''Microvenator'' (meaning "small hunter") is a

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 ...

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 the

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

Cloverly Formation The Cloverly Formation is a formation (geology), geological formation of Early Cretaceous, Early and Late Cretaceous age (Valanginian to Cenomanian stage) that is present in parts of Montana, Wyoming, Colorado and Utah in the western United State ...

in what is now south central

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...

. ''Microvenator'' was an

oviraptorosauria Oviraptorosaurs ("egg thief lizards") are a group of feathered maniraptoran dinosaurs from the Cretaceous Period (geology), Period of what are now Asia and North America. They are distinct for their characteristically short, beaked, parrot-like s ...

theropod Theropoda (; from ancient Greek , (''therion'') "wild beast"; , (''pous, podos'') "foot"">wiktionary:ποδός"> (''pous, podos'') "foot" is one of the three major groups (clades) of dinosaurs, alongside Ornithischia and Sauropodom ...

. 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 ...

fossil is an incomplete skeleton, most likely a juvenile with a length of , and consequently, the adult size remains uncertain. ''Microvenator celer'' is primitive and may be the "sister taxon to all other oviraptorosaurs."Varricchio, D. J. 2001. Late Cretaceous oviraptorosaur (Theropoda) dinosaurs from Montana. pp. 42–57 in D. H. Tanke and K. Carpenter (eds.), Mesozoic Vertebrate Life. Indiana University Press, Indianapolis, Indiana.

Discovery

Barnum Brown Barnum Brown (February 12, 1873 – February 5, 1963), commonly referred to as Mr. Bones, was an American paleontologist. He discovered the first documented remains of ''Tyrannosaurus'' during a career that made him one of the most famous fossil ...

collected the

type specimen In biology, a type is a particular wikt:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to ancho ...

(AMNH 3041) in 1933 by a field party working for the

American Museum of Natural History The American Museum of Natural History (AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. Located in Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 21 interconn ...

and he erroneously included ''

Deinonychus ''Deinonychus'' ( ; ) is a genus of Dromaeosauridae, dromaeosaurid Theropoda, theropod dinosaur with one described species, ''Deinonychus antirrhopus''. This species, which could grow up to long, lived during the early Cretaceous Period (ge ...

'' teeth with the specimen. Because of this, Brown informally dubbed it "Megadontosaurus" ("big-toothed lizard"), Brown made illustrations of it, but never published the name, a fate shared with several other

dinosaurs (''

'', ''

Sauropelta ''Sauropelta'' ( ; meaning 'lizard shield') is a genus of nodosaurid dinosaur that existed in the Early Cretaceous Period of North America. One species (''S. edwardsorum'') has been named. Anatomically, ''Sauropelta'' is one of the most well-und ...

'' and ''

Tenontosaurus ''Tenontosaurus'' ( ; ) is a genus of iguanodontian ornithopod dinosaur. It had an unusually long, broad tail, which like its back was stiffened with a network of bony tendons. The genus is known from the late Aptian to Albian ages of the Early ...

''). AMNH 3041 consists of a partial posterior skull, right dentary, 23 vertebrae, four ribs, the left coracoid, a partial left forelimb, a partial pelvis, and partial hindlimbs. It was not until 1970 that

John Ostrom John Harold Ostrom (February 18, 1928 – July 16, 2005) was an American paleontologist who revolutionized the modern understanding of dinosaurs. Ostrom's work inspired what his pupil Robert T. Bakker has termed a " dinosaur renaissance". Begin ...

described the type specimen as part of his work on the Cloverly Formation, naming it ''Microvenator celer'' meaning "swift small hunter" due to its long legs. Ostrom originally theorized it was part of

Othniel Marsh Othniel Charles Marsh (October 29, 1831 – March 18, 1899) was an American professor of paleontology. A prolific fossil collector, Marsh was one of the preeminent paleontologists of the nineteenth century. Among his legacies are the discovery or ...

's Coeluridae due to features in the cervical vertebrae. Ostrom also referred a single tooth from the

Yale Peabody Museum The Peabody Museum of Natural History at Yale University (also known as the Yale Peabody Museum of Natural History or the Yale Peabody Museum) is one of the oldest, largest, and most prolific university natural history museums in the world. It ...

collection, YPM 5366, to this new species that likely belongs to ''

''.Ostrom, John H. (1970) ''Stratigraphy and Paleontology of the Cloverly Formation (Lower Cretaceous) of the Bighorn Basin Area, Wyoming and Montana''. Yale University Press, 2020, . The illustrations that Brown had prepared were finally published in a detailed and exhaustive monograph by Mackovicky and Sues in 1998. They confirmed that ''Microvenator'' is an

n, and that it is the earliest known member of this group from North America. A second species, "Microvenator chagyabi", has also been named for an indeterminate

coelurosauria Coelurosauria (; from Greek, meaning "hollow-tailed lizards") is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. Coelurosauria is a subgroup of theropod dinosaurs that includes compsognathids, tyra ...

, from the

Lura Formation The Lura Formation is a geological formation in western China, which outcrops in Tibet, whose strata date back to the Early Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.Weishampel, David B; et al. ...

Tibet Tibet (; ''Böd''; ), or Greater Tibet, is a region in the western part of East Asia, covering much of the Tibetan Plateau and spanning about . It is the homeland of the Tibetan people. Also resident on the plateau are other ethnic groups s ...

. However, it is not formally named, and remains a ''

nomen nudum In Taxonomy (biology), taxonomy, a ''nomen nudum'' ('naked name'; plural ''nomina nuda'') is a designation which looks exactly like a scientific name of an organism, and may have originally been intended to be one, but it has not been published ...

''.

Paleoenvironment

''Microvenator'' fossils are extremely rare, with only the type specimen described, likely due to lack of teeth and frail bones. ''Microvenator'' coexisted with notable dinosaurs like ''

,'' and ''

Acrocanthosaurus ''Acrocanthosaurus'' ( ; ) is a genus of carcharodontosaurid dinosaurs that existed in what is now North America during the Aptian and early Albian stages of the Early Cretaceous, from 113 to 110 million years ago. Like most dinosaur genera, ...

'' in the Himes Member of the Cloverly Formation.

References

{{Taxonbar, from=Q133881 Caenagnathidae Dinosaur genera Albian dinosaurs Cloverly Formation Taxa named by John Ostrom Fossil taxa described in 1970 Dinosaurs of the United States

Discovery

Paleoenvironment

See also

References