Scollard Formation

Maastrichtian

Alberta, Canada

Dinosaurs:

Tyrannosauridae indet.

Albertosaurus sarcophagus

Tyrannosaurus rex

Ornithomimidae indet.

Ricardoestesia gilmorei

Ricardoestesia isosceles

Dromaeosauridae indet.

Dromaeosaurus albertensis

Saurornitholestes langstoni

Paronychodon sp.

Troodon sp.

Caenagnathidae indet.

Ornithischia indet.

Ankylosaurus magniventris

Pachycephalosaurus sp.

Ceratopsidae indet.

Leptoceratops sp.

            Leptoceratops gracilis

Triceratops horridus (including Triceratops albertensis)

Triceratops prorsus

            Torosaurus sp.

Iguanodontia indet.

Thescelosaurus neglectus (including Thescelosaurus edmontonensis)

Parksosaurus warreni

Hadrosauridae indet.

Edmontosaurus annectens

Other Animals:

Myledaphus bipartitus

Cyclurus fragosus

Lepisosteus sp.

Albanerpetontidae indet.

Champsosaurus sp.

Haptosphenus placodon

Stypodontosaurus melletes

Chamops segnis

Odaxosaurus piger

Colpodontosaurus cracens

Parasaniwa wyomingensis

Paraderma bogerti

Crocodylidae indet.

Borealosuchus griffithi

Testudines indet.

Paracimexomys priscus

Cimolomys trochuus

Cimolomys gracilis

Cimolodon nitidus

Ptilodontidae indet.

Mesodma thompsoni

Mesodma formosa

Mesodma hensleighi

Nortedelphys jasoni

Nortedelphys magnus

Aletridelphys florencae

Pediomys elegans

Aletridelphys hatcheri

Leptalestes krejcii

Alphadon sp.

Alphadon marshi

Alphadon wilsoni

Turgidodon rhaister

Didelphodon coyi

Didelphodon vorax

Cimolestes propalaeoryctes

Cimolestes cerberoides

Cimolestes magnus

Batodon tenuis

Schowalteria clemensi

Gypsonictops hypoconus

Gypsonictops illuminatus

Alostera saskatchewanensis

Plants:

Microcarpolithes multistriatus

Costatheca tenuis

Costatheca striata

Dictyothylakos sp.

Erlansonisporites sparassis

Balmeisporites sp.

Spermatites minimus

Azollopsis spinata

Azolla lauta

Azolla filosa

Azolla distincta

Aquilapollenites reticulatus

            Aquilapollenites reductus

            Aquilapollenites cf. attenuatus

            Wodehouseia spinata

Notes:

The Scollard spans the uppermost dinosaur-bearing strata: a final stronghold for dinosaurs. As a Lancian faunal stage, ceratopsians were the predominant herbivore with hadrosaur populations comparatively low. Paul (2010) indicated that the primary Triceratops in the formation was T. prorsus, rather than T. horridus. The member housing the Borealosuchus is assumed to be from the Paleocene (Wu et al. 2001), however, these crocodiles have been found in indisputably Maastrichtian strata so there is no reason to believe this individual was living after the Flood. Additionally, the supposed presence of Albertosaurus in the formation may be a mistake, since albertosaurs are not known to have survived into the Maastritchtian ecological phase. If it was present, it was very rare, and the larger, more powerful Tyrannosaurus would have made life miserable for their smaller relative. Absence of coniferous trees, like sequoias or cypress, may only be a reflection of preservation happenstance or poor sampling. Either way, it seems likely that those trees, characteristic of Maastrichtian habitats, would have been present in the original environment. Certain members of the formation house fantastic arrays of microscopic pollen fossils and, some of these, especially those housing the aquatic azolla varieties, seem preserved separately from the members predominated by vertebrate fossils. Interestingly, these coaly strata tend to overlay the vertebrate fauna (Dawson et al. 1994), indicating that the plants were suspended in deepening water after the animal inhabitants of the region had already been buried. It is even possible that the azolla found the rising waters favourable for reproduction and began to release their pollen in great amounts. Indeed, the most prevalent pollen in the formation is from various forms of Salviniacea (floating ferns). Sometimes the azolla members are considered part of the Paleocene Paskapoo Formation. Because the plants and animals are so separated in the formation it is likely that a very significant portion of the ecosystem is not represented. The insect fauna may be represented by the termite poop fossils of Microcarpolithes (Gunther et Hills 1972). Although once considered an angiosperm plant seed, Microcarpolithes is probably from members of the dry-wood termite families Kalotermitidae or Mastotermitidae (Vasile et al. 2013). The original authors back in 1972 may have been referencing seeds, not insects, but given the confident assignment of other members of the genus to termite families (Colin et al. 2011), it certainly seems possible that M. multistriatus are coprolites. Costatheca has been considered a genus of mollusc (Rozanov et al. 1969 and Sepkoski 2002) or a plant (Kar et al. 2005). There are two species of Costatheca described from the formation (Gunther et Hills 1972). but these are clearly species of plant based on spore fossils. Mammals are surprisingly diverse with a variety of multituberculates, marsupials, and placentals. However, none of these got much bigger than the modern possum or badger and likely spent the majority of their lives in the treetops or undergrowth, hiding from the more dominant dinosaur species until after the end of the Cretaceous. Lizards were common and diverse.

References:

Colin, J.-P., D. Néraudeau, A. Nel, et V. Perrichot. 2011. “Termite coprolites (Insecta: Isoptera) from the Cretaceous of western France: A paleoecological insight.” Revue de micropaléontologie 54: 129-139.

Dawson, F. M., C. G. Evans, R. Marsh, R. Richardson. 1994. “Uppermost Cretaceous and Tertiary Strata of the Western Canada Sedimentary Basin.” In G. D. Mossop and I. Shetsen. Geological Atlas of the Western Canada Sedimentary Basin. Canadian Society of Petroleum Geologists and Alberta Research Council. 387-405.

Gunther, P. R., et L. V. Hills. 1972. “Megaspores and other palynomorphs of the Brazeau Formation (Upper Cretaceous), Nordegg Area, Alberta.” Geoscience and Man 4: 29-48.

Kar, R. K., A. Sahni, K. Ambwani, et D. Dutta. 2005. “Fossil flora (Costatheca and Spermatites) from the Upper Maastrichtian Deccan Intertrappean Beds of India.” Geologica Carpathica 56(2): 149-154.

Paul, G. S. 2010. The Princeton Field Guide to Dinosaurs. Princeton, NJ: Princeton University Press.

Rozanov, A. Y., V. V. Missarzhevsky, N. A. Volkova, L. G. Voronova, I. N. Krylov, B. M. Keller, I. K. Korolyuk, K. Lendzion, R. Mikhnyar, N. G. Pykhova, et A. D. Sidorov. 1969. “Tommotskiu jarus i problema nizhney granisty kembriya.” Trudy Geoligske Institut Leningrad 206: 1-379.

Sepkoski, J. J. 2002. “A compendium of fossil marine animal genera.” Bulletin of American Paleontology 363: 1-560.

Vasile, S., E. R. Boder, Z. Csiki-Sava, et Z. Szentesi. 2013. “Isopteran trace fossils from the Upper Cretaceous of Central-Eastern Europe.” In D. Tabara (ed). The Ninth Romanian Symposium on Paleontology, Iasi: Abstract Book. Iasi: University of Iasi.

Wu, X.-C., D. B. Brinkman, et R. C. Fox. 2001. “A new crocodilian (Archosauria) from the basal Paleocene of the Red Deer River Valley, southern Alberta.” Canadian Journal of Earth Science 38: 1689-1704.