AN EXCEPTIONALLY PRESERVED PARASITIC ARTHROPOD, HEYMONSICAMBRIA-TAYLORI N-SP (ARTHROPODA-INCERTAE SEDIS, PENTASTOMIDA), FROM CAMBRIAN-ORDOVICIAN BOUNDARY BEDS OF NEWFOUNDLAND, CANADA

A three-dimensionally and completely preserved phosphatized microfossi l has been found in Cambrian - Ordovician boundary bed limestones of t he Green Point Formation at Green Point, western Newfoundland, Canada. It represents a new form of larvae, previously described by D. Waloss ek and K.J. Muller from Upper Cambrian anthraconitic limestones (''Ors ten''). These authors identified the fossils as instars of marine stem -group representatives of the ''tongue worms,'' Pentastomida. Pentasto mida are parasites that today infest various land tetrapods and are pr esumed to represent one of the closest extant relatives of the Euarthr opoda. This new fossil possesses remarkably well-preserved trunk limb vestigia and anal region. It is another example of exceptional three-d imensionally preserved, phosphatized fossils of the Orsten type that i s no longer spatiotemporally restricted to the Upper Cambrian of Swede n.