Context: The Cretaceous is a geologic period and system that spans 79 million years from the end of the Jurassic Period million years ago (Mya) to the beginning of the Paleogene Period Mya. It is the last period of the Mesozoic Era. The Cretaceous Period is usually abbreviated K, for its German translation "Kreide" (chalk)., Chalk is a soft, white, porous, sedimentary carbonate rock, a form of limestone composed of the mineral calcite. Calcite is an ionic salt called calcium carbonate or CaCO. It forms under reasonably deep marine conditions from the gradual accumulation of minute calcite shells (coccoliths) shed from micro-organisms called coccolithophores. Flint (a type of chert unique to chalk) is very common as bands parallel to the bedding or as nodules embedded in chalk. It is probably derived from sponge spicules or other siliceous organisms as water is expelled upwards during compaction. Flint is often deposited around larger fossils such as Echinoidea which may be silicified (i.e. replaced molecule by molecule by flint)., The Late Cretaceous (100.566 Ma) is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series. The Cretaceous is named after the white limestone known as chalk which occurs widely in northern France and is seen in the white cliffs of south-eastern England, and which dates from this time., Chasmosaurinae is a subfamily of ceratopsid dinosaurs. "Triceratops" is a well-known example. They were one of the most successful groups of herbivores of their time. Chasmosaurines appeared in the early Campanian, and became extinct, along with all other non-avian dinosaurs, during the CretaceousPaleogene extinction event. Broadly, the most distinguishing features of chasmosaurinae are prominent brow horns and long frills lacking long spines; centrosaurines generally had short brow horns and relatively shorter frills, and often had long spines projecting from their frills. Chasmosaurines are currently known definitively from rocks in western Canada, the western United States, and northern Mexico., A neck frill is the relatively extensive margin seen on the back of the heads of reptiles with either a bony support such as those present on the skulls of dinosaurs of the suborder Marginocephalia or a cartilaginous one as in the frill-necked lizard. In technical terms, the bone-supported frill is composed of an enlarged parietal bone flanked by elongated squamosals and sometimes ringed by epoccipitals, bony knobs that gave the margin a jagged appearance. In the early 1900s, the parietal bone was known among paleontologists as the dermosupraoccipital. In some genera, such as "Triceratops", "Pentaceratops", "Centrosaurus" and "Torosaurus", this extension is very large. Despite the neck frill predominantly being made of hard bone, some neck frills are made of skin, as is the case with the frill-necked lizard of today that resides in Australia., Asia is Earth's largest and most populous continent, located primarily in the eastern and northern hemispheres and sharing the continental landmass of Eurasia with the continent of Europe. Asia covers an area of , about 30% of Earth's total land area and 8.7% of the Earth's total surface area. The continent, which has long been home to the majority of the human population, was the site of many of the first civilizations. Asia is notable for not only its overall large size and population, but also dense and large settlements as well as vast barely populated regions within the continent of 4.4 billion people., The Campanian is, in the ICS' geologic timescale, the fifth of six ages of the Late Cretaceous epoch (or, in chronostratigraphy: the fifth of six stages in the Upper Cretaceous series). The Campanian spans the time from 83.6 ± 0.7 Ma to 72.1 ± 0.6 Ma (million years ago). It is preceded by the Santonian and it is followed by the Maastrichtian., A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthparts adapted to rasping or grinding. Horses and other herbivores have wide flat teeth that are adapted to grinding grass, tree bark, and other tough plant material., 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. The earliest known ceratopsian, "Yinlong downsi", lived between 161.2 and 155.7 million years ago. The last ceratopsian species, "Triceratops prorsus", became extinct during the CretaceousPaleogene extinction event, ., Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the Cretaceous period, about 99 million years ago and diversified after the rise of flowering plants. More than 12,500 of an estimated total of 22,000 species have been classified. They are easily identified by their elbowed antennae and the distinctive node-like structure that forms their slender waists., The Paleogene (or ; also spelled Palaeogene or Palæogene; informally Lower Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago (Mya) to the beginning of the Neogene Period Mya. It is the beginning of the Cenozoic Era of the present Phanerozoic Eon. The Paleogene is most notable for being the time during which mammals diversified from relatively small, simple forms into a large group of diverse animals in