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Ann Arbor, MI 48106 EVOLUTIONARY MORPHOLOGY OF THE LOCOMOTOR APPARATUS IN ARACHNIDA DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of the Ohio State University By Jeffrey Walden Shultz, B.S., M.S. $ $ $ $ The Ohio State University 1990 Dissertation Committee: Approved by Barry D. Valentine Abbot S. Gaunt Thomas E. Hetherington Iviser Donald E. Johnston Department of Zoology the Memory of My Grandfather, George Vernon Bechstein (1911-1989) ACKNOWLEDGEMENTS I gratefully acknowledge the assistance of Barry D. Valentine, Abbot S. Gaunt, Thomas E. Hetherington and Donald E. Johnston. I thank A. S. Gaunt and T. E. Hetherington for equipment loans and Norman F. Johnson for access to his computer and assisting in the PAUP analysis. Specimens examined during this study were obtained from Norman I. Platnick (American Museum of Natural History), Herbert W. Levi (Museum of Comparative Zoology, Harvard University), Jonathan Coddington (National Museum of Natural History), D. E. Johnston (Acarological Laboratory, Ohio State University) and the private collection of B. D. Valentine. I thank Roy A. Norton, D. E. Johnston and Bret S. Beall for sharing their knowledge of arachnids. I am especially indebted to my wife, Janet, for her assistance and encouragement. Funding for this project was obtained through grants to the author from the Exline-Frizzel Fund for Arachnological Research (California Academy of Sciences), Sigma Xi and an Alumni Graduate Research Award (Ohio State University). VITA December 8, 1959 Born - Albion, Michigan 1982 B.S., Michigan State University, East Lansing, Michigan 1985 M.S., Ohio University, Athens, Ohio PUBLICATIONS Shul.tz* J. W. 1987. The origin of the spinning apparatus in spiders. Biological Reviews 62: 89-113. Shultz, J. W. 1987. Walking and surface film locomotion in terrestrial and semi-aquatic spiders. Journal of Experimental Biology 128: 427-444. Shultz, J. W. 1989. Morphology of locomotor appendages in Arachnida: evolutionary trends and phylogenetic implications. Zoological Journal of the Linnean Society 97: 1-56. Shultz, J. W. 1990. Evolutionary morphology and phylogeny of Arachnida. Cladistics 6: 1-38. FIELDS OF STUDY Major Field: Zoology Studies on functional morphology and motor coordination of spider locomotion. Studies on comparative anatomy and phylogeny of arachnids. TABLE OF CONTENTS ACKNOWLEDGEMENTS ....................................... iii VITA ...................................................... iv LIST OF TABLES ......................................... vi LIST OF FIGURES ..........................................vii INTRODUCTION ............................................ 1 CHAPTER . PAGE I. EVOLUTIONARY MORPHOLOGY AND PHYLOGENY OF ARACHNIDA ....................................... 30 Introduction .............................. 30 Phylogenetic Analysis .................... 33 Arachnid Taxonomy ............ 98 II. MORPHOLOGY OF LOCOMOTOR APPENDAGES IN ARACHNIDA ......................................118 Introduction ............................. 118 M e t h o d s ..................................... 122 R e s u l t s ........................................ 126 D i s c u s s i o n ................................... 202 III. MUSCLE FIRING PATTERNS IN TWO ARACHNIDS USING DIFFERENT METHODS OF PROPULSIVE LEG E X T E N S I O N ......................................237 Introduction ............................. 237 Materials and M e t h o d s .................... 243. R e s u l t s ........................................ 246 D i s c u s s i o n ................................... 263 IV. EVOLUTION AND FUNCTIONAL MORPHOLOGY OF HYDRAULIC LOCOMOTION IN ARACHNIDA .......... 280 Introduction .............................. 280 Materials and Methods .................... 303 R e s u l t s ........................................ 310 D i s c u s s i o n ................................... 