UNLV Retrospective Theses & Dissertations 1-1-1994 Phylogeography of the desert horned lizard (Phrynosoma platyrhinos) and the short-horned lizard (Phrynosoma douglassi): Patterns of divergence and diversity Kenneth Bruce Jones University of Nevada, Las Vegas Follow this and additional works at: https://digitalscholarship.unlv.edu/rtds Repository Citation Jones, Kenneth Bruce, "Phylogeography of the desert horned lizard (Phrynosoma platyrhinos) and the short-horned lizard (Phrynosoma douglassi): Patterns of divergence and diversity" (1994). UNLV Retrospective Theses & Dissertations. 2987. http://dx.doi.org/10.25669/hcai-vpf6 This Dissertation is protected by copyright and/or related rights. It has been brought to you by Digital Scholarship@UNLV with permission from the rights-holder(s). You are free to use this Dissertation in any way that is permitted by the copyright and related rights legislation that applies to your use. 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Ml 48106-1346 USA 313/761-4700 800/521-0600 PHYLOGEOGRAPHY OF THE DESERT HORNED LIZARD (PHRYNOSOMA PLATYRHINOS1 AND THE SHORT-HORNED LIZARD (PHRYNOSOMA DOUGLASSD: PATTERNS OF DIVERGENCE AND DIVERSITY by Kenneth Bruce Jones A thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Environmental Biology Department of Biological Studies University of Nevada, Las Vegas December 1995 UMI Number: 9614365 UMI Microform 9614365 Copyright 1996, by UMI Company. A11 rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. UMI 300 North Zeeb Road Ann Arbor, MI 48103 ®1996 Kenneth Bruce Jones All Rights Reserved The Thesis of Kenneth Bruce Jones for the degree of Doctor of Philosophy in Environmental Biology is approved. Chairperson, Brett R. Riddle, Ph.D. Examining Committee Member, Daniel B. Thompson, Ph.D. Examining Committee Member, Stanley D. Smith, Ph.D. Examining Committee Member, James H. Brown, Ph.D. Graduate Faculty Representative, Frederick Bachhuber, Ph.D. Interim Dean, Graduate College, Cheryl L. Bowles, Ed.D ABSTRACT Historical environmental change is thought to have played an important role in the diversification of the biota of western North America. Many patterns of diversification have been associated with glacial-interglacial cycles of the latest Pleistocene. Recent evidence on diversification patterns in small mammals suggests a response to older environmental change, especially the uplift of the western North American cordillera. To evaluate the relative influence of old and recent historical environmental change on lineage diversification, mitochondrial DNA molecular phylogeographies of Phrvnosoma douelassi (the short-homed lizard) and Phrvnosoma platvrhinos (the desert homed lizard) were analyzed. Both species are widespread and have relatively old histories in western North America. P. douelassi and R platvrhinos demonstrated multiple scales of lineage diversification representating responses to relatively old and recent historical environmental change. Deep levels of divergence in P. douelassi were structured geographically among Kuchler Physiographic regions and were temporally concordant with the late Tertiary uplift of the western North American cordillera. Significant phylogenetic gaps between regions suggest long-term barriers to gene flow among regions. P. platvrhinos demonstrated a deep divergence between the southern Sonoran Desert and the remainder of the species’ range. With the assumption of 2% divergence per million years, this divergence roughly corresponds to the Bouse Embayment, a large lake incursion that divided areas east and west of the Colorado River during the Pliocene. Assuming a roughly consistent rate of molecular evolution, both species exhibit divergence depths within regions indicative of response to Pleistocene glacial-interglacial cycles. The depth of lineage diversity in P. douelassi and P. platvrhinos was concordant with a model of habitat change during the last glacial maximum. Regions that maintained large patches of suitable habitat during the last glacial maximum had deep levels of divergence whereas regions that lost large areas of suitable habitat had shallow levels of within-region divergence. The phylogeographic patterns of P. douelassi and P. platvrhinos. and results of simulated habitat change, do not support a model of mass habitat shift to the south in response to glaciation. Rather, results of this study suggest that suitable habitats and populations persisted in many areas within the current ranges of both species ranges during the last glacial maximum, although the distribution of P. platvrhinos was more limited. TABLE OF CONTENTS ABSTRACT....................................................................................................................... iii TABLE OF CONTENTS.................................................................................................... v LIST OF FIGURES....................................................................................................... vii LIST OF TABLES.............................................................................................................ix ACKNOWLEDGEMENTS ........................................................................................... x CHAPTER 1 INTRODUCTION...................................................................................... 1 Statement of the Problem .........................................................................................1 Molecular Phylogeography .................................................................................... 5 The Western United States as a Study Area ............................................................9 Woodland and Desert Taxa as Indicators of Concordance between Environmental Change and Lineage Divergence ............................................ 11 Phrvnosoma platvrhinos and Phrvnosoma douelassi as Indicators of Lineage Response to Historical Environmental Change ............................13 Hypotheses .............................................................................................................15 CHAPTER 2 PHYLOGEOGRAPHY OF PHRYNOSOMA DOUGLASSI..................18 Introduction ...........................................................................................................18 Methods and Materials .......................................................................................... 22 DNA Extraction ........................................................................................ 24 PCR Amplification .................................................................................. 25 RFLP Digestion of Amplified mtDNA Fragments ..................................27 Sequencing Procedure .............................................................................. 28 Data Analysis ............................................................................................ 29 Restriction-Site Data Analysis ......................................................29 Sequence Data Analysis ................................................................32 R esults.................................................................................................................. 36 Distribution and Ecology .......................................................................... 36 Phylogenetic Relationships and Phylogeography - Restriction-site Analysis ..............................................................39 Discussion ............................................................................................................ 59 Phylogeographic Patterns ..........................................................................63