Evolutionary basis of parallelism in North American scincid lizards
- 30 October 2006
- journal article
- research article
- Published by Wiley in Evolution & Development
- Vol. 8 (6) , 477-490
- https://doi.org/10.1111/j.1525-142x.2006.00121.x
Abstract
This study uses a phylogenetic framework to explore the causes of parallelism in two North American scincid lizard assemblages: the skiltonianus and fasciatus species groups of the genus Plestiodon. Each group consists of several closely related species with conserved neonate morphology; features that distinguish species become accentuated during ontogeny, and these differences often resemble different endpoints along a developmental continuum. This continuum is believed to be an expression of the ancestral ontogeny, and has led to the hypothesis that evolutionary change in development has generated much of the observed morphological diversity. However, progress on understanding these mechanisms is limited by a lack of well-supported phylogenetic data for the fasciatus group, and for Plestiodon in general. Recent phylogenetic studies on the skiltonianus group have revealed previously undetected cases of parallelism, and raise the possibility that similar cases have yet to be discovered in the fasciatus group. Here, I estimate a phylogeny to test the monophyly of the fasciatus group and infer its relationship with other North American Plestiodon using 2537 bp from six mtDNA genes. I use the phylogeny to reconstruct the mode (graduated vs. punctuated) and direction of body size evolution, to map the evolution of two predominant color morphs, and to test whether size and color pattern evolve concertedly. The results show that the morphotypes of the traditional fasciatus group constitute good species, but that the species group is rendered paraphyletic by several geographically overlapping species that deviate from the fasciatus-like ontogeny. Body size evolution has occurred gradually and bi-directionally, and shifts to large body size have been consistently associated with the loss of the striped color pattern during ontogeny. I show that parallelism, a lack of rigorous phylogenetic analysis, and a reliance on shared ontogenetic features for predicting phylogenetic relatedness, has misled the traditional systematics of these lizards, but that general ideas concerning the role of development in their morphological evolution remain supported. I close by proposing that the processes influencing repeated phyletic patterns in the skiltonianus and fasciatus groups represent adherence to an ancestral ground state, and discuss the importance of using phylogenies for the initial characterization of evolutionary changes in development.Keywords
This publication has 42 references indexed in Scilit:
- Adaptive versus non‐adaptive phenotypic plasticity and the potential for contemporary adaptation in new environmentsFunctional Ecology, 2007
- Evaluating the Performance of a Successive-Approximations Approach to Parameter Optimization in Maximum-Likelihood Phylogeny EstimationMolecular Biology and Evolution, 2005
- Likelihood of Ancestor States in Adaptive RadiationEvolution, 1997
- Inferring evolutionary processes from phylogeniesZoologica Scripta, 1997
- Phylogenies and the Comparative Method: A General Approach to Incorporating Phylogenetic Information into the Analysis of Interspecific DataThe American Naturalist, 1997
- Phylogenetic Relationships among Phrynosomatid Lizards as Inferred from Mitochondrial Ribosomal DNA Sequences: Substitutional Bias and Information Content of Transitions Relative to TransversionsMolecular Phylogenetics and Evolution, 1995
- Heterochrony and Evolution of Sexual Dimorphism in the fasciatus Group of the Scincid Genus EumecesJournal of Herpetology, 1991
- Multidimensional Analysis of an Evolving LineageScience, 1987
- Skink Reproduction and Sexual Dimorphism: Eumeces fasciatus in the Southeastern United States, with Notes on Eumeces inexpectatusJournal of Herpetology, 1986
- A Pre-pattern formation mechanism for animal coat markingsJournal of Theoretical Biology, 1981