biology

Metoposaurus

Metoposaurus 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 Metoposaurus rather than just read about it. In short: Metoposaurus meaning "front lizard" is an extinct genus of stereospondyl temnospondyls, known from the Late Triassic of Germany, Italy, Poland, and Portugal. This animal was mostly aquatic, possessing small, weak limbs, sharp teeth, and a large, flat head.

Key takeaways

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

Reference excerpt

Metoposaurus meaning "front lizard" is an extinct genus of stereospondyl temnospondyls, known from the Late Triassic of Germany, Italy, Poland, and Portugal. This animal was mostly aquatic, possessing small, weak limbs, sharp teeth, and a large, flat head. This highly flattened creature mainly fed on fish, which it captured with its wide jaws lined with needle-like teeth. Many Metoposaurus mass graves have been found, probably from creatures that grouped together in drying pools during drought.

Discovery and species

Discovery The earliest mention of Metoposauridae dates back to 1842 when Von Meyer described the dorsal view of the skull roof of a labyrinthodont from the Keuper Schilfsandstein of Feuerbacher Haide near Stuttgart. Later, Meyer attempted a reconstruction of the same specimen and named it Metopias diagnosticus. However, Lydekker later renamed the species as Metoposaurus diagnosticus in 1890 because the name Metopias was already in use.

Species Based on the position of the lacrimal in the skull, Metoposauridae is divided into two lineages. The group with the lacrimal external to the orbit includes Koskinonodon bakeri, Dutuitosaurus ouazzoui, Arganasaurus lyazidi, and Apachesaurus gregorii. They show a tendency towards a decreasing depth of the otic notch and a decrease in body size. Metoposaurus diagnosticus, Metoposaurus diagnosticus krasiejowensis and Panthasaurus maleriensis fall in the category of the lacrimal forming the orbital margin.

Metoposaurus diagnosticus (Meyer, 1842) Fossils were found among other locations in the Gres à Avicula contorta Formation of France, the Weser Formation of Germany and the Raibl Formation of Italy. The species has an anterior top of the lacrimal closer to the nares than the top of the prefrontal; interclavicle with posterior part longer than in Panthasaurus maleriensis. Metoposaurus diagnosticus diagnosticus lived in the western Germanic Basin, from at least the Schilfsandstein to the Lehrberg Beds sedimentation.

Metoposaurus krasiejowensis (Sulej, 2002) Fossils were found in the Drawno Beds Formation of Poland. The species has a very short perineal part of the parietal with the high value of the expansion angle of the sutures separating partially from the supratemporal (mean angle value of 21.81). Some skulls possess a large quadrate foramen and small paraquadrate foramen. It had an estimated skull length up to 47.5 cm (18.7 in).

Metoposaurus algarvensis (Brusatte et al. 2015) From the Late Triassic Grès de Silves Formation in the Algarve, Portugal. It has a broader skull than any other Metoposaurus. It was named by Stephen Brusatte, Richard Butler, Octávio Mateus and Sebastien Steyer. It had an estimated mandible length up to 65 cm (26 in).

Formerly assigned species Metoposaurus maleriensis (Chowdhury, 1965) Described from the Maleri Formation of Central India, was renamed Panthasaurus maleriensis by Chakravorti and Sengupta (2018).

Metoposaurus azerouali (Dutuit, 1976) Described from the Argana Group of Morocco. Reassigned to Arganasaurus by Buffa et al. (2019).

Synonyms and nomina dubia Metoposaurus stuttgartensis: synonymous, is first described by Fraas (1913) from the Keuper Lehbergstufe of Sonnenberg, near Stuttgart. Fraas identified the species based on the interclavicle and left clavicle, vertebrae and rib fragments which are now located in the Stuttgart Museum. Metoposaurus santaecrucis Nomina dubia it was described by Koken (1913) based on the partial skull found in Heiligenkreuz and the specimen is now located in the University Museum of Tübingen. Metoposaurus heimi synonymous it was described by Kuhn (1932) based on a complete skull from the middle Keuper Blasensandstein in Upper Franconia. The specimen is currently located in the Museum of Paleontology and Historical Geology, Munich.

Description

Skull

Lacrimal The lacrimal contacts the nasal medially, the maxilla laterally, the prefrontal posteromedially, and the jugal posteriorly. Metoposaur taxonomy was based on the position of the lacrimal bone, and differing opinions have been published. According to a photograph published by Hunt (1993), it is noted that the lacrimal enters the orbit, contrary to the previous finding by Fraas (1889). According to Lucas, close examination of the skull and other metoposaur skulls does not support this claim, and it has been noted that the misidentification was possibly due to the poor preservation of the fossil. In 2007, Sulej noted that the variability in the position of the lacrimal is narrow enough to be used for phylogenic analysis, but with caution.

Parietal A study conducted by Sulej (2007) shows that the parietal contacts the frontal anteriorly, the postfrontal anterolaterally, the supratemporal laterally, and the postparietal posteriorly. The pineal foramen is in the posterior region of the parietal. An interesting feature pointed out by Sulej on examining the skull of Metoposaurus diagnosticus krasiejowensis is that it has a shorter prepineal region of the parietal than Metoposaurus diagnosticus diagnosticus and the expansion angle of the suture separating the parietal from the supratemporal has a lower value.

Maxilla The maxilla forms a large, completely dentigerous shelf bearing 83 to 107 teeth. The first teeth are large, and tooth size decreases markedly further posteriorly. On the ventral side, the maxilla contacts the ectopterygoid, palatine and vomer. In the choanal region, the maxilla is slightly broadening medially on the palatal side where it borders the choana. The margin of the choana is variable. In most skulls, it is weakly distinguished and rounded, but in a few cases it is more solid and sharply outlined.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Metoposaurus

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

In research: Metoposaurus 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 Metoposaurus 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: Metoposaurus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Fossil taxa described in 1890, Fossils of France, Fossils of Germany, so understanding it makes those chapters shorter.
In everyday life: Look for Metoposaurus 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 Metoposaurus in 20 minutes

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

Frequently asked questions

What is Metoposaurus in simple terms?

Why does Metoposaurus 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 Metoposaurus?

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 Metoposaurus.