''Dynamoterror'' (meaning "powerful terror") 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 "unispe ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

tyrannosaurid Tyrannosauridae (or tyrannosaurids, meaning "tyrant lizards") is a family of coelurosaurian theropod dinosaurs that comprises two subfamilies containing up to fifteen genera, including the eponymous ''Tyrannosaurus''. The exact number of genera ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

from

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

that lived during the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent 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 ''cre ...

(lower

Campanian The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...

age, 78 Ma) in what is now the upper Allison Member of the

Menefee Formation The Menefee Formation is an upper Santonian to lower Campanian geologic Formation (geology), formation found in Colorado and New Mexico, United States. Description The Menefee Formation consists of fluvial sandstone, shale, and coal. Based on am ...

. The type and only species, ''Dynamoterror dynastes'', is known from a

subadult A juvenile is an individual organism (especially an animal) that has not yet reached its adult form, sexual maturity or size. Juveniles can look very different from the adult form, particularly in colour, and may not fill the same niche as t ...

or adult individual about 9 metres (30 feet) long with an incomplete associated

skeleton A skeleton is the structural frame that supports the body of most animals. There are several types of skeletons, including the exoskeleton, which is a rigid outer shell that holds up an organism's shape; the endoskeleton, a rigid internal fra ...

. It was named in

2018 Events January * January 1 – Bulgaria takes over the Presidency of the Council of the European Union, after the Estonian presidency. * January 4 – SPLM-IO rebels loyal to Chan Garang Lual start a raid against Juba, capital of ...

by Andrew T. McDonald, Douglas G. Wolfe and Alton C. Dooley, Jr. ''Dynamoterror'' was closely related to ''

Teratophoneus ''Teratophoneus'' ("monstrous murderer"; Greek: ''teras'', "monster" and ''phoneus'', "murderer") is a genus of Tyrannosaurinae, tyrannosaurine Theropoda, theropod dinosaur that lived during the late Campanian age of the Late Cretaceous period, ...

'' and ''

Lythronax ''Lythronax'' () is a genus of tyrannosaurid dinosaur that lived in North America around 81.9-81.5 million years ago during the Late Cretaceous period. The only known specimen was discovered in Utah in the Wahweap Formation of the Grand Stairca ...

''.

Discovery

In August 2012, a partial

of a

was discovered and collected from the Lower

Allison Member of the

in the

San Juan Basin The San Juan Basin is a geologic structural basin located near the Four Corners region of the Southwestern United States. The basin covers 7,500 square miles and resides in northwestern New Mexico, southwestern Colorado, and parts of Utah a ...

of northwestern

. The remains were found by geology students Brian Watkins and Eric Gutiérrez on an expedition led by Andrew McDonald of the Western Science Center, and Douglas Wolfe, the CEO of the Zuni Dinosaur Institute for Geosciences. Subsequent expeditions at the Menefee Formation in 2013 and 2018 did not reveal any additional elements. The specimen was subsequently named and described in 2018 by Andrew T. McDonald, Douglas G. Wolfe, and Alton C. Dooley, Jr. The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

specimen, UMNH VP 28348, consists of the left and right frontals, fragmentary

vertebral centra Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal ...

, fragments of dorsal ribs, right

metacarpal In human anatomy, the metacarpal bones or metacarpus, also known as the "palm bones", are the appendicular bones that form the intermediate part of the hand between the phalanges (fingers) and the carpal bones ( wrist bones), which articulate ...

II, the supraacetabular crest of the right ilium,

phalanx The phalanx (: phalanxes or phalanges) was a rectangular mass military formation, usually composed entirely of heavy infantry armed with spears, pikes, sarissas, or similar polearms tightly packed together. The term is particularly used t ...

2 of left pedal digit IV, phalanx 4 of left pedal digit IV, and other unidentifiable bone fragments. The holotype specimen is currently housed at the

Natural History Museum of Utah The Natural History Museum of Utah is a museum located in Salt Lake City, Utah, United States. The museum shows exhibits of natural history subjects, with an emphasis on Utah and the Intermountain West. The mission of the museum is to illumina ...

Salt Lake City Salt Lake City, often shortened to Salt Lake or SLC, is the capital and most populous city of the U.S. state of Utah. It is the county seat of Salt Lake County, the most populous county in the state. The city is the core of the Salt Lake Ci ...

Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...

