''Anzu'' (named for
Anzû
Anzû, also known as dZû and Imdugud ( Sumerian: ''AN.IM.DUGUD MUŠEN''), is a lesser divinity or monster in several Mesopotamian religions. He was conceived by the pure waters of the Apsu and the wide Earth, or as son of Siris. Anzû was depi ...
, a bird-like
daemon
Daimon or Daemon (Ancient Greek: , "god", "godlike", "power", "fate") originally referred to a lesser deity or guiding spirit such as the daimons of ancient Greek religion and mythology and of later Hellenistic religion and philosophy.
The word ...
in
Ancient Mesopotamian religion
Mesopotamian religion refers to the religious beliefs and practices of the civilizations of ancient Mesopotamia, particularly Sumer, Akkad, Assyria and Babylonia between circa 6000 BC and 400 AD, after which they largely gave way to Syria ...
) is a
monospecific
In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
caenagnathid dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
from
North Dakota
North Dakota () is a U.S. state in the Upper Midwest, named after the Native Americans in the United States, indigenous Dakota people, Dakota Sioux. North Dakota is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north a ...
, South Dakota and
Montana
Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columbi ...
that lived during 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 ...
(upper
Maastrichtian
The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from ...
stage, 67.2-66.0 Ma) in what is now the
Hell Creek Formation
The Hell Creek Formation is an intensively studied division of mostly Upper Cretaceous and some lower Paleocene rocks in North America, named for exposures studied along Hell Creek, near Jordan, Montana. The formation stretches over portions of ...
.
The
type species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...
and only species, ''Anzu wyliei'' is known from numerous skeletons that preserve
cranial
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...
and
postcranial Postcrania (postcranium, adjective: postcranial) in zoology and vertebrate paleontology is all or part of the skeleton apart from the skull. Frequently, fossil remains, e.g. of dinosaurs or other extinct tetrapods, consist of partial or isolated s ...
elements.
[ It was named in ]2014
File:2014 Events Collage.png, From top left, clockwise: Stocking up supplies and personal protective equipment (PPE) for the Western African Ebola virus epidemic; Citizens examining the ruins after the Chibok schoolgirls kidnapping; Bundles of wat ...
by Matthew C. Lamanna, Hans-Dieter Sues, Emma R. Schachner, and Tyler R. Lyson.[
It was named one of the "Top 10 New Species" for new species discovered in 2014 by the International Institute for Species Exploration in 2015.
]
History of discovery
Several large skeletons from the late Maastrichtian
The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from ...
Hell Creek Formation
The Hell Creek Formation is an intensively studied division of mostly Upper Cretaceous and some lower Paleocene rocks in North America, named for exposures studied along Hell Creek, near Jordan, Montana. The formation stretches over portions of ...
of Montana
Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columbi ...
and South Dakota
South Dakota (; Sioux language, Sioux: , ) is a U.S. state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Lakota people, Lakota and Dakota peo ...
were initially referred to as "cf. ''Chirostenotes
''Chirostenotes'' ( ; named from Greek 'narrow-handed') is a genus of oviraptorosaurian dinosaur from the late Cretaceous (about 76.5 million years ago) of Alberta, Canada. The type species is ''Chirostenotes pergracilis''.
History of discovery ...
''",[Varricchio, D. J. (2001). Late Cretaceous Oviraptorosaur (Theropoda) dinosaurs from Montana. ''Mesozoic Vertebrate Life.'' D. H. Tanke and K. Carpenter. Bloomington, Indiana University Press: 42–57.] though more recent studies concluded that they represent new species.
In 1998 Fred Nuss of Nuss Fossils discovered the site containing the holotype, CM 78000. The first two partial skeletons of ''Anzu'' were discovered in 1998 by Fred Nuss Fossils on a private South Dakota ranch.[ The two specimens weren't buried together – the skeletons rested about 330 feet apart with the second individual in a rock layer about 11 feet below the first – but, once prepped by the commercial outfit Triebold Paleontology, it was clear that both represented the same dinosaur. Both were mostly disarticulated and appeared to have been transported by a water current. A third referred specimen, fragmentary skeleton MRF 319, studied by Tyler Lyson of the ]National Museum of Natural History
The National Museum of Natural History is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., United States. It has free admission and is open 364 days a year. In 2021, with 7 ...
