biology

Sinornithoides

Sinornithoides 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 Sinornithoides rather than just read about it. In short: Sinornithoides (meaning "Chinese bird form") is a genus of troodontid theropod dinosaurs that lived during the Early Cretaceous (Aptian or Albian stage, around 113 million years ago) of Inner Mongolia, China. It contains only a single species, S. youngi.

Key takeaways

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

Reference excerpt

Sinornithoides (meaning "Chinese bird form") is a genus of troodontid theropod dinosaurs that lived during the Early Cretaceous (Aptian or Albian stage, around 113 million years ago) of Inner Mongolia, China. It contains only a single species, S. youngi. Sinornithoides measured approximately 1 metre (3.3 ft) long, and probably ate invertebrates and other small prey.

Discovery In 1988, a Chinese-Canadian expedition discovered the remains of a small theropod near Huamuxiao, in the Ordos Basin of Inner Mongolia. Sinornithoides youngi, the type species, was named and described in 1993/1994 by Dale Russell and Dong Zhiming based on this fossil specimen from the Lower Cretaceous Ejinhoro Formation. The generic name is derived from Latin Sinae, "Chinese", and Greek ὄρνις, ornis, "bird", en ~ειδής, ~eides, a suffix meaning "~like", in reference to the bird-like build. The specific name honours Yang Zhongjian. It is represented by a holotype, IVPP V9612, an almost complete skeleton with skull, which is articulated and nearly complete except for the roof of the skull, some cervical and many dorsal vertebrae, along with some other referred skeletal elements. The holotype is preserved in much the same roosting position as another troodontid fossil, that of Mei long, with its snout tucked under its left hand. It represents a subadult individual.

Description

Sinornithoides is a troodontid, a group of small, bird-like, gracile maniraptorans. All troodontids have many unique features of the skull, such as closely spaced teeth in the lower jaw, and large numbers of teeth. Troodontids have sickle-claws and raptorial hands, and some of the highest non-avian encephalization quotients, meaning they were behaviourally advanced and had keen senses. In 2010, Gregory S. Paul estimated its body length at 1.1 metres, its weight at 2.5 kilogrammes.

In 1994, Sinornithoides was one of the most completely known troodontids, especially as regarded the palate, but the lack of sufficient fossil material to compare it with induced Russell and Dong not to indicate any diagnostic traits. The skull of Sinornithoides is elongated and pointed. However, the head is relatively short compared to the body as a whole. The praemaxilla is short. There is a fenestra promaxillaris, a small opening in the front of the maxilla side, which is rare among troodontids. There are four premaxillary and about twenty-three maxillary teeth. The maxillary teeth have no serrations on their front edge; the denticles on the concavely curved rear edge are small. The maxillary teeth are rather recurved. The lacrimal bone lacks a pneumatic channel. In the braincase the subotic recess is large. The tips of the lower jaws do not curve towards each other but touch at their inner sides. The external mandibular fenestra is large. The dentary, lower jaw, teeth are quite pointed and have no front edge denticles; their rear edge is very straight. The holotype preserves a furcula and a basket of fifteen pairs of gastralia. The arms are weakly developed, with a slender humerus and ulna. The front top of the third metatarsal is not fully overgrown by the second and fourth metatarsals. The sickle claw of the second toe is relatively large and long for a troodontid.

Classification Sinornithoides was in 1994 assigned to the Troodontidae. A possible position of Sinornithoides in the evolutionary tree of the Paraves is shown by the cladogram below, following a 2012 analysis by Turner, Makovicky and Norell.

Illustrations

Worked examples

Example 1 — a first encounter with Sinornithoides

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

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

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

Frequently asked questions

What is Sinornithoides in simple terms?

Why does Sinornithoides 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 Sinornithoides?

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 Sinornithoides.