''Suskityrannus'' (meaning "

coyote The coyote (''Canis latrans'') is a species of canis, canine native to North America. It is smaller than its close relative, the wolf, and slightly smaller than the closely related eastern wolf and red wolf. It fills much of the same ecologica ...

tyrant", ''suski'' meaning "coyote" in Zuni) is a genus of small tyrannosauroid theropod from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

in southern

Laramidia Laramidia was an island continent that existed during the Late Cretaceous period (99.6–66 Ma), when the Western Interior Seaway split the continent of North America in two. In the Mesozoic era, Laramidia was an island land mass separated from A ...

. It contains a single species, ''Suskityrannus hazelae,'' believed to have lived roughly 92 million years ago. The type specimen was found in the

Turonian The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded by t ...

-age Moreno Hill Formation of the Zuni Basin in western

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, Ker ...

Discovery and naming

First mentioned as a small

dromaeosaurid Dromaeosauridae () is a family of feathered theropod dinosaurs. They were generally small to medium-sized feathered carnivores that flourished in the Cretaceous Period. The name Dromaeosauridae means 'running lizards', from Greek ('), meaning ...

by Wolfe and Kirkland in their description of ''

Zuniceratops ''Zuniceratops'' ('Zuni-horned face') was a ceratopsian dinosaur from the mid Turonian of the Late Cretaceous Period of what is now New Mexico, United States. It lived about 10 million years earlier than the more familiar horned Ceratopsidae ...

'', ''Suskityrannus'' was informally referred to as the "Zuni coelurosaur", "Zuni tyrannosaur", and by the 2011 documentary ''

Planet Dinosaur ''Planet Dinosaur'', is a six-part documentary television series created by Nigel Paterson and Phil Dobree, produced by the BBC, and narrated by John Hurt. It first aired in the United Kingdom in 2011, with VFX studio Jellyfish Pictures a ...

'' "Zunityrannus" prior to its scientific description. The original fossils were found by Robert Denton, a professional geologist from Virginia, and a native Mesa teen

Sterling Nesbitt Sterling Nesbitt (born March 25, 1982, in Mesa, Arizona) is an American paleontologist best known for his work on the origin and early evolutionary patterns of archosaurs. He is currently an associate professor at Virginia Tech in the Department of ...

, who was a museum volunteer that came to a dig with paleontologist Doug Wolfe. In 2019 ''Suskityrannus'' was formally described as a genus of primitive tyrannosauroid. Both the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

specimen MSM P4754 (partially articulated skull and a few postcranial bones) and the

paratype In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype nor a syntype). Of ...

specimen MSM P6178 (partially articulated and associated remains including a few skull bones and an incomplete postcranial skeleton) are preserved in the collections of the

Arizona Museum of Natural History The Arizona Museum of Natural History (originally the Mesa Southwest Museum) is the only natural history museum in the greater Phoenix area and is located in Mesa, Arizona. It exhibits the natural and cultural history of the Southwestern Unite ...

Description

The two specimens of ''Suskityrannus'' stood roughly tall and long and likely weighed between . Both are likely to have been juveniles. One of the specimens is believed to have been 3 years old when it died, based on bone rings. The skull of ''Suskityrannus'' and its foot are more slender than other tyrannosaurs. The species already possesses many key features of the tyrannosaurid body plan, including the phylogenetically earliest record of an arctometatarsalian foot in tyrannosauroids. Additionally, as an early tyrannosaur, ''Suskityrannus'' may have had feathers, despite no feathers being found with its fossils. Doug Wolfe noted that the brain of ''Suskityrannus'' was relatively large compared to its body plan.

Classification

Below is the phylogenetic analysis on the placement of ''Suskityrannus''.

Paleobiology

The area in

where ''Suskityrannus'' lived is an area rich in fossils. The fossil record of the Moreno Hill Formation documents a transition period between early

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

fauna and the latest Cretaceous fauna. The area was a thickly forested coastal region with a humid climate. ''Zuniceratops'', ''

Nothronychus ''Nothronychus'' (meaning "slothful claw") is a genus of therizinosaurid theropod dinosaurs that lived in North America during the Late Cretaceous period. The type species, ''Nothronychus mckinleyi'', was described by James Kirkland and Doug ...

,'' and a few specimens of '' Jeyawati'' are known from this region. The formation also contains a currently undescribed

ankylosaurid Ankylosauridae () is a family of armored dinosaurs within Ankylosauria, and is the sister group to Nodosauridae. The oldest known Ankylosaurids date to around 122 million years ago and went extinct 66 million years ago during the Cretaceous–Pal ...

dinosaur. Fossils of a

crocodilia Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period ( Cenomanian stage) and are the closest living ...

n and a possible marine turtle belonging to the

Cheloniidae Cheloniidae is a family of typically large marine turtles that are characterised by their common traits such as, having a flat streamlined wide and rounded shell and almost paddle-like flippers for their forelimbs. They are the only sea turtles t ...

, were also found in the same locality as well. ''Suskityrannus'' filled the major phylogenetic, morphological and temporal gaps that researchers needed to piece together

tyrannosauroid Tyrannosauroidea (meaning 'tyrant lizard forms') is a superfamily (or clade) of coelurosaurian theropod dinosaurs that includes the family Tyrannosauridae as well as more basal relatives. Tyrannosauroids lived on the Laurasian supercontinent b ...

evolution.

References

{{Taxonbar, from=Q20728010 Tyrannosaurs Fossil taxa described in 2019 Late Cretaceous dinosaurs of North America