title: Molecular and Morphological Investigations of the Stauros-bearing, Raphid Pennate Diatoms (Bacillariophyceae): Craspedostauros E.J. Cox, and Staurotropis T.B.B. Paddock, and their Relationship to the Rest of the Mastogloiales.
abstract: Several lineages of raphe-bearing diatoms possess a "stauros," which is a transverse, usually thickened area free of pores across the center of the valve. It has been suggested that this structure has evolved several times across the raphid diatoms, but we have noticed similarities beyond the stauros between two marine genera-Craspedostauros and Staurotropis-in the structure of their pore occlusions. We have isolated, cultured and extracted DNA from several strains of both genera to infer the phylogenetic relationship between these taxa, as well as test the suggested relationship of Craspedostauros to Achnanthes and Mastogloia based on plastid morphology. DNA sequence data (nuclear-encoded rRNA SSU, plastid-encoded rbcL and psbC) suggest that, except for Mastogloia, these genera are closely-related, though not sister taxa. The DNA phylogeny also suggests that the Mastogloiales are not monophyletic, with clades containing Achnanthes and Craspedostauros sister to clades containing taxa in the Bacillariales. Using evidence from molecular and morphological data, we describe the following new taxa: Craspedostauros alyoubii and C. paradoxa from the Red Sea and Guam, respectively; Staurotropis khiyamii and S. americana from the Red Sea and the Gulf of Mexico, respectively; and Dreuhlago cuneata n. gen., n. sp. from Guam.
authors.affiliation: Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA. Electronic address: mashworth@utexas.edu.
authors.forename: Matt P
authors.initials: MP
authors.lastname: Ashworth
authors.affiliation: Division of Natural Sciences, University of Guam, Mangilao, Guam, USA.
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Lobban
authors.affiliation: Palaeoceanology Unit, Faculty of Geosciences, University of Szczecin, Szczecin, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Witkowski
authors.affiliation: Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA.
authors.forename: Edward C
authors.initials: EC
authors.lastname: Theriot
authors.affiliation: Biotechnology Research Group, Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Meeshal J
authors.initials: MJ
authors.lastname: Sabir
authors.affiliation: Department of Biological Sciences, Faculty of Science, Jeddah University, Jeddah, Saudi Arabia.
authors.forename: Mohammad N
authors.initials: MN
authors.lastname: Baeshen
authors.affiliation: Biotechnology Research Group, Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Nahid H
authors.initials: NH
authors.lastname: Hajarah
authors.affiliation: Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Nabih A
authors.initials: NA
authors.lastname: Baeshen
authors.affiliation: Biotechnology Research Group, Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Jamal S
authors.initials: JS
authors.lastname: Sabir
authors.affiliation: Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA; Biotechnology Research Group, Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Robert K
authors.initials: RK
authors.lastname: Jansen
mesh_terms: D020418:Algal Proteins / Q000235:genetics; D017377:Diatoms / Q000145:classification* / Q000235:genetics / Q000648:ultrastructure; D019143:Evolution, Molecular; D008855:Microscopy, Electron, Scanning; D010802:Phylogeny; D017422:Sequence Analysis, DNA
chemical_list: D020418:Algal Proteins
keywords: Craspedostauros; Diatoms; Druehlago; Mastogloiales.; Staurotropis; phylogeny