science

Trimerocephalus

Trimerocephalus is a science 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 Trimerocephalus rather than just read about it. In short: Trimerocephalus is a genus of eyeless trilobites from the order Phacopida, family Phacopidae. It lived during the final stage of the Devonian, the Famennian, and became extinct at the end of this stage, together with all other trilobites with the exception of some Proetida.

Key takeaways

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

Reference excerpt

Trimerocephalus is a genus of eyeless trilobites from the order Phacopida, family Phacopidae. It lived during the final stage of the Devonian, the Famennian, and became extinct at the end of this stage, together with all other trilobites with the exception of some Proetida. It can be found in Australia, the Czech Republic, France, Germany, Iran, Kazakhstan, Morocco, Poland, the Russian Federation (Urals), Spain, and the United Kingdom (England).

Distribution Species belonging to the genus Trimerocephalus have been found in Europe, Morocco, Iran and Australia.

T. caecus has been found in the Upper Devonian (Lower Famennian) of Poland (Holy Cross Mountains), Germany (Harz Mountains, Rhineland, Thuringia), the Russian Federation (Ural Mountains), North Africa, and France (Armorican Massif). T. lentiginosus has been excavated from the Upper Devonian of the Russian Federation (Famennian, South Ural Mountains). T. cryptophthalmoides is present in the Upper Devonian (Lower Famennian) of Kazakhstan, and the Russian Federation (South Ural Mountains). T. dianopsoides occurs in the Upper Devonian of Poland (Famennian, Holy Cross Mountains). T. interruptus is deposited in the Upper Devonian of Poland (Famennian, Holy Cross Mountains). T. lacunosus has been identified in the Upper Devonian of Germany (Famennian, Thuringia). T. lelievrei was collected in the Upper Devonian of Morocco (Famennian, Tafilalt). T. mastophthalmus is known from the Upper Devonian of Germany (Lower Famennian, Rhineland, Harz Mountains, Thuringia), Poland (Holy Cross Mountains), England, southwestern Asia, and Kazakhstan. T. mimbi has been found in the Upper Devonian of West-Australia (Famennian, McWhae Ridge, west side South Lawford Range, Virgin Hills Formation). T. nigritus is present in the Upper Devonian of France (lower Famennian, Red cephalopod limestones, lower member of "griottes" limestones formation, Lower Palmatolepis rhomboidea subzone, Old quarry of Concours-le-Haut near Causses-et-Veyran, Montagne Noire). T. polonicus occurs in the Upper Devonian of Poland (Famennian, Holy Cross Mountains). T. procurvus has been identified in the Upper Devonian (Famennian) of Spain (Cantabrian Mountains) and Germany. T. shotoriensis was excavated from the Upper Devonian of Eastern Iran (Famennian, lower Palmatolepis marginifera- to upper Palmatolepis trachytera-zone, Shotori-Range). T. sponsor has been identified in the Upper Devonian (Famennian) of the Czech Republic (Moravia) and Spain (Cantabrian Mountains). T. steinachensis is known from the Upper Devonian of Germany (Famennian, Thuringia, Harz Mountains). T. tardispinosus has been found in the Upper Devonian of Australia (Famennian, Palmatolepis rhomboidea-zone; McWhae Ridge, west side South Lawford Range, Virgin Hills Formation). T. trifolius occurs in the Upper Devonian of Poland (Famennian, Holy Cross Mountains). T. vodorezovi is present in the Upper Devonian of Kazakhstan (Famennian).

Taxonomy Acuticryphops is probably ancestral to Trimerocephalus, and mainly differs from its descendants in having an eye lobe with a small number of lenses. Crônier, 2003, erected the subgenus Trimerocephalus (Trifoliops) containing T. trifolius and T. nigritus. In order not to be polyphyletic, T. (Trifoliops) would need to include at least T. steinachensis, and preferably T. dianopsoides as well. These species are in the same clade as T. mastophtalmus however, which is the type of the genus Trimerocephalus, which would by definition be in the nominal subgenus Trimerocephalus (Trimerocephalus). This in turn would prompt the erection of another subgenus with all remaining species shown in the cladogram.

Description Trimerocephalus is one of several phacopid genera that is eyeless (others being Dianops, Ductina, and Trimerocephaloides). The dorsal facial sutures are not functional, so cranidia and free cheeks (or librigenae) are not found separated. The marginal ridge bordering the cheeks is wide and convex. The part of the margin that is tucked-under (or doublure) and only visible when viewing the cephalon from the belly (or ventral side), is short and flat. The vincular furrow, a groove that fits the margin of the tailpiece or pygidium when the animal was enrolled, is wide and deep. The pygidium is about 3 times wider than long.

Palaeobiology

Life history As in other phacopine trilobites from the Late Devonian, in Trimerocephalus lelievrei, ontogenetic changes in size mainly occur during the holaspid phase of its life, while changes in shape primarily take place during the meraspid period.

References

Illustrations

Worked examples

Example 1 — a first encounter with Trimerocephalus

Start with the simplest possible case. Write down what Trimerocephalus claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 Trimerocephalus 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 Trimerocephalus 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 Trimerocephalus

In research: Trimerocephalus appears in science 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 Trimerocephalus 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: Trimerocephalus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Devonian trilobites of Africa, Devonian trilobites of Asia, Devonian trilobites of Europe, so understanding it makes those chapters shorter.
In everyday life: Look for Trimerocephalus 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 Trimerocephalus in 20 minutes

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

Frequently asked questions

What is Trimerocephalus in simple terms?

Why does Trimerocephalus matter?

Because it connects several science 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 Trimerocephalus?

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 Trimerocephalus.