Andrew G. Neuman

Cretaceous Esocoidei (Teleostei); early radiation of the pikes in North American fresh waters

ABsTRAcr-Contrary to ideas that Cretaceous fresh waters contained few teleosts, there were several taxa of Esocoidei (pikes and relatives) in North American Cretaceous rivers. Dentaries and palatines of Campanian to Maastrichtian age all have C-shaped tooth bases and other distinctive features of shape and foramina. The fossils include at least three distinct kinds, two of which are described here as new genera and species in the Esocidae: Estesesoxfoxi n. gen. and sp. and Oldmanesox canadensis n. gen. and sp. These old, diverse, and apparently primitive specimens show that pikes radiated when Eurasia and North America were still joined. Some references in the literature to the Cretaceous fish Platacodon Marsh are based on referred dentaries that are here identified as esocoid fossils. The Esocidae are the first example of a family of Recent North American freshwater teleosts that has been shown to have speciated in Cretaceous fresh waters and survived the terminal Cretaceous extinction.

TELEOST CENTRA FROM UPPERMOST JUDITH RIVER GROUP (DINOSAUR PARK FORMATION, CAMPANIAN) OF ALBERTA, CANADA

Abstract The diversity and distribution of teleosts in the Dinosaur Park Formation of Alberta, Canada, is evaluated on the basis of precaudal centra. In order to avoid the erection of redundant taxa, and to include all teleost precaudal centra in a single system, a parataxonomic system is erected. Fifteen distinct basal groups, termed morphoseries, are described. Growth-related changes and serial variation along the column are taken into account in defining these groups, so each morphoseries is interpreted as representing a distinct, low-level taxon of teleost. One of the morphoseries could be identified as hiodontid and two as acanthomorph on the basis of derived character-states. This is the first Cretaceous record of hiodontids in North America. In addition, elopomorphs, clupeomorphs, salmoniforms, and osteoglossoforms are recognized on the basis of general similarity with the precaudal centra in extant members of these groups. Two teleosts of intermediate level of evolution, but of uncertain relationships, are also present. Differences in the stratigraphic distributions of the morphoseries allow two distinct assemblages of teleosts to be recognized in the formation. One is present in fluvial-dominated localities of the Dinosaur Park Formation, the second in a complex of mud-filled channels in the Lethbridge Coal Zone. The paleoecological complexity present in the formation, and the high level of diversity of teleosts in these beds, emphasizes the importance of including disarticulated remains in studies of the diversity and distribution of teleosts in the Cretaceous.

A new articulated freshwater fish (Clupeomorpha, Ellimmichthyiformes) from the Horseshoe Canyon Formation, Maastrichtian, of Alberta, CanadaThis article is one of a series of papers published in this Special Issue on the theme Albertosaurus.

Horseshoeichthys armaserratus, gen. et sp. nov., (Clupeomorpha: Ellimmichthyiformes: Sorbinichthyidae) is described from the Horseshoe Canyon Formation (Maastrichtian), Albertosaurus bonebed locality, Alberta, Canada. Horseshoeichthys armaserratus is classified as an ellimmichthyiform based on the following characters: the presence of a sixth infraorbital with a sensory canal that leads to the fifth infraorbital, absence of a supraorbital bone, subrectangular predorsal scutes, parietals in contact with each other at the midline, and two supramaxillae. The specimen is classified in the Sorbinichthyidae Family as it has abdominal ribs articulating in pits on the centra, posterior spines on predorsal scutes, and absence of a median spine on predorsal scutes. A new genus and species is proposed based on the presence of (anteriorly) Y-shaped mesethmoid, supraorbital, subrectangular predorsal scutes with coarse, rounded serrae on the posterior margin and a large anterior projection, scales with serrae on the ci...

Seventy-five-million-year-old tropical tetra-like fish from Canada tracks Cretaceous global warming

Newly discovered fossil fish material from the Cretaceous Dinosaur Park Formation of Alberta, Canada, documents the presence of a tropical fish in this northern area about 75 million years ago (Ma). The living relatives of this fossil fish, members of the Characiformes including the piranha and neon tetras, are restricted to tropical and subtropical regions, being limited in their distribution by colder temperatures. Although characiform fossils are known from Cretaceous through to Cenozoic deposits, none has been reported previously from North America. The modern distribution of characiforms in Mexico and southern Texas in the southernmost United States is believed to have been the result of a relatively recent colonization less than 12 Ma. The new Canadian fossils document the presence of these fish in North America in the Late Cretaceous, a time of significantly warmer global temperatures than now. Global cooling after this time apparently extirpated them from the northern areas and these fishes only survived in more southern climes. The lack of early Cenozoic characiform fossils in North America suggests that marine barriers prevented recolonization during warmer times, unlike in Europe where Eocene characiform fossils occur during times of global warmth.

