An unidentified type of parasitic agnathan was utilized by International Genetic Technologies to obtain ancient DNA from marine life. Not much is known about them, aside from their status as blood-feeding jawless fish; they have been found in ice samples dating as far back as the Cambrian period, and appear to persist today (DNA samples as old as Anomalocaris and as recent as the colossal squid have been found in their gut contents). This suggests that they represent an evolutionary lineage of parasites, rather than a single species. Whole specimens are commonly found in ice samples; the extreme age and deep-sea locations of some of these samples suggest that they are not water ice but a more exotic substance.
