biology

Obrimus

Obrimus 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 Obrimus rather than just read about it. In short: Obrimus is a stick insect genus native to the Philippines. It is type genus for the tribe and the subfamily in which it is listed.

Key takeaways

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

Reference excerpt

Obrimus is a stick insect genus native to the Philippines. It is type genus for the tribe and the subfamily in which it is listed.

Characteristics The species of this genus correspond in the habitus to the other representatives of the Obrimini, appear somewhat longer-legged compared to these and also have longer antennae than these. Like almost all other Obrimini, they are wingless in either sex. They are similar in size and appearance to the species of the genus Brasidas. As with these, the females have a relatively long and straight ovipositor. Obrimus species usually have more and sharper spines, but these are often thinner than those of most other Obrimini species. Like the representatives of the genus Brasidas, they have depressions in the metasternum, which here are merely formed as poorly or sometimes barely recognizable, flat slits on the outer edge of the metasternum, while in Brasidas they are holes or pits. The shape of the eggs also differs significantly from that of other genera. The eggs are 4 to 5 millimetres (0.16 to 0.20 in) long and 3 to 4 millimetres (0.12 to 0.16 in) wide. The micropylar plate has three arms and is located on the dorsal area, which is bulging. The egg shape is reminiscent of that of Sungaya eggs. However, behind the tip at the lower pole there is another blunt pole, so that the eggs below, more or less clearly recognizable, have two blunt ends. The lid (operculum) sits diagonally on the egg and falls off sharply to the ventral side.

Taxonomy The genus Obrimus was established in 1875 by Carl Stål. The generic name is borrowed from Greek mythology. As the only species, and thus type species, Stål named Obrimus bufo, which until then was listed in the genus Acanthoderus. Further species were described in this genus by Stål in 1877 and by Josef Redtenbacher in 1906. However, these were transferred in 1939 by James Abram Garfield Rehn and John William Holman Rehn into the genera Aretaon (Aretaon asperrimus and Aretaon muscosus both described in Obrimus in 1906), Trachyaretaon, which was described by Rehn and Rehn as a subgenus of Aretaon (Trachyaretaon echinatus described in Obrimus in 1877) and Brasidas (Brasidas cavernosus described in Obrimus in 1877, Brasidas foveolatus described in 1906 in Obrimus). Conversely, Frank H. Hennemann in 2023 transferred Obrimus quadratipes back to the genus Obrimus due to the slit-shaped depressions in the metasternum, in which it was described in 1890 by Ignacio Bolívar. Rehn and Rehn had transferred the species to the genus Brasidas in 1939 due to incorrectly identified material. The following species are listed in the genus Obrimus:

Obrimus bicolanus Rehn, J. A. G. & Rehn, J. W. H., 1939 Obrimus bufo (Westwood, 1848) Obrimus mesoplatus (Westwood, 1848) Obrimus quadratipes Bolívar, 1890 Obrimus uichancoi Rehn, J.A.G. & Rehn, J.W.H., 1939 In a study based on genetic analysis to clarify the phylogeny of the Heteropterygidae published by Sarah Bank et al. in 2021, samples from Obrimus bicolanus and Obrimus bufo were also sequenced. The study found that the genus Obrimus forms a common clade with the sister genus Brasidas.

Distribution Of the representatives known so far, only the occurrence of the two species described by Rehn and Rehn is known in more detail. Both appear on Luzon. While Obrimus bicolanus comes from the southeast of the island, more precisely from the Bicol region, Obrimus uichancoi was collected in the north in the province Apayao. Only the Philippines are given as location of the two other species.

Terraristic A single representative of the genus is currently in the terrariums of lovers. The stock goes back to specimens that Thierry Heitzmann collected in 2010 on Luzon and bred for the first time. Eggs of the species were brought to Europe by Hennemann, Joachim Bresseel and Bruno Kneubühler and successfully bred in 2011. Kneubühler initially passed on his animals as Obrimus sp. "Pulog", later as Obrimus bicolanus "Pulog". The Phasmid Study Group lists the species under the PSG number 324. Animals of this breeding line are no longer in breeding.

References

External links Media related to Obrimus at Wikimedia Commons Data related to Obrimus at Wikispecies

Illustrations

Worked examples

Example 1 — a first encounter with Obrimus

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

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

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

Frequently asked questions

What is Obrimus in simple terms?

Obrimus is a stick insect genus native to the Philippines. It is type genus for the tribe and the subfamily in which it is listed.

Why does Obrimus 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 Obrimus?

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 Obrimus.