New eugeneodontid sharks from the Lower Triassic Sulphur Mountain Formation of Western Canada

Abstract Eugeneodontid sharks, previously believed to have become virtually extinct during the great end-Permian extinction event, are here shown to be diverse in the Early Triassic of western Canada. Although the specimens are probably predominantly Olenekian in age, they show an abundance similar to that of the Late Permian of East Greenland. Similar in size and morphology to their Palaeozoic predecessors, this diverse assemblage is seen to have a short duration within the Early Triassic. A number of identifiable dentitions and postcranial skeletal remains suggest the presence of at least two caseodontid species (Caseodus varidentis sp. nov. and Fadenia uroclasmato sp. nov.) and an edestoid (Paredestus bricircum gen. et sp. nov.) Many other specimens recovered from the Lower Triassic Vega-Phroso Siltstone Member (Sulphur Mountain Formation) at Wapiti Lake are too poorly preserved for identification but help demonstrate the major taxonomic problems in eugeneodontid systematics. We discuss the survival of this highly specialized group of ‘sharks’ and comment on their biogeographical distribution across the Permo-Triassic boundary.

Teudopsis cadominensis , a new teuthid squid from the Toarcian (Lower Jurassic) of Alberta

A new species of teuthid squid, Teudopsis cadominensis, is described from the Toarcian (Lower Jurassic) Poker Chip Shale of the Fernie Formation in central-western Alberta. Fossil squids are rare in the Mesozoic of North America; this species is the first record of the family Palaeololiginidae in North America and the first member of the suborder Mesoteuthina in the Jurassic of North America.

New articulated osteoglossomorph from Late Cretaceous freshwater deposits (Maastrichtian, Scollard Formation) of Alberta, Canada

ABSTRACT Articulated fishes are rare in Late Cretaceous non-marine deposits of the Western Interior; fishes are more often represented by disarticulated elements in vertebrate microfossil localities. A new Maastrichtian locality of the Scollard Formation in central Alberta, Canada, has been named Pisces Point to reflect the diversity of articulated fishes that are now being recovered from this site. Material collected from the Pisces Point locality includes a percopsiform, a semionotiform, at least one esociform, and at least two osteoglossomorphs. One of these is described here as a new genus and species, †Wilsonichthys aridinsulensis. A phylogenetic analysis shows this new taxon to be the sister group of most other Osteoglossiformes. The new articulated material allows us to identify some of the microfossil remains previously collected from other Late Cretaceous sites as belonging to the same or a similar taxon.

A coelacanth scale from the Upper Triassic Pardonet Formation, British Columbia, Canada

A large ichthyosaur specimen was first reported from the Sikanni Chief River (Pink Mountain), British Columbia, Canada by Keary Walde in 1992. It was excavated by the Canada-Japan Project for Triassic Marine Environments in 1998 to 1999 (Nicholls and Manabe, in prep). During the excavation, an isolated scale was found from the same site and stratigraphic level of the ichthyosaur. This is the first vertebrate specimen from the site excepting ichthyosaurs. The characters of the scale indicate it belongs to a coelacanth. This is the first record of a coelacanth from the Upper Triassic in Canada.

Erratum: Non-marine fishes of the late Santonian Milk River Formation of Alberta, Canada – evidence from vertebrate microfossil localities

The diversity of fishes from the late Santonian Milk River Formation is investigated using a combined taxonomic/morphotype approach. Twenty-one taxa are present, including four elasmobranchs, seven basal actinopterygians, and of ten teleosts. The Milk River fish assemblage is more similar to assemblages from southern Utah than it is to the late Campanian assemblage of Alberta in the presence of the elasmobranch Lonchidion and a member of amiid subfamily Vidalamiinae, the relatively high abundance of the ostariophysan teleost U3/BvD, and the absence of sturgeon, Holostean A, Holostean B, and Coriops . This similarity is hypothesized to be the result of a northern shift in the distribution of these taxa during times of high global temperature, resulting in the presence of a “southern” faunal assemblage in Alberta during the late Santonian. In the relative abundance patterns of major groups of fish, the Milk River Formation assemblage is similar to late Campanian assemblages and different from those of late Maastrichtian in that amiids and lepsisoteids are of relatively low abundance. The abundance of acanthomorph teleosts in the Milk River Formation is similar to that of contemporaneous assemblages from Utah, which supports a pattern of increasing abundance of acanthomorphs from their first occurrence in non-marine vertebrate assemblages of the Western Interior in the Coniacian through to the end of the Cretaceous.