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A PHYLOGENETIC STUDY OF THE SHRIMP GENUS Palaemonetes HeUer 1869 FROM NORTH AMERICA (CRUSTACEA: DECAPODA) by JAMES THOMAS COLLINS, B.B.A., M.S. A DISSERTATION IN ZOOLOGY Submitted to the Graduate Faculty of Texas Tech University in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY Approved August, 1998 T "i ACKNOWLEDGMENTS V J j ^ I would like to express my sincere gratitude to Dr. Marilyn A. Houck. As r ^ n chair of my committee, she provided guidance, encouragement, and enthusiasm ' throughout the course of my work in her lab. And also to Dr. Houck, a very special thank you for the long hours spent helping me in the preparation of this manuscript. I would like to thank Dr. Ned E. Strenth for introducing me to the genus Palaemonetes, and for his help and guidance over the years as I struggled to understand this group of decapods. To Dr. Richard E. Strauss, thank you for the computer programs necessary for the analysis of my data. I also wish to thank Dr. Llewellyn D. Densmore EQ and Dr. Michael R. Willig, both of whom provided support and guidance through the course of this study. I would like to express my appreciation to N. E. Strenth, H. L. McCutchen, and S. Jasper for the loan of specimens fi^om then- personal collections. I would also like to thank R. Manning for arranging for the visit to the Smithsonian and sending the specimens to Texas Tech University. I thank G. Longley for permission to collect fi"om the artesian well on campus at Southwest Texas State University. The Biology Department provided me with financial support, as a teaching assistant and a summer mini grant, for which I am extremely grateful. I would also like to acknowledge Drs. Clifford B. Fedler and Nick C. Parker and Marilyn A. Houck for allowing me the opportunity to work as a research assistant under a Department of Interior grant. It is a pleasure to acknowledge the many friends and graduate students, both in the lab and in the Department of Biology, who offered their support. A special thank you goes to Sara, Doug, Leslie, Darin, and Elizabeth who over the years have listened and offered support when I needed it. A special thank you to my wife, Gloria, who lovingly endured the years of graduate school and was instrumental in my success. I would also like to express my thanks to our son. Cliff, for encouragement and friendship along the way. And to the ii memory of my Mother, for her support and encouragement to go forward and achieve my goal I dedicate this dissertation. ui nn^ TABLE OF CONTENTS ACKNOWLEDGMENTS ii LIST OF TABLES v LIST OF FIGURES vi CHAPTER L INTRODUCTION 1 Taxonomic and Systematic Review 1 Research Objectives 10 IL MATERL\LS AND METHODS 12 Specimens 12 Equipment and Handling Procedures 16 Statistical Protocols 17 Statistical Procedures 19 General procedures 19 Influence of gender on character discrimination 21 Comparison of species within the genus Palaemonetes 22 Comparison within species of P. kadiakensis 22 Evaluation of character contribution to discrimination 22 m. RESULTS AND DISCUSSION 223 Influence of Gender on Character Discrimination 223 Analysis of All Taxa 223 Comparison of Species within the Genus Palaemonetes 47 Comparison of Discrete Characters 49 Comparison within Species of P. kadiakensis 68 IV. CONCLUSIONS 91 LITERATURE CITED 94 APPENDIX: COLLECTION NUMBERS AND RAW DATA 100 IV y LIST OF TABLES 2.1 Populations collection data 13 2.2 List of characters used in the analyses 18 3.1 Rao's V hierarchy for the 26 characters used in the analyses of all taxa 40 3.2 Rao's V hierarchy for the 30 characters used in the analyses of Palaemonetes 62 3.3 Rao's V hierarchy for the 30 characters used in the analyses of Palaemonetes kadiakensis 87 A. 1 Collection numbers and raw data utilized in this study ofthe North American Palaemonetes 100 LIST OF HGURES 3.1 Convex hulls and centroids indicating the discrimination among males and females, for all taxa studied 24 3.2 Relationship between the first two axes of discrimination as determined by principal component analysis (PCA) 25 3.3 Centroids and one standard deviation about the centroids as determined by principal component analysis (PCA) for all taxa studied 26 3.4 Convex hulls and centroids indicating discrimination due to the two major shape axes as determined by principal component analysis (PCA) for all taxa studied 28 3.5 Centroids and one standard deviation about the centroids due to the two major shape axes, as determined by principal conponent analysis (PCA), for all taxa studied 29 3.6 Vector plot showing character correlations contributing to character variation resulting in shape discrimination, as determined by principal con^nent analysis (PCA), for species of all taxa studied 30 3.7 Vector plot showing character correlations representing major character variation contributing to discrimination, as determined by principal conqwnent analysis (PCA), for all taxa studied 