Is The Amphibian Tree of Life really fatally flawed?

FROST, DARREL R.; GRANT, TARAN; FAIVOVICH, JULIAN; BAIN, RAOUL H.; HAAS, ALEXANDER; HADDAD, CELIO F. B.; DE SA, RAFAEL O.; CHANNING, ALAN; WILKINSON, MARK; DONNELLAN, STEPHEN C.; RAXWORTHY, CHRISTOPHER J.; CAMPBELL, JONATHAN A.; BLOTTO, BORIS L.; MOLER, PAUL; DREWES, ROBERT C.; NUSSBAUM, RONALD A.; LYNCH, JOHN D.; GREEN, DAVID M.; WHEELER, WARD C.

CLADISTICS (PRINT)

WILEY-BLACKWELL PUBLISHING, INC

Año: 2008 vol. 24 p. 385 - 395

0748-3007

Wiens (2007, Q. Rev. Biol. 82, 55?56) recently published a severe critique of Frost et al.?s (2006, Bull. Am. Mus. Nat. Hist. 297, 1?370) monographic study of amphibian systematics, concluding that it is ??a disaster?? and recommending that readers ??simply ignore this study??. Beyond the hyperbole, Wiens raised four general objections that he regarded as ??fatal flaws??: (1) the sampling design was insufficient for the generic changes made and taxonomic changes were made without including all type species; (2) the nuclear gene most commonly used in amphibian phylogenetics, RAG-1, was not included, nor were the morphological characters that had justified the older taxonomy; (3) the analytical method employed is questionable because equally weighted parsimony ??assumes that all characters are evolving at equal rates??; and (4) the results were at times ??clearly erroneous??, as evidenced by the inferred non-monophyly of marsupial frogs. In this paper we respond to these criticisms. In brief: (1) the study of Frost et al. did not exist in a vacuum and we discussed our evidence and evidence previously obtained by others that documented the non-monophyletic taxa that we corrected. Beyond that, we agree that all type species should ideallybe included, but inclusion of all potentially relevant type species is not feasible in a study of the magnitude of Frost et al. and we contend that this should not prevent progress in the formulation of phylogenetic hypotheses or their application outside of systematics. (2) Rhodopsin, a gene included by Frost et al. is the nuclear gene that is most commonly used in amphibian systematics, not RAG-1. Regardless, ignoring a study because of the absence of a single locus strikes us as unsound practice.With respect to previously hypothesized morphological synapomorphies, Frost et al. provided a lengthy review of the published evidence for all groups, and this was used to inform taxonomic decisions. We noted that confirming and reconciling all morphological transformation series published among previous studies needed to be done, and we included evidence from the only published data set at that time to explicitly code morphological characters (including a number of traditionally appliedsynapomorphies from adult morphology) across the bulk of the diversity of amphibians (Haas, 2003, Cladistics 19, 23?90).