A fossilized aroid infructescence, Albertarum pueri gen.nov. et sp.nov., of Late Cretaceous (Late Campanian) age from the Horseshoe Canyon Formation of southern Alberta, Canada

2005 ◽  
Vol 83 (6) ◽  
pp. 591-598 ◽  
Author(s):  
Josef Bogner ◽  
Georgia L Hoffman ◽  
Kevin R Aulenback
Keyword(s):  
Late Cretaceous ◽  
New Genus ◽  
Before Present ◽  
Delta Plain ◽  
Southern Alberta ◽  
Stratigraphic Position ◽  
Absolute Age ◽  
Horseshoe Canyon Formation ◽  
Axile Placentation

A fossilized aroid infructescence has been recovered from the Horseshoe Canyon Formation in southern Alberta, Canada. Its stratigraphic position places it near the end of the Campanian Stage of the Late Cretaceous Epoch, at an absolute age of approximately 72 million years before present. It is one of the few Cretaceous aroid fossils known at present, and it represents a new genus of Araceae, here named Albertarum. The infructescence is fertile to the apex, and the flowers must have been bisexual. Flowers bear remains of a long, attenuated style, surrounded by a perigone of six tepals. A fracture reveals ellipsoid seeds with a thick, ribbed testa and traces of a raphe, arranged in groups of three. The gynoecium was probably trilocular with one ovule per locule, and ovules were anatropous, probably with apical–parietal or axile placentation. Bisexual, perigoniate flowers occur in subfamilies Gymnostachydoideae, Orontioideae, Pothoideae, Monsteroideae, and Lasioideae, no genera of which have ribbed seeds, but the infructescence and stylar region of Albertarum resemble those of extant Symplocarpus (Orontioideae). The Horseshoe Canyon Formation was deposited in a delta plain setting, and like Symplocarpus, Albertarum probably grew in a wetland environment.Key words: fossil, Araceae, Symplocarpus, Albertarum, Limnobiophyllum, Mayoa.

A history of Albertosaurus discoveries in Alberta, CanadaThis article is one of a series of papers published in this Special Issue on the theme Albertosaurus.

2010 ◽  
Vol 47 (9) ◽  
pp. 1197-1211 ◽  
Author(s):  
Darren H. Tanke ◽  
Philip J. Currie
Keyword(s):  
New Genus ◽  
Geographic Range ◽  
Special Issue ◽  
Southern Alberta ◽  
Considerable Confusion ◽  
Taxonomic Uncertainty ◽  
History Of ◽  
Information Politics ◽  
Horseshoe Canyon Formation

After many years of taxonomic uncertainty, Albertosaurus was established as a new genus in 1905, the year Alberta became a province of Canada. Gorgosaurus is a closely related tyrannosaurid from the Judithian beds of southern Alberta that was subsequently synonymized with Albertosaurus. Although most researchers consider the genera as distinct, there has been considerable confusion over the temporal and geographic range of Albertosaurus. Albertosaurus sarcophagus is only known from 13 skulls and (or) skeletons of varying completeness, and one (possibly two) bonebeds, all from the Horseshoe Canyon Formation (Campanian–Maastrichtian) of Alberta. Many of the major Albertosaurus specimens are scientifically compromised due to poor collection techniques, incomplete locality and stratigraphic information, politics, vandalism, accidents, gunplay, and landowner issues. The background of each specimen is discussed to eliminate some of the sources of confusion and to document how much of each specimen is preserved.

Stratigraphy of the Danek Bonebed (Upper Cretaceous Horseshoe Canyon Formation, central Alberta) and correlations with strata in the Drumheller and Grande Prairie regions

2014 ◽  
Vol 51 (11) ◽  
pp. 975-981 ◽  
Author(s):  
David A. Eberth ◽  
Phil R. Bell
Keyword(s):  
Upper Cretaceous ◽  
Faunal Assemblage ◽  
The North ◽  
Southern Alberta ◽  
North Slope Of Alaska ◽  
Stratigraphic Position ◽  
Geologic Time Scale ◽  
Assemblage Zone ◽  
Considerable Work ◽  
Horseshoe Canyon Formation

