biology

Petrocardium

Petrocardium 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 Petrocardium rather than just read about it. In short: Petrocardium is an extinct genus of monocot plants in the family Araceae. At present it contains only two species Petrocardium cerrejonense and Petrocardium wayuuorum, the type species.

Key takeaways

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

Reference excerpt

Petrocardium is an extinct genus of monocot plants in the family Araceae. At present it contains only two species Petrocardium cerrejonense and Petrocardium wayuuorum, the type species. The genus is solely known from the Middle to Late Paleocene (about 60 to 58 Ma), Cerrejón Formation deposits in Colombia.

History and classification The genus is known only from the two holotype specimens, number ING-0902, type specimen for Petrocardium wayuuorum, and ING-0804, type specimen for Petrocardium cerrejonense. The leaves are currently residing in the collections housed by the Colombian Geological Institute in Bogotá, Colombia. Both ING-0902 and ING-0804 were collected from Cerrejón Formation exposures in the Cerrejón coal mine, located in the Ranchería Basin, Colombia. They were first studied by a group of researchers from Florida Museum of Natural History, the Smithsonian Museum of Natural History and led by Fabiany Herrera from the Smithsonian Tropical Research Institute. Herrera and associates published their 2008 type description in the American Journal of Botany. The generic epithet Petrocardium is Greek in derivation and is said to be a combination of the words petro meaning "rock" and cardium which means "heart" and references the heart shaped nature of the leaf fossils in the rocks. The proper words for rock and heart in Greek are however πέτρα (petra) and καρδία (kardia). The specific epithet "wayuuorum" was chosen by the authors to honor the Wayuu Amerindian tribe which lives in the Rancheria Basin area of Colombia. The specific epithet "cerrejonense" is a derivation of Cerrejón and reflects the type locality, the Cerrejón Formation.

Description Although several angiosperm families, such as Alismataceae, and Potamogetonaceae have leaf morphologies similar to Petrocardium, its lack of the primary vein structure found in those families excludes them as relatives. Petrocardium is placed as incertae sedis within the Araceae due to the unique combination of leaf morphology characteristics present in both species. Of the modern Araceae genera, Petrocardium is most similar to the modern tropical genus Anthurium in tribe Pothoeae. However it is not close in structure to the other three genera in the tribe, Pedicellarum, Pothoidium, and Pothos. This disparity lead the research team to leave the genus unplaced as to subfamily and tribe. Overall the genus possesses entire margined leaves with a generally ovate shape. The leaf apex is long and tapers to a point, while the base is heart to arrowhead shaped. The overall depositional environment, at an estimated paleolatitude of 5 degrees North, was that of sedimentation associated with a fluvial channel area formed within a Neotropical rainforest basin.

Petrocardium wayuuorum The single known specimen of P. wayuuorum, ING-0902, was recovered from locality 0315, a 6 metres (20 ft) by 50 centimetres (20 in) lens of fine grained sandstone in the Cerrejón Formation. The specimen is missing the basal portion of the leaf but shows a smooth margin in the preserved regions of the leaf blade and was either cordate or sagittate. The overall size of the leaf was 6.2 by 3.8 centimetres (2.4 by 1.5 in), and has a vein structure similar to that of Anthurium species that form secondary veins which group in single cluster of veins parallel to the outer margin of the leaf. This secondary vein structure is used to distinguish P. wayuuorum from P. cerrejonense.

Petrocardium cerrejonense As with P. wayuuorum, P. cerrejonense is known from only one partial leaf and specimen ING-0804, is also from locality 0315. The specimen is incomplete with only portions of the tip and middle area of the leaf blade known. The overall size of the leaf was over 9.5 by 24.3 centimetres (3.7 by 9.6 in), with an acuminate tip and smooth margin. P. cerrejonense has a vein structure similar to that of Anthurium species which form secondary veins which group into two clusters of veins parallel to the outer margin of the leaf and the secondary vein structure is used to distinguish P. cerrejonense from P. wayuuorum.

References

Worked examples

Example 1 — a first encounter with Petrocardium

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

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

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

Frequently asked questions

What is Petrocardium in simple terms?

Petrocardium is an extinct genus of monocot plants in the family Araceae. At present it contains only two species Petrocardium cerrejonense and Petrocardium wayuuorum, the type species.

Why does Petrocardium 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 Petrocardium?

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 Petrocardium.