During this period, earliest known
agoniatitidammonoid fossils began appearing within this stage after first appearing in previous stage and began to evolutionarily radiate within this stage, in which a new ammonoid order
Goniatitida rises in the end of Zlichovian stage (Siberian representation; corresponds to early Eifelian and after the end of Early Devonian, before 391.9
mya). Later agoniatitid ammonoids would die out in the
Taghanic event in the upper middle
Givetian. Goniatite ammonoids would give rise to further ammonoid orders, thus starting ammonoid dominance of marine fossils in further periods until their end at the
Cretaceous-Paleogene mass extinction event.
In North America the Emsian Stage is represented by Sawkill or Sawkillian time.
One of the most basal
tetrapodomorph fish known. The genus is important to the study of the evolution of tetrapods due to the unique nature of its nostrils, which provide vital evidence regarding the evolutionary transition of fish-like nostrils to the vertebrate choanae
^Kaufmann, B.; Trapp, E.; Mezger, K. (2004). "The numerical age of the Upper Frasnian (Upper Devonian) Kellwasser horizons: A new U-Pb zircon date from Steinbruch Schmidt(Kellerwald, Germany)". The Journal of Geology. 112 (4): 495–501.
^Algeo, T. J. (1998). "Terrestrial-marine teleconnections in the Devonian: links between the evolution of land plants, weathering processes, and marine anoxic events". Philosophical Transactions of the Royal Society B: Biological Sciences. 353 (1365): 113–130.