biology

Ignotosaurus

Ignotosaurus 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 Ignotosaurus rather than just read about it. In short: Ignotosaurus is an extinct genus of silesaurid dinosauriform known from the Late Triassic (Carnian) Cancha de Bochas Member of the Ischigualasto Formation in the Ischigualasto-Villa Unión Basin in northwestern Argentina. It was therefore contemporary with early dinosaurs such as Herrerasaurus, and lived in the same place.

Key takeaways

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

Reference excerpt

Ignotosaurus is an extinct genus of silesaurid dinosauriform known from the Late Triassic (Carnian) Cancha de Bochas Member of the Ischigualasto Formation in the Ischigualasto-Villa Unión Basin in northwestern Argentina. It was therefore contemporary with early dinosaurs such as Herrerasaurus, and lived in the same place.

Etymology The name, meaning 'unknown lizard' from the Latin 'ignotus' 'unknown' and the Greek 'σαυρος' 'lizard', is quite apt as there is only one specimen known and this specimen is only known from the right ilium. This ilium is approximately 70 millimetres (2.8 in) long, but it is difficult to say accurately how large Ignotosaurus was.

Description The ilium is slender, and its blade has an extremely thin central portion (only 1 millimetre (0.039 in) thick), hence the specific name 'fragilis'. It has the saddle-shaped lateral profile of most silesaurids, and is longer than it is deep. The acetabulum has a back wall created by a ventral flange and this closes a socket as it is in contact with the ischium and pubis. The supraacetabular crest is laterally oriented and forms part of the articulation for the femur. A ridge rises from the dorsal edge of this crest and joins the preacetabular process, as in the close relative Silesaurus. The preacteabular process is flattened anteroposteriorly and is angled at 90° to the iliac blade, pointing anterolaterally - these are the diagnostic features of this species. The end of the process has a rugose growth, but it is less extensive than that of Silesaurus. The postacetabular process is long and has a brevis fossa present on the ventral side. It has a thick rectangular cross-section and a rugose area at the end. The pubic peduncle is long and stout, with a prominent dorsal margin. Ignotosaurus is thought to be most closely related to Silesaurus, Sacisaurus and Eucoelophysis, but as only one of the three characteristic features for silesaurids is preserved this is not certain (the other features are on the femur and tibia, which are not preserved). It is thought that the Ischigualasto Formation at this time was a river basin habitat with abundant vegetation. As Ignotosaurus was probably a herbivore, like other silesaurids, it would probably have flourished here, competing for food with rhynchosaurs, cynodonts and possibly some early dinosaurs.

References

Bibliography Martínez, Ricardo N.; Apaldetti, Cecilia; Alcober, Oscar A.; Colombi, Carina E.; Sereno, Paul C.; Fernández, Eliana; Santi Malnis, Paula; Correa, Gustavo A.; Abelin, Diego (2013), "Vertebrate succession in the Ischigualasto Formation", Journal of Vertebrate Paleontology, Memoir 12: Basal sauropodomorphs and the vertebrate fossil record of the Ischigualasto Formation (Late Triassic: Carnian-Norian) of Argentina: 10–30, retrieved 2019-03-29

Illustrations

Worked examples

Example 1 — a first encounter with Ignotosaurus

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

In research: Ignotosaurus 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 Ignotosaurus 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: Ignotosaurus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Carnian reptiles, Fossil taxa described in 2013, Ischigualasto Formation, so understanding it makes those chapters shorter.
In everyday life: Look for Ignotosaurus 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 Ignotosaurus in 20 minutes

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

Frequently asked questions

What is Ignotosaurus in simple terms?

Why does Ignotosaurus 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 Ignotosaurus?

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 Ignotosaurus.