Palaeosaniwa

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Palaeosaniwa
Temporal range: Late Cretaceous [1] 70.6–66.0  Ma
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Palaeosaniwa.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Anguimorpha
Genus: Palaeosaniwa
Species:
P. canadensis
Binomial name
Palaeosaniwa canadensis
Gilmore, 1928
Synonyms [1]
  • Megasaurus robustusGilmore, 1928

Palaeosaniwa canadensis is an extinct species of carnivorous lizard from the late Cretaceous of North America. The name, given by Charles Whitney Gilmore in 1928, means "ancient Saniwa from Canada".

Contents

Description

Palaeosaniwa is among the largest terrestrial lizards known from the Mesozoic era, with an estimated body mass of 6 kg (13 lb) and a snout–vent length about 82 cm (32 in). [2] Its total body length would have been around 1–2 m (3 ft 3 in – 6 ft 7 in), smaller than the adult Komodo dragon and other Mesozoic lizards of East Asia ( Asprosaurus and Chianghsia ). [3] [4] [5] Some specimens attributed to cf. P. canadensis is estimated to have skull length up to 15 centimetres (5.9 in) which is comparable to a young specimen of komodo dragon around 1.6 m (5.2 ft) long. [6] It is similar to modern varanid lizards (particularly the Komodo dragon) in having bladelike teeth with minute serrations. These teeth would have been effective for seizing and cutting large prey items, and suggest that Palaeosaniwa fed on other vertebrates. Adult Palaeosaniwa would have been large enough to prey on any of the avialans or mammals known from the time, small non-avian dinosaurs, and the eggs and juveniles of large dinosaurs.

Distribution

Palaeosaniwa was originally described from the late Campanian of Alberta. More recently it has been reported from the late Campanian of Montana, and the late Maastrichtian of Montana and Wyoming. It is known primarily from isolated teeth and vertebrae, but two partial skeletons have also been discovered. The type species, P. canadensis, is from Alberta. Although the Maastrichtian Palaeosaniwa has traditionally been referred to this species, it succeeds it by roughly ten million years. Given the distance in time between these animals, they are likely to represent distinct species, but the available fossils are too incomplete to be certain.

Relationships

Palaeosaniwa is a member of the Platynota, a group that includes the monitor lizards (Varanidae) and Gila monsters (Helodermatidae). Originally, it was thought to be a member of the Varanidae, but has also been interpreted as a relative of the Helodermatidae. [7] The most recent analysis places Palaeosaniwa outside of either Varanidae or Helodermatidae, as a stem member of the Varanoidea. Its precise affinities remain poorly understood, but it may be related to other Late Cretaceous, North American carnivorous lizards such as Parasaniwa , Paraderma , Labrodioctes , and Cemeterius .

Related Research Articles

<span class="mw-page-title-main">Varanidae</span> Family of lizards

The Varanidae are a family of lizards in the superfamily Varanoidea and order Anguimorpha. The family, a group of carnivorous and frugivorous lizards, includes the living genus Varanus and a number of extinct genera more closely related to Varanus than to the earless monitor lizard (Lanthanotus). Varanus includes the Komodo dragon, crocodile monitor, savannah monitor, the goannas of Australia and Southeast Asia, and various other species with a similarly distinctive appearance. Their closest living relatives are the earless monitor lizard and Chinese crocodile lizard. The oldest members of the family are known from the Late Cretaceous of Mongolia.

<span class="mw-page-title-main">Mosasaur</span> Extinct marine lizards of the Late Cretaceous

Mosasaurs are an extinct group of large aquatic reptiles within the family Mosasauridae that lived during the Late Cretaceous. Their first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764. They belong to the order Squamata, which includes lizards and snakes.

<i>Saurornitholestes</i> Extinct genus of dinosaurs

Saurornitholestes is a genus of carnivorous dromaeosaurid theropod dinosaur from the late Cretaceous of Canada (Alberta) and the United States.

<span class="mw-page-title-main">Carcharodontosauridae</span> Extinct family of dinosaurs

Carcharodontosauridae is a group of carnivorous theropod dinosaurs. In 1931, Ernst Stromer named Carcharodontosauridae as a family, which, in modern paleontology, indicates a clade within Carnosauria. Carcharodontosaurids include some of the largest land predators ever known: Giganotosaurus, Mapusaurus, Carcharodontosaurus, and Tyrannotitan all rivaled Tyrannosaurus in size. Estimates give a maximum weight of 8–10 metric tons for the largest carcharodontosaurids, while the smallest carcharodontosaurids were estimated to have weighed at least 500 kilograms (1,100 lb).