the wake of the CretaceousPaleogene extinction event that ended the preceding Cretaceous Period. , The Centrosaurinae is a subfamily of ceratopsid dinosaurs named by paleontologist Lawrence Lambe, in 1915, with "Centrosaurus" as the type genus. The centrosaurines are further divided into two tribes, the centrosaurins and the pachyrhinosaurins., In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoological names with "-inae"., Eurasia is the combined continental landmass of Europe and Asia. The term is a portmanteau of its constituent continents. Located primarily in the Northern and Eastern Hemispheres, it is bordered by the Atlantic Ocean to the west, the Pacific Ocean to the east, the Arctic Ocean to the north, and by Africa, the Mediterranean Sea, and the Indian Ocean to the south. The division between Europe and Asia as two different continents is a historical and cultural construct, with no clear physical separation between them; thus, in some parts of the world, Eurasia is recognized as the largest of five or six continents. In geology, Eurasia is often considered as a single rigid megablock. However, the rigidity of Eurasia is debated based on the paleomagnet data., A genus ( genera) is a taxonomic rank used in the biological classification of living and fossil organisms in biology. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus., 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 . The Maastrichtian was preceded by the Campanian and succeeded by the Danian (part of the Paleogene and Paleocene)., Ceratopsidae ( sometimes spelled Ceratopidae ) is a speciose group of marginocephalian dinosaurs including Triceratops and Styracosaurus . All known species were quadrupedal herbivores from the Upper Cretaceous , mainly of Western North America ( though Sinoceratops is known from Asia ) and are characterized by beaks , rows of shearing teeth in the back of the jaw , and elaborate horns and frills . The group is divided into two subfamilies . The Ceratopsinae or Chasmosaurinae are generally characterized by long , triangular frills and well - developed brow horns . The Centrosaurinae had well - developed nasal horns or nasal bosses , shorter and more rectangular frills , and elaborate spines on the back of the frill . These horns and frills show remarkable variation and are the principal means by which the various species have been recognized . Their purpose is not entirely clear . Defense against predators is one possible purpose -- although the frills are comparatively fragile in many species -- but it is more likely that , as in modern ungulates , they may have been secondary sexual characteristics used in displays or for intraspecific combat . The massive bosses on the skulls of Pachyrhinosaurus and Achelousaurus resemble those formed by the base of the horns in modern musk oxen , suggesting that they may have butted heads . Centrosaurines have frequently been found in massive bone beds with few other species present , suggesting that the animals might have lived in large herds ., Triceratops is a genus of herbivorous ceratopsid dinosaur that first appeared during the late Maastrichtian stage of the late Cretaceous period, about 68 million years ago (mya) in what is now North America. It is one of the last known non-avian dinosaur genera, and became extinct in the CretaceousPaleogene extinction event 66 million years ago. The term "Triceratops", which literally means "three-horned face", is derived from the Greek - ("tri-") meaning "three",  ("kéras") meaning "horn", and  ("ops") meaning "face"., Dinosaurs are a diverse group of animals of the clade Dinosauria that first appeared during the Triassic. Although the exact origin and timing of the evolution of dinosaurs is the subject of active research, the current scientific consensus places their origin between 231 and 243 million years ago. They became the dominant terrestrial vertebrates after the TriassicJurassic extinction event 201 million years ago. Their dominance continued through the Jurassic and Cretaceous periods and ended when the CretaceousPaleogene extinction event led to the extinction of most dinosaur groups 66 million years ago., Styracosaurus (; meaning "spiked lizard" from the Ancient Greek "styrax/" "spike at the butt-end of a spear-shaft" and "sauros/" "lizard") was a genus of herbivorous ceratopsian dinosaur from the Cretaceous Period (Campanian stage), about 75.5 to 75 million years ago. It had four to six long horns extending from its neck frill, a smaller horn on each of its cheeks, and a single horn protruding from its nose, which may have been up to 60 centimetres (2 ft) long and 15 centimetres (6 in) wide. The function or functions of the horns and frills have been debated for many years., Centrosaurus is a genus of herbivorous ceratopsian dinosaurs from the late Cretaceous of Canada. Their remains have been found in the Dinosaur Park Formation, dating from 76.5 to 75.5 million years ago., Subject: ceratopsidae, Relation: taxon_rank, Options: (A) division (B) family (C) form (D) genus (E) group (F) series (G) subfamily (H) suborder
Output: family