science

Lepidotes

Lepidotes 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 Lepidotes rather than just read about it. In short: Lepidotes (from Greek: λεπιδωτός lepidōtós, 'covered with scales') (previously known as Lepidotus) is an extinct genus of Mesozoic ray-finned fish. It has long been considered a wastebasket taxon, characterised by "general features, such as thick rhomboid scales and, for most of the species, by semi-tritorial or strongly tritorial dentition". with dozens of species assigned to it.

Key takeaways

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

Reference excerpt

Lepidotes (from Greek: λεπιδωτός lepidōtós, 'covered with scales') (previously known as Lepidotus) is an extinct genus of Mesozoic ray-finned fish. It has long been considered a wastebasket taxon, characterised by "general features, such as thick rhomboid scales and, for most of the species, by semi-tritorial or strongly tritorial dentition". with dozens of species assigned to it. Fossils attributed to Lepidotes have been found in Jurassic and Cretaceous rocks worldwide. It has been argued that Lepidotes should be restricted to species closely related to the type species L. gigas, which are only known from the Early Jurassic of Western and Central Europe, with most other species being not closely related, with other species transferred to new genera such as Scheenstia. Lepidotes belongs to Ginglymodi, a clade of fish whose only living representatives are the gars (Lepisosteidae). The type species L. gigas and close relatives are thought to be members of the family Lepidotidae, part of the order Lepisosteiformes within Ginglymodi, with other species occupying various other positions within Ginglymodi.

Description

Inhabiting both freshwater lakes and shallow seas, Lepidotes was typically about 30 centimetres (12 in) long. The body was covered with thick, enamelled scales. Lepidotes was one of the earliest fish in which the upper jawbones were no longer attached to the jugal bone. This allowed the jaws to be stretched into a 'tube' so that the fish could suck in prey from a greater distance than in previous species. This system is still seen in some modern fish, such as carp. Lepidotes scales are ovular in shape, and are 18.5 millimetres (0.73 in) long and 3 millimetres (0.12 in) thick at the thickest point. The scales are smooth and shiny on the external surface, with only a few small depressions scattered toward the centre that are shaped like punctures. Stomach contents of Lepidotes from the Early Jurassic of Germany have found remains of crustacean cuticles, and it is suggested that they fed on relatively soft-bodied prey, which was grasped with the slender marginal teeth, before being crushed by the rounded palatal teeth.

Distinguishing characteristics Many characteristics were identified by Woodward in 1895, and they are listed below:

a fusiform trunk only moderately compressed; the fact that the marginal teeth are compressed; the presence of stouter inner teeth that are smooth; ossified ribs; very large fin-fulera on all fins; that all paired fins are small; short and deep dorsal and anal fins; very robust, smooth or feebly oriented scales; flank scales that are not much deeper than wide; scales ventrally nearly as deep as broad; and the presence of inconspicuous dorsal and ventral ridge-scales.

Taxonomy Currently valid species after.

L. gigas The type species of the genus, it is known from the Early Jurassic (Toarcian) of Germany.

L. elvensis L. elvensis was described by Ducrotay de Blainville in 1818. It is known from an almost complete specimen housed in the Paris Museum of Natural History. The specimen measures up to 75 centimetres (2.46 ft) long. The specimen is from the Upper Lias, in Bavaria. The specimens P. 7406, P. 7407, P. 7408, P. 2014, P. 2054, P. 3529a, P. 3529b, 18992, 18993/94 19662, 32421, and 32422 have all been assigned to this species. The external bones of this species are smooth, but some have sparsely placed coarse tuberculations (protuberances). The frontal bone is more than twice the length of the parietal in the specimens. It also has a comparatively narrow marginal symphysis (articulation). Other specimens are known from France.

L. semiserratus This species was named by Agassiz in 1837 and is known from some incomplete remains. It has been classified as closely related to L. elvensis. It is more elongate than L. elvensis, being four times as long as tall. It also has more sharply angulated sutures between its parietals, and the parietals are also proportionally longer. It is known from the specimens P. 1127, P. 7409, P. 2012, P. 2012a, P. 3527, P. 3528, P. 3528a, P. 5213, P. 5228, P. 6394, P. 7410, and 35556, all from the Upper Lias of Yorkshire, England

L. buelowianus Known from the Early Jurassic of (Toarcian) Germany.

Reassigned species "Lepidotes" latifrons from the Middle-Late Jurassic of England has been reassigned to the genus Isanichthys. Many other European species from the Late Jurassic-Early Cretaceous have been reassigned to Scheenstia.

References

Illustrations

Worked examples

Example 1 — a first encounter with Lepidotes

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

In research: Lepidotes 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 Lepidotes 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: Lepidotes is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cenomanian genus extinctions, Crato Formation, Cretaceous Argentina, so understanding it makes those chapters shorter.
In everyday life: Look for Lepidotes 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 Lepidotes in 20 minutes

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

Frequently asked questions

What is Lepidotes in simple terms?

Why does Lepidotes 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 Lepidotes?

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 Lepidotes.