SYSTEMATICS AND EVOLUTIONARY HISTORY OF SEA CATFISHES (SILURIFORMES: ARIIDAE) Except where reference is made to the work of others, the work described in this dissertation is my own or was done in collaboration with my advisory committee. This dissertation does not include proprietary or classified information. _____________________________ Ricardo Betancur-R. Certificate of Approval: _____________________________ _____________________________ Kenneth M. Halanych Jonathan W. Armbruster, Chair Associate Professor Associate Professor Biological Sciences Biological Sciences _____________________________ ______________________________ Scott R. Santos Mark H. Sabaj Associate Professor Collection Manager of Fishes Biological Sciences Academy of Natural Sciences, Philadelphia _____________________________ George T. Flowers Interim Dean Graduate School SYSTEMATICS AND EVOLUTIONARY HISTORY OF SEA CATFISHES (SILURIFORMES: ARIIDAE) Ricardo Betancur-R. A Dissertation Submitted to the Graduate Faculty of Auburn University in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Auburn, Alabama May 9, 2009 SYSTEMATICS AND EVOLUTIONARY HISTORY OF SEA CATFISHES (SILURIFORMES: ARIIDAE) Ricardo Betancur-R. Permission is granted to Auburn University to make copies of this dissertation at its discretion, upon the request of individuals or institutions and at their expense. The author reserves all publication rights. ______________________________ Signature of Author ______________________________ Date of Graduation iii VITA Ricardo Betancur Rodríguez, son of Christian Betancur Botero and Maria Cristina Rodríguez Vélez, was born in Medellín, Colombia on December 15, 1976. He received a Bachelor of Science in Marine Biology in 2000 from Universidad Jorge Tadeo Lozano (Bogotá, Colombia). Ricardo pursed his degree for Magister in Sciences in Marine Biology from 2001 through 2004 at Universidad Nacional de Colombia (Bogotá) and received Cum Laude honors. He entered Graduate School, Auburn University, in August, 2004. Ricardo finished his degree requirements for a Doctor of Philosophy in Biological Sciences in May, 2009. iv DISSERTATION ABSTRACT SYSTEMATICS AND EVOLUTIONARY HISTORY OF SEA CATFISHES (SILURIFORMES: ARIIDAE) Ricardo Betancur-R. Doctor of Philosophy, May 9, 2009 (M.Sc. Universidad Nacional de Colombia, 2004) (B.Sc. Universidad Jorge Tadeo Lozano, 2000) 200 Typed Pages Directed by Jonathan W. Armbruster Ariids or sea catfishes are one of the two otophysan fish families (out of 67 families in four orders) that inhabit primarily marine and brackish waters, although some ariid species occur strictly in fresh waters. The Ariidae includes over a 150 species and many are of primary importance for tropical fisheries. Their classification has remained in disarray and recent studies that have intended to elucidate relationships among ariids have mostly focused on taxa from restricted geographic areas and comprehensive phylogenies are lacking. Furthermore, few efforts have been made to hypothesize biogeographic scenarios and evolutionary trends among ariids. This study inferred molecular phylogenies (up to ~4 kb) for ariids based on the most inclusive taxon sampling to date (123 species/entities). The results support the monophyly of the Ariidae (four anatomical and three molecular synapomorphies) and the sister-taxa relationship between ariids and the Malagasy family Anchariidae. The Ariidae is divided into two v basal lineages. The Galeichthyinae, new subfamily, includes one genus and four species from southern Africa (three species) and southwestern South America (one species), representing a remarkable case of transoceanic disjunction. Molecular data provided fully-resolved and well-supported phylogenies for galeichthyines, indicating that the South American species is nested within the African clade. An earlier study attributed galeichthyines’ disjunct distribution to vicariance promoted by the final separation of Africa and South America (~105 mya). However, chronological estimations via molecular clocks show that the timing of intercontinental divergence was 15.4–2.5 mya, implying transoceanic dispersal or recent vicariance. The subfamily Ariinae includes the remaining taxa (~97% of ariid diversity). The topologies support the monophyly of ariines but up to ten genera previously validated are incongruent with the molecular phylogenies. New World ariines were paraphyletic and Old World ariines were grouped into a well-supported clade further divided into subclades mostly restricted to major Gondwanan landmasses. The general area cladogram derived from the area cladograms of ariines and other fish groups is largely congruent with the geological area cladogram of Gondwana. Nonetheless, molecular clock analyses provided highly