biology

Loncosaurus

Loncosaurus 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 Loncosaurus rather than just read about it. In short: Loncosaurus (meaning uncertain; either Araucanian "chief" or Greek "lance" "lizard") is an extinct genus of ornithopod dinosaur from the Upper Cretaceous of Provincia de Santa Cruz, Argentina. The type (and only known) species is Loncosaurus argentinus, described by the famous Argentinian paleontologist Florentino Ameghino, but is considered a dubious name.

Key takeaways

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

Reference excerpt

Loncosaurus (meaning uncertain; either Araucanian "chief" or Greek "lance" "lizard") is an extinct genus of ornithopod dinosaur from the Upper Cretaceous of Provincia de Santa Cruz, Argentina. The type (and only known) species is Loncosaurus argentinus, described by the famous Argentinian paleontologist Florentino Ameghino, but is considered a dubious name. Details on this animal are often contradictory, befitting a genus that was long confused for a theropod. Teeth attributed to cf. "Carnosaurus" may have actually belonged to Loncosaurus.

History The holotype femur and tooth were discovered by Carlos Ameghino, Florentino's brother, between 1887 and 1898. Ameghino named this dinosaur in 1899 from a proximal femur (MACN-1629) and tooth found near Rio Sehuen, Santa Cruz, in the Cardiel Formation (Upper Cretaceous). Either way, he thought the remains belonged to a "megalosaurid" dinosaur, a carnivore, which Friedrich von Huene agreed with. Upon further review, von Zittel assigned it to the Coeluridae, recognized today as a "wastebasket taxon" for small carnivorous dinosaurs. The carnivore tooth helped this misidentification take hold. It was ignored for decades until Ralph Molnar reassessed it. He found that the tooth did not belong to the same animal as the femur and removed it from the type, and suggested that the femur belonged to a hypsilophodont or turtle. Professional opinion has not changed much since then, although based on size, it appears more likely to be an iguanodont than a hypsilophodont. Reviews either put it at Ornithopoda incertae sedis or Iguanodontia. Oddly, a semipopular reference reassigned it to Genyodectes without comment, a view which has not been followed since.

Paleobiology Coria estimates the size of the Loncosaurus type individual at about 5 m (16.4 feet) long. As a small to medium-sized ornithopod, it would have been an agile bipedal herbivore.

References

Worked examples

Example 1 — a first encounter with Loncosaurus

Start with the simplest possible case. Write down what Loncosaurus 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 Loncosaurus 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 Loncosaurus 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 Loncosaurus

In research: Loncosaurus 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 Loncosaurus 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: Loncosaurus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Campanian dinosaurs, Dinosaur genera, Dinosaurs of Argentina, so understanding it makes those chapters shorter.
In everyday life: Look for Loncosaurus 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 Loncosaurus in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Loncosaurus 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 Loncosaurus out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Loncosaurus in simple terms?

Why does Loncosaurus 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 Loncosaurus?

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 Loncosaurus.