, was discovered by Scott Haire, who spotted the bones at his uncle's ranch at Marmarth, North Dakota
Marmarth ( ) is the largest city in Slope County, North Dakota, Slope County in the U.S. State of North Dakota with a population of 101 as of 2020 United States census, 2020 census. It is situated in the southwestern part of Slope County, along th ...
. A rear lower jaw fragment, FMNH PR 2296, was also referred.
These four fossils found at Hell Creek together make up a fairly complete skeleton of ''Anzu wyliei'', comprising about 75 to 80 per cent of the whole skeleton. Three researchers, Emma Schachner of the University of Utah
The University of Utah (U of U, UofU, or simply The U) is a public research university in Salt Lake City, Utah. It is the flagship institution of the Utah System of Higher Education. The university was established in 1850 as the University of De ...
, Matthew Lamanna of the Carnegie Museum of Natural History
The Carnegie Museum of Natural History (abbreviated as CMNH) is a natural history museum in the Oakland neighborhood of Pittsburgh, Pennsylvania. It was founded by Pittsburgh-based industrialist Andrew Carnegie in 1896.
Housing some 22 millio ...
and Tyler Lyson of the Smithsonian in Washington realized in 2006 that they each had partial skeletons of the same species and began collaborating to study it, assisted by Hans-Dieter Sues
Hans-Dieter Sues (born January 13, 1956) is a German-born American paleontologist who is Senior Scientist and Curator of Vertebrate Paleontology at the National Museum of Natural History of the Smithsonian Institution in Washington, DC.
He receiv ...
, a paleontologist
Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...
at the National Museum of Natural History of the Smithsonian Institution
The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums and education and research centers, the largest such complex in the world, created by the U.S. government "for the increase and diffusion of knowledge". Founded ...
in Washington. The main fossils are being held at the Carnegie Museum of Natural History in Pittsburgh
Pittsburgh ( ) is a city in the Commonwealth (U.S. state), Commonwealth of Pennsylvania, United States, and the county seat of Allegheny County, Pennsylvania, Allegheny County. It is the most populous city in both Allegheny County and Wester ...
.
The genus is notable as the first well-preserved example of a North American oviraptorosaur. According to Sues, "for almost a hundred years, the presence of oviraptorosaurs in North America was only known from a few bits of skeleton, and the details of their appearance and biology remained a mystery. With the discovery of ''A. wyliei'', we finally have the fossil evidence to show what this species looked like and how it is related to other dinosaurs."
The creature's appearance – "big crests on their skulls, a beak, no teeth, and a very bird-like skeleton" – and its discovery in the Hell Creek Formation led to it being jokingly nicknamed the "chicken from hell". Matthew Lamanna, who devised the species' name, originally wanted to use a Latin or Greek version of "chicken from hell". However, he found that this nickname does not translate well in those languages, so he eventually settled on evoking and using the name of the bird-like daemon
Daimon or Daemon (Ancient Greek: , "god", "godlike", "power", "fate") originally referred to a lesser deity or guiding spirit such as the daimons of ancient Greek religion and mythology and of later Hellenistic religion and philosophy.
The word ...
Anzu Anzu may refer to:
*Anzû, a divine storm-bird in several Ancient Mesopotamian religion, Mesopotamian religions
*Anzu (dinosaur), ''Anzu'' (dinosaur), a genus of theropod dinosaur containing the species ''Anzu wyliei''
As a given name
is a Japan ...
from the mythology of ancient Sumer
Sumer () is the earliest known civilization in the historical region of southern Mesopotamia (south-central Iraq), emerging during the Chalcolithic and early Bronze Ages between the sixth and fifth millennium BC. It is one of the cradles of c ...
, which itself roughly translates to "heavenly eagle".[Alster, B. (1991)]
Contributions to the Sumerian lexicon
''Revue d'Assyriologie et d'archéologie orientale'', 85(1): 1–11. The specific name, ''wyliei'', honors Wylie J. Tuttle, the grandson of one of the museum's donors, Lee B. Foster.
