biology

Metacrinia

Metacrinia 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 Metacrinia rather than just read about it. In short: Metacrinia is a genus of frog in the family Myobatrachidae. It is monotypic, being represented by the single species, Metacrinia nichollsi, commonly known as the Forest toadlet or Nicholls toadlet.

Key takeaways

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

Reference excerpt

Metacrinia is a genus of frog in the family Myobatrachidae. It is monotypic, being represented by the single species, Metacrinia nichollsi, commonly known as the Forest toadlet or Nicholls toadlet. It is endemic to Southwest Australia, occurring between Dunsborough and Albany.

Description Metacrinia nichollsi is a squat frog with short limbs and reaches 25 millimetres (0.98 in) in length. The dorsal colouration is very dark brown or black occasionally with pink flecks. The ventral surface is grey, dark blue or black with white marbling. There are yellow or orange markings at the base of each arm and on the underside of the thighs and lower belly. The skin on the dorsum is warty and the belly is granular. The tympanum is visible and the fingers and toes are free of webbing. It is the only described species in the genus Metacrinia. The toadlet is poorly studied, but the diverse appearance of the toadlet suggests there may be more than one species.

Ecology and behaviour This species is found amongst leaf litter, under stones and logs in karri and jarrah forests. Breeding occurs in late summer with most activity after rain. The males make a short "ark" similar to that of species in the genus Pseudophryne. 25–30 eggs are laid in damp ground cover where they develop directly without a larval (tadpole) stage. The species was assessed as Least Concern in 2004.

Similar species Metacrinia may be confused with Günther's toadlet, Pseudophryne guentheri. It can be distinguished by the orange ventral markings.

References

Further reading Barker, J.; Grigg, G. C.; Tyler, M. J. (1995). A Field Guide to Australian Frogs. Surrey Beatty & Sons.

Illustrations

Worked examples

Example 1 — a first encounter with Metacrinia

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

In research: Metacrinia 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 Metacrinia 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: Metacrinia is common in secondary-school and first-year university syllabi. It links to neighbouring topics Amphibians of Western Australia, Endemic fauna of Southwest Australia, Frogs of Australia, so understanding it makes those chapters shorter.
In everyday life: Look for Metacrinia 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 Metacrinia in 20 minutes

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

Frequently asked questions

What is Metacrinia in simple terms?

Metacrinia is a genus of frog in the family Myobatrachidae. It is monotypic, being represented by the single species, Metacrinia nichollsi, commonly known as the Forest toadlet or Nicholls toadlet.

Why does Metacrinia 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 Metacrinia?

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 Metacrinia.