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We review the distinguished and varied career of our friend and colleague, palaeontologist Dr. Dale A. Russell, following the recent news of his death. Dale relished his work and approached his research — whether it be on mosasaur systematics, dinosaur extinction, or the evolution of animal intelligence — with great gusto. A deep and contextual thinker, Dale had a penchant for metanarrative rarely equaled in these times of increased research specialization. This quality, combined with his outgoing and collaborative nature, allowed Dale to make friends and colleagues with highly varied research interests throughout the world. We remember Dale fondly and cherish the opportunity to share the stories of his adventures (and misadventures) across the globe. [ABSTRACT FROM AUTHOR]

An heterostiid arthrodire, Herasmius dayi sp. nov., is described from upper Lower Devonian marine deposits of the Bear Rock Formation along the Anderson River, Northwest Territories, Canada. New elements described for the genus for the first time include the suborbital, submarginal (also new for the family Heterostiidae), the lateral shoulder girdle with posterior lateral, anterior dorso-lateral, and posterior dorso-lateral plates and possible infragnathal plate. We present a new reconstruction of the cranial region of Herasmius, previously known only from supposedly freshwater - shallow marine deposits of roughly the same age in the Wood Bay Group of Spitsbergen. The late Early Devonian fishes that are common to the Arctic region of northwestern Canada and the island of Spitsbergen in the Svalbard archipelago of Norway, the porolepiform Heimenia and the arthrodire Herasmius described here, demonstrate the existence of a barrier-free paleogeographic connection between those continental blocks by the late Early Devonian. Comparison of the entire Anderson River vertebrate fauna with other boreal faunas of similar age indicates additional paleogeographic connections north of and around the Old Red Sandstone Continent to the Baltic region, central Europe, and even to the New Siberian Islands and South China, in contrast to most current published paleogeographical reconstructions. [ABSTRACT FROM AUTHOR]

Abstract: The Western Interior Seaway (WIS) was an epicontinental sea that extended north–south through the middle of North America during the last half of the Cretaceous, linking the Tethys Sea to the south with the boreal paleo-Arctic Ocean to the north. Aptian–Maastrichtian sedimentary deposits from the seaway crop out in the Western Interior Basin of Canada and the United States. Vertebrate remains are commonly well-preserved, and in certain stratigraphic units, abundant. The classic vertebrate fauna of the WIS, from the Upper Cretaceous Niobrara Chalk, has been studied for 150years, but relatively little has been known of the seaway''s earlier faunas until recent years. Studies of mid-Cenomanian vertebrate faunas, particularly from lag deposits (bonebeds and calcarenites) in Canada and the United States have significantly altered the previous picture of the overall biodiversity and biogeography of the WIS during the ‘mid-Cretaceous.’ These mid-Cenomanian faunas include diverse fish assemblages of chondrichthyans (cartilaginous fishes) and osteichthyans (bony fishes) as well as various forms of tetrapods, including marine turtles, plesiosaurs, and hesperornithiform and ichthyornithiform birds. Our compilation of faunas indicates that at least 70 vertebrate taxa are recorded from five mid-Cenomanian WIS ‘localities’ situated in Alberta, Saskatchewan, the Black Hills region of South Dakota and Wyoming, Kansas, and Colorado. The faunas include 41 chondrichthyans, 21 osteichthyans, 10 non-avian tetrapods, and five avian taxa. Our study, combined with previous faunal studies, suggests that the combination of the following eight chondrichthyan species characterizes mid-Cenomanian time, which has been referred to as the ‘Woodbinian Age’ in the marine realm of North America: Ptychodus decurrens, P. occidentalis, Squalicorax curvatus, Cretodus semiplicatus, Carcharias amonensis, C. saskatchewanensis, Eostriatolamia tenuiplicatus, and Cretomanta canadensis. This is the geologic time when non-ptychodontid hybodonts became rare faunal components in most areas, and when a number of other fish lineages, particularly teleosts, emerged and diversified. Many of these persisted into the early Campanian, or the ‘Niobrara Age’ that followed the Woodbinian. Therefore, mid-Cenomanian time in the WIS can also be characterized by the genesis of the ‘Niobraran fauna,’ a significant radiation and diversification of fish taxa. The five mid-Cenomanian WIS ‘localities’ highlighted in this study are separated by as much as 18° latitude, a north–south distance of more than 2300km. These faunas demonstrate some clinal trends, such as more diverse faunas of benthic chondrichthyans mixed with dolichosaurid lizards to the south, and a more diverse fauna of birds to the north. However, the faunas overall show strong taxonomic homogeneity, particularly among many chondrichthyans that were cosmopolitan, indicating that passage throughout the seaway as well as to both the Boreal and Tethys oceans was utilized. These faunas also demonstrate high osteichthyan diversity in the northern waters of the WIS, which were once thought to have supported only a depauperate, cold-adapted fauna. Because of the surprisingly great diversity in vertebrate taxa, ecosystem structure and dynamics of the WIS during the mid-Cenomanian were unquestionably complex. [Copyright &y& Elsevier]

