because the vertebrate fossil record of the Famennian is sparse, many extinctions attributed to the Kellwasser event may have actually been caused by the Hangenberg event. Among vertebrates, 44% of high-level clades and over 96% of species were lost during the Hangenberg Event, which occurred globally and did not discriminate between freshwater and marine species. Placoderm diversity had already decreased in the Kellwasser Event, and all remaining subgroups (arthrodires, antiarchs, phyllolepids, and ptychodontids) died out abruptly at the end of the Devonian. Sarcopterygians (lobe-finned fish) were also strongly affected: onychodontidans, porolepiforms, tristichopterids, and most other “osteolepidids” went extinct. Some large fish, namely rhizodonts, megalichthyids, and a few acanthodians, survived but failed to significantly increase their ecological disparity, eventually dying out later in the Paleozoic. Dipnoans (lungfish) persisted through the extinction more easily than other sarcopterygians, though they were apparently extirpated from marine environments. Among the most major ecological changes associated with the extinction are the rise of chondrichthyans (sharks and kin) and actinopterygians (ray-finned fish), which took over in diversity and relative abundance during the Early Carboniferous. These survivors were generally small and fast-breeding, resulting in a decrease in average vertebrate body size across the extinction. Even so, few Devonian chondrichthyan and actinopterygian species survived into the Carboniferous, indicating that these groups also experienced extinctions. Sharks that survived the extinction were greatly reduced in size; only sharks less than a meter long remained, and it would take 40 million years before they started to increase in size again. Four-limbed vertebrates (stegocephalians, aka “tetrapods” in the broad sense of the term) evidently survived, eventually leading to the earliest true amphibians, reptiles, and synapsids in the Carboniferous. However, no known Famennian “tetrapod” persisted into the Carboniferous, with “ichthyostegalian”-grade stegocephalians such as Ichthyostega and Acanthostega disappearing from the fossil record. A distinct gap in time traditionally separated the Famennian “tetrapod” faunas from their successors in the Early Carboniferous. This fossil hiatus, known as “Romer’s Gap”, has been linked to the Hangenberg Event. However, recent and continued discovery of many Visean and Tournaisian “tetrapods” has helped to close in this gap, suggesting that the Hangenberg Event affected some vertebrates less severely than previously thought. Coprolitic evidence from early Tournaisian deposits in eastern Greenland has also supported the notion that tetrapods were not as affected by the Hangenberg Event as previously thought. Plants During the Famennian, the world was covered by a fairly homogenous and