Taxonomic history A system of classification for the Verrucariaceae was first suggested by German botanist
Franz Gerhard Eschweiler in 1824. In his scheme,
taxa were distributed between two
taxonomic ranks intended as names of orders ("
cohors"), the Dermatocarpeae and the Verrucariae, based on thallus structure. The Dermatocarpeae contained
squamulose (scaly) and
foliose (leafy) species, while the Verrucariae had the crustose species. Although several genera were included in each cohor, most of these are now known to be not closely related and are classified in other families; the only currently applicable genera from Eschweiler's list are
Dermatocarpon and
Endocarpon in the Dermatocarpeae, and
Verrucaria in the Verrucariae. Because Eschweiler published these taxa as "cohors", they do not meet the requirements of
valid publication according to
nomenclatural rules, and the
authorship of the family cannot be attributed to him. The family was validly published by
Jonathan Carl Zenker three years later in 1827 (as Verrucariae), with
Verrucaria assigned as the
type genus. In Zenker's proposed classification, the family was divided into
Cryolichenes (
Verrucariae), which contained
Verrucaria and other unrelated crustose genera, and
Phyllolichenes (
Endocarpa), with genus
Endocarpon representing the squamulose and foliose taxa. Nearly a century later,
Alexander Zahlbruckner's publication
Catalogus Lichenum Universalis (1922) became an influential work for lichen classification. He divided the order Verrucariales into two families, Dermatocarpaceae and Verrucariaceae, the latter of which was divided into 13 genera, 9 of which remain in the family. Around this time, German lichenologist
Georg Hermann Zschacke contributed the first extensive
monographic series on the family in a set of publications from 1913 to 1927. His classification scheme was similar to that of Zahlbruckner. Historically, there were three main
morphological criteria used to separate genera in the Verrucariaceae: spore
septation (the degree of partitioning by septa); the structure of the
thallus; and the presence or absence of
algae in the spore-bearing tissue, the
hymenium. However, even before the advent of
molecular phylogenetics, the use of these have been contentious, as several authors have considered them artificial, and not representative of true
phylogenetic relationships. As one example, the use of the degree of spore septation as a major character to
circumscribe genera was shown to be problematic when it was demonstrated that in some instances, spore septation is variable with a single species. In 1953, Czech lichenologist
Miroslav Servít proposed a new system of classification for the Verrucariaceae, based largely on characteristics of the —the upper, often
pigmented, part of the fruiting body covering the . Josef Halda summarised Servít's contribution: "Servít's studies contributed to complicacy of the taxonomy of the whole order Verrucariales. The huge amount of newly described taxa (families, genera, species, varieties or forms) and new combinations almost brought an end to good orientation necessary for new researchers. Any of his studies is not really a revision since it contains only a further list of new taxa and their combinations within the many genera and family framework. Servít neither returned to his newly described taxa nor he revised them in his monographs". Servít's classification was not widely adopted by future authors, and according to
Cécile Gueidan and colleagues, it was the lack of clear morphological characteristics in the Verrucariaceae that hindered future proposals for changes in classification. Because of the relatively simple morphology of most of the crustose Verrucariaceae (especially in the type genus
Verrucaria), and the fact that this morphology is often variable depending on environmental conditions, identification and delimitation of the species in this family is difficult. Many morphological
traits are
symplesiomorphic or
homoplastic, and are not suitable as distinguishing characters to define genera. Studies have demonstrated several examples of
cryptic species–genetically distinct lichens that are difficult or impossible to distinguish by morphology alone–in the genera
Hydropunctaria,
Sporodictyon, and
Verrucaria. These difficulties are reflected in the number of species of uncertain status described by previous lichenologists: of the 84 Verrucariaceae species described by Zahlbruckner, about 37 are currently accepted as valid species; Zschacke described 133 species, of which about 50 are now accepted; of Servít's 424 described species, only about 60 are accepted.
Molecular phylogenetics }} The first molecular phylogenetic studies involving the Verrucariaceae, published between 2001 and 2006, were used to show the higher-level relationships in the
Eurotiomycetes. This research showed that Verrucariales has a
sister relationship to the
Chaetothyriales, an
order of non-lichenised fungi. In 2007 and 2009 publications, Cécile Gueidan and colleagues used molecular data from 83 Verrucariaceae taxa to demonstrate that many of the morphologically defined genera were
polyphyletic—of mixed evolutionary origins. In their analysis, they identified 4 major
lineages in the family, including ten
monophyletic subgroups. They proposed several taxonomic changes to more closely align the morphology-based classification with the molecular phylogeny, including the new genera
Parabagliettoa,
Hydropunctaria, and
Wahlenbergiella and several
new combinations.
Ancestral state reconstruction analysis suggests that the
most recent common ancestor of the Verrucariaceae was probably crustose, had a weakly differentiated upper , a
hymenium free of algae, and ascospores (i.e., without
septa). The first lichen-forming fungus to have its
genome sequenced was the
mycobiont of
Endocarpon pusillum, the type species of
Endocarpon and a member of the Verrucariaceae.
Etymology As is
standard practice in
botanical nomenclature, the name Verrucariaceae is based on the name of the type genus,
Verrucaria, with the ending
-aceae indicating the
rank of family. The genus name is derived from the
Latin word
verruca (meaning "wart") and the suffix
-aria (meaning "belonging to" or "possession").
Synonymy Some genera now classified in the Verrucariaceae were considered by past authors to be distinctive enough to warrant inclusion in their own family. These historical family names are considered
synonymous with Verrucariaceae: • Endocarpaceae – type genus:
Endocarpon • Dermatocarpaceae – type genus:
Dermatocarpon • Glomerillaceae – type genus:
Glomerilla • Endopyreniaceae – type genus:
Endocarpon • Mastodiaceae – type genus:
Mastodia • Pyrenothamniaceae – type genus:
Pyrenothamnia , now synonymised with
Endocarpon • Thelidiaceae – type genus:
Thelidium • Bagliettoaceae – type genus:
Bagliettoa • Staurotheleaceae – type genus:
Staurothele ==Description==