Dead clade walking
Dead clade walking refers to a clade (group) of organisms which survived a mass extinction but became extinct a few million years after the mass extinction or failed to recover in numbers and diversity.
Origin of phrase
The phrase "dead clade walking" was coined by David Jablonski (2002) as a reference to Dead Man Walking, a film whose title is based on American prison slang for a condemned prisoner's last walk to the execution chamber.
Jablonski found that the extinction rate of marine invertebrates was significantly higher in the stage (major subdivision of an epoch – typically 2–10 million years' duration) following a mass extinction than in the stages preceding the mass extinction. His analysis focused on marine molluscs since they constitute the most abundant group of fossils and are therefore the least likely to produce sampling errors. Jablonski suggested that two possible explanations deserved further study:
- Post-extinction physical environments differed from pre-extinction environments in ways which were disadvantageous to the "dead clades walking".
- Ecosystems that developed after recoveries from mass extinctions may have been less favorable for the "dead clades walking".
In popular culture
- An episode of the CBS series Elementary was named "Dead Clade Walking", and featured a Nanotyrannus skeleton found "significantly above" the K-T boundary.
- Jablonski, D. (2002) Survival without recovery after mass extinctions. PNAS 99, 8139-8144
- Korn, D., Belka , Z., Fröhlich, S., Rücklin, M., and Wendt, J. (Jan 2007). "The youngest African clymeniids (Ammonoidea, Late Devonian) – failed survivors of the Hangenberg Event". Lethaia 37 (3): 307–315. doi:10.1080/00241160410002054.
- "Popular phrases like ‘Lazarus taxon’, ‘Elvis taxon’, and ‘dead clade walking’ were first coined for gastropods ...": Nützel, A. (September 2005). "Recovery of gastropods in the Early Triassic". Comptes Rendus Palevol 4 (6-7): 501–515. doi:10.1016/j.crpv.2005.02.007.
- Moore, A. "‘Elementary’ Season 2, Episode 15: ‘Dead Clade Walking’". Atlanta Blackstar. Retrieved 31 January 2014.