Phylogenetic relationships among coprinoid taxa and allies based on data from restriction site mapping of nuclear rDNA

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Abstract
Phylogenetic relationships among coprinoid and closely related taxa were studied using restriction site data. Seven taxa in Coprinus (C. comatus, C. atramentarius, C. cinereus, C. micaceus, C. corduporus, C. plicatilis, C. curtus), five potential sister group taxa (Psathyrella gracilis, Panaeolus semiovatus, Bolbitius vitellinus, Agrocybe praecox, Stropharia rugosoannulata), and two secotioid taxa (Podaxis pistillaris and Montagnea arenaria) were investigated. Restriction analysis was carried out on enzymatically amplified portions of the nuclear gene coding for the large ribosomal subunit RNA and the internally transcribed spacer region II. A total of 153 sites were mapped, of which 54 were phylogenetically informative. Six equally-most parsimonious networks were resolved using cladistic methods. One of these six networks was identified as best supported using a stepmatrix to weight restriction site gains over losses (character-state weighting). This tree demonstrates that: 1, the genus Coprinus is at least paraphyletic and probably polyphyletic; 2, Psathyrella is derived from within Coprinus; 3, the two secotioid taxa are closely related to Coprinus comatus, and, 4, the sister genus to Coprinus is Bolbitius. The branches of the character-state weighted tree have support similar to identical branches from the equally weighted tree as evidenced by three robustness indices. The character-state weighted tree provides a phylogenetic hypothesis similar to a strict consensus tree from unweighted parsimony analysis, but has the advantage of being fully resolved and thus provides a more detailed hypothesis for future research.