<i>Chirostenotes</i> Extinct genus of dinosaurs

Chirostenotes is a genus of oviraptorosaurian dinosaur from the late Cretaceous of Alberta, Canada. The type species is Chirostenotes pergracilis.

<span class="mw-page-title-main">Horseshoe Canyon Formation</span> Geological formation in Canada

The Horseshoe Canyon Formation is a stratigraphic unit of the Western Canada Sedimentary Basin in southwestern Alberta. It takes its name from Horseshoe Canyon, an area of badlands near Drumheller.

<i>Globidens</i> Extinct genus of lizards

Globidens is an extinct genus of mosasaurid oceanic lizard classified as part of the Globidensini tribe in the Mosasaurinae subfamily.

<i>Halisaurus</i> Extinct genus of lizards

Halisaurus is an extinct genus of mosasaur named by Othniel Charles Marsh in 1869. The holotype, consisting of an angular and a basicranium fragment discovered near Hornerstown, New Jersey, already revealed a relatively unique combination of features and prompted a new genus to be described. Its name is a portmanteau of the Ancient Greek ἅλς and σαῦρος. It was renamed by Marsh to Baptosaurus in 1870, since he believed the name to already be preoccupied by the fish Halosaurus. According to modern rules, a difference of a letter is enough and the substitute name is unneeded, making "Baptosaurus" a junior synonym.

<span class="mw-page-title-main">Varanoidea</span> Superfamily of reptiles

Varanoidea is a superfamily of lizards, including the well-known family Varanidae. Also included in the Varanoidea are the Lanthanotidae, and the extinct Palaeovaranidae.

<span class="mw-page-title-main">Centrosaurinae</span> Extinct subfamily of dinosaurs

Centrosaurinae is a subfamily of ceratopsid, a group of large quadrupedal ornithischian dinosaur. Centrosaurine fossil remains are known primarily from the northern region of Laramidia but isolated taxa have been found in China and Utah as well.

<i>Pluridens</i> Extinct genus of lizards

Pluridens is an extinct genus of marine lizard belonging to the Mosasauridae. Pluridens is placed in the subfamily Halisaurinae with the genera Phosphorosaurus, Eonatator and Halisaurus. Compared to related halisaurines, Pluridens had longer jaws with more teeth, and smaller eyes. It also grew large size, measuring 5–6 m (16–20 ft) long and perhaps over 9 m (30 ft) in some individuals. The jaws in some specimens are robust, and sometimes show injuries suggestive of combat. The jaws may have been used for fighting over mates or territories.

<i>Taniwhasaurus</i> Extinct genus of marine squamate reptiles

Taniwhasaurus is an extinct genus of mosasaurs that lived during the Campanian stage of the Late Cretaceous. It is a member of the subfamily Tylosaurinae, a lineage of mosasaurs characterized by a long toothless conical rostrum. Two valid species are attached to the genus, T. oweni and T. antarcticus, known respectively from the fossil record of present-day New Zealand and Antarctica. Two other species have been nominally classified within the genus, T. 'capensis' and T. 'mikasaensis', recorded in present-day South Africa and Japan, but their attribution remains problematic due to the fragmentary state of their fossils. The generic name literally means "taniwha lizard", referring to a supernatural aquatic creature from Māori mythology.

<span class="mw-page-title-main">Pierre Shale</span> Geologic formation of the Upper Cretaceous from Pembina Valley in Canada to New Mexico, USA

The Pierre Shale is a geologic formation or series in the Upper Cretaceous which occurs east of the Rocky Mountains in the Great Plains, from Pembina Valley in Canada to New Mexico.

Socognathus is a genus of prehistoric chamopsiid polyglyphanodontian lizards containing species that lived from the Middle Campanian stage to the late Maastrichtian. Several specimens of the type species, Socognathus unicuspis, have been found in Alberta, Canada. A second species, Socognathus brachyodon is known from the late Maastrichtian Lance Formation; its fossils have been found in Wyoming, United States.

