Genetic variation in piciform birds: monophyly and generic and familial relationships

-Interand intrafamilial relationships within the New World Piciformes were examined through an electrophoretic analysis of 20 protein-coding loci (19 of which varied between taxa). One individual from each of 26 species representing 25 genera and 5 families was analyzed; Momotus momota (Coraciiformes, Momotidae) was used as an outgroup. Although levels of genetic differentiation were high (the mean Nei's unbiased distance was 1.07), the data proved useful for phylogenetic inference. The jackknife technique was used to estimate the robustness of phylogenetic hypotheses. At the interfamilial level, the results suggest the following groupings: f[{(Bucconidae) (Galbulidae)]{(Picidae)[(Capitonidae) (Ramphastidae)]}]. These results were consistent with hypotheses of familial relationships proposed by two recent cladistic analyses of morphological character complexes (Simpson and Cracraft 1981, Swierczewski and Raikow 1981). Our data challenge the currently accepted monophyly of the Piciformes, however, in much the same way as do DNA-DNA hybridization data. Agreement among independently derived hypotheses of interfamilial relationships suggests confidence in our knowledge of evolutionary patterns among piciform taxa. Hypotheses of intrafamilial relationships, some of which agreed with morphological patterns obtained in other studies, were presented. This study shows that starch-gel electrophoresis may be useful at higher taxonomic levels. Received 10 November 1986, accepted 4 June 1987. RECENT years have witnessed a plethora of biochemical systematic studies (Avise and Aquadro 1982). These studies have demonstrated that molecular characters have both advantages and limitations for phylogeny reconstruction (Lanyon 1985b). There are several types of limitations. For example, molecular methods are scale dependent. That is, one would generally not use starch-gel electrophoresis of proteins to investigate relationships of higher taxa (Buth 1984) because often taxa share no alleles, which contributes no phylogenetic information. In other instances molecular methods may be unable to resolve evolutionary patterns because of the relationship between the nature and rate of character evolution (e.g. allelic substitutions occurring more or less uniformly over time) and the nature of the evolutionary history itself (Fiala and Sokal 1985). For example, if cladogenetic events are close in time and lineages are shortlived before fragmentation (speciation), then there is a low probability of the origin (and retention through evolutionary time, given a 1 Present address: Division of Birds, Field Museum of Natural History, Roosevelt Road at Lake Shore Drive, Chicago, Illinois 60605 USA. fast rate of change) of a synapomorphic character state, such as a particular allele. Nonetheless, the potential of biochemical methods for the inference of evolutionary history is widely appreciated (Buth 1984, Wilson et al. 1985, Sibley and Ahlquist 1986) because they allow direct access to genetic information. A framework of quantitative models provides objective methods for estimating phylogenies (Felsenstein 1982). Probably few phylogenetic estimates, however, irrespective of the data or methods used to construct them, are immune to bias. Recently, statistical or quantitative tests have been developed to assess the accuracy of a particular phylogenetic pattern (e.g. Templeton 1983, Felsenstein 1985, Lanyon 1985a). Furthermore, systematic studies that compare patterns of morphological, biochemical, and behavioral variation may lead to more robust estimates of evolutionary history (Wagner 1961, Miyamoto 1981, Lanyon and Lanyon 1986). Such multidisciplinary approaches can exploit positive aspects of each suite of characters, and permit evaluation of whether consistent patterns emerge. A disadvantage of this approach is that it requires investigators to become familiar with many different techniques, which can increase greatly the time required to complete studies 724 The Auk 104: 724-732. October 1987 This content downloaded from 207.46.13.98 on Wed, 29 Jun 2016 04:59:19 UTC All use subject to http://about.jstor.org/terms October 1987] Piciform Biochemical Systematics 725 of even small assemblages. It is possible to simulate such a multidisciplinary study by integrating independently or collaboratively gathered data sets of several investigators. We examined phylogenetic patterns in electrophoretic characters (allozymes) in the Piciformes. Recent hypotheses (Fig. 1) of piciform relationships have been based on hindlimb musculature (Swierczewski and Raikow 1981), osteological characters (Simpson and Cracraft 1981), and the anatomy of the feeding apparatus (Burton 1984). We compare phylogenetic patterns derived from analysis of our allozyme data set with those derived from analyses of muscle and skeletal variation. We illustrate the importance of examining the robustness of phylogenetic estimates through the use of the jackknife technique (Lanyon 1985a). Furthermore, this is one of the few systematic applications of protein electrophoresis at higher taxonomic levels in birds (Lanyon 1985b); we suggest that the limits of the technique for avian systematics are unknown.