Using phylogenetic species recognition to delimit species boundaries within Lasiosphaeria

Abstract

The genus Lasiosphaeria recently has been circumscribed more narrowly to include five mor-phospecies united by tomentose ascomata containing yellow centrum pigments. Species boundaries have not been established and phylogenetic relationships have not been clearly defined for these morphospecies. To delimit species boundaries and determine phylogenetic relationships among species, maximum parsimony, maximum likelihood and Bayesian analyses were conducted on sequence data from four nuclear genes, the ribosomal internal transcribed spacer (ITS) region, 28S large subunit (LSU) rDNA, β-tubulin and ribosomal polymerase II subunit 2 (RPB2). Representatives of L. glabrata, L. ovina, L. rugulosa and L. sorbina resolved as four highly supported monophyletic groups in almost all analyses and are recognized as well-defined species employing principles of genealogical concordance. These species delimitations are corroborated further by morphology. Representatives of L. lanuginosa were polyphyletic in almost all analyses. Although molecular analyses revealed that this morphospecies comprises several phylogenetic species, formal taxonomic recognition of these lineages is premature, so L. lanuginosa currently is treated as a morphological species complex. Complete species descriptions, including teleomorph, anamorph and culture characteristics, are given for L. glabrata, L. ovina, L. sorbina and the L. lanuginosa species complex along with detailed discussions of significant morphological characters used in recognizing species. These species are compared to five additional morphospecies that also may belong in the genus.

• Ascomycetes
• β-tubulin
• Cercophora
• genealogical concordance phylogenetic species recognition
• ITS
• LSU
• morphological species recognition
• phylogenetics
• RPB2
• Sordariales
• species concepts
• systematics

This work was supported in part by a NSF DDIG Grant (Doctoral Dissertation Improvement Grant, DEB-0105077) to ANM through the University of Illinois at Chicago (UIC) and in part by a NSF PEET Grant (Partnerships for Enhancing Expertise in Taxonomy, DEB-9521926) to SMH through The Field Museum of Natural History (FMNH). ANM also was supported during this study by a Lester Armour Graduate Fellowship from FMNH. Fieldwork for ANM was supported in part by an ASPT (American Society of Plant Taxonomists) Graduate Student Research Grant, an Explorers Club Research Grant and a UIC Provost Award. Fieldwork for SMH was supported in part by the National Research Council Resident Research Associate Post-doctoral Program in co-operation with the USDA Forest Service, Madison, Wisconsin. The authors are most grateful to Bert and Gill Brand, Misericordia Calduch, George Carroll, Fernando Fernández, Jacques Fournier, Thomas Læssøe, Kerry Robinson, Amy Rossman, Gary Samuels and Alberto Stchigel for providing specimens or cultures. The curators of the herbaria listed are thanked for material made available on loan. Andrea Adie is thanked for sequencing ITS for C. areolata. Sequences were generated in the Pritzker Laboratory for Molecular Systematics and Evolution at FMNH. This work represents a portion of a thesis in partial fulfillment of the requirements for the doctoral degree at the Graduate College of the University of Illinois at Chicago.