323 LIST OF R E F E R E N C E S........................................ 335 v LIST OF TABLES TABLE PAGE 1. Characters and character states used in the phylogenetic analysis of the 11 Recent arachnid orders. Plesiomorphic states are coded with a 0. The complete data matrix is presented in Table 2 .............37 2. Data matrix used in computer-assisted phylogenetic analysis of the arachnid orders. Plesiomorphic states were determined by explicit argumentation given in the text and are presented in the matrix by the line labeled "Ancestor". Multistate characters are coded a, b, c, etc. Missing or equivocal characters are indicated by a 9. A list of characters and character polarities is given in Table 1 ..................41 3. A new taxonomic system for Arachnida based on the results of the present s t u d y .............99 4. Polarities of appendicular characters used in reconstructing phylogenetic relationships among the arachnid orders (see Fig. 9). 204 5. Regression statistics for timing parameters (s, y) of six muscles versus levator cycle period (s, x) in the vinegaroon, Mastigoproctus giganteus (Uropygi) .......... 260 6. Regression statistics for timing parameters (s, y) of seven muscles versus levator cycle period (s, x) in the scorpion, Pandinus imperator (Scorpiones) ............... 261 vi LIST OF FIGURES FIGURES PAGE 1. Phylogenetic relationships of the arachnid orders suggested by Weygoldt & Paulus1 (1979) qualitative analysis. In light of the characters and interpretations of the present investigation, the topology of Weygoldt & Paulus' cladogram has a consistency index of 0.49 and a length of 159 steps (cf. Fig. 4 ) ............................ 31 2. Phylogenetic relationships of major arthropod groups used in polarizing characters in Arachnida.............................................. 36 3. Hypothetical arachnid illustrating the plesiomorphic states of major external characters used in the present analysis. 61 4. Cladogram showing possible relationships of the Recent arachnid orders. This minimal length topology was discovered through branch-and-bound analysis of 64 characters. The most parsimonious distribution of characters has a consistency index of 0.59 and a length of 133 steps. Reinterpretation of a single character (54) increased the length of the tree by one step but does not affect the branching pattern discovered by parsimony analysis ........................... 97 5. Anterior views of muscles (1-13) in the walking legs of selected chelicerates. A-C, Leg 4 of Limulus polyphemus (Xiphosura). D-F, Leg 4 of Liphistius sumatranus (Araneae). G-I, Leg 4 of Phrynus marginemaculatus (Amblypygi). J-L. Leg 4 of Mastieoproctus giganteus (Uropygi, Thelyphonda) ......................... 131 FIGURES PAGE 6. Anterior views of muscles (1-13) in the walking legs of selected chelicerates. A-C, Leg 3 of Schizomus sp. (Uropygi, Schizomida). D-F, Leg A of Eukoenenia sp. (Palpigradi). G-I, Leg 2 of Cryptocellus gamboa (Ricinulei). J, Leg 4 of C. gamboa. K-M, Leg 4 of Amblyomma americanum (Acari, Parasitiformes). N-P, Leg 4 of Dinothrombium sp. (Acari, Acariformes) . , 152 7. Anterior views of muscles (1-13) of the fourth walking leg in selected opilionid arachnids. A-C, Leiobunum vittatum (Palpatores). D-F, Siro acaroides (Cyphophthalmi). G-I, Cynorta subserialis (Laniatores) ................................ , 173 8. Anterior views of of muscles (1-13) in the walking legs of selected chelicerates. A-C, Leg 4 of Pandinus imperator (Scorpiones). D-F, Leg 4 of Chthonius tetrachelatus (Pseudoscorpiones). G-I, Leg 1 of C. tetrachelatus. J-L, Leg 2 of Paragaleodes scalaris (Solifugae). M, Leg 4 of £. scalaris...................... 184 9. Cladogram showing the possible relationships of the arachnid orders and the distribution of appendicular characters. Numbers correspond to characters listed in Table 4 . 203 10. Skeletomuscular anatomy