variable estimations on the timing of ariine diversification (~28–105 mya). Habitat distributions (freshwater vs. marine) were optimized onto the phylogeny to test whether freshwater ariids are primitive (i.e., retain the ancestral freshwater otophysan condition) or derived (i.e., involve marine-to-freshwater transitions). The reconstructions support the latter scenario, suggesting a single invasion of marine waters at the root of the ariid tree followed by multiple events of freshwater recolonization in the Ariinae. Ariids provide an extraordinary example of bidirectional habitat transitions in fishes. vi ACKNOWLEDGMENTS I am indebted to my advisor, Jonathan W. Armbruster, for his valuable suggestions and support on both intellectual and financial aspects of my study. I thank Kenneth M. Halanych, Mark H. Sabaj, Scott R. Santos, and Stephen A. Bullard (outside reviewer) for their contributions on my dissertation committee for critically reviewing the manuscripts. I also thank my former advisor and friend, Arturo Acero P., for his continuous interest and support on my research. I am grateful to Alexandre P. Marceniuk and Patricia J. Kailola for our shared interest on ariid systematics and for collaborating in several stages of this and other related projects. Because of collaborations with some persons mentioned above, I write in the plural first-person for Chapters I and II. Estoy en deuda infinita con mis padres por su interminable apoyo y comprensión durante todas las etapas de mi carrera. I am more than grateful to my parents for their endless support and encouragement during every stage of my career. vii Style manual of journal used: Molecular Phylogenetics and Evolution Computer software used: Microsoft Word 2003 (text), Microsoft Excel 2003 (tables), Corel Draw X1 (figures), Corel Photopaint X1 (figures), Sequencher 4.8 (contig assemblage), Clustal X (sequence alignment), PAUP* 4.0b10 (maximum parsimony reconstructions, genetic distance calculations, hypothesis testing), ModelTest 3.7 (model testing), Garli 0.96 (maximum likelihood reconstructions), RAxML 7.04 (maximum likelihood reconstructions), MrBayes 3.1.2 (Bayesian inference), MacClade 4.06 (dataset handling, ancestral character reconstructions), Mesquite 2.5 (ancestral character reconstructions), DIVA 1.2 (dispersal-vicariance analyses), Component 2.0 (Component analyses), r8s 1.71 (divergence time estimations), MULTIDIVTIME (divergence time estimations), and others. viii TABLE OF CONTENTS CHAPTER I – MONOPHYLY, AFFINITIES, AND SUBFAMILIAL CLADES OF SEA CATFISHES .......................................................................................................................1 ABSTRACT........................................................................................................................1 1. Introduction..................................................................................................................... 2 2. Results and Discussion ................................................................................................... 3 2.1 Monophyly of the Ariidae.......................................................................................... 3 2.2 Interfamilial relationships ........................................................................................ 7 2.3 Suprageneric systematics of the Ariidae................................................................. 10 ACKNOWLEDGMENTS ................................................................................................ 13 REFERENCES ................................................................................................................. 14 CHAPTER II – SUBFAMILY GALEICTHYINAE: PHYLOGENETIC RELATIONSHIPS AND EVOLUTIONARY HISTORY ............................................... 29 ABSTRACT...................................................................................................................... 29 1. Introduction................................................................................................................... 30 2. Materials and Methods.................................................................................................. 33 2.1 Taxon sampling, DNA data, and phylogenetic reconstructions ............................. 33 2.2 Divergence time estimations................................................................................... 34 3. Results........................................................................................................................... 37 3.1 Dataset attributes and phylogenetic inference ....................................................... 37 ix 3.2 Divergence time estimations..................................................................................