Sprecher
Beschreibung
When ecosystems are devastated by environmental crises and mass extinction events, recovery is rarely immediate. Instead, the first plants to reclaim these disrupted landscapes are often hardy opportunists that establish short-lived pioneer communities before more complex forests can return. We show that a similar ecological response followed the end-Triassic mass extinction, approximately 201 million years ago.
We show that the extinction of ‘seed-ferns’, such as Lepidopteris, was followed by a short-lived proliferation of sphenopsids (horsetail) and lycopsids (club mosses). New fossil discoveries from Lower Jurassic (Hettangian) deposits in Sweden record the last known appearance of the distinctive pleuromeian lycopsids. These fossils allow us to link the parent plant, Lycostrobus scottii, with both its large and small reproductive spores. Using occurrences of the characteristic megaspore Nathorstisporites hopliticus, we track the distribution of L. scottii across the critical interval spanning the Triassic–Jurassic transition and reconstruct its geographic and temporal history.
Our phylogenetic analyses identify Lycostrobus scottii as the youngest representative of the Pleuromeiaceae and recover this family as the sister group of the Chaloneriaceae. Taken together, the evidence suggests that pleuromeian lycopsids briefly flourished on a global scale in the wake of the end-Triassic ecological collapse. As Late Triassic forests disappeared, these resilient herbaceous plants rapidly spread into newly available habitats, forming widespread pioneer vegetation during the earliest Jurassic.