. The generic name, ''Dynamoterror'', is derived from the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

word "''dynamis''" (power) and the

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

word "''terror''". The specific name, ''dynastes'', is derived from the Latin word "''dynastēs''" (ruler). The

binomial name In taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, altho ...

honours “''Dynamosaurus imperiosus''”, a

junior synonym In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The botanical and zoological codes of nomenclature treat the concept of synonymy differently. ...

of ''

Tyrannosaurus ''Tyrannosaurus'' () is a genus of large theropod dinosaur. The type species ''Tyrannosaurus rex'' ( meaning 'king' in Latin), often shortened to ''T. rex'' or colloquially t-rex, is one of the best represented theropods. It lived througho ...

'', as it had been a "childhood favourite" of one of the authors. In 2020, Chan-gyu Yun considered ''Dynamoterror'' as a ''

nomen dubium In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium,'' it may be impossible to determine whether a ...

'' because of the highly fragmentary nature of the holotype specimen and lack of

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 ...

, as two of the original autapomorphies are present in other tyrannosaurids. Additionally, the fragmentary nature of the frontal makes it uncertain whether the autapomorphies are even comparable to other tyrannosaurids. In 1993, Adrian P. Hunt and Spencer G. Lucas reported

tooth A tooth (: teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tea ...

fragments and a

metatarsal The metatarsal bones or metatarsus (: metatarsi) are a group of five long bones in the midfoot, located between the tarsal bones (which form the heel and the ankle) and the phalanges ( toes). Lacking individual names, the metatarsal bones are ...

of a tyrannosaurid from the Menefee Formation. In 2006, ''Lewis et al.'' reported another tooth fragment. McDonald ''et al.'' (2018) suggested that, due to the lack of overlapping material, the previously reported tyrannosaurid material could not be referred to ''Dynamoterror''. In 2018, Sebastian G. Dalman and Spencer G. Lucas described five tyrannosaurid specimens from the Menefee Formation: NMMNH P-8313 (a right anterior

scapula The scapula (: scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on either side ...

), NMMNH P-22133 (a metatarsal II), NMMNH P-61274 (a shaft of an anterior thoracic rib), NMMNH P-71332 (a lateral tooth), and NMMNH P-78032 (a left

postorbital The ''postorbital'' is one of the bones in vertebrate skulls which forms a portion of the dermal skull roof and, sometimes, a ring about the orbit. Generally, it is located behind the postfrontal and posteriorly to the orbital fenestra. In some ve ...

). A more complete specimen of ''Dynamoterror'' was identified in 2021,A.T. McDonald, D.G. Wolfe, A.C. Dooley. (2021) New data on the tyrannosaurid dinosaur ''Dynamoterror'', including a more complete skeleton, from the

(middle

) of

, USA: Implications for tyrannosaurid evolution in southern

Laramidia Laramidia was an island continent that existed during the Late Cretaceous period (99.6–66 Year#SI prefix multipliers, Ma), when the Western Interior Seaway split the continent of North America in two. In the Mesozoic era, Laramidia was an island ...

. ''The Society of Vertebrate Paleontology''. but has not yet been described in detail. It is known as specimen WSC 1027 and is also from the Menefee Formation. A detailed description of this specimen is ongoing as of 2024.

Description

Size and distinguishing traits

Based on a specimen of a subadult ''Tyrannosaurus'', LACM 23845, the holotype specimen of ''Dynamoterror'' had a similar body length of 9 metres (30 feet). ''McDonald et al.'' (2018) originally diagnosed ''Dynamoterror'' based on the prefrontonasal and prefrontolacrimal processes being in close proximity to each other, separated only by a shallow notch, and the presence of a subrectangular, concave, laterally-projecting caudal part of the postorbital suture, separated from the rostral part by a deep groove. However, they noted that the second diagnostic trait should be provisional, given the ontogenetic variation observed in the postorbital suture in other tyrannosaurids.

Cranium

The measurements and depth/width

ratio In mathematics, a ratio () shows how many times one number contains another. For example, if there are eight oranges and six lemons in a bowl of fruit, then the ratio of oranges to lemons is eight to six (that is, 8:6, which is equivalent to the ...

of the frontals suggests that the holotype specimen of ''Dynamoterror'' represents a subadult or adult individual. The base of the nasal process consists of the medial-most feature on the rostral surface of the frontal. The nasal process projects towards the

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit ** podium * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ...

and possesses a deep notch towards the sides of the base. The deep notch marks the posterior-most point of the contact with the nasal. As in ''

'' and ''

'', towards the sides of the deep notch is the conical prefrontonasal process. Towards the sides of the prefrontal process is a shallower notch that marks where the prefrontal exposure is on the

skull roof The skull roof or the roofing bones of the skull are a set of bones covering the brain, eyes and nostrils in bony fishes, including land-living vertebrates. The bones are derived from dermal bone and are part of the dermatocranium. In com ...

and towards the side of the shallow notch is the prefrontolacrimal process. The prefrontolacrimal process differs from that of '' Nanuqsaurus'' and ''Teratophoneus'' by its smaller size, but is similar to that of ''Lythronax'', ''

Daspletosaurus ''Daspletosaurus'' ( ; meaning "frightful lizard") is a genus of tyrannosaurid dinosaur that lived in Laramidia between about 77 and 74.4 million years ago, during the Late Cretaceous Period. The genus ''Daspletosaurus'' contains three named ...