Although considerable work has been conducted on the stratigraphy and dinosaur assemblages of the Horseshoe Canyon Formation of southern Alberta, equivalent strata and assemblages in central Alberta remain poorly understood. Data from the Danek Bonebed (Edmonton, Alberta) are beginning to fill this gap. The bonebed occurs 4 m above the #9 Big Island Coal Seam. This stratigraphic position lies just below the middle of the Horseshoe Canyon Formation in the Edmonton region, and also lies below a thick, stratigraphically significant non-coaly interval that is expressed throughout central and southern Alberta. The stratigraphic position of the Danek Bonebed equates best with the uppermost Horsethief Member of the Horseshoe Canyon Formation in the Drumheller region and the upper part of Unit 4 of the Wapiti Formation in the Grande Prairie region. In both Drumheller and Grande Prairie, the correlated position of the bonebed underlies a zone of marine transgression (Drumheller Marine Tongue), which, in turn, includes the Campanian–Maastrichtian boundary. In the context of Geologic Time Scale 2004, we infer a late Campanian age of 71.0–71.3 Ma for the bonebed. The Danek’s dinosaurian assemblage is limited taxonomically, but compares well with the Edmontosaurus regalis – Pachyrhinosaurus canadensis fossil assemblage zone in the Drumheller region. We propose that a mega-herbivore faunal assemblage, characterized by Edmontosaurus and Pachyrhinosaurus, extended continuously across the climatically wet coastal plain of latest Campanian southern and central Alberta, and likely extended northwest into the North Slope of Alaska, where it persisted into the early Maastrichtian.

The Gedan floristic assemblage from the Late Cretaceous deposits of the Kholchan Formation of the Okhotsk-Chukotka volcanogenic belt

Palaeobotany ◽  
2014 ◽  
Vol 5 ◽  
pp. 73-93 ◽  
Author(s):  
L. B. Golovneva ◽  
S. V. Shczepetov
Keyword(s):  
River Basin ◽  
Late Cretaceous ◽  
Middle Part ◽  
Isotopic Data ◽  
Volcanogenic Belt ◽  
Stratigraphic Position ◽  
Cretaceous Deposits

The Gedan floristic assemblage occurs from upper layers of the Kholchan Formation of the Okchotsk-Chukotka volcanogenic belt (OCVB). The locality is situated at the Gedan River in the middle part of the Arman River basin. The Gedan assemblage is composed of 6 taxa: Cladophlebis sp., Sphenobaiera sp., Ginkgo ex gr. adiantoides (Ung.) Heer, Taxodium amguemensis (Efimova) Golovn., Metasequoia sp., Pagiophyllum sp. The similarity of the Gedan floristic assemblage with the Karamken and the Khirumki floristic assemblages from the Kholchan Formation of the Okhotsk sector of the OCVB allows us to join them in the Kholchan flora. This flora is distinct from more ancient Arman flora, which dated as the Turonian-Coniacian and from younger Ola flora, which dated as the Santonian-early Campanian. The age of the Kholchan flora is estimated as the Coniacian on the basis of stratigraphic position, presence of Podozamites, Metasequoia and Quereuxia and also isotopic data. This flora is equivalent with the Chaun flora of Central Chukotka, with the Aleeki flora from the Villigha and Toomahni Rivers interfluve and with the Ulya flora from the southern part of the Okhotsk-Chukotka volcanogenic belt.

Rediscovery of Choroterpes atramentum in Costa Rica, type species of Tikuna new genus (Ephemeroptera: Leptophlebiidae: Atalophlebiinae), and its role in the "Great American Inter-change"

Zootaxa ◽  
2005 ◽  
Vol 932 (1) ◽  
pp. 1 ◽  
Author(s):  
HARRY M. SAVAGE ◽  
R. WILLS FLOWERS ◽  
WENDY PORRAS V.
Keyword(s):  
Costa Rica ◽  
Central America ◽  
Late Cretaceous ◽  
Type Species ◽  
New Genus ◽  
South American ◽  
Early Tertiary ◽  
Geological Formation

A new genus, Tikuna, is described based on recent collections of adults and nymphs of Choroterpes atramentum Traver from western Costa Rica. All recent collections are from streams on or near the Nicoya Complex, the oldest geological formation in Lower Central America. Tikuna belongs to a lineage of South American Atalophlebiinae (Leptophlebiidae: Ephemeroptera) whose origin is hypothesized to have been in the late Cretaceous–early Tertiary. Some implications of the distribution of Tikuna for theories on the origin of Costa Rica’s biota are discussed.

scholarly journals Coal petrology analysis and implications in depositional environments from upper Cretaceous to Miocene: a study case in the Eastern Cordillera of Colombia

