ORIGINAL ARTICLE
Saxiloba: a new genus of placodioid lichens from
the Caribbean and Hawaii shakes up the Porinaceae tree
(lichenized Ascomycota: Gyalectales)
1 1 | Botanischer Garten und Botanisches Museum, Freie Universität Berlin,
Königin-Luise-Straße 6–8, 14195 Berlin, Germany |
2 | Licenciatura en Biología, Universidad Distrital Francisco José de
Caldas, Cra. 4 No. 26D-54, Torre de Laboratorios, Herbario, Bogotá
D.C., Colombia |
3 | Departmento de Micologia, Universidade Federal de Pernambuco, Av.
Nelson Chaves s/n, Recife, PE 50670-420, Brasil |
4 | Jardín Botánico Nacional, Carretera del Rocío km 3½, Calabazar,
19230 Habana, Cuba |
5 | National Tropical Botanical Garden, 3530 Papalina Road, Kalaheo,
HI 96741 USA |
Online publication date: 2020-12-29
Publication date: 2020-12-29
Plant and Fungal Systematics 2020; 65(2): 577–585
KEYWORDS
ABSTRACT
The new genus Saxiloba is described with the two species S. firmula from the
Caribbean and S. hawaiiensis from Hawaii. Saxiloba is characterized by a unique, placodioid
thallus forming distinct lobes, growing on rock in shaded to exposed situations with
a trentepohlioid photobiont and a fenestrate thallus anatomy with distinct surface lines.
The material is often sterile, but Porina-like perithecia and ascospores had previously been
described for the Caribbean taxon and were here confirmed for both species. Molecular
sequence data also confirmed placement of this lineage in Porinaceae. Its position within
that family supports the notion that Porinaceae should be subdivided into a larger number
of genera than proposed in previous classification attempts. Compared to other Porinaceae,
Saxiloba exhibits a unique morphology and anatomy that recalls taxa in the related family
Graphidaceae and it substantially expands the known phenotypic variation within Porinaceae.
The two recognized species are similar in overall morphology but, apart from their
disjunct distribution and different substrate ecology, differ in lobe configuration, color and
disposition of the crystal clusters and resulting surface patterns.