biology

Tongnanlong

Tongnanlong 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 Tongnanlong rather than just read about it. In short: Tongnanlong (meaning "Tongnan District dragon") is a genus of mamenchisaurid dinosaur from the Late Jurassic Suining Formation of Chongqing, China. The type species is Tongnanlong zhimingi.

Key takeaways

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

Reference excerpt

Tongnanlong (meaning "Tongnan District dragon") is a genus of mamenchisaurid dinosaur from the Late Jurassic Suining Formation of Chongqing, China. The type species is Tongnanlong zhimingi.

Discovery and naming The Tongnanlong holotype specimen, TNM 0254, consists of three dorsal and six caudal vertebrae, left shoulder girdle (scapula and coracoid) and hindlimb elements (partial tibia, fibula, three metatarsals, and two unguals). It was discovered in 1998 during construction of a building along Dafo Street. It was described as a new genus and species of dinosaur in 2025. The generic name, Tongnanlong, combines a reference to Tongnan District, Chongqing, where it was found, with the Chinese word long, meaning "dragon". The specific name, zhimingi, refers to prominent Chinese paleontologist Dong Zhiming.

Description Tongnanlong is estimated as being up to 25–26 m (82–85 ft) long, making it one of the largest mamenchisaurids.

Classification

Wei et al. (2025) inserted Tongnanlong into the phylogenetic analysis previously used in the description of Jingiella. It placed Tongnanlong as a derived member of the Mamenchisauridae close to Mamenchisaurus. A cladogram adapted from their analysis is shown below:

Paleoenvironment Other animals from the Suining Formation include fellow mamenchisaurid dinosaurs Qijianglong guokr and Mamenchisaurus anyuensis, the lungfish Ceratodus szechuanensis, and the turtle Plesiochelys tatsuensis.

References

Worked examples

Example 1 — a first encounter with Tongnanlong

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

In research: Tongnanlong 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 Tongnanlong 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: Tongnanlong is common in secondary-school and first-year university syllabi. It links to neighbouring topics Dinosaur genera, Dinosaurs of China, Fossil taxa described in 2025, so understanding it makes those chapters shorter.
In everyday life: Look for Tongnanlong 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 Tongnanlong in 20 minutes

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

Frequently asked questions

What is Tongnanlong in simple terms?

Tongnanlong (meaning "Tongnan District dragon") is a genus of mamenchisaurid dinosaur from the Late Jurassic Suining Formation of Chongqing, China. The type species is Tongnanlong zhimingi.

Why does Tongnanlong 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 Tongnanlong?

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 Tongnanlong.