Albertavenator

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Albertavenator
Temporal range: Late Cretaceous, 71.5–71  Ma
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Albertavenator.png
Illustration of the holotype frontal of Albertavenator
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Family: Troodontidae
Genus: Albertavenator
Evans et al., 2017
Type species
Albertavenator curriei
Evans et al., 2017

Albertavenator (meaning "Alberta hunter") [1] is a genus of small-bodied troodontid theropod dinosaur that lived during the early Maastrichtian stage of the Late Cretaceous period, approximately 71 million years ago. It is known from the Horseshoe Canyon Formation in Alberta, Canada, and is currently represented by a single species, Albertavenator curriei. The species name honors Canadian paleontologist Philip J. Currie for his extensive contributions to theropod research. The animal is known from parts of the skull. [1] [2]

Contents

History of Discovery

The holotype specimen of Albertavenator (TMP 1993.105.0001), consisting of a partial left frontal bone, was collected in the early 1990s from the Horsethief Member of the Horseshoe Canyon Formation, near the town of Drumheller, Alberta. A second, smaller frontal (TMP 1996.005.0008) was later referred to the same taxon. Initially, these remains were not recognized as distinct and were considered to belong to Troodon, a genus historically used as a wastebasket taxon for small theropods based on isolated teeth and fragmentary remains. [2]

Detailed study of the frontal bone morphology revealed significant differences from other known troodontids, especially in the proportions and features of the cranial roof. As a result, the material was described as a new genus and species in 2017 by a team led by David C. Evans. The recognition of Albertavenator marked an important step in refining our understanding of Late Cretaceous small theropod diversity in North America, especially within the poorly understood troodontids. [2] [3]

Description

Although only cranial material is known, specifically the frontal bones, Albertavenator exhibits several distinct anatomical features. The frontal bone is notably short and broad, with a length-to-width ratio of less than 1.3, which is shorter than any other known Late Cretaceous troodontid. The bone also displays a unique configuration of the frontoparietal suture, with an enlarged lappet overlapping the anteromedial process of the parietal, and a truncated supraciliary foramen. These autapomorphic features distinguish Albertavenator from other troodontids such as Troodon and Stenonychosaurus. [2]

Life restoration of the head Albertavenator LM.png
Life restoration of the head

Taxonomy

Albertavenator is assigned to the family Troodontidae within the clade Paraves. Although a detailed phylogenetic analysis was not conducted in the original description, the authors compared frontal morphology across multiple North American troodontids, concluding that Albertavenator is distinct from both Troodon and Stenonychosaurus. Its recognition underscores the underestimated diversity of small theropods in the Late Cretaceous and the limitations of using isolated teeth for taxonomic identification. [2]

Paleoecology

The Horseshoe Canyon Formation (HCF) of Alberta is a Late Cretaceous (~early Maastrichtian) unit composed of floodplain, estuarine, swamp and coastal deposits, dominated by sandstones, mudstones, and coal seams. Many plants such as redwoods, spruces, katsura relatives, plane trees and ferns including the modern cinnamon fern were common place in the formation. [4] The fauna includes hadrosaurs (e.g., Edmontosaurus), ceratopsians, ankylosaurs, and a diversity of theropods including large tyrannosaurids (such as Albertosaurus). [5] It was much cooler in temperature than other formations nearby. [6]


See also

References

  1. 1 2 DinoChecker Archives ALBERTAVENATOR
  2. 1 2 3 4 5 Evans, D.C.; Cullen, T.M.; Larson, D.W.; Rego, A. (2017). "A new species of troodontid theropod (Dinosauria: Maniraptora) from the Horseshoe Canyon Formation (Maastrichtian) of Alberta, Canada". Canadian Journal of Earth Sciences. 54 (8): 813–826. Bibcode:2017CaJES..54..813E. doi:10.1139/cjes-2017-0034.
  3. Cullen, Thomas M.; Zanno, Lindsay; Larson, Derek W.; Todd, Erinn; Currie, Philip J.; Evans, David C. (September 2021). "Anatomical, morphometric, and stratigraphic analyses of theropod biodiversity in the Upper Cretaceous (Campanian) Dinosaur Park Formation1". Canadian Journal of Earth Sciences. 58 (9): 870–884. doi:10.1139/cjes-2020-0145. ISSN   0008-4077.
  4. Aulenback, Kevin R. (2009-06-30). Identification Guide to the Fossil Plants of the Horseshoe Canyon Formation of Drumheller, Alberta. University of Calgary Press. doi:10.2307/j.ctv6cfq46. ISBN   978-1-55238-494-7. JSTOR   j.ctv6cfq46.
  5. Larson, Derek W.; Brinkman, Donald B.; Bell, Phil R. (September 2010). Sues, Hans-Deiter (ed.). "Faunal assemblages from the upper Horseshoe Canyon Formation, an early Maastrichtian cool-climate assemblage from Alberta, with special reference to the Albertosaurus sarcophagus bonebedThis article is one of a series of papers published in this Special Issue on the theme Albertosaurus ". Canadian Journal of Earth Sciences. 47 (9): 1159–1181. doi:10.1139/E10-005. ISSN   0008-4077.
  6. Larson, Derek W.; Brinkman, Donald B.; Bell, Phil R. (September 2010). "Faunal assemblages from the upper Horseshoe Canyon Formation, an early Maastrichtian cool-climate assemblage from Alberta, with special reference to the Albertosaurus sarcophagus bonebedThis article is one of a series of papers published in this Special Issue on the theme Albertosaurus". Canadian Journal of Earth Sciences. 47 (9): 1159–1181. doi:10.1139/E10-005. ISSN   0008-4077.