Paraphyly and cryptic diversity unveils unexpected challenges in the “naked lichens” (Calvitimela, Lecanoromycetes, Ascomycota)
- Author:
- Fjelde M.O., Timdal E., Haugan R. & Bendiksby M.
- Year:
- 2024
- Journal:
- Molecular Phylogenetics and Evolution
- Pages:
- 190: 107944 [16 p.]
- Url:
- https://doi.org/10.1016/j.ympev.2023.107944
Molecular phylogenetics has revolutionized the taxonomy of crustose lichens and revealed an extensive amount
of cryptic diversity. Resolving the relationships between genera in the crustose lichen family Tephromelataceae
has proven difficult and the taxon limits within the genus Calvitimela are only partly understood. In this study, we
tested the monophyly of Calvitimela and investigated phylogenetic relationships at different taxonomic levels
using an integrative taxonomic approach. We performed a global sampling of all species currently assigned to
Calvitimela and conducted additional sampling of C. melaleuca sensu lato across Norway. We included 108
specimens and produced more than 300 sequences from five different loci (ITS, LSU, MCM7, mtSSU, TEF1-α). We
inferred phylogenetic relationships and estimated divergence times in Calvitimela. Moreover, we analyzed
chemical and morphological characters to test their diagnostic values in the genus. Our molecular phylogenetic
results show evolutionarily old and deeply divergent lineages in Calvitimela. The morphological characters are
overlapping between divergent subgenera within this genus. Chemical characters, however, are largely informative
at the level of subgenera, but are often homoplastic at the species level. The subgenus Calvitimela is found
to include four distinct genetic lineages. Detailed morphological examinations of C. melaleuca s. lat. reveal differences
between taxa previously assumed to be morphologically cryptic. Furthermore, young evolutionary ages
and signs of gene tree discordance indicate a recent divergence and possibly incomplete lineage sorting in the
subgenus Calvitimela. Phylogenetic analysis and morphological observations revealed that C. austrochilensis and
C. uniseptata are extraneous to Calvitimela (Tephromelataceae). We also found molecular evidence supporting
C. septentrionalis being sister to C. cuprea. In the subgenus Severidea, one new grouping is recovered as a highly
supported sister to C. aglaea. Lastly, two fertile specimens were found to be phylogenetically nested within the
sorediate species C. cuprea. We discuss the need for an updated classification of Calvitimela and the evolution of
cryptic species. Through generic circumscription and species delimitation we propose a practical taxonomy of
Calvitimela.
Keywords: Cryptic species; Integrative taxonomy; Lichenized fungi; Phylogenetics; Substitutional saturation; Secondary chemistry.
- Id:
- 36180
- Submitter:
- zpalice
- Post_time:
- Thursday, 18 January 2024 20:04