A Phylogeny of the Gulls (Aves: Larinae) Inferred from Osteological and Integumentary Characters

Abstract

Gulls (Aves: Larinae) are among the best-studied of birds, yet prior attempts to reconstruct gull relationships have met with little success. In the present study I use 117 characters from the skeleton and 64 from the integument to test gull monophyly and estimate gull phylogeny. One shortest tree, requiring 9747 unweighted changes and having a CI of 0.267, was obtained; on this tree the genus Larus is polyphyletic. Although the tree is fully resolved, support for many of the inferred clades is poor. In a comparison of osteological and integumentary evidence, I found that incongruence between the osteological and integumentary character sets accounts for only a minority of the total incongruence observed, and suggest that low between-set incongruence may be a consequence of the low signal-to-noise ratio in each set of characters. I also found that osteological evidence is particularly important for determining higher-level structure, whereas integumentary evidence is important for resolving lower-level relationships within the gull group. Finally, I found that integumentary characters are not dramatically more homoplasious than osteological characters, and argue that casual dismissal of integumentary characters as "too labile" is unwarranted. © 1998 The Willi Hennig Society * Correspondence to: P. C. Chu, Section of Birds, Carnegie Museum of Natural History, 4400 Forbes Avenue, Pittsburgh. PA 15213-4080, U.S.A. E-mail: CHUP@CLPGH.ORG. Fax: +1 412 622-8837. INTRODUCTIONThe gulls of North America are worked up to the fullest extent that the specimens at my command allow; but, in the apparent hopelessness of arriving at ultimate truth with regard to these birds, I am prepared to relinquish any of the views now entertained... (Coues, 1862: 292) Gulls (Aves: Larinae) are among the best-studied of birds (e.g. Rex, 1905;Tinbergen, 1953;Moynihan, 1962;Schumacher et al., 1972;Midtgård, 1984;Weber, 1990), yet phylogenetic relationships within the gull assemblage have proved difficult to reconstruct, due in no small part to, "There being scarcely any appreciable differences of form among most of the Lari " (Coues, 1874: 619). Members of the assemblage are, indeed, similar in appearance: all have long, narrow wings; a short tail in which all feathers are about equal in length; complete webs between the toes; adult plumages that are pale with a darker mantle; carotenoid pigmentation restricted to the unfeathered parts of the integument; and a complex plumage ontogeny.Current taxonomy groups the gulls with the skuas, terns, and skimmers (Nitzsch, 1840;Beddard, 1896), and the collection of taxa thus formed is viewed as a subset of the shorebird assemblage (Seebohm, 1888;Gadow, 1892;Wetmore, 1930).Gull taxa have been treated as a discrete taxonomic entity since at least the mid-19th century (e.g. Coues, 1862); however, despite long-standing consensus 2 Chu Copyright © 1998 by The Willi Hennig Society All rights of reproduction in any form reserved within the ornithological community, recent studies are divided as to whether...

Dutch Avifaunal List: Taxonomic Changes in 2004–2008

“…Both Chu (1998) and Pons et al (2005) indicate a separate position of Swallow-tailed Gull Creagrus furcatus, the kittiwakes Rissa, Sabine's Gull Xema sabini and Ivory Gull Pagophila eburnea from all other gulls, supporting the continued recognition of these genera. Both studies indicate that the 'masked gulls' (which include Slender-billed Gull, Bonaparte's Gull and Black-headed Gull) are not part of the main clade of gulls.…”

“…robust to additional data), we recommend a taxonomic arrangement that is intermediate between the two extremes proposed by Chu (1998) and Pons et al (2005). This arrangement recognises the genera Creagrus, Rissa, Xema, Pagophila, Chroicocephalus, Rhodostethia, Hydrocoloeus and Larus.…”

“…We have considered five alternative rearrangements, including those proposed by Chu (1998) and Pons et al (2005). These proposals range from including all species of gulls in a single genus (Chu 1998) to recognising 10 genera, including several genera that are not presently recognised (Pons et al 2005).…”

“…These proposals range from including all species of gulls in a single genus (Chu 1998) to recognising 10 genera, including several genera that are not presently recognised (Pons et al 2005).…”

“…Two studies, one based on morphology (Chu 1998) and another based on mitochondrial DNA sequences (Pons et al 2005) have examined phylogenetic relationships of the entire gull clade. Both studies indicate that the genus Larus, as currently defined (e.g.…”