'', ''

'', and ''

Tarbosaurus ''Tarbosaurus'' ( ; meaning "alarming lizard") is a genus of large tyrannosaurid dinosaur that lived in Asia during the Late Cretaceous epoch, about 70 million years ago (Maastrichtian age). It contains the single type species: ''Tarbosaurus ...

''. The close proximity of the prefrontonasal and prefrontolacrimal processes, separated by a shallow notch, is a unique trait of ''Dynamoterror''. Towards the sides of the prefrontolacrimal process is a smooth surface that extends towards the back and then begins to curve towards the sides, which marks the medial-most point of the lacrimal suture. Towards the sides of the smooth surface is ventrolateral portion of the lacrimal suture that forms a rostrally facing cup-like structure that is as rostrally concave and ventrolaterally convex, as in ''Lythronax'', ''Daspletosaurus'', ''Tyrannosaurus'', ''Tarbosaurus'', and ''Nanuqsaurus''. Dynamoterror_frontals_in_ventral_view

The right frontal's dorsal surface possesses a slight swelling posterior to the nasal, prefrontonasal, and prefrontolacrimal processes. Towards the rear of the swelling, the dorsal surface becomes concave and begins to slope towards the rear and sides to form the frontal portion of the supratemporal fossa. The dorsal surface rises towards the rear and the middle to form the frontal portion of the

sagittal crest A sagittal crest is a ridge of bone running lengthwise along the midline of the top of the skull (at the sagittal suture) of many mammalian and reptilian skulls, among others. The presence of this ridge of bone indicates that there are excepti ...

, which would have been very tall. Such a prominent sagittal crest is also seen in ''Teratophoneus'', ''Lythronax'', ''

Bistahieversor ''Bistahieversor'' (meaning "Bistahi destroyer"), also known as the "Bisti Beast", is a genus of basal Eutyrannosauria, eutyrannosaurian Theropoda, theropod dinosaur. The genus contains only a single known species, ''B. sealeyi'', described in 2 ...

'', and an unnamed tyrannosaurine from the

Aguja Formation The Aguja Formation is a geological formation in North America, exposed in Texas, United States and Chihuahua and Coahuila in Mexico, whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered ...

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

. The tall sagittal crest of ''Dynamoterror'' and other tyrannosaurines differs from that of albertosaurines, such as ''

Albertosaurus ''Albertosaurus'' (; meaning "Alberta lizard") is a genus of large tyrannosaurid theropod dinosaur that lived in northwestern North America during the early to middle Maastrichtian age of the Late Cretaceous period, about 71 million yea ...

'' and ''

Gorgosaurus ''Gorgosaurus'' ( ; ) is a genus of tyrannosaurid theropod dinosaur that lived in western North America during the Late Cretaceous Period (Campanian), between about 76.5 and 75 million years ago. Fossil remains have been found in the Ca ...

'', as both have much lower sagittal crests on the frontals. The large supratemporal fossae and tall sagittal crest on the frontals provide an expanded attachment area for large jaw-closing

muscles Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contra ...

. The rostral region of the ventral surface is covered by an elongated and wide fossa that is defined towards the rostrum by the prefrontal suture, towards the middle by the interfrontal suture, towards the sides by the crista cranii, and towards the rear by the ethmoid scar. The fossae form the rear extent of the olfactory region of the

nasal cavity The nasal cavity is a large, air-filled space above and behind the nose in the middle of the face. The nasal septum divides the cavity into two cavities, also known as fossae. Each cavity is the continuation of one of the two nostrils. The nas ...