2021 ◽  
Author(s):  
Clara Guatame ◽  
Marco Rincón
Keyword(s):  
Late Cretaceous ◽  
Foreland Basin ◽  
Late Eocene ◽  
Depositional Environments ◽  
Estuarine System ◽  
Eastern Cordillera ◽  
Stratigraphic Position ◽  
San Fernando ◽  
Coal Facies ◽  
Oil Sector

AbstractThe Piedemonte Llanero Basin is located on the eastern side of the Eastern Cordillera of the Colombian Andes. It has been the subject of numerous geological studies carried out for the oil sector, mainly. This study presents the coal-petrographical features of 15 coal seams of four geological formations from Late Cretaceous to Middle Miocene (Chipaque formation, Palmichal group, Arcillas del Limbo formation, and San Fernando formation). Analysis of 33 samples indicates enrichment in vitrinite, while liptinite and inertinite concentrations vary according to the stratigraphic position. Reflectance indicates that the coal range gradually decreases from highly volatile bituminous C (Chipaque formation) to subbituminous C (San Fernando formation). The microlithotypes with the highest concentrations are clarite and vitrinertoliptite. Maceral composition and coal facies indicate changes in the depositional conditions of the sequence. The precursor peat from Late Cretaceous to Late Paleocene accumulated under limnic conditions followed by telmatic in Late Eocene–Early Miocene. The coal facies indices show wet conditions in forest swamps with variations in the flooding surface, influxes of brackish water and good tissue preservation. The tectonic conditions along the Piedemonte Llanero basin is evident, from post-rift to foreland basin, evidenced by oxic and anoxic periods reflected in the maceral composition and its morphology. The coal environment corresponds to an estuarine system started in the Chipaque formation evolving to the lacustrine conditions in the San Fernando formation.

scholarly journals Notes on Cretaceous amber Braconidae (Hymenoptera), with descriptions of two new genera

2016 ◽  
pp. 1 ◽  
Author(s):  
Michael S. Engel
Keyword(s):  
Late Cretaceous ◽  
New Genus ◽  
Hind Wing ◽  
New Combination ◽  
New Genera ◽  
New Genus And Species ◽  
Incertae Sedis

A new genus and species of basal cyclostome Braconidae is described and figured from a male preserved in mid-Cretaceous amber from northern Myanmar.  <strong><em>Rhetinorhyssalus morticinus</em></strong> Engel, new genus and species, is interesting for its combination of primitive features such as a minute apical costal cell and anal stubs in the forewing, while lacking 2Cu in the hind wing, a putatively derived trait.  As such, the genus may represent a lineage diverging from the braconid stem subsequent to many protorhyssalines, while remaining basal relative to generalized cyclostome groups such as Rhyssalinae.  In addition, the Late Cretaceous <em>Diospilus allani</em> Brues, in Campanian Canadian amber, is transferred to <strong><em>Diorhyssalus</em></strong> Engel, new genus, and its similarity to <em>Rhetinorhyssalus</em> is discussed.  This transfer results in the new combination, <em>Diorhyssalus allani</em> (Brues).  Both genera are tentatively considered as subfamily <em>incertae sedis</em>.

A taxonomic assessment of the type series of Albertosaurus sarcophagus and the identity of Tyrannosauridae (Dinosauria, Coelurosauria) in the Albertosaurus bonebed from the Horseshoe Canyon Formation (Campanian–Maastrichtian, Late Cretaceous)This article is one of a series of papers published in this Special Issue on the theme Albertosaurus.

2010 ◽  
Vol 47 (9) ◽  
pp. 1213-1226 ◽  
Author(s):  
Thomas D. Carr
Keyword(s):  
Late Cretaceous ◽  
Type Specimen ◽  
Special Issue ◽  
Diagnostic Characters ◽  
Type Series ◽  
Growth Changes ◽  
Horseshoe Canyon Formation

