Leptoceratopsidae is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

neoceratopsian 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

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 ...

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 ...

and

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

. Leptoceratopsids resembled, and were closely related to, other neoceratopsians, such as the

families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideal ...

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 ...

and

Ceratopsidae 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 ...

, but they were more primitive and generally smaller.

Phylogeny

Leptoceratopsidae was originally named by

Franz Nopcsa von Felső-Szilvás Baron Franz Nopcsa von Felső-Szilvás (also Baron Nopcsa von Felső-Szilvás, Baron Nopcsa, Ferenc Nopcsa, báró felsőszilvási Nopcsa Ferenc, Baron Franz Nopcsa, and Franz Baron Nopcsa; May 3, 1877 – April 25, 1933) was a Hungarian aristoc ...

in 1923 as a subfamily Leptoceratopsinae, and its type species is ''

Leptoceratops gracilis ''Leptoceratops'' (meaning 'Thin-horned face' and derived from Greek ''lepto-/λεπτο-'' meaning 'small', 'insignificant', 'slender', 'meagre' or 'lean', ''kerat-/κερατ-'' meaning 'horn' and ''-ops/ωψ'' meaning face), is a genus of lep ...

''. Mackovicky, in 2001, defined it as a

stem-based taxon Phylogenetic nomenclature is a method of nomenclature for taxa in biology that uses phylogenetic definitions for taxon names as explained below. This contrasts with the traditional approach, in which taxon names are defined by a '' type'', which ...

and a family consisting of ''Leptoceratops gracilis'' and all species closer to ''Leptoceratops'' than to ''

Triceratops horridus ''Triceratops'' ( ; ) is a genus of herbivorous chasmosaurine ceratopsid dinosaur that first appeared during the late Maastrichtian stage of the Late Cretaceous period, about 68 million years ago in what is now North America. It is one ...

''.Makovicky, P.J. 2001. A ''Montanoceratops cerorhynchus'' (Dinosauria: Ceratopsia) braincase from the Horseshoe Canyon Formation of Alberta, In: Tanke, D.H. & Carpenter, K. (Eds.). ''Mesozoic Vertebrate Life''. Bloomington: Indiana University Press. Pp. 243-262. The

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...

below follows the topologies from a 2015 analysis by Yiming He, Peter J. Makovicky, Kebai Wang, Shuqing Chen, Corwin Sullivan, Fenglu Han, Xing XuMichael J. Ryan, David C. Evans, Philip J. Currie, Caleb M. Brown and Don Brinkman.

Palaeobiogeography

Definitive leptoceratopsids have so far been found exclusively in 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 ...

period (late

Santonian The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya (million years ago) and 83.6 ± 0.7 mya. 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 ...

stages) of

and Western

; however, material referred to leptoceratopsids from the early

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. Campanian s ...

North Carolina North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia and So ...

and

Sweden Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on ...

extends their geographic range into Eastern North America and

. A possible leptoceratopsid

ulna The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of t ...

, named '' Serendipaceratops'', has been found in

Victoria Victoria most commonly refers to: * Victoria (Australia), a state of the Commonwealth of Australia * Victoria, British Columbia, provincial capital of British Columbia, Canada * Victoria (mythology), Roman goddess of Victory * Victoria, Seychelle ...

, Australia. However, a 2010 study showed that it could not be confidently referred to any ornithischian family, and is considered a '' nomen dubium''.Agnolin, F.L., Ezcurra, M.D., Pais, D.F. and Salisbury, S.W. (2010). "A reappraisal of the Cretaceous non-avian dinosaur faunas from Australia and New Zealand: Evidence for their Gondwanan affinities." ''Journal of Systematic Palaeontology'', 8(2): 257-300. Leptoceratopsids range in age from ''

Gryphoceratops ''Gryphoceratops'' is an extinct genus of leptoceratopsid ceratopsian dinosaur known from the Late Cretaceous of Alberta, southern Canada. Discovery ''Gryphoceratops'' is known only from the holotype ROM 56635, a partial right dentary. Th ...

'', of the late

, to ''

Leptoceratops ''Leptoceratops'' (meaning 'Thin-horned face' and derived from Greek ''lepto-/λεπτο-'' meaning 'small', 'insignificant', 'slender', 'meagre' or 'lean', ''kerat-/κερατ-'' meaning 'horn' and ''-ops/ωψ'' meaning face), is a genus of l ...

'', right at the end of the

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 ...

in the late

. ''Gryphoceratops'' is the first definitive record of Santonian leptoceratopsid. It was named based on a partial left

dentary In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movabl ...

from

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 ...

. ''Gryphoceratops'' represents the oldest known leptoceratopsid and probably the smallest adult ceratopsian known from North America. Leptoceratopsids are known from Eastern North America by a partial

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 ...

dated to the early Campanian of North Carolina, whilst the European material referred to Leptoceratopsidae consists of isolated teeth and

vertebrae The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic i ...

from the early Campanian of Sweden. The former represents the first known ceratopsian from Eastern North America, and its specialised maxillary anatomy supports the hypothesis that

Appalachia Appalachia () is a cultural region in the Eastern United States that stretches from the Southern Tier of New York State to northern Alabama and Georgia. While the Appalachian Mountains stretch from Belle Isle in Newfoundland and Labrador, Ca ...

was isolated from Western Europe and

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 ...

for an extended period during the Late Cretaceous, resulting in an endemic Late Cretaceous fauna. The shared presence of leptoceratopsids in Appalachia and Western Europe has implications for their biogeographic dispersal, suggesting the possibility that leptoceratopsids entered Appalachia through either Western Europe or Laramidia; however, it is also possible that the European leptoceratopsids also represented a distinct endemic assemblage, as the

Fennoscandian Shield The Baltic Shield (or Fennoscandian Shield) is a segment of the Earth's crust belonging to the East European Craton, representing a large part of Fennoscandia, northwestern Russia and the northern Baltic Sea. It is composed mostly of Archean an ...

was also an isolated landmass during the Late Cretaceous.

References

{{Taxonbar, from=Q123245 Cretaceous dinosaurs Dinosaurs of Asia Dinosaurs of North America Taxa named by Franz Nopcsa von Felső-Szilvás Prehistoric dinosaur families

Phylogeny

Palaeobiogeography

See also

References