, which would have been lined with a

mucous membrane A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It ...

in life. The ethmoid scar separates the rostral fossa from the

olfactory bulb The olfactory bulb (Latin: ''bulbus olfactorius'') is a neural structure of the vertebrate forebrain involved in olfaction, the sense of smell. It sends olfactory information to be further processed in the amygdala, the orbitofrontal cortex (OF ...

fossa. The orbitosphenoid suture is lined with a set of ridges, bumps, and depressions. The medial surface of the frontal possesses a vertical interfrontal suture that consists of a series of overlapping, V-shaped ridges. A narrow, deep, vertical groove separates the lacrimal and postorbital sutures, as in ''Lythronax'', ''Teratophoneus'', and ''Albertosaurus''. The postorbital suture is composed of a rostral part and a caudal part. The rostral part possesses an abdominal margin that is convex and projects farther towards the sides than the upper side margin. Towards the underside of the rostral part is the orbit wall. Both the rostral and caudal parts are separated by a deep, inclined groove that opens towards the underside onto the orbital wall. This inclined groove is present on both frontals. The caudal part of the postorbital suture is subrectangular and slightly concave, which is unique to ''Dynamoterror'', but might be subject to ontogenetic variation.

Postcrania

One of the most complete vertebral fragments of ''Dynamoterror'' is known to be part of the centrum of a middle

caudal vertebra Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal ...

. As in ''Tyrannosaurus'', the middle caudal centrum exhibits a pronounced chevron articulation facet. The articulation facet is offset from the underside margin of the caudal face of the centrum. Based on comparisons of the ilia of ''Teratophoneus'' and ''Tyrannosaurus'', a broadly arched bone fragment was identified as the supraacetabular crest of the right ilium. The underside surface of the right ilium fragment is smooth and gently concave. The supraacetabular crest is very thin at the side margins, but becomes considerably thicker towards the rear and middle, as its upper margin slopes steeply dorsally to merge with the side surface of the blade of the ilium. Based on the right manus of ''Tyrannosaurus'' and the left manus of ''Daspletosaurus'', the right

II was identified. The right metacarpal II is nearly straight and the articular surface nearest to the centre tapers and curves towards its upper side margin. The underside surface of the metacarpal II shaft is flat and becomes wider towards the distal articular surface. The metacarpal II does not have an apparent articulation surface on the side surfaces, while the medial surface is broad and gently concave. The broadness and concave shape of the medial surface of the metacarpal II forms a surface for articulation with the side surfaces of metacarpal I. Pedal digit IV-2 has a proximal articular surface that is subrectangular and divided into two facets by a ridge. Away from the centre of the proximal articular surface, the shaft of pedal digit IV-2 is constricted towards the middle and sides and towards the upper side and sides. A deep circular pit with a pronounced bump is present on the underside of the medial surface of the shaft. In comparison to pedal digit IV-2, pedal digit IV-4 is smaller in all dimensions. The proximal articular surface of pedal digit IV-4 is similarly divided as pedal digit IV-2. However, the facets of IV-4 are equal in size and are separated by a distinct ridge. The distal articular surface possesses a much deeper trochlea than on IV-2 that separates the medial and lateral

condyle A condyle (;Entry "condyle"
in

s. The lateral condyle is deeper towards the upper and under side than the medial condyle and both of them bear a deep circular fovea.

Classification

''McDonald et al.'' (2018) originally placed ''Dynamoterror'' within

Tyrannosaurinae Tyrannosaurinae (or tyrannosaurines) is one of the two extinct subfamilies of Tyrannosauridae, a family of coelurosaurian theropods that consists of at least three tribes and several genera. All fossils of these genera have been found in the L ...

, in a

polytomy An internal node of a phylogenetic tree is described as a polytomy or multifurcation if (i) it is in a rooted tree and is linked to three or more child subtrees or (ii) it is in an unrooted tree and is attached to four or more branches. A tree ...

with ''Lythronax'', ''Nanuqsaurus'', ''Teratophoneus'', ''Daspletosaurus'', ''Zhuchengtyrannus'', and a clade containing ''Tarbosaurus'' and ''Tyrannosaurus''. The authors suggested that the polytomy was likely caused by the fragmentary nature of the holotype specimen of ''Dynamoterror''. The authors also suggested that the area of origin for the large-bodied tyrannosaurine clade is difficult to determine due to the small amount of

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 supercontinen ...

specimens known from the Campanian of

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

and the lack of diagnostic early tyrannosaurid material from northern

. However, ''Voris et al.'' (2020) later assigned ''Dynamoterror'' within a clade containing ''Teratophoneus'' and ''Lythronax'' only. The authors suggested that this clade likely had different feeding strategies to tyrannosaurids belonging to the clade Daspletosaurini because of the differing skull morphologies. A study by Yun (2020) determined ''Dynamoterror'' to be a nomen dubium due to the holotype's undiagnostic, fragmentary nature. A phylogenetic analysis conducted by Voris et al. (2020) is reproduced below. The results of an earlier analysis by McDonald et al. (2018) are reproduced below.

