''Leptoceratops'' (meaning 'Thin-horned face' and derived from

Greek Greek may refer to: Greece 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 ...

''lepto-/λεπτο-'' meaning 'small', 'insignificant', 'slender', 'meagre' or 'lean', ''kerat-/κερατ-'' meaning 'horn' and ''-ops/ωψ'' meaning face), is a

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 ...

leptoceratopsid Leptoceratopsidae is an extinct family of neoceratopsian dinosaurs from Asia, North America and Europe. Leptoceratopsids resembled, and were closely related to, other neoceratopsians, such as the families Protoceratopsidae and Ceratopsidae, bu ...

ceratopsian Ceratopsia or Ceratopia ( or ; Greek: "horned faces") is a group of herbivorous, beaked dinosaurs that thrived in what are now North America, Europe, and Asia, during the Cretaceous Period, although ancestral forms lived earlier, in the Jurassic. ...

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 ...

s from the late

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 ...

Period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

(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 ...

age, 68.8-66 Ma ago) of what is now Western

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. Their skulls have been found in

Alberta Alberta ( ) is one of the thirteen provinces and territories of Canada. It is part of Western Canada and is one of the three prairie provinces. Alberta is bordered by British Columbia to the west, Saskatchewan to the east, the Northwest Ter ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

and

Wyoming Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the south ...

Description

''Leptoceratops'' could probably stand and run on their hind legs: analysis of forelimb function indicates that even though they could not

pronate Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relative ...

their hands, they could walk on four legs. Paul proposed that ''Leptoceratops'' was around long and could have weighed , but Tereschenko proposed a maximum length of .

Discovery and species

The first small ceratopsian named ''Leptoceratops'' was discovered in 1910 by

Barnum Brown Barnum Brown (February 12, 1873 – February 5, 1963), commonly referred to as Mr. Bones, was an American paleontologist. Named after the circus showman P. T. Barnum, he discovered the first documented remains of ''Tyrannosaurus'' during a career ...

in the

Red Deer Valley Red is the color at the long wavelength end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–740 nanometres. It is a primary color in the RGB color model and a seconda ...

in Alberta, Canada. He described it four years later. The first specimen had a part of its skull missing, but there were later well-preserved finds by C. M. Sternberg in 1947, including one complete fossil. Later material was found in 1978 in the Bighorn Basin of northern Wyoming. 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 ...

is ''Leptoceratops gracilis''. In 1942, material collected in

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 ...

was named ''Leptoceratops cerorhynchos,'' but this was later renamed ''

Montanoceratops ''Montanoceratops'' is an extinct genus of small ceratopsian dinosaur that lived approximately 70 million years ago during the latter part of the Cretaceous Period in what is now Montana and Alberta. ''Montanoceratops'' was a small sized, modera ...

''.

Classification

''Leptoceratops'' belonged to the Ceratopsia, a group of herbivorous dinosaurs with

parrot Parrots, also known as psittacines (), are birds of the roughly 398 species in 92 genera comprising the order Psittaciformes (), found mostly in tropical and subtropical regions. The order is subdivided into three superfamilies: the Psittacoid ...

-like beaks that thrived in

and

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

during the Cretaceous Period. Although traditionally allied with the

Protoceratopsidae Protoceratopsidae is a family of basal (primitive) ceratopsians from the Late Cretaceous period. Although ceratopsians have been found all over the world, protoceratopsids are only definitively known from Cretaceous strata in Asia, with most spec ...

, it is now placed in its own family,

Leptoceratopsidae Leptoceratopsidae is an extinct family of neoceratopsian dinosaurs from Asia, North America and Europe. Leptoceratopsids resembled, and were closely related to, other neoceratopsians, such as the families Protoceratopsidae and Ceratopsidae, but t ...

, along with dinosaurs such as ''

Udanoceratops ''Udanoceratops'' (meaning "Udan's horned face") is a genus of large leptoceratopsid dinosaur that lived during the Late Cretaceous period of Mongolia, in what is now the Djadokhta Formation. Discovery ''Udanoceratops'' was first named and d ...

'' and ''

Prenoceratops ''Prenoceratops'', (meaning 'bent or prone-horned face' and derived from Greek ''prene-/πρηνη-'' meaning 'bent forwards' or 'prone', ''cerat-/κερατ-'' meaning 'horn' and ''-ops/ωψ'' meaning 'face') is a genus of ceratopsian dinosaur f ...

''. The relationships of Leptoceratops to

ceratopsids 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 k ...

are not entirely clear. Although most studies suggest that they lie outside the protoceratopsids and ceratopsids, some studies suggest that they may be allied with Ceratopsidae. The absence of

premaxilla 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 b ...

ry teeth is one feature that supports this arrangement.

Paleobiology

Behavior

In 2019, fossils from the Hell Creek Formation found three fossil bone beds which revealed that not only was ''Leptoceratops'' a social animal, but also raised its young in burrows.

Diet

''Leptoceratops'', like other ceratopsians, would have been a

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 ...

. The jaws were relatively short and deep, and the jaw muscles would have inserted over the large parietosquamosal frill, giving ''Leptoceratops'' a powerful bite. The teeth are unusual in that the dentary teeth have dual wear facets, with a vertical wear facet where the maxillary teeth sheared past the crown, and a horizontal wear facet where the maxillary teeth crushed against the dentary teeth. This shows that ''Leptoceratops'' chewed with a combination of shearing and crushing. Between the shearing/crushing action of the teeth and the powerful jaws, ''Leptoceratops'' was probably able to chew extremely tough plant matter. Given its small size and quadrupedal stance, ''Leptoceratops'' would have been a low feeder.

Flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

s, also known as angiosperms, were the most diverse plants of the day, although

ferns A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes except th ...

cycads Cycads are seed plants that typically have a stout and woody (ligneous) trunk with a crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants of a species are either male or ...

and

conifers Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All extan ...

may still have been more common in terms of numbers. A 2016 study revealed that ''Leptoceratops'' was able to chew its food much like several groups of mammals, which meant that it had a diet that consisted of tough, fibrous plant material.

References

* B. Brown. 1914. Leptoceratops, a new genus of Ceratopsia from the Edmonton Cretaceous of Alberta. Bulletin of the American Museum of Natural History 33(36):567-580

Sources

* * {{Taxonbar, from=Q131328 Leptoceratopsids Late Cretaceous dinosaurs of North America Fossil taxa described in 1914 Taxa named by Barnum Brown Lance fauna Hell Creek fauna Scollard fauna Paleontology in Alberta Paleontology in Wyoming Maastrichtian genus first appearances Maastrichtian genus extinctions Ornithischian genera