Posted by: Scott Mardis on March 14th, 2014
Matt Bille, at his blog Matt’s Sci/Tech Blog, recently posted about another article by Sharon Hill questioning the validity of the so-called “Prehistoric Survivor Paradigm”, the idea that presumably extinct animals have managed to survive into the modern era without leaving a conspicuous fossil record and are in fact responsible for various modern day “monster” sightings and data.
Vertebrate paleontologist Darren Naish has also been very critical of this idea, particularly in regard to the idea of relict plesiosaurs (see this Cryptomundo post).
While I encourage you to read and listen to what Sharon Hill and Darren Naish have to say and they do make some powerful arguments, I feel some very relevant things to the debate have been left out. We must remember that the best case for most cryptids at this point in time is based on ambiguous, circumstantial evidence and any possible connections to extinct animals are tenuous at best. Assuming the bulk of descriptive and photographic evidence might be correct and bear some resemblance to a known fossil form, we should not overlook the remarkable phenomenon of convergent evolution. It’s within the realm of possibility that some recently evolved animal, unknown to us in fossil form, has developed features similar to some well known extinct forms.
Having said that, there is the phenomenon of “reworked” fossils. These are fossils of animals believed to have gone extinct found in younger fossil deposits after their presumed extinctions. They are called “reworked” because it is thought they have been worked out of their original strata into younger deposits by a host of physical phenomena. The mechanisms are usually tidal and fluvial erosion, tectonic activity, glacial scouring, erosion by wind and rain, volcanism, burrowing by animals on land and in the sea, even dislodgement by tree roots. The dating of fossils is done by radiometric dating, rare earth element testing and by the range correlation of diagnostic microfossils directly associated with the fossil or within the fossil matrix. Sometimes this information is not available, so assumptions have to be made based on the general consensus of the geologic range of the particular animal or the taphonomic state of the fossil itself. There do remain questions in some cases and there is considerable debate about the possible validity of some reputed Paleocene dinosaur specimens.
There have been isolated dinosaur teeth found in Miocene fossil deposits in France and in Louisiana.
There are also the geological phenomena of “lazarus taxa” and “ghost lineages”. A lazarus taxon is the reemergence in the fossil record of a type that had been thought to have died out much earlier. The term ghost lineage refers to the missing fossil record of such a lazarus taxon. One example might be the controversial putative Paleocene therapsid (mammal-like reptile) Chronoperates paradoxus from Canada, which if correctly interpreted gives the therapsids as a group a 100 million year range extension. Additionally, the Iranian ichthyosaur Malawania is believed to have a 66 million year ghost lineage and the Megachasmid sharks (Megamouth) may have a 70 million year ghost lineage between the mid-Cretaceous and Miocene [PDF] download pdf – Vlaams Instituut voor de Zee. This is compared to only a 65 million year extinction record for the plesiosaurs.
This is all very speculative but I submit to you that you cannot ignore this evidence in question to the whole PSP debate. The presence of living plesiosaurs or non- avian dinosaurs today will only be demonstrated by confirmed type specimens. And while the fossil records of plesiosaurs and coelacanths may show very different patterns of diversity through time and deposition, the post-Cretaceous coelacanth fossil record is only represented by two specimens, the recently described Macropomoides palaestina from the Miocene of Israel and a highly questionable specimen from the Paleocene of Sweden [PDF] – Columbus State University.
Scott Mardis has been an active field investigator of the Lake Champlain “Monster” since 1992. He is a former sustaining member of the defunct International Society of Cryptozoology and a former volunteer worker in the Vertebrate Paleontology Dept. of the Philadelphia Academy of Natural Sciences (1990-1992). He co-authored a scientific abstract about the Lake Champlain hydrophone sounds for the Acoustical Society of America in 2010. He currently lives in Bradenton, Florida.