Questions and Answers
What are trilobites?
How many different trilobite species are known?
Over 50,000
Gonatoparians have facial sutures that end at the tip of the genal angle.
True
To which subclass do ammonoids belong?
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What are belemnites classified as?
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What significant evolutionary advancement did trilobites exhibit?
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Ammonoids existed from the _____ to _____ period.
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What classification do nautiloids belong to?
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What is the time range for the subclass Ammonoidea?
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Suture lines in these organisms show comparison of name, era, and _____.
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Study Notes
Trilobites
- Extinct marine arthropods classified under the class Trilobita.
- Formed one of the earliest known groups of arthropods.
- Belonged to Phylum Arthropoda and Subphylum Trilobitomorpha.
- Existed from the Cambrian to Permian periods.
- Over 50,000 species identified, showcasing diverse facial features.
Gonatoparian
- Defined by facial suture ending at the tip of the genal angle.
- Genera exhibiting this suture type include Calymene and Trimerus from Calymenina (Phacopida).
Ammonoids
- Extinct group of marine molluscs in the subclass Ammonoidea, part of Class Cephalopoda.
- Closely related to modern coleoids (octopuses, squid, cuttlefish) rather than nautiloids like Nautilus.
- Existed from the Devonian to the Cretaceous periods.
Subclass Nautiloidea
- Existed from the Late Cambrian to recent times.
- Includes the living genus Nautilus.
Subclass Coleoidea
- Originated in the Carboniferous and persists to the present.
- Characterized by organisms like Belemnite.
Subclass Ammonoidea
- Existed from the Early Devonian to the Late Cretaceous.
Eyes
- Trilobites developed highly advanced eyes over 520 million years ago during the early Cambrian.
- Marked a significant evolutionary advancement in fossil records.
- Sophisticated eyes evolved during the Devonian due to the presence of more advanced predators.
Suture Lines
- Suture lines provide information for comparison, including names, eras, and periods associated with various organisms.
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Description
Test your knowledge on marine arthropods like trilobites and ammonoids, as well as their subclasses such as Nautiloidea and Coleoidea. Explore the diverse history and classifications of these fascinating extinct creatures that roamed the oceans from the Cambrian to the Cretaceous periods.
