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THE PENNSYLVANIA STATE UNIVERSITY SCHREYER HONORS COLLEGE DEPARTMENT OF BIOLOGY MOLECULAR PHYLOGENY AND BIOGEOGRAPHY OF NEOTROPICAL LIZARDS OF THE FAMILY DIPLOGLOSSIDAE STEPHANIE L. DENNISON Spring 2010 A thesis submitted in partial fulfillment of the requirements for a baccalaureate degree in Biology with honors in Biology Reviewed and approved* by the following: S. Blair Hedges Professor of Biology Thesis Supervisor Daniel J. Cosgrove Professor of Biology Honors Adviser * Signatures are on file in the Schreyer Honors College ABSTRACT The lizard family Diploglossidae is distributed in the West Indies, Central America, and South America. In English speaking countries they are known as galliwasps. As part of an ongoing investigation of the historical biogeography of the West Indies, the phylogenetic relationships and biogeography of these Neotropical lizards were studied. Although several morphological and molecular studies have been conducted in the past, they were limited in scope. Consequently, the phylogenetic relationships, taxonomy, and biogeography of diploglossids remain controversial. The purpose of this thesis, therefore, is to obtain a better understanding of the phylogeny and biogeography of the lizard family Diploglossidae. New DNA sequences were collected from three mitochondrial genes (ND2, 12S, and 16S ribosomal RNA) and one nuclear gene (RAG1) for up to 145 diploglossid lizards and one outgroup species, and subjected to phylogenetic analyses. Based on these analyses, two separate West Indian and Central American lineages of Celestus and Diploglossus were identified, the two tetradactyl genera Sauresia and Wetmorena were found to be nested among West Indian Celestus, and many subspecies and populations of the Genus Celestus and Diploglossus were found to form distinct evolutionary lineages that might warrant recognition of full species. In order to further resolve diploglossid molecular phylogeny, future research in this area should focus on filling in the gaps in the mitochondrial and nuclear sequence data set, as well as continuing to add specimens. In addition, morphological characters should be examined to determine whether some genetically distinct subspecies should be i elevated to species. Finally, molecular divergence times should be determined in order to make more specific conclusions regarding biogeography. ii TABLE OF CONTENTS ABSTRACT ......................................................................................................................... i INTRODUCTION ...............................................................................................................1 Biogeography of the West Indies .............................................................................1 Diploglossidae..........................................................................................................2 MATERIALS AND METHODS .........................................................................................7 Molecular Methods ..................................................................................................7 Phylogenetic Analysis ............................................................................................11 RESULTS AND DISCUSSION ........................................................................................12 FIGURES AND TABLES .................................................................................................19 Table 1 ...................................................................................................................19 Figure 1 ..................................................................................................................20 Figure 2 ..................................................................................................................26 Figure 3 ..................................................................................................................27 ACKNOWLEDGEMENTS ...............................................................................................28 REFERENCES ..................................................................................................................29 APPENDICES ...................................................................................................................32 iii A. Specimen Localities ..........................................................................................32 B. 12S, 16S, ND2, RAG1 Primers .........................................................................35 C. 12S, 16S rRNA mtDNA Sequence Data ...........................................................37 D. ND2 mtDNA Sequence Data ............................................................................95 E. RAG1 nucDNA Sequence Data ......................................................................177 iv INTRODUCTION Biogeography of the West Indies The West Indies is an archipelago located in the Caribbean Sea and comprised of three major island groups: the Greater Antilles (Hispaniola, Jamaica, Cuba, and Puerto Rico), the Lesser Antilles (Windward and Leeward Islands), and the Bahamas (3,000 individual islands). Two characteristics that define these island groups include: biota and geological history (Hedges 1996a). More specifically, the West Indies is home to a major proportion of the Earth’s known terrestrial biota (Mittermeier et al. 2004). Many of the species that comprise this biota are not only endemic to the West Indies, but also to specific islands within the West Indies, and to specific localities within each island. Furthermore, the West Indies is an archipelago that has undergone many major geological changes and therefore has a complex geological history. Together, these characteristics (biota and geological history) have facilitated the exploration of the historical biogeography of these islands (Hedges 2001). Previous research in this area has focused on the testing of two biogeographic models: dispersal and vicariance. The dispersal model suggests that Caribbean animals arrived at their localities by way of the flight or flotsam. The vicariance model suggests that proto-Antillean landmasses connecting North and South America, fragmented during the late Cretaceous, and subsequently traveled eastward while carrying biota (Hedges 2006). The dispersal theory has been supported by a wide and thorough range of evidence. According to Hedges (2006) factors such as: taxonomy, phylogeny, the fossil record, paleogeography, water currents, divergence time estimates from molecular clocks, and many more, provide strong evidence that overwater dispersal was the mechanism for most West Indian 1 terrestrial biota. While no model has been definitively discounted, a strong trend in support of the dispersal theory has developed (Hedges 2006). In order to contribute further to this support, scientists continue to expand the geological fossil record, make molecular divergence times available, and determine the biogeography and phylogenetic relationships among endemic terrestrial animals (Hedges 2001). Diploglossidae Diploglossidae is a family of Neotropical lizards (Vidal and Hedges 2009) whose biogeography and phylogenetic relationships are not well established. The family is composed of three genera; Celestus, Diploglossus, and Ophiodes, and approximately 46 species: 25 found in the West Indies and 21 found in Central and South America (Savage et al. 2008). Despite previous work on the biogeography and phylogeny of these lizards, they remain poorly known. There are three major questions: the generic composition of Diploglossidae (Ophiodes and Celestus, Ophiodes and Diploglossus, or Ophiodes and both), the generic allocation of the two tetradactyl diploglossid genera Sauresia and Wetmorena, and the definition and naming of all Diploglossidae species. Generic Composition of Diploglossidae The most steadfast debate regarding the systematics of the lizard family Diploglossidae is its generic composition. While the existence of the genus Ophiodes has never been questioned, it remains unclear whether or not the remaining extant species compose one or two genera. Initial investigations regarding this uncertainty were based upon morphological characters alone, while later investigations utilized morphological characters, immunological distance data, and DNA sequence data (Hedges 2001). 2 The presence or the absence of the claw sheath was the primary morphological character used to determine the generic composition of Diploglossidae. Based upon the presence or the absence of the claw sheath respectively, most authors (Stejneger 1904, Barbour 1910, Burt and Burt 1932, Stuart 1963, Peters and Donoso 1970, Meyer and Wilson 1973, and Savage and Lips 1993) recognized two genera: Diploglossus Wiegmann (1834) and Celestus Gray (1839). The validity of utilizing the presence or absence of the claw sheath, however, was questioned by other authors (Boulenger 1885, Dunn 1939, Underwood 1959, Campbell and Camarillo 1994, and Werler and Campbell 2004), who instead proposed the existence of one diploglossid genus, Diploglossus. Further morphological studies were based upon the developmental stage of the osteoderm canal system. Strahm and Schwartz (1977) utilized this new morphological character and ultimately recognized two distinct genera, Celestus and Diploglossus. The developmental stage of the osteoderm canal system was later shown to be a result of ontology (Wilson et al. 1986), however, and similar to the presence or absence of the claw sheath, was ultimately