The type series of Albertosaurus sarcophagus , consisting of a type (CMN 5600) and a paratype (CMN 5601) is inadequately established, since it has not been demonstrated that the specimens represent the same taxon. This problem has arisen because the original diagnostic characters have a wider distribution among Tyrannosauridae or they are in error, and both specimens consist of incomplete and damaged skulls. The type series was studied to test for the presence of diagnostic characters in the type specimen and, if so, to provide a rationale for referring the paratype to the taxon. Of the bones shared between the skulls, only five could be compared. One character, the enlarged posterior pneumatic recess of the palatine, is shared between the two specimens; this condition differs from the situation seen in other tyrannosaurids. This character provided the rationale for assessing the identity of the specimens collected from the Albertosaurus bonebed, from which one palatine was collected that exhibits the diagnostic recess. Isolated cranial bones from the bonebed were compared with those preserved in the type series to evaluate their referral to A. sarcophagus ; additional characters shared between the type series and the specimens from the bonebed were identified in the maxilla, lacrimal, and palatine. This evidence supports the hypothesis that A. sarcophagus is the tyrannosaurid preserved in the bonebed. A hypothesis of the principal growth changes in the skull in A. sarcophagus, which includes the type series and bonebed material, is proposed.

Parataxonomic classification of ornithoid eggshell fragments from the Oldman Formation (Judith River Group; Upper Cretaceous), southern Alberta

1996 ◽  
Vol 33 (12) ◽  
pp. 1655-1667 ◽  
Author(s):  
Darla K. Zelenitsky ◽  
L. V. Hills ◽  
Philip J. Currie
Keyword(s):  
Late Cretaceous ◽  
Shell Thickness ◽  
Upper Cretaceous ◽  
Theropod Dinosaur ◽  
Surface Sculpture ◽  
External Zone ◽  
Theropod Dinosaurs ◽  
Southern Alberta ◽  
The Family

Examination of a large number of eggshell fragments collected from the Oldman Formation of southern Alberta reveals a greater ootaxonomic diversity than is known from complete eggs or clutches. Three new oogenera and oospecies of the ornithoid-ratite morphotype and one of the ornithoid-prismatic morphotype are established, based on the eggshell fragments. Porituberoolithus warnerensis oogen. et oosp. nov. and Continuoolithus canadensis oogen. et oosp. nov. have a microstructure similar to that of elongatoolithid eggs of theropod dinosaurs. Tristraguloolithus cracioides oogen. et oosp. nov. and Dispersituberoolithus exilis oogen. et oosp. nov. possess an external zone and thus have a microstructure like modern avian eggshell. Tristraguloolithus has a shell thickness, microstructure, and surface sculpture similar to those of recent bird eggshell of the family Cracidae (order Galliformes). Dispersituberoolithus exhibits the primitive or normal eggshell condition of some recent neognathous avian taxa. The ootaxa described indicate a diversity of both avian and theropod dinosaur egg layers within Devil's Coulee and Knight's Ranch, southern Alberta, during the Late Cretaceous.

scholarly journals Transitional evolutionary forms in chasmosaurine ceratopsid dinosaurs: evidence from the Campanian of New Mexico

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9251
Author(s):  
Denver W. Fowler ◽  
Elizabeth A. Freedman Fowler
Keyword(s):  
New Mexico ◽  
Phylogenetic Relationship ◽  
Late Cretaceous ◽  
Phylogenetic Hypothesis ◽  
Stepwise Change ◽  
Horseshoe Canyon Formation

Three new chasmosaurines from the Kirtland Formation (~75.0–73.4 Ma), New Mexico, form morphological and stratigraphic intermediates between Pentaceratops (~74.7–75 Ma, Fruitland Formation, New Mexico) and Anchiceratops (~72–71 Ma, Horseshoe Canyon Formation, Alberta). The new specimens exhibit gradual enclosure of the parietal embayment that characterizes Pentaceratops, providing support for the phylogenetic hypothesis that Pentaceratops and Anchiceratops are closely related. This stepwise change of morphologic characters observed in chasmosaurine taxa that do not overlap stratigraphically is supportive of evolution by anagenesis. Recently published hypotheses that place Pentaceratops and Anchiceratops into separate clades are not supported. This phylogenetic relationship demonstrates unrestricted movement of large-bodied taxa between hitherto purported northern and southern provinces in the late Campanian, weakening support for the hypothesis of extreme faunal provincialism in the Late Cretaceous Western Interior.

A new genus of Late Cretaceous cycad stem from Argentina, with reappraisal of known forms

2005 ◽  
Vol 29 (1) ◽  
pp. 87-100 ◽  
Author(s):  
Analía E. Artabe ◽  
Alba B. Zamuner ◽  
Dennis W. Stevenson
Keyword(s):  
Late Cretaceous ◽  
New Genus
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