Acid preparation of samples of a bonebed from the Cenomanian of central Canada yielded several thousand well-preserved chondrichthyan teeth, in addition to numerous other vertebrate remains. Teeth and other remains of one species of chimaeroid, one species of hybodont shark, three species of Ptychodus, 10 species of neoselachian sharks and two species of batoid were recorded. The family Archaeolamnidae fam. nov., genera Meristodonoides gen. nov. and Telodontaspis gen. nov. and species Ptychodus rhombodus sp. nov., Telodontaspis agassizensis gen et sp. nov., Eostriatolamia paucicorrugata sp. nov., Roulletia canadensis sp. nov., Cretorectolobus robustus sp. nov. and Orectoloboides angulatus sp. nov. are described. Status of the genus Palaeoanacorax and the species Cretoxyrhina denticulata, Squalicorax curvatus and ‘ Rhinobatos’ incertus are discussed, and reconstructed dentitions of Archaeolamna and Roulletia presented. The fauna is of low diversity and dominated by active hunters, with many species apparently endemic to the northern Western Interior Seaway. [ABSTRACT FROM AUTHOR]

Percid remains from Pliocene deposits on Ellesmere Island, Arctic Canada, are identified as a species of Sander, similar to the walleye and sauger of North America and the pike–perch of Europe and western Asia. They are named as a new species, Sander teneri. These remains are the most northerly percid elements found to date and suggest the palaeoenvironment was significantly warmer in the Pliocene than it is currently. The fossil remains show the presence in North America of the family Percidae as well as the genus Sander prior to the Pleistocene, indicating a previously proposed Pleistocene immigration from Europe or Asia can be discounted. These fossils contradict an earlier hypothesis that percids, in particular Sander, crossed from Eurasia to North America in the Pleistocene; instead, the fossils show percids were already in the area by the Pliocene. [ABSTRACT FROM AUTHOR]

A black marine mudstone in allomember A of the middle Cenomanian Dunvegan Formation, Alberta, yielded a well-preserved, deep-bodied fish skeleton attributable to a new genus and species, Tycheroichthys dunveganensis, in the Paraclupeidae (Clupeomorpha, Ellimmichthyiformes). This new taxon appears most closely related to members of the subfamily Paraclupeinae, which includes largely freshwater and estuarine or marginal marine species known from South and Central America and China. The Dunvegan Formation represents a large delta complex deposited in the Western Interior Seaway at about 65°N, where mean sea water temperature may have been about 10 °C. The specimen was found about 60 km from the contemporaneous shoreline, and, in life, apparently inhabited a shallow, muddy pro-delta environment characterized by high turbidity and variable salinity. The fish may have died when it was engulfed by brackish floodwater that also introduced suspended mud that rapidly buried the body, preventing physical disarticulation of the skeleton. River outflow probably produced a salinity- and density-stratified water column that limited oxygen transfer to the sea floor, leading to dysaerobic bottom water and an absence of scavengers. High terrestrial phytodetrital content of the sediment also favoured anaerobic conditions that limited bacterial decay. [ABSTRACT FROM AUTHOR]

A new genus and species of an Early Devonian (Emsian) mesacanthid acanthodiform from outcrops of the Bear Rock Formation along the Anderson River, Northwest Territories, Canada, is described. The new taxon is distinct from other mesacanthid genera and (or) species in having mesiolaterally expanded skull roof plates and paired nasal bones. Mesacanthids have fin-spines that are similar in size, number, position, and proportions. This new genus is the fourth in the family Mesacanthidae. The wider distribution and apparent taxonomic diversity represented by the discovery of the new genus are indications that the latest-surviving and arguably most advanced acanthodian group, the Acanthodiformes, was already well established in the Early Devonian.Une description est donnée d'un nouveau genre et d'une nouvelle espèce de poisson, un acanthodiforme mésacanthide du Dévonien inférieur (Emsian), provenant d' affleurements de la formation de Bear Rock et mis au jour le long de la rivière Anderson, dans les Territoires du Nord-Ouest, au Canada. Il se distingue des autres espèces et genres de Mesacanthidae par une expansion mésiolatérale des plaques de la voûte crânienne et une paire d'os nasaux. Les espèces et les genres de mésacanthes se ressemblent quant à la taille, au nombre, à la position et aux proportions des rayons épineux des nageoires. Le genre qui vient d' être découvert est le quatrième de la famille. La distribution plus étendue et la diversité taxonomique révélées par la découverte de ce nouveau genre semblent indiquer que, le dernier survivant et peut-être le plus évolué des acanthodiens, les Acanthodiformes, était déjà bien établi dans la période du Dévonien inférieur. [ABSTRACT FROM AUTHOR]

Here we describe a new hesperornithiform specimen from the Upper Cretaceous Kanguk Formation of Devon Island, Nunavut, Canada. This specimen (NUVF 286) is referred to cf. Hesperornis sp. based on size and shape of femora and teeth preserved with other skeletal elements. Previous osteohistologic analyses indicate a subadult ontogenetic stage at the time of death. This new cf. Hesperornis specimen includes the first teeth associated with a high-latitude hesperornithiform, allowing for comments on the trophic behavior of these birds. Paleoecological reconstructions based on current knowledge of polar assemblages and comparisons to modern birds suggest that high-latitude hesperornithiform birds may have had more varied diets than previously assumed. [ABSTRACT FROM AUTHOR]