Paleoecology

Deinosuchus_hatcheri_-_Natural_History_Museum_of_Utah_-_DSC07251

''Dynamoterror'' is known from the upper Allison Member of the Menefee Formation which has been dated to the lower

age, about 78.5 Ma. The Menefee Formation represents a widespread alluvial floodplain and consists of

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.Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, ...

siltstone Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility. Although its permeabil ...

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

, and

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other Chemical element, elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal i ...

. The sandstones that compose the Menefee Formation are fixed within carbonaceous shales of coastal swamp or

lagoon A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into ''coastal lagoons'' (or ''barrier lagoons'') an ...

origin and are thought to have been created by flood tidal deltas that ran north and east across New Mexico and towards the retreating

Western Interior Seaway The Western Interior Seaway (also called the Cretaceous Seaway, the Niobraran Sea, the North American Inland Sea, or the Western Interior Sea) was a large inland sea (geology), inland sea that existed roughly over the present-day Great Plains of ...

. ''Dynamoterror'' was contemporaneous with an indeterminate

ankylosaur Ankylosauria is a group of herbivorous dinosaurs of the clade Ornithischia. It includes the great majority of dinosaurs with armor in the form of bony osteoderms, similar to turtles. Ankylosaurs were bulky quadrupeds, with short, powerful l ...

, the indeterminate

nodosaurid Nodosauridae is a family of ankylosaurian dinosaurs known from the Late Jurassic to the Late Cretaceous periods in what is now Asia, Europe, North America, and possibly South America. While traditionally regarded as a monophyletic clade as the s ...

Invictarx ''Invictarx'' (meaning "unconquerable fortress") is a monotypic taxon, monospecific genus of nodosauridae, nodosaurid dinosaur from New Mexico that lived during the Late Cretaceous (lower Campanian, 78.5 Ma) in what is now the upper Allison Membe ...

'', an indeterminate

hadrosaurid Hadrosaurids (), also hadrosaurs or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae. This group is known as the duck-billed dinosaurs for the flat duck-bill appearance of the bones in their snouts. The ornithopod fami ...

, the centrosaurine

ceratopsid Ceratopsidae (sometimes spelled Ceratopidae) is a family of ceratopsian dinosaurs including ''Triceratops'', '' Centrosaurus'', and '' Styracosaurus''. All known species were quadrupedal herbivores from the Upper Cretaceous. All but one species are ...

Menefeeceratops ''Menefeeceratops'' (meaning "Menefee Formation horned face") is a genus of ceratopsid dinosaur from the Menefee Formation in New Mexico, United States. It is potentially the oldest known member of the ceratopsids, as well as the centrosaurine s ...

'', the brachylophosaurin hadrosaurid '' Ornatops'', an indeterminate tyrannosaurid, and a

dromaeosaurid Dromaeosauridae () is a family (biology), family of feathered coelurosaurian Theropoda, theropod dinosaurs. They were generally small to medium-sized feathered carnivores that flourished in the Cretaceous period (geology), Period. The name Drom ...

similar to ''

Saurornitholestes ''Saurornitholestes'' ("lizard-bird thief") is a genus of carnivorous dromaeosaurid theropod dinosaur from the late Cretaceous of Canada (Alberta and Saskatchewan) and the United States (Montana, New Mexico, Alabama, and South Carolina). Two spe ...

''. Non-dinosaur taxa contemporaneous with ''Dynamoterror'' include an indeterminate

crocodylia Crocodilia () is an Order (biology), order of semiaquatic, predatory reptiles that are known as crocodilians. They first appeared during the Late Cretaceous and are the closest living relatives of birds. Crocodilians are a type of crocodylomorp ...

n, the alligatoroids '' Brachychampsa'' and ''

Deinosuchus ''Deinosuchus'' is an extinct genus of eusuchian, either an Alligatoroidea, alligatoroid Crocodilia, crocodilian or a stem-group crocodilian, which lived during the Late Cretaceous around . The first remains were discovered in North Carolina ...

'', an indeterminate baenid

turtle Turtles are reptiles of the order (biology), order Testudines, characterized by a special turtle shell, shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Crypt ...

, an indeterminate turtle, and an indeterminate trionychid turtle.

References

{{Taxonbar, from=Q57194687 Tyrannosauridae Dinosaur genera Campanian dinosaurs Fossil taxa described in 2018 Dinosaurs of the United States

Discovery

Description

Size and distinguishing traits

Cranium

Postcrania

Classification

Paleoecology

See also

References