chemistry

Plagiaulacida

Plagiaulacida is a chemistry 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 Plagiaulacida rather than just read about it. In short: Plagiaulacida is a group of extinct multituberculate mammals. Multituberculates were among the most common mammals of the Mesozoic, "the age of the dinosaurs".

Key takeaways

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

Reference excerpt

Plagiaulacida is a group of extinct multituberculate mammals. Multituberculates were among the most common mammals of the Mesozoic, "the age of the dinosaurs". Plagiaulacids are a paraphyletic grouping, containing all multituberculates that lie outside of the advanced group Cimolodonta. They ranged from the Middle Jurassic Period to the early Late Cretaceous of the Northern Hemisphere. During the Cenomanian, they were replaced by the more advanced cimolodontans. Kielan-Jaworowska and Hurum (2001) divides "Plagiaulacida" into three informal lineages, the paulchoffatiids, the plagiaulicids, and the allodontids.

Allodontid line The Allodontid line may be a superfamily, Allodontoidea. Both allodontids and paulchoffatiids (below) were among the most basal of the plagiaulacids. The Allodontid line contains: The family Allodontidae is known from two genera from the Upper Jurassic Morrison Formation of North America. The family Zofiabaataridae contains a single genus, Zofiabaatar and is also from the Morrison Formation. The affinities of a further Morrison Formation genus, Glirodon, are unclear, but it's also within the Allodontid line.

Paulchoffatiid line The Paulchoffatiid line may be a superfamily, Paulchoffatioidea. Some remains from the Middle Jurassic of England might belong within this group. Representatives are best known from the Upper Jurassic, (especially from Guimarota, Portugal), though some were still extant during the Lower Cretaceous. The genera of the family Paulchoffatiidae are divided into two of subfamilies, plus a couple of harder-to-place individuals:

Subfamily Paulchoffatiinae includes Paulchoffatia and its relatives. This taxon contains nine genera. Subfamily Kuehneodontinae consists solely of the genus Kuehneodon, though there are half-a-dozen named species. Other genera include Angrivarodon, Galveodon, and Sunnyodon, based on teeth from the Lower Cretaceous of Germany, Spain, and England respectively. Also referable to the paulchoffatiid line, but not the family itself, is the family Pinheirodontidae, which is known from Early Cretaceous teeth found in Iberia and England. As well as Rugosodon from the Middle-Late Jurassic of China.

Plagiaulacid line (possibly Superfamily Plagiaulacoidea) Family Plagiaulacidae is known from the Upper Jurassic (North America) to Lower Cretaceous (Europe), being represented by Plagiaulax, Bolodon, and Morrisonodon. Family Albionbaataridae is known from the Upper Jurassic to Lower Cretaceous of Europe and Asia, (China – undescribed, 2001). These were shrew-sized Multituberculates, with some similarities to the paulchoffis. Members of the family Eobaataridae display dental similarities with members of Paracimexomys group, (Cimolodonta). They are known from the Upper Jurassic to Lower Cretaceous of Europe and Asia. Sinobaatar was described after the study by Kielan-Jaworowska and Hurum (2001). The Mongolian word 'baatar' is frequently employed in the nomenclature of Multituberculates. This reflects the fact that many of the most complete fossils have been recovered from sites in Mongolia, though this more applies to members of the more derived Cimolodonta. A couple of further genera possibly fit somewhere within "Plagiaulacida". This has been tentatively proposed for Janumys of the Middle Cretaceous. Its contemporary, Ameribaatar, is of uncertain affinities. Both were first described late in 2001.

Taxonomy Subclass †Allotheria Marsh, 1880

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Plagiaulacida

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

In research: Plagiaulacida appears in chemistry 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 Plagiaulacida 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: Plagiaulacida is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cretaceous mammals, Jurassic mammals, Multituberculata, so understanding it makes those chapters shorter.
In everyday life: Look for Plagiaulacida 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 Plagiaulacida in 20 minutes

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

Frequently asked questions

What is Plagiaulacida in simple terms?

Plagiaulacida is a group of extinct multituberculate mammals. Multituberculates were among the most common mammals of the Mesozoic, "the age of the dinosaurs".

Why does Plagiaulacida matter?

Because it connects several chemistry 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 Plagiaulacida?

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 Plagiaulacida.