize with at least one other group, although only a few hybrid specimens between. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original British Ornithologists' Club. London : The Club
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