UC Riverside UC Riverside Electronic Theses and Dissertations Title A Bridge Too Many? Phylogeny and Biogeography of the Upper Cambrian Saukiid Trilobites Permalink https://escholarship.org/uc/item/3pz0555k Author Collette, Joseph Henry Publication Date 2014 Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA RIVERSIDE A Bridge Too Many? Phylogeny and Biogeography of the Upper Cambrian Saukiid Trilobites A Dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Geological Sciences by Joseph Henry Collette August 2014 Dissertation Committee: Dr. Nigel C. Hughes, Chairperson Dr. Peter M. Sadler Dr. Mary L. Droser Copyright by Joseph Henry Collette 2014 The Dissertation of Joseph Henry Collette is approved: Committee Chairperson University of California, Riverside ABSTRACT OF THE DISSERTATION A Bridge Too Many? Phylogeny and Biogeography of the Upper Cambrian Saukiid Trilobites. by Joseph Henry Collette Doctor of Philosophy, Graduate Program in Geological Sciences University of California, Riverside, August 2014 Dr. Nigel C. Hughes, Chairperson The family Saukiidae Ulrich and Resser, 1933 was one of the largest groups of late Cambrian trilobites, with representatives occurring on all major paleogeographic plates. However, inconsistent systematic practices that have been historically applied to this group have resulted in a muddled concept of the Saukiidae and an exaggerated species count. This has led to erroneous placement of many taxa due to a lack of distinct characters with which to diagnose some saukiid genera and species. To mitigate past systematic digressions and to re-elevate Saukiidae to a useful concept, a series of cladistic analyses were performed that incorporated all global occurrences of the Saukiidae for which there is a good fossil record. As a further test of the familial relationships of the Saukiidae, members of the Ptychaspididae and Pterocephaliidae were included to test what effect, if any, different outgroups would have on character polarity and the iv branching point with the Saukiidae. Results vary with outgroup choice, but suggest that some of the characters uniting Ptychaspididae and Saukiidae may be convergent. Because the 'upside-down' stratigraphic placement of taxa recovered with this outgroup is inconsistent with stratigraphic evidence, the Pterocephaliidae outgroup is preferred. The preferred phylogeny indicates that the Saukiidae is monophyletic, and is composed of two distinct groups of subfamilial rank: the Saukiinae, n. subfam., defined by the absence of a preglabellar field (Calvinella, Danzhaisaukia, Eosaukia, Linguisaukia, Lophosaukia, Mictosaukia, Saukia, Sinosaukia, and Tellerina); and the Prosaukiinae n. subfam., defined by possession of a preglabellar field (Anderssonella, Hoytaspis, Lichengia, Pacootasaukia, Prosaukia, and Saukiella). The ancestral geographic area(s) for each node on the preferred cladogram was then computed using Fitch optimization. The Fitch analysis revealed that toward the base of the tree, descendants that had originated from ancestors living in Laurentia likely moved westward towards Australia and North China, most likely as larvae. Further up the tree, a single dispersal event appears to have moved eastward toward South China; all taxa in a more derived position to this dispersal occur in Gondwana indicating a radiation across Gondwana from this event, and a likely Laurentian origin of the family Saukiidae. v TABLE OF CONTENTS ABSTRACT OF THE DISSERTATION ....................................................................... iv TABLE OF CONTENTS ................................................................................................ vi LIST OF FIGURES ........................................................................................................ xi LIST OF TABLES ........................................................................................................ xix INTRODUCTION ............................................................................................................1 MATERIALS AND METHODS ......................................................................................9 Cladistic Analyses .................................................................................................9 Outgroup Selection .............................................................................................11 Specific Problems in Character Coding ..............................................................12 Qualitative Character Selection and Coding .......................................................13 Morphometric Character Selection and Coding .................................................21 Gap-weighted Morphometric Character Selection and Coding ..........................21 Geometric Morphometric Landmark Analysis (GMLA) ....................................25 Shape Analyses ...................................................................................................27 Stratigraphic Consistency ...................................................................................28 Modified Brooks Parsimony Analyses (mBPA) .................................................31 RESULTS .......................................................................................................................33 Results of Cladistic Analyses..............................................................................33 Discussion ...............................................................................................35 Measures of Stratigraphic Consistency ...............................................................47 vi Results of Stratigraphic Consistency ......................................................51 Paleobiogeography ..............................................................................................54 Results of Fitch Parsimony Optimization ...............................................57 modified Brooks Parsimony Analysis (mBPA) ..................................................63 Results of mBPA.....................................................................................66 SYSTEMATIC PALEONTOLOGY. .............................................................................70 Family DIKELOCEPHALIIDAE Miller, 1889 ..................................................74 Genus BRISCOIA Walcott 1924 ............................................................74 Briscoia septentrionalis Kobayashi 1935 ...................................74 Genus DIKELOCEPHALUS Owen 1852 ..............................................76 Dikelocephalus minnesotensis Owen 1852 .................................76 Dikelocephalus freeburgensis Feniak 1948 ................................78 Genus HAMASHANIA ..........................................................................80 Hamashania pulchera Kobayashi 1942 ......................................80 Family SAUKIIDAE Ulrich and Resser 1933 ....................................................83 Genus ANDERSSONELLA Shergold, 1975 ..........................................83 Anderssonella beauchampi Shergold 1975 .................................83 Genus CALVINELLA Walcott 1914 .....................................................85 Calvinella ozarkensis Walcott 1914 ...........................................87 Calvinella prethoparia Longacre 1970 .......................................90 Calvinella spiniger (Hall 1863) ..................................................93 Calvinella wisconsinensis Ulrich and Resser 1933 ....................96 vii Genus DIEMANOSAUKIA Jago and Corbett 1990 ..............................97 Diemanosaukia miserabilis Jago and Corbett 1990....................98 Genus EOSAUKIA Lu 1954 ................................................................102 Eosaukia acuta (Kuo and Duan in Kuo, Duan, and An 1982) .102 Eosaukia angustilimbata (Qian 1986) ......................................104 Eosaukia bella (Walcott 1906) .................................................107 Eosaukia latilimbata Lu 1954 ...................................................109 Eosaukia micropora (Qian 1985) .............................................113 Eosaukia rectangula Lu and Zhou 1990 ...................................115 Eosaukia walcotti (Mansuy 1915) ............................................116 Genus LICHENGIA Kobayashi 1942a .................................................120 Lichengia simplex Shergold 1991 .............................................120 Genus LINGUISAUKIA Peng 1984 ....................................................122 Linguisaukia spinata Peng 1984 ...............................................123 Genus LOPHOSAUKIA Shergold 1972 ..............................................127 Lophosaukia torquta Shergold 1972 .........................................128 Lophosaukia jiangnanensis Lu and Lin 1984 ...........................130 Lophosaukia rectangulata Ergaliev 1980 .................................131 Genus MICTOSAUKIA Shergold 1975 ...............................................133 Mictosaukia globosa (Robison and Pantoja-Alor 1968) ...........134 Mictosaukia luanhensis Zhou and Zhang 1978 ........................135 Mictosaukia orientalis (Resser and Endo in Endo 1931) .........137 viii Mictosaukia striata (Resser and Endo 1937) ............................140 Genus PACOOTASAUKIA Sohn and Choi 2005................................142 Pacootasaukia jokliki (Shergold