biology

Machairoceratops

Machairoceratops is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Machairoceratops rather than just read about it. In short: Machairoceratops (meaning "bent sword horned face"), previously known as the "Wahweap centrosaurine B", is an extinct genus of centrosaurine ceratopsian dinosaur known from the Late Cretaceous Wahweap Formation (late Campanian stage) of Grand Staircase–Escalante National Monument, southern Utah, United States. Discovery It contains a single species, M. cronusi, first described and named in 2016 by Eric K.

Key takeaways

Machairoceratops belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Machairoceratops to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Machairoceratops from memory before moving on to harder problems.

Reference excerpt

Machairoceratops (meaning "bent sword horned face"), previously known as the "Wahweap centrosaurine B", is an extinct genus of centrosaurine ceratopsian dinosaur known from the Late Cretaceous Wahweap Formation (late Campanian stage) of Grand Staircase–Escalante National Monument, southern Utah, United States.

Discovery It contains a single species, M. cronusi, first described and named in 2016 by Eric K. Lund, Patrick M. O'Connor, Mark A. Loewen, and Zubair A. Jinnah. The generic name is derived from Greek machairis, meaning "bent sword", in reference to its unique frill ornamentation showing two forward curving horns on the frill's uppermost part, and Latinized Greek ceratops, meaning "horned-face", which is a common suffix for ceratopsian genera names. The specific name cronusi refers to Cronus, a Greek god who deposed his father Uranus by castrating him with a sickle or scythe based on the mythology, and as such is shown carrying a curved bladed weapon. Machairoceratops is known solely from the holotype UMNH VP 20550, found in 2006, which is housed at the Natural History Museum of Utah. It is represented by a partial skull including two curved and elongate eyesocket horncores, the left jugal bone, a nearly complete but slightly deformed braincase, the left squamosal bone, and a parietal bone complex and its unique horn ornamentation, all collected in association.

Description

Machairoceratops was a quadrupedal herbivore with a frill protecting its neck. The top of the parietal bone features only one pair of long, curved, anteroposteriorly oriented spikes measuring 44 cm in length. The sides of the frill lack the smaller epiparietales that are present in other centrosaurines. This feature might be due to taphonomy, ontogeny or is unique to Machairoceratops. The squamosal has a fan-shaped form, characteristic of centrosaurines, but it also lacks any epiossifications. The postorbital horns, measuring 27 cm in length, are detached from the skull, and their exact orientation is unknown. The holotype of Machairoceratops is very close in size or the same size as Diabloceratops.

Phylogeny Lund et al. (2016) tested the position of Machairoceratops within Centrosaurinae by performing maximum parsimony and Bayesian phylogenetic species level analyses. The maximum parsimony analysis yielded a large polytomy at the base of Centrosaurinae, with only Centrosaurini, most of Pachyrhinosaurini (Einiosaurus, Wendiceratops and Pachyrostra), and a clade formed by Avaceratops and Nasutoceratops being resolved. The Bayesian analysis yielded a fully resolved topology which is shown below.

The cladogram with comparative illustrations of the reconstructed frills of well-known genera below follows the 2024 phylogenetic analysis by Loewen and colleagues, and shows the position of Machairoceratops within Ceratopsidae:

Paleoecology

Habitat The Wahweap Formation has been radiometrically dated as being between 82.2 and 77.3 million years old. The precise age of Machairoceratops has been estimated to be 80.06 Ma, with a range of uncertainty between 80.68-79.26 Ma. During the time that Machairoceratops lived, the Western Interior Seaway was at its widest extent, almost completely isolating southern Laramidia from the rest of North America. The area where dinosaurs lived included lakes, floodplains, and east-flowing rivers. The Wahweap Formation is part of the Grand Staircase region, an immense sequence of sedimentary rock layers that stretch south from Bryce Canyon National Park through Zion National Park and into the Grand Canyon. The presence of rapid sedimentation and other evidence suggests a wet, seasonal climate.

Paleofauna Machairoceratops shared its paleoenvironment with other dinosaurs, such as the hadrosaur Acristavus gagslarsoni, centrosaur Diabloceratops eatoni and the lambeosaur Adelolophus hutchisoni, unnamed ankylosaurs and pachycephalosaurs, and the theropod Lythronax argestes, which was likely the apex predator in its ecosystem. Vertebrates present in the Wahweap Formation at the time of Machairoceratops included freshwater fish, bowfins, abundant rays and sharks, turtles like Compsemys, crocodilians, and lungfish. A fair number of mammals lived in this region, which included several genera of multituberculates, cladotherians, marsupials, and placental insectivores. The mammals are more primitive than those that lived in the area that is now the Kaiparowits Formation. Trace fossils are relatively abundant in the Wahweap Formation, and suggest the presence of crocodylomorphs, as well as ornithischian and theropod dinosaurs. In 2010 a unique trace fossil was discovered that suggests a predator-prey relationship between dinosaurs and primitive mammals. The trace fossil includes at least two fossilized mammalian den complexes as well as associated digging grooves presumably caused by a maniraptoran dinosaur. The proximity indicates a case of probable active predation of the burrow inhabitants by the animals that made the claw marks. Invertebrate activity in this formation ranged from fossilized insect burrows in petrified logs to various mollusks, large crabs, and a wide diversity of gastropods and ostracods.

See also Timeline of ceratopsian research 2016 in paleontology

References

Illustrations

Worked examples

Example 1 — a first encounter with Machairoceratops

Start with the simplest possible case. Write down what Machairoceratops claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Machairoceratops before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Machairoceratops ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Machairoceratops

In research: Machairoceratops appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Machairoceratops in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Machairoceratops is common in secondary-school and first-year university syllabi. It links to neighbouring topics Campanian dinosaurs, Centrosaurinae, Dinosaur genera, so understanding it makes those chapters shorter.
In everyday life: Look for Machairoceratops outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Machairoceratops in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Machairoceratops means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Machairoceratops out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Machairoceratops in simple terms?

Why does Machairoceratops matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Machairoceratops?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Machairoceratops.