biology

Opisthoteuthis extensa

Opisthoteuthis extensa 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 Opisthoteuthis extensa rather than just read about it. In short: Insigniteuthis extensa (formerly allocated to genus Opisthoteuthis) is a species of flapjack octopus from waters off Indonesia and north-western Australia. The species was originally described from a single female specimen captured in 1899 off the west coast of Sumatra (Indonesia), at 768 m depth.

Key takeaways

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

Reference excerpt

Insigniteuthis extensa (formerly allocated to genus Opisthoteuthis) is a species of flapjack octopus from waters off Indonesia and north-western Australia. The species was originally described from a single female specimen captured in 1899 off the west coast of Sumatra (Indonesia), at 768 m depth. The relatively basic original description rendered the species difficult to distinguish from others in the genus, with some authors even proposing similarity with Opisthoteuthis pluto. The species was recently redescribed by re-examination of the type specimen and three additional specimens, two mature males from near the type locality, and another from off northwestern Australia, depth range 694–1073 m. The species has up to 80 suckers per arm, mature males have a 'distal enlarged sucker field', a region with 4 enlarged suckers (2 or 3 massively per field) on each of arm pairs III and IV (near the junction with the webbing). The species also has multiple 'web nodules' (5–11) along the ventral edge of each arm (a rather unique feature). Internally with 6 or 7 lamellae on each gill, and with the shell and reproductive systems having more subtle differences relative to other species. The configuration of enlarged suckers was found to be very similar to Insigniteuthis dongshaensis from the South China Sea (another species originally allocated to genus Opisthoteuthis).

References

Illustrations

Worked examples

Example 1 — a first encounter with Opisthoteuthis extensa

Start with the simplest possible case. Write down what Opisthoteuthis extensa 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 Opisthoteuthis extensa 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 Opisthoteuthis extensa 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 Opisthoteuthis extensa

In research: Opisthoteuthis extensa 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 Opisthoteuthis extensa 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: Opisthoteuthis extensa is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cephalopods described in 1915, Cephalopods of Asia, IUCN Red List data deficient species, so understanding it makes those chapters shorter.
In everyday life: Look for Opisthoteuthis extensa 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 Opisthoteuthis extensa in 20 minutes

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

Frequently asked questions

What is Opisthoteuthis extensa in simple terms?

Why does Opisthoteuthis extensa 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 Opisthoteuthis extensa?

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 Opisthoteuthis extensa.