Description
''Anzu wyliei'' is characterized by a toothless beak, a prominent crest, long arms ending in slender, relatively straight claws, long powerful legs with slender toes, and a relatively short tail. ''Anzu'' measured about long, up to tall at the hips and in body mass, and was among the largest North American oviraptorosaurs.
When the type specimen
In biology, a type is a particular wiktionary:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to a ...
of ''Anzu'' was described, several autapomorphies
In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to t ...
(derived traits unique to a genus) were established. There is a high crescent-like crest on the skull, formed by the upper branches of the praemaxilla
The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has ...
e. The occipital condyle
The occipital condyles are undersurface protuberances of the occipital bone in vertebrates, which function in articulation with the superior facets of the atlas vertebra.
The condyles are oval or reniform (kidney-shaped) in shape, and their anteri ...
is wider than the foramen magnum
The foramen magnum ( la, great hole) is a large, oval-shaped opening in the occipital bone of the skull. It is one of the several oval or circular openings (foramina) in the base of the skull. The spinal cord, an extension of the medulla oblon ...
. The front part of the lower jaw, which is fused with its counterpart, has a prominent flange on its outer side. The retroarticular process, a prominent projection at the rear of the lower jaw, is elongated, about as long as the jaw joint surface. The lower end of the radius
In classical geometry, a radius ( : radii) of a circle or sphere is any of the line segments from its center to its perimeter, and in more modern usage, it is also their length. The name comes from the latin ''radius'', meaning ray but also the ...
is divided into two rounded processes. The first phalanx of the second finger has a trough along the lower edge of its inner side. The front side of the astragalus
''Astragalus'' is a large genus of over 3,000 species of herbs and small shrubs, belonging to the legume family Fabaceae and the subfamily Faboideae. It is the largest genus of plants in terms of described species. The genus is native to tempe ...
(ankle bone) has a tubercle at the base of its ascending process.[
An additional four possible autapomorphies were identified in the referred specimens. The main body of the ]maxilla
The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...
has no depression around the antorbital fenestra
An antorbital fenestra (plural: fenestrae) is an opening in the skull that is in front of the eye sockets. This skull character is largely associated with archosauriforms, first appearing during the Triassic Period. Among extant archosaurs, birds ...
. The nasal branch of the maxilla is elongated and constructed like an inverted L. The branch of the jugal
The jugal is a skull bone found in most reptiles, amphibians and birds. In mammals, the jugal is often called the malar or zygomatic. It is connected to the quadratojugal and maxilla, as well as other bones, which may vary by species.
Anatomy ...
towards the quadratojugal The quadratojugal is a skull bone present in many vertebrates, including some living reptiles and amphibians.
Anatomy and function
In animals with a quadratojugal bone, it is typically found connected to the jugal (cheek) bone from the front and ...
is vertically deep. The same branch is forked at its rear end.[
]
Classification
''Anzu'' was placed in the Oviraptorosauria
Oviraptorosaurs ("egg thief lizards") are a group of feathered maniraptoran dinosaurs from the Cretaceous Period of what are now Asia and North America. They are distinct for their characteristically short, beaked, parrot-like skulls, with or wit ...
, as a member of the Caenagnathidae
Caenagnathidae is a family of bird-like maniraptoran theropod dinosaurs from the Cretaceous of North America and Asia. They are a member of the Oviraptorosauria, and close relatives of the Oviraptoridae. Like other oviraptorosaurs, caenagnathids ...
. A cladistic
Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived char ...
analysis showed it was a possible sister species
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree.
Definition
The expression is most easily illustrated by a cladogram:
Taxon A and t ...
of ''Caenagnathus
''Caenagnathus'' ('recent jaw') is a genus of caenagnathid oviraptorosaurian dinosaur from the late Cretaceous period (Campanian stage; ~75 million years ago). It is known from partial remains including lower jaws, a tail vertebra, hand bones ...
''.[
It had been expected that oviraptorosaurs would be found in North America, as well as the documented specimens in Asia, as the two continents had a land connection during the Cretaceous, but the discovery of ''Anzu wyliei'' indicates that North American oviraptorosaurs were related more closely to each other than to their counterparts in Asia.]
