7 January 2010，自然杂志报道：
Tetrapod trackways from the early Middle Devonian period of Poland
The fish--tetrapod transition was thus seemingly quite well documented. There was a consensus that the divergence between some elpistostegalians (such as Tiktaalik or Panderichthys) and tetrapods might have occurred during the Givetian, 391--385 Myr ago. Coeval with the earliest fossil tetrapods, trackways dating to the Late Devonian were evidence for their ability to walk or crawl on shores.
Now, however, Niedźwiedzki et al. lob a grenade into that picture. They report the stunning discovery of tetrapod trackways with distinct digit imprints from Zachemie, Poland, that are unambiguously dated to the lowermost Eifelian (397 Myr ago). This site (an old quarry) has yielded a dozen trackways made by several individuals that ranged from about 0.5 to 2.5 metres in total length, and numerous isolated footprints found on fragments of scree. The tracks predate the oldest tetrapod skeletal remains by 18 Myr and, more surprisingly, the earliest elpistostegalian fishes by about 10 Myr.
在波兰发现了比科学家们认为的最早的四足类脊椎动物早了1800万年的四足类动物脚印，比它们的“祖先”鲸 早了1000万年！
Jennifer Clack: the track discovery " blows the whole story out of the water."
Per Ahlberg： "These results force us to reconsider our whole picture of the transition from fish to land animals"
(Per Ahlberg和Jennifer A. Clack是两位鱼到四足动物进化的专家)
