Verrucaria elaeomelaena

Schiavo, Lo, 2015, Revision of the Verrucaria elaeomelaena species complex and morphologically similar freshwater lichens (Verrucariaceae, Ascomycota), Phytotaxa 197 (3), pp. 161-185 : 175

Verrucaria elaeomelaena agg.

The species complex consists of V. elaeomelaena s.str., V. alpicola , V. humida and several additional taxa for which not enough material has been available yet for sequencing and where no morphological characters are known which would justify a separation at species level. Verrucaria basaltica ( Fig. 6A ), V. maas-geesterani ( Fig. 6B ) and V. pachyspora ( Fig. 6C ) may belong in this species complex, but no material was available for sequencing. The V. elaeomelaena complex is characterised by a crustose, subgelatinous thallus with prominent perithecia with a widely-spreading involucrellum reaching down to the bottom of the thallus. The involucrellum is usually covered by a thalline mantle which reaches often to the tip or at least into its upper half. The ascospores are of medium to large size compared to other crustose Verrucariaceae (20–46 μm) and with a generally small length/width ratio (<2.3), but exceptions exist in several groups. Pycnidia were observed in some of the specimens from low elevations (reported as V. andesiatica in Orange 2009b) but neither in V. alpicola nor in populations with near identical sequences to the epitype of V. elaeomelaena ( V. elaeomelaena s.str.).

The measured data given below are based on the sequenced specimens used in this study. It is likely that with more specimens sequenced the range of measured data and the confirmed distribution range will become wider. The morphological variation documented for British material of V. andesiatica in Orange (2009b) refers to silicolous populations of V. elaeomelaena s.lat. Morphological data given for V. margacea “ s.str. ” in Thüs & Schultz (2008) are a mixture of measurements from V. margacea and silicolous populations of V. elaeomelaena s.lat.

Figures

FIGURE 6. Habitus of European freshwater species of Verrucaria with large ascospores and spreading involucrellum. A. Holotype of Verrucaria basaltica (PRM). B. Holotype of Verrucaria pachyspora (PRM). C. Isotype of Verrucaria maasgeesterani (PRM). D. Specimen Thüs W Ice016 of Verrucaria margacea (BM). E. Isotype of Verrucaria margacea (W). Scale bar: A–E = 1 mm.