Lichens of Ile Amsterdam and Ile Saint Paul (TAAF, southern Indian Ocean)

Abstract

Lichens collected in 2007 on Ile Amsterdam and Ile Saint Paul in the Indian Ocean are reported. The diversity is rather poor, with 77 and 40 species collected, respectively. Of those, the islands share 25 species. Caloplaca amsterdamensis Aptroot & Ertz is newly described. Two species, viz. Lecanora subsulphurata and Opegrapha consimillima are the only other endemic species known from these islands. The lichen flora is distinctly temperate to subtropical, with only a few subantarctic elements. Temperate oceanic islands in other oceans share significantly more species with Ile Saint Paul and/or Ile Amsterdam than the neighbouring subantarctic islands. All previously reports of lichens from these islands have been examined and cross-referenced, leading to the new synonymization of several species previously described from Ile Saint Paul, viz. Buellia sancti-pauli, Caloplaca fulgescens, Lecidea conioptoides, L. parasemopsis, L. sancti-pauli, and Verrucaria aethioboliza. It also transpired that the previous report of the genus Orceolina from Ile Saint Paul is incorrect, with the effect that the genus is still only known from Kerguelen. Nearly all species are new records for Ile Amsterdam and most are new for Ile Saint Paul. Some species, viz. Bacidia arnoldiana, B. egenula, B. fraxinea, C. limonia, C. oasis, C. ulcerosa, Fuscopannaria ignobilis, Pertusaria amarescens, Porina curnowii, Porpidia ochrolemma, Pyrenula laevigata, Scoliciosporum intrusum (with the new synonym S. camptosporum), and Verrucaria dolosa are reported for the first time from the Southern Hemisphere.