science

Steneosaurus

Steneosaurus is a science 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 Steneosaurus rather than just read about it. In short: Steneosaurus (from Greek: στενός stenós, 'narrow' and Greek: σαῦρος saûros, 'lizard') is a dubious genus of teleosaurid crocodyliform from the Middle or Late Jurassic (Callovian or early Oxfordian) of France and possibly also India. The genus has been used as a wastebasket taxon for thalattosuchian fossils for over two centuries, and almost all known historical species of teleosauroid have been included within it at…

Key takeaways

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

Reference excerpt

Steneosaurus (from Greek: στενός stenós, 'narrow' and Greek: σαῦρος saûros, 'lizard') is a dubious genus of teleosaurid crocodyliform from the Middle or Late Jurassic (Callovian or early Oxfordian) of France and possibly also India. The genus has been used as a wastebasket taxon for thalattosuchian fossils for over two centuries, and almost all known historical species of teleosauroid have been included within it at one point. The genus has remained a wastebasket, with numerous species still included under the label 'Steneosaurus', many of which are unrelated to each other (either paraphyletic or polyphyletic with respect to each other and other genera of teleosauroids).

Discovery and assigned species The type species, S. rostromajor, was only formally recognised as such in 2020, and this revision determined the type specimen of Steneosaurus was undiagnostic, and so declared the genus Steneosaurus a nomen dubium. The history of this specimen has been detailed in 2017. It was discovered in three pieces by abbot Charles Bacheley (1716-1795) in the Vaches Noires near Villers-sur-Mer (Calvados, France). Bacheley offered these pieces to Alexandre Besson (1725-1809) who had built up an important cabinet of fossils and minerals in Paris. Besson gave one of the pieces (the posterior portion) to Barthélémy Faujas de Saint-Fond (1741-1819), professor of geology in the Muséum national d'Histoire naturelle, Paris. Georges Cuvier first illustrated in 1808 the two anterior pieces of the specimen kept in the Besson collection and then figured the third piece (posterior portion from the Faujas de Saint-Fond collection) in 1824 in association with the anterior pieces (Besson collection) and other cranial remains belonging to Metriorhynchidae. The large skulls of two marine crocodiles, about 1,602 millimetres (1.602 m) in length, were found in the Chari Formation, India and have been putatively identified as Steneosaurus by Phansalkar et al. (1994). The remaining species referred to Steneosaurus thus require new generic names, and some species have already been assigned to new genera prior to Steneosaurus being declared a nomen dubium. Species in this genus are traditionally classed into two skull groups: longirostrine (long, narrow jaws) and mesorostrine (slightly shorter jaws).

Longirostrine 'S.' atelestatus Eudes-Deslongchamps, 1868 - Oxfordian Marnes de Villers of France 'S.' blumembachi Eudes-Deslongchamps, 1868 - Oxfordian Marnes de Villers of France 'S.' oplites Eudes-Deslongchamps, 1863 - Toarcian La Caine-Curcy of France 'S.' rudis Sauvage, 1874 - France

Reassigned species 'Steneosaurus' baroni Newton, 1893 = Andrianavoay 'Steneosaurus' bollensis Von Meyer, 1830 = Macrospondylus 'S.' bouchardi - Sauvage, 1872 = Proexochokefalos 'Steneosaurus' boutilieri Eudes-Deslongchamps, 1869 = Yvridiosuchus 'Steneosaurus' brevior Blake, 1876 = Mystriosaurus 'Steneosaurus' deslongchampsianus (Lennier, 1887) 'Steneosaurus' edwardsi (Eudes-Deslongchamps, 1868) = Neosteneosaurus 'Steneosaurus' gracilirostris (Westphal, 1961) = Plagiophthalmosuchus 'Steneosaurus' heberti Morel de Glasville, 1876 = Proexochokefalos 'Steneosaurus' larteti (Eudes-Deslongchamps, 1868) = Deslongchampsina 'Steneosaurus' leedsi (Andrews, 1909) = Charitomenosuchus 'Steneosaurus' megarhinus (Hulke, 1871) = Bathysuchus 'Steneosaurus' megistorhynchus (Geoffrey Saint-Hilaire in Eudes-Deslongchamps, 1869) = Seldsienean 'Steneosaurus' obtusidens Andrews, 1909 = Lemmysuchus

Classification A 2005 phylogenetic analysis into the evolutionary relationships of Thalattosuchia did not support the monophyly of Steneosaurus, as the genera Machimosaurus and Teleosaurus both fell within Steneosaurus. Reinforcing the paraphyly of Steneosaurus, the Callovian species "Steneosaurus" obtusidens has been recovered as the sister species of Machimosaurus in recent cladistic analyses of Thalattosuchia and renamed Lemmysuchus, while 'Steneosaurus' bollensis was recovered in a basal position to other members of Steneosaurus sensu lato.

Illustrations

Worked examples

Example 1 — a first encounter with Steneosaurus

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

In research: Steneosaurus appears in science 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 Steneosaurus 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: Steneosaurus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Aalenian life, Bajocian life, Bathonian life, so understanding it makes those chapters shorter.
In everyday life: Look for Steneosaurus 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 Steneosaurus in 20 minutes

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

Frequently asked questions

What is Steneosaurus in simple terms?

Why does Steneosaurus matter?

Because it connects several science 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 Steneosaurus?

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 Steneosaurus.