...DAVID M. RUDKIN; GRAHAM A. YOUNG; ROBERT J. ELIAS; EDWARD P. DOBRZANSKI Abstract The largest known trilobite fossil, a virtually complete articulated dorsal shield of the asaphid Isotelus rex new species, has been recovered from Upper Ordovician (Cincinnatian, Richmondian) nearshore carbonates...

... (Isotelus rex) has a reconstructed exoskeletal length of 72 cm ( Rudkin et al., 2003 ). The Arouca lagerstätte has produced a 70-cm-long, almost complete fossil of Ogyginus forteyi ( Fig. 2F ); however, extrapolation from a 21-cm-long isolated pygidium of Hungioides bohemicus ( Fig. 2B ) suggests a total...

... (anterior to the mouth), and an association with Rusophycus trace fossils. The large size attained by asaphids is also appropriate; indeed, the largest trilobite known is Isotelus rex (Rudkin et al., 2003 ) at > 70 cm long. The typical ventral features are shown again in the Asaphellus species...

... that moderately to extremely large species of Isotelus occur in many of these units, including the largest trilobite ever described, I. rex , in the Cincinnatian of Manitoba ( Rudkin et al. 2003 ). The temporal and geographic distribution of large Isotelus species in eastern North America has been recently...

... extended during the two months of study. Acknowledgment for assistance in the field is made to John Fitts, Rex McGehee, Norval Ballard, Ross Maxwell, Everett Orr, and J. O. Beach. 1 Manuscript received, September 15, 1933. 2 Professor of paleontology, University of Oklahoma. ©...

... is transversely elongated with medially opposed gnathal edges ( Fig. 3b ). Compared with the Vicissicaudatan Sidneyia inexpectans and the trilobite Redlichia rex ( Stein 2013 ; Zacaï et al. 2016 ; Holmes et al. 2020 ), the protopods of A. serratum exhibit a more robust construction, suggesting...

... . 4 – 10 . Rudkin , D. M. , G. A. , Young , R. J. , Elias , E. P. , and Dobrzanski , 2003 , The world's biggest trilobite: Isotelus rex new species from the Upper Ordovician of northern Manitoba, Canada : Journal of Paleontology , 77 . 99 – 112 . Sanders , H. L...

... nutrient regeneration and its coupling to primary productivity in coastal waters . Nature 255 ( 5505 ), 215 – 17 . Rudkin DM , Young GA , Elias RJ and Dobrzanski EP ( 2003 ) The world’s biggest trilobite— Isotelus rex new species from the upper Ordovician of northern...

... of the largest individual arthropod fossils found to date globally, comparable with the largest specimen of the Ordovician trilobite, Isotelus rex ( Rudkin et al. 2003 ). It may also record the largest known arthropod in Earth history. The upper size estimate of a 2.63 m length and c. 50 kg weight exceeds...

... the Paleozoic and modern biotas are reported in Table 3 : the five extant species are the lingulate brachiopod Glottidia pyramidata , bryozoan Bugula neritina , crab Cancer irroratus , isopod Cirolana polita , and snail Mitrella marquesa ; the five extinct, Paleozoic species are the trilobite Isotelus...

.... Young , G.A. Elias , R.J. Dobrzanski , E.P. 2003 . The world’s biggest trilobite – Isotelus rex new species from the Upper Ordovician of northern Manitoba, Canada . Journal of Paleontology , 77 : 99 – 112 . 10.1666/0022-3360(2003)077<0099:TWBTIR>2.0.CO;2 . Rudwick, M.J.S...

... trangressive sequence and the Montmorency Fault at the Montmorency Falls, Quebec. Geological Society of America, Northeastern Section, Centennial Field Guide 5, pp. 357–362. Rudkin, D.M., Young, G.A., Elias, R.J., and Dobrzanski, E.P. 2003. The world’s biggest trilobite — Isotelus rex new species from...