31 3.8 Plot ofthe major size axis versus the major shq)e axis, as determined by discriminant fimction analysis (DFA) for all taxa studied 32 3.9 Centroids and one standard deviation about the centroids as determined by discriminant function analysis (DFA) for all taxa studied 34 VI 3.10 Plot ofthe major size axes, as determined by discriminant function analysis (DFA) for all taxa studied 35 3.11 Vector plot showing character correlations contributing to character variation resuhing in discrimination, as determined by discriminant function analysis (DFA), for all taxa studied 36 3.12 Vector plot showing character correlations contributing to character variation resulting in shape discrimination, as determined by discrimmant function (DFA), for all taxa studied 37 3.13 Plot ofthe cumulative Rao's V values for all taxa studied 38 3.14 Cumulative Rao's V values for all taxa studied 39 3.15 Plot ofthe major axes, as determined by size-fi^ee discriminant function analysis (DFA) for all taxa studied 41 3.16 Centroids and one standard deviation about the centroids as determined by size-fi-ee discriminant analysis (SF) for all taxa studied 42 3.17 Unrooted phenogram (UPGMA) ofthe relationships among all taxa studied, using size-fi*ee Mahalanobis distances 44 3.18 Unrooted neighbor joining phenogram of the relationships among all taxa studied 45 3.19 Neighbor joining phenogram of the relationships among all taxa studied, rooted with Leander as the outgroup 46 3.20 Convex hulls and centroids indicating the discrimination among males and females, for species of Palaemonetes 48 3.21 Relationship between the first two axes of discrimmation as determined by principal component analysis (PCA) 49 vn 3.22 Centroids and one standard deviation about the centroids as determined by principal component analysis (PCA) for species of Palaemonetes studied 50 3.23 Convex hulls and centroids indicating the discrimination (PCA) among species of Palaemonetes, due to the two major shape axes 51 3.24 Vector plot showing character correlations contributing to character variation resulting in discrimination, as determined by principal component analysis (PCA), for species of Palaemonetes studied 53 3.25 Plot ofthe major size axis versus the major shape axis, as determined by discriminant function analysis for all species of Palaemonetes 54 3.26 Vector plot showing character correlations contributing to character variation resulting in discrimination, as determined by discriminant fimction analysis (DFA), for species of Palaemonetes studied 55 3.27 Plot ofthe major size axes, as determined by discriminant function analysis (DFA) for populations of Palaemonetes studied 56 3.28 Centroids and one standard deviation about the centroids as determined by discriminant analysis for species of Palaemonetes studied 57 3.29 Vector plot showing character correlations contributing to character variation resulting in shape discrimination, as determined by discriminant function analysis (DFA), for species of Palaemonetes studied 58 3.30 Plot ofthe cumulative Rao's V values for all species of Palaemonetes studied 60 3.31 Cumulative Rao's V values for all species of Palaemonetes studied 61 Vlll 3.32 Plot ofthe major axes, as determined by size-fi-ee discriminant function analysis (SF) for all species of Palaemonetes studied.. 63 3.33 Centroids and one standard deviation about the centroids for the shape axes, as determined by size-fi-ee discriminant analysis (SF), for species of Palaemonetes studied 64 3.34 Unrooted neighbor joining phenogram ofthe relationships among species of Palaemonetes studied 65 3.35 Unrooted phenogram (UPGMA) ofthe relationships among Palaemonetes species studied, using size fi-ee Mahalanobis distances 66 3.36 Convex hulls and centroids indicating the discrimination among males and females, for populations of P. kadiakensis 69 3.37 Relationship between the first two axes of discrimination as determined by principal component analysis (PCA); convex hulls with centroids for populations of P. kadiakensis studied 70 3.38 Centroids and one standard deviation about the centroids as determined by principal component analysis (PCA) for populations of P. kadiakensis studied 71 3.39 Vector plot showing character correlations contributing to character variation resulting in shape discrimination, as determined by discriminant function analysis (DFA), for species of Palaemonetes studied 73 3.40 Convex hulls and centroids indicating the discrimination among all taxa (PCA), due to the two major shape axes for P. kadiakensis populations studied 74 3.41 Centroids and one standard deviation about the centroids due to the two major shape axes, as determined by principal component analysis (PCA), for populations of P. kadiakensis studied 75 IX 3.42 Vector plot showing character correlations contributing to character variation resuhing in shape discrimination, as determined by principal component analysis (PCA), for the populations of P.