biology

Pycnonemosaurus

Pycnonemosaurus 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 Pycnonemosaurus rather than just read about it. In short: Pycnonemosaurus (meaning 'dense forest lizard') is a genus of carnivorous theropod dinosaur that belonged to the family Abelisauridae. It was found in the Upper Cretaceous red conglomerate sandstones of the Cachoeira do Bom Jardim Formation, Mato Grosso, Brazil, and it lived during the late Campanian to early Maastrichtian stage of the Late Cretaceous.

Key takeaways

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

Reference excerpt

Pycnonemosaurus (meaning 'dense forest lizard') is a genus of carnivorous theropod dinosaur that belonged to the family Abelisauridae. It was found in the Upper Cretaceous red conglomerate sandstones of the Cachoeira do Bom Jardim Formation, Mato Grosso, Brazil, and it lived during the late Campanian to early Maastrichtian stage of the Late Cretaceous.

Discovery and naming The type species, Pycnonemosaurus nevesi, was scientifically described by Kellner and Campos in 2002. The only known specimen (DGM 859-R) was found in a red conglomeratic sandstone at the Jangada Roncador locality (then known as Fazenda Roncador), in Mato Grosso State that is exposed close to Paulo Creek, which is currently referred to the Cachoeira do Bom Jardim Formation. During 1952-1953, Llewellyn Ivor Price visited a farm named "Roncador" in the state of Mato Grosso and collected several dinosaur bones. These remains were found by the owner of the farm, Max de Barros Erhart, and his hired workers at the Paulo Creek site. The most important specimen found was the incomplete skeleton of a large abelisaurid theropod, which was found near several titanosaurid sauropod bones. Pycnonemosaurus nevesi was named from the Greek word pycnós meaning dense, némos meaning pastures and woods, and saûrus meaning reptile or lizard. This naming was an allusion to Mato Grosso State, where the remains were found. The specific name was named after the late Dr. Iedo Batista Neves, who passed in 2000, who encouraged the pursuit of paleontological studies, particularly of Alexander Kellner.

Description

Thus far, the remains of Pycnonemosaurus have been fragmentary. No elements were well preserved, and the bone surface is well abraded that indicates the elements were partially exposed at the discovery location before being collected. The type specimen, housed at the Earth Sciences Museum, Rio de Janeiro, consists of five incomplete teeth, parts of seven caudal vertebrae, the distal part of a right pubis, a right tibia, and the distal articulation of the right fibula. The small pubic foot and hatchet-shaped cnemial crest of the tibia distinguishes this species within the abelisaurs. The caudal vertebra has distinct abelisaurid features, such as a fan-shaped transverse process and a cranial projection. However, these awl-like projections are somewhat unlike related abelisaurids, such as Aucasaurus, in that they diminish more towards the distal caudals. All remains were found associated and are presently regarded as belonging to the same individual.

The type specimen of Pycnonemosaurus belongs to an immature individual of uncertain ontogenetic stage, probably a subadult. Initial size estimates of this specimen put the animal at 6–7 metres (20–23 ft) in length and 1.2 tonnes (1.3 short tons) in weight, but later analyses have found that it was likely larger, being about 8.9 metres (29.2 ft) long. This new size estimate currently makes Pycnonemosaurus the largest formally described member of the Abelisauridae thus far. Another estimation gave a length of 9 metres (29.5 ft) and a weight of 3.6 tonnes (4.0 short tons).

Classification The following cladogram follows an analysis of 2021 during the description of Llukalkan.

Paleoecology

Pycnonemosaurus is the best known abelisaurid from Brazil, where most theropod material is presently rare besides preserved teeth and footprints. Even though only a few species are known from Brazil, it is one of the most informative countries concerning the Lower Cretaceous period. Initially, the deposits in which this dinosaur was found were assigned to the Bauru Group, and later more specifically to the Cambambe Formation, with a possible temporal range spanning from the Campanian to the Maastrichtian stages. However, these deposits have since been reassigned to the Campanian-aged Cachoeira do Bom Jardim Formation. This formation is believed to have been deposited in a semi-arid climate, representing the intermediate parts of alluvial fans. Pycnonemosaurus was a predator, probably preying on titanosaurs found in the same locality. Its teeth were small yet sharp, and were used to get a hold of struggling prey as the abelisaur shook and tore them apart.

Illustrations

Worked examples

Example 1 — a first encounter with Pycnonemosaurus

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

In research: Pycnonemosaurus 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 Pycnonemosaurus 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: Pycnonemosaurus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Abelisauridae, Campanian dinosaurs, Dinosaur genera, so understanding it makes those chapters shorter.
In everyday life: Look for Pycnonemosaurus 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 Pycnonemosaurus in 20 minutes

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

Frequently asked questions

What is Pycnonemosaurus in simple terms?

Why does Pycnonemosaurus 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 Pycnonemosaurus?

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 Pycnonemosaurus.