Department of Biological Sciences, Humboldt State University, Arcata, CA 95521, USA.
Am J Bot. 2013 Feb;100(2):450-9. doi: 10.3732/ajb.1200470. Epub 2013 Jan 10.
Colonists of even the most inhospitable environments, lichens are present in all terrestrial ecosystems. Because of their ecological versatility and ubiquity, they have been considered excellent candidates for early colonizers of terrestrial environments. Despite such predictions, good preservation potential, and the extant diversity of lichenized fungi, the fossil record of lichen associations is sparse. Unequivocal lichen fossils are rare due, in part, to difficulties in ascertaining the presence of both symbionts and in characterizing their interactions. This study describes an exceptionally well-preserved heteromerous lichen from the Lower Cretaceous of Vancouver Island.
The fossil occurs in a marine carbonate concretion collected from the Apple Bay locality on Vancouver Island, British Columbia, and was prepared for light microscopy and SEM using the cellulose acetate peel technique.
The lichen, Honeggeriella complexa gen. et sp. nov., is formed by an ascomycete mycobiont and a chlorophyte photobiont, and exhibits heteromerous thallus organization. This is paired with a mycobiont-photobiont interface characterized by intracellular haustoria, previously not documented in the fossil record.
Honeggeriella adds a lichen component to one of the richest and best characterized Early Cretaceous floras and provides a significant addition to the sparse fossil record of lichens. As a heteromerous chlorolichen, it bridges the >350 million-year gap between previously documented Early Devonian and Eocene occurrences.
即使是最不适宜居住的环境中的殖民者，地衣也存在于所有陆地生态系统中。由于其生态多功能性和普遍性，它们一直被认为是陆地环境早期殖民者的优秀候选者。尽管有这样的预测、良好的保存潜力和现存地衣真菌的多样性，但地衣组合的化石记录却很少。由于难以确定共生体的存在并描述其相互作用，明确的地衣化石很少见。
该化石来自不列颠哥伦比亚省温哥华岛苹果湾地点采集的海洋碳酸盐凝块，使用纤维素醋酸酯皮技术进行了光镜和 SEM 准备。
地衣 Honeggeriella complexa gen. et sp. nov. 由子囊菌菌元和绿藻光合生物组成，表现出异层组织的地衣结构。这与一个菌元-光合生物界面配对，其特征是细胞内吸器，以前在化石记录中没有记录过。
Honeggeriella 在地衣丰富且特征描述最好的早白垩世植物群之一中增加了地衣成分，并为地衣稀疏的化石记录提供了重要补充。作为一种异层的绿藻地衣，它填补了以前记录的早泥盆世和始新世之间超过 3500 万年的差距。
