Relationships among Sarcoscypha species: evidence from molecular and morphological characters

Abstract

Cladistic analyses employing the criterion of unweighted parsimony were performed on a matrix of morphological characters and on a combined data matrix of morphological and molecular characters (from the internal transcribed spacer region of the nuclear ribosomal DNA including the 5.8S ribosomal RNA gene and the flanking ITS-1 and ITS-2 regions) in order to infer relationships among the species of Sarcoscypha. The outgroup taxa for both analyses were Microstoma floccosum, Nanoscypha tetraspora, Nanoscypha sp., and Pithya cupressina. Fifteen morphological characters were identified and analyzed using NONA. These characters were combined with 104 informative molecular characters for a total of 119 phylogenetically informative characters in the combined analysis. An initial analysis of morphological data produced 166 most parsimonious trees. The consensus tree resolved the two Nanoscypha species plus S. striatispora as a monophyletic group, but showed no resolution among the remaining species of Sarcoscypha. A second analysis of the morphological data with only the core species of Sarcoscypha and with Pithya as the outgroup still showed little resolution. The analysis of molecular data alone produced a consensus tree with a toplogy much like that from a previously published analysis including fewer taxa and supported the transfer of S. striatispora to Nanoscypha. The analysis of combined morphological and molecular data produced two equally parsimonious trees. The only differences in the results from the combined and molecular analyses were: (i) the three accessions of S. austriaca formed a monophyletic group in the consensus tree from the combined analysis but not the molecular analysis, and (ii) Pithya cupressina was sister to Sarcoscypha in the combined analysis whereas Pithya, Nanoscypha, and Sarcoscypha formed an unresolved trichotomy in the consensus tree from the molecular analysis. Both the molecular and the combined analyses resolved two major clades within the core Sarcoscypha. All analyses placed S. striatispora outside the major clade formed from the remaining species of Sarcoscypha but nested within the Nanoscypha clade. A new combination is made for Sarcoscypha striatispora.

Key Words:

• cladistic analysis
• Microstoma
• morphology
• Nanoscypha
• phylogeny
• Pithya
• Sarcoscyphaceae
• systematics