INTRODUCTION Iguanidae*^ is a large family (ca. 54 genera and 546 species) of lizards found in the Ameri-cas, the Fiji Island group and the Tongatapu and Va'vau groups in the Tonga Islands in the south-west Pacific Ocean, and Madagascar and the Comoro Archipelago in the western Indian Ocean (Fig. 1). The unusual distribution of the family may be an artifact of paraphyly; to date, no apomorphies have been presented to support the monophyly of Iguanidae* exclusive of the Australo-Afro-Asian Acrodonta (Agamidae* [35 genera, 319 species; Wermuth, 1967; Moody, 1980] -I-Chamaeleonidae^ [6 genera, 128 species; Klaver and Bohme, 1986]) (Fig. 1). Indeed, Schwenk (1988) has suggested that one group of iguanids (anoles) may be more closely related to Agamidae* + Chamaeleonidae than to other 'We use an asterisk beside a taxonomic name (the metataxon convention — Gauthier, 1986; Gauthier et al., 1988 [cf. Donoghue, 1985]) to denote a nominal supraspecific taxon for which evidence of either monophyly or paraphyly is ambiguous or absent. Although this practice cannot be applied to unitary lineages (=species) (Frost and Hillis, 1990; but see Donoghue, 1985, and de Queiroz and Donoghue, 1988) we "flag" some monotypic fossil genera in this way to denote the lack of character evidence for grouping specimens under these binomials. Although, as used here, the metataxon convention is substantively the same as the shutter quotation convention of Wiley (1979), in this paper quotations surround names that represent nominal taxa that are demonstrably not monophyletic, but whose correction is outside of the scope of this paper. Because the historical reality of metataxa is questionable, their treatment as entities rather than sets in text is arbitrary. Casual collectives (e.g., agamids) are not asterisked because they are not formal names and as such are treated as are other casual collectives (e.g., lizards). ^Because this family-group name is based on the Latin Chamaeleo, rather than the Greek Chamaeleon, the formation of the family-group name must be Chamaeleonidae, rather than the oft-used Chamaeleontidae. iguanids. Both Agamidae* and Chamaeleonidae have been recognized universally by modern sys-tematists, although monophyly of Agamidae* remains ambiguous {contra Moody, 1980; Bor-suk-Bialynicka and Moody, 1984). Iguania (Iguanidae* -f-[Agamidae* -i-Cha-maeleonidae]) has been established as the sister-taxon of Scleroglossa (=Scincogekkonomorpha [S ukhanov, 1 96 1 ]) , the non-iguanian members of Squamata (i.e., other lizards and snakes) (Camp, 1923;Estese?a/., 1988; but see Northcutt, 1978) and, as such, can be assumed to be of great antiquity. Even though the earliest fossil iguanid is from the Upper Cretaceous (Estes and Price, 1973), fossil acrodonts (e.g., iMimeosaurus*) are also known from the Upper Cretaceous, and several scleroglossan squamate groups were well-diversified by the Upper Jurassic (Estes, 1983a,b). Thus, if the hypotheses of squamate phylogeny are correct, Iguania must have been present in the Jurassic. Major, likely monophyletic, groups within Iguanidae* were first recognized by Etheridge (1959, 1964, 1966, 1967), Etheridge in PauU et al. (1976), and Etheridge and de Queiroz (1988). As currently understood, Iguanidae* is com-posed of eight monophyletic groups of uncertain relationships to each other or to Agamidae* -i-Chamaeleonidae. These groups are: (1) anoloids (11 genera; >200 species); (2) basiliscines (3 genera; 9 species); (3) crotaphytines (2 genera; 7 species); (4) iguanines (8 genera; 25 species); (5) morunasaurs (3 genera; 11 species); (6) oplurines (2 genera; 7 species); (7) sceloporines (10 gen-era; 105 species); and (8) tropidurines (14 gen-era; 182 species). The purpose of this study is to reevaluate the evidence for relationships within Iguania as well as to investigate the possible paraphyly of Igua-nidae* with respect to Agamidae* 4-Chamaele-onidae, and Agamidae* with respect to Chamae-leonidae, and to provide a taxonomy logically consistent (Hull, 1964; Wiley, 1981a) with the recovered phylogeny within Iguania.
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