New Zealand Lithothelium (Pyrenulaceae) — description of a new species Lithothelium kiritea sp. nov., with notes on L. australe

Abstract

Lithothelium kiritea A.J. Marshall, Aptroot, de Lange & Blanchon sp. nov. (Pyrenulaceae) is described from Aotearoa / New Zealand. The new species has a mainly coastal and mostly westerly distribution in Aotearoa / New Zealand and is thus far known only from the bark of living Cordyline australis (Asparagaceae). The new species is separated from Lithothelium australe (treated here as endemic to the Chatham Islands), by its corticolous, rather than saxicolous habit, white to pale buff (when fresh) thallus and large ascospores (measuring 32−40 × 12−15 μm). Lithothelium kiritea is easily recognised and usually abundant in the locations where it has been found, yet it seems to have not been collected until 1973 when it was sampled once and then not collected again until 2018. Currently, specimens matching L. kiritea have not been reported from Australia, so we recommend it be searched for there. Within Aotearoa / New Zealand, we propose that the species be assessed as ‘Not Threatened’ using the New Zealand Threat Classification System.