Insights on The Morphological and Phylogenetic Delimitation of Dacrymyces Nees

Dacrymycetes has four families and 13 genera, few of them with molecular data available and then usually polyphyletic in phylogenetic analyses. Dacrymyces Nees is one of the polyphyletic genera in Dacrymycetes and it was introduced to accommodate one species, D. stillatus Nees. The morphological features of the genus are a homogeneous composition of the intra-structure and an amphigenous or superior hymenium. In this study, we included Neotropical specimens in the phylogeny of the Dacrymycetes and Dacrymyces s.s. is emended to include species with resupinate basidiomata, unilateral hymenium and heterogeneous context. In this new delimitation, the new species Dacrymyces avobrunneus is described using morphological and molecular data and three new combinations (D. ceraceus comb. nov., D. maxidorii comb. nov. and D. spathularia comb. nov.) are proposed based on DNA analyses.


Introduction
Dacrymycetes is a class of Basidiomycota characterized by the presence of continuous parenthosomes covering the dolipore septa (Oberwinkler 1993, Wells 1994, long bifurcate basidia, except in Unilacryma unispora (L.S. Olive) Shirouzu, Tokum. & Oberw., and basidiospores normally septate (McNabb 1964;1965a-e;1966;Shirouzu et al. 2013a;Oberwinkler 2014). Mostly of the species are brown-rot (Oberwinkler 1993), although white-rot was also reported (Seifert 1983). Dacrymyces was introduced to accommodate one species, D. stillatus Nees (1816), which presented teleomorphic and anamorphic stage. The morphological features of the genus are a homogeneous composition of the intra-structure, and an amphigenous or superior hymenium (McNabb 1973). The last revision of the genus was performed by McNabb (1973) using morphological features and included 31 species in Dacrymyces. Currently, the genus has 131 species names in Index Fungorum, although some of these were considered invalid or synonymized by McNabb (1973).
showed that the molecular, morphological, cytological and secondary compounds data produced similar phylogenies and, for some species complexes (e.g., Calocera cornea complex or D. stillatus complex), the inclusion of different approaches would be important to delimit these species.   (Table 1). Sequence alignments were constructed using the online version of MAFFT (Katoh and Toh 2008), using the Q-INS-I option with default parameters. Ambiguously regions in the alignment (e.g., large gaps) were manually removed prior to subsequent analysis.

Results
Phylogenetic reconstruction was based on the alignment of the ITS+nLSU dataset (1282 characters, including gaps) of 141 sequences representing eight genera belonging to Dacrymycetes. ML and BI analyses produced trees with nearly congruent topologies and therefore only the ML tree is shown (Fig.  1). The sequences from the studied specimens were grouped within a clade with high support (bp = 98, ub=91 and pp = 0.99), which we treated as the Dacrymyces sensu stricto clade.
The Dacrymyces s.s clade comprises 18 species, including the specimens studied in the current work: the new species D. avobrunneus (bp = 100, ub = 100, pp = 1) and the new combination D. maxidorii (bp = 98.1, ub = 100, pp = 1). In addition, sequences of materials previously identi ed as species of Cerinomyces [C. ceraceus Ginns Remarks: Dacrymyces is traditionally recognized by the homogeneous composition of the intra-structure and an amphigenous hymenium (McNabb 1973). Previously, the species with unilateral hymenium were placed in Dacryopinax, with a heterogeneous composition in Ditiola, and resupinate in Cerionomyces (McNabb 1964(McNabb , 1965a(McNabb , 1966(McNabb , 1973. However, the morphological features do not agree with the phylogenetic analyses, and it cannot be used separately to recognize or distinguish the genera in Based on our phylogenetic analyses (Fig. 1), species with resupinate basidiomata, heterogeneous composition of the context and unilateral hymenium are grouped in the Dacrymyces s.s. clade clade with high support (bp = 100, ub = 100, pp = 1). Thus, we emend the genus description to comprise species with these morphological features.
Remarks: The new species D. avobrunneus is similar to D. maxidorii, but it can be differentiated by the spathulate pileus, globose to subglobose hairs, heterogenous context, absence of hyphidia and smaller basidia (30-36.5 × 4.5 µm) (Lowy 1981). Dacrymyces avobrunneus differs from other species in Dacrymyces due to the unilateral hymenium and heterogeneous context. Remarks: Dacrymyces maxidorii is characterized by the presence of cylindrical hairs with globose to subglobose in ated parts forming chains in abhymenial surface (Lowy 1981 Alvarenga), all with Neotropical distribution, although only D. avobrunneus is, so far, phylogenetically close to this species (Fig. 1).
Distribution: This species is recorded in tropical and subtropical regions (GBIF 2021).

Discussion
In our study, the Dacrymyces s.s. clade is phylogenetically separated from the Calocera s.s. and Dacryopinax s.s. clades (bs = 98, ub = 91, pp = 0.99) as well as from other sequences of material identi ed as Dacrymyces. Usually, species in Dacrymycetes with amphigeneous or superior hymenium are placed in Dacrymyces; with unilateral hymenium are included in Dacryopinax; with coralloid basidiomata are described in Calocera, and resupinate species are treated in Cerinomyces. The tradition of using morphology to delimitate taxa continued up to recently (e.g., Shirouzu et al. 2009Shirouzu et al. , 2013Shirouzu et al. , 2017, including studies that used molecular data. However, evidences showed that the morphology does not agree with the phylogenetic history of the taxa (Shirouzu et al. 2013(Shirouzu et al. , 2017; Zamora and Ekamn 2020). Recently, Zamora and Ekamn (2020) showed similar results on the Dacrymyces s.s. clade, although they did not focus in this speci c group.
Here, the combinations D. ceraceus, D. maxidori and D. spathularia are proposed based on phylogenetic data, as well as following comments of previous results (Shirouzu et al. 2013(Shirouzu et al. , 2017Zamora and Ekamn, 2020). Other species clearly placed in the Dacrymyces s.s. clade, however, were not combined to this genus. Cerinomyces lagerheinii was described using samples from Ecuador, but the sequences available are from the USA. This species is reported in Brazil, Ecuador, French Polynesia, Mexico, New Zealand and Venezuela (GBIF 2021). A revision of these samples, older names, and sequencing of the type material or material from the type locality are desirable to know the truly distribution range and boundaries of the species. The sequences used to C. grandinioides and G. buccina are not either from their types materials or specimens collected in the type locality (Kenya and unknown locality in Europe, respectively), so those sequence may not represent the species (McNabb 1964, 1965b).
The Dacrymyces s.s. clade was phylogenetically well delimited and an emend to this genus is herein proposed to include species with resupinate basidiomata, unilateral hymenium and heterogeneous composition, following the morphological features of the new combinations and the new species. In addition, the knowledge about Dacrymyces richness in Brazil was updated to seven species by the addition of one new taxon and two combinations of previously described species. Therefore, the inclusion of specimens and sequences from samples collected in the Neotropics can be important to understand the morphological delimitation of Dacrymyces, as well as the knowledge about the Dacrymycetes diversity. Figure 1 Phylogenetic reconstruction of sequences of Dacrymycetes specimens inferred from a combined dataset of ITS and nLSU. Branches are labeled with ML bootstrap and UFBoot2 equal to or higher than 70%, and BI posterior probabilities equal to or higher than 0.95 respectively. The sequences in bold were generated in this study. The tree was rooted with Corpinus comatus (ALFTOL626) and Suillus pictus (AFTOL717) following Shirouzu et al. (2017).