<i>Zhuchengtyrannus</i> Tyrannosaurid theropod dinosaur genus from Late Cretaceous period

Zhuchengtyrannus is a genus of tyrannosaurid theropod dinosaur known from the Campanian stage of the Late Cretaceous of Shandong Province, China. It belongs to the subfamily Tyrannosaurinae, and contains a single species, Zhuchengtyrannus magnus.

Asprosaurus is an extinct genus of anguimorph lizard from the Late Cretaceous of South Korea. Named in 2015 from the Seonso Conglomerate Formation, the type species Asprosaurus bibongriensis is the first Mesozoic lizard to have been discovered on the Korean peninsula. Because Asprosaurus is known only from fragmentary material, its relationships with other lizards are uncertain. However, features of the lower jaw suggest that it may be a member of a clade called Monstersauria, which includes the living Gila monster.

<i>Leptorhynchos gaddisi</i> Extinct species of dinosaur

Leptorhynchos is an extinct genus of caenagnathid theropod from the Late Cretaceous of what is now the US state of Texas, although it has been suggested to also exist in Alberta and South Dakota. The type species is L. gaddisi, and it is currently the only widely accepted valid species. The generic name of Leptorhynchos comes from the Greek "leptos" meaning "small" and "rhynchos" meaning "beak". The specific epithet is in honor of the Gaddis family, who owned the land on which the holotype was discovered.

<i>Thalassotitan</i> Large bodied African mosasaur

Thalassotitan is an extinct genus of large mosasaurs that lived during the late Maastrichtian of the Cretaceous period in what is now Morocco, around 66 million years ago. The only known species is T. atrox, described in 2022 from fossils discovered in the Ouled Abdoun Basin, where many other mosasaurs have been found. It was assigned to the tribe Prognathodontini alongside other mosasaurs like Prognathodon and Gnathomortis. The prognathodontines are separated from other mosasaurs based on their massive jaws and robust teeth.

References

  1. 1 2 "Palaeosaniwa canadensis". Fossilworks . Gateway to the Paleobiology Database . Retrieved 2 May 2021.
  2. Longrich, Nicholas R.; Bhullar, Bhart-Anjan S.; Gauthier, Jacques A. (26 December 2012). "Mass extinction of lizards and snakes at the Cretaceous–Paleogene boundary". Proceedings of the National Academy of Sciences. 109 (52): 21396–21401. Bibcode:2012PNAS..10921396L. doi: 10.1073/pnas.1211526110 . ISSN   0027-8424. PMC   3535637 . PMID   23236177. Supplementary Information
  3. Longrich, Nicholas R.; Horner, John R.; Erickson, Gregory M.; Currie, Philip J. (2010). "Cannibalism in Tyrannosaurus rex". PLOS ONE. 5 (10): e13419. Bibcode:2010PLoSO...513419L. doi: 10.1371/journal.pone.0013419 . ISSN   1932-6203. PMC   2955550 . PMID   20976177.
  4. Cabezuelo Hernández, A.; Bolet, A.; Torices, A.; Pérez-García, A. (1 March 2022). "Identification of a large anguimorph lizard (Reptilia, Squamata) by an articulated hindlimb from the upper Maastrichtian (Upper Cretaceous) of Basturs-1 (Lleida, Spain)". Cretaceous Research. 131: 105094. Bibcode:2022CrRes.13105094C. doi: 10.1016/j.cretres.2021.105094 . ISSN   0195-6671. S2CID   244352137.
  5. Park, Jin-Young; Evans, Susan E.; Huh, Min (2015). "The first lizard fossil (Reptilia: Squamata) from the Mesozoic of South Korea" (PDF). Cretaceous Research. 55: 292–302. doi:10.1016/j.cretres.2015.03.001.
  6. Hamilton, Samantha M.; Paparella, Ilaria; Bell, Phil R.; Campione, Nicolás E.; Fanti, Federico; Larson, Derek W.; Sissons, Robin L.; Vavrek, Matthew J.; Balsai, Michael J.; Sullivan, Corwin (2023). "New Lizard Specimens from the Campanian Wapiti Formation of Alberta, Canada". Geosciences. 13 (11): 337. Bibcode:2023Geosc..13..337H. doi: 10.3390/geosciences13110337 . hdl: 11585/954542 . ISSN   2076-3263.
  7. Michael Joseph Balsai, The phylogenetic position of Palaeosaniwa and the early evolution of the Platynotan (Varanoid) anguimorphs (January 1, 2001). Univ. of Pennsylvania – Electronic Dissertations. Paper AAI3031637]