Paleobiology
''Anzu'' was probably an omnivore
An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nutr ...
or herbivore
A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...
, although the beak is not as heavily constructed as in the Asian Oviraptoridae
Oviraptoridae is a group of bird-like, herbivorous and omnivorous maniraptoran dinosaurs. Oviraptorids are characterized by their toothless, parrot-like beaks and, in some cases, elaborate crests. They were generally small, measuring between one ...
. Other differences from its Asian cousins include size – the Asian Oviraptoridae were smaller – as well as thicker legs and different lower jaws.
The fossils of ''Anzu wyliei'' were found in mudstone
Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from '' shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology. ...
rock that had once been part of ancient floodplains. This indicates that the species likely had a lifestyle significantly different from its Asian counterparts, which lived in arid or semi-arid conditions. Its lifestyle, according to Stephen Brusatte
Stephen Louis Brusatte (born April 24, 1984) is an American paleontologist and evolutionary biologist, who specializes in the anatomy and evolution of dinosaurs. He was educated at the University of Chicago for his BS degree, at the University of ...
of the University of Edinburgh
The University of Edinburgh ( sco, University o Edinburgh, gd, Oilthigh Dhùn Èideann; abbreviated as ''Edin.'' in post-nominals) is a public research university based in Edinburgh, Scotland. Granted a royal charter by King James VI in 15 ...
, was that of "a fast-running, ecological generalist that didn't quite fit the usual moulds of meat-eating or plant-eating dinosaur." Its jaw morphology suggests that it could eat a variety of food items, including vegetation, small animals, and possibly eggs.
While a number of its features were similar to those of modern birds, it was not an avian dinosaur and its line died out in the Cretaceous–Paleogene extinction event
The Cretaceous–Paleogene (K–Pg) extinction event (also known as the Cretaceous–Tertiary extinction) was a sudden mass extinction of three-quarters of the plant and animal species on Earth, approximately 66 million years ago. With the ...
66 million years ago, along with all the rest of the non-avian dinosaurs. Its bird-like features are instead an example of convergent evolution
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...
. Matthew Lamanna comments that "it would have had a lot of birdy behaviors. When people think of a dinosaur, they think of something like a ''T. rex'' or a brontosaurus, and when they think of a bird, they think of something like a sparrow or a chicken. This animal, ''Anzu'', has a mosaic of features of both of those groups, and so it basically provides a really nice link in the evolutionary chain."
The purpose of ''Anzu's'' large crest is unclear; Sues notes that it "is very large and made of paper-thin bone, so it was not able to take much stress. All oviraptosaurs have this crest but it is certainly the largest in ''A. wyliei''. The most likely function is for display, showing off to members of your own species. The Australian cassowary
Cassowaries ( tpi, muruk, id, kasuari) are flightless birds of the genus ''Casuarius'' in the order Casuariiformes. They are classified as ratites (flightless birds without a keel on their sternum bones) and are native to the tropical forest ...
has a similar crest which is thought to be used to attract mates, so it is possible that ''A. wyliei'' could have used its crest in a similar fashion." The fossils showed evidence of injuries, including a healed broken rib and an arthritic toe that was probably the result of a tendon being ripped away from the bone (an avulsion fracture
An avulsion fracture is a bone fracture which occurs when a fragment of bone tears away from the main mass of bone as a result of physical trauma. This can occur at the ligament by the application of forces external to the body (such as a fall ...
). It is not known whether this indicates that the animals fought each other, or were injured by predators.
See also
* Timeline of oviraptorosaur research
This timeline of oviraptorosaur research is a chronological listing of events in the history of paleontology focused on the oviraptorosaurs, a group of beaked, bird-like theropod dinosaurs. The early history of oviraptorosaur paleontology is cha ...
References
External links
Artist's impression of ''Anzu wyliei''
{{Taxonbar, from=Q15966623
Caenagnathids
Late Cretaceous dinosaurs of North America
Maastrichtian life
Paleontology in North Dakota
Paleontology in South Dakota
Hell Creek fauna
Fossil taxa described in 2014
Taxa named by Matt Lamanna
Taxa named by Hans-Dieter Sues