The Circumscription of the Dicranaceae (Bryopsida) Based on the Chloroplast Regions trnL—trnF and rps4

Abstract

The Dicranaceae have been classified as one of the largest, most heterogeneous families of the moss subclass Dicranidae. Circumscriptions of the family have varied, with some studies excluding selected subfamilies and recognizing them at the familial rank, whereas others have retained a broader familial concept. As well, classifications have varied in their generic circumscriptions of the subfamilies. Chloroplast DNA sequence data (trnL (UAA)—trnF (GAA) and rps4) were used to examine the monophyly of the family and phylogenetic relationships among the subfamilial and generic taxa. Special emphasis was given to subfamily Dicranoideae, with 18 of the 23 genera sampled. Seventy-four trnL-F and rps4 sequences formed a matrix of 1161 aligned base pairs (bp). Phylogenetic analyses using MP and ML criteria were based on 983 bp (333 parsimony informative) after ambiguous data were removed. Our results support the following inferences: 1) Dicran- aceae as traditionally defined are polyphyletic; 2) subfamilies Campylopodioideae, Dicranelloideae, Rhabdoweisioideae, and Trematodontoideae are excluded from a robust monophyletic concept of the Dicranaceae; 3) subfamily Dicranoideae is polyphyletic unless 16 genera are excluded from the subfamily, seven of which are transferred to the Rhabdoweisiaceae; 3) subfamily Paraleucobryoideae is polyphyletic with Brothera resolved in the Leucobryaceae clade and Paraleucobryum nested within subfamily Dicranoideae; 4) Dicnemonaceae (including Mesotus) and Wardiaceae are nested within traditional members of the Dicranaceae; and 5) four clades—Dicranoideae, Mesotoideae, Dicranoloma group plus Wardia, and the Leucoloma group, form a robust monophyletic taxon, considered here as a restricted concept of Dicranaceae (sensu stricto). This circumscription excludes 18 genera that have previously been included in the Dicranaceae.