Phylogeny, taxonomy and diversification events in the Caliciaceae

Abstract

Although the high degree of non-monophyly and parallel evolution has long been acknowledged within the mazaediate Caliciaceae (Lecanoromycetes, Ascomycota), a natural re-classification of the group has not yet been accomplished. Here we constructed a multigene phylogeny of the Caliciaceae-Physciaceae clade in order to resolve the detailed relationships within the group, to propose a revised classification, and to perform a dating study. The few characters present in the available fossil and the complex character evolution of the group affects the interpretation of morphological traits and thus influences the assignment of the fossil to specific nodes in the phylogeny, when divergence time analyses are carried out. Alternative fossil assignments resulted in very different time estimates and the comparison with the analysis based on a secondary calibration demonstrates that the most likely placement of the fossil is close to a terminal node rather than a basal placement in the Calicium clade. Our dating analysis show two successive events giving rise to main clades of mazaediate taxa within the Caliciaceae, in the Upper-Lower Cretaceous boundary and in the Paleocene. As a result of this study, Cyphelium is synonymized with Calicium, Acolium is resurrected, and the new genera Allocalicium and Pseudothelomma are described. Twelve new combinations are proposed: Acolium karelicum, Acolium marcianum, Allocalicium adaequatum, Calicium carolinianum, Calicium lecideinum, Calicium lucidum, Calicium notarisii, Calicium pinicola, Calicium trachyliodes, Pseudothelomma occidentale, Pseudothelomma ocellatum and Thelomma brunneum. A key for the mazaedium-producing Caliciaceae is included.

Caspary's fungi from Baltic amber: historic specimens and new evidence

“…The overall morphology of Calicium succini (Caspary's Stilbum succini ) including the single ascoma, the well‐developed spore mass (mazaedium), one‐septate ascospores, and the stipe, capitulum, mazaedium and ascospores of the fossil correspond exactly with those of several extant Calicium species (Tibell ). Another fossil Calicium has been found from Baltic amber (Rikkinen ), and this fossil has been used as a minimum age constraint for the genus Calicium and the family Caliciaceae in dating studies (Prieto & Wedin , ; Beimforde et al . ).…”

Morphological Convergence in Forest Microfungi Provides a Proxy for Paleogene Forest Structure

“…The ascospores of this fossil are similar to those of another Calicium specimen recently found from Bitterfeld amber, which also revealed many details in ascospore ultrastructure (Rikkinen et al, 2018). The preserved features of the two fossils correspond with those of extant species in Calicium Clade A (Prieto and Wedin, 2017). A third Calcium specimen from Baltic amber does not belong to the same clade but cannot be safely assigned to any one extant group because species of two extant lineages produce comparable ascomata and similar ascospores (Rikkinen et al, 2018).…”

Calicioid lichens and fungi in amber – Tracing extant lineages back to the Paleogene

“…Remarks: This fossil was originally described and illustrated as Stilbum succini by Caspary (1886) and Caspary and Klebs (1907a, b), and then transferred to the genus Calicium by Kettunen et al (2018). The preserved features correspond well with those of extant species in Calicium Clade A (Prieto and Wedin, 2017). The size and shape of ascospores are also similar to those of amber specimen GZG.BST.27300 which contains abundant and well preserved ascomata which also reveal details of ascospore ultrastructure.…”

“…by Rikkinen (2003b) and has been used as a minimum age constraint for Calicium (Caliciales) in dating studies Wedin, 2013, 2017;Beimforde et al, 2014). The preserved features of this fossil correspond well with those that characterize extant species of Calicium Subclade B3 (Prieto and Wedin, 2017).…”

“…Now further polishing has brought the capitulum and some detached ascospores closer and revel that some spores appear 'longitudinally striate', most probably because they have spirally arranged ridges on the surface, which later becomes distorted by irregular cracks. Nevertheless, the exact affinity of the fossil still remains uncertain as also extant species of Calicium Subclade B1 (Prieto and Wedin, 2017), including C. adspersum Persoon and C. chlorosporum F. Wilson, have spirally arranged ridges on the ascospore surface. Extant species of this group tend to have a dense yellow (rarely brown) pruina on the mazaedium and excipulum, but this feature would not necessarily have been preserved, especially as the mazaedium of the fossil was probably reduced in size before the detached ascoma was engulfed in fresh resin and finally preserved.…”