Thylacocephala

Thylacocephala is an extinct class of marine arthropods known from fossils, distinguished by a large bivalved carapace, stalked eyes, and specialized raptorial appendages.

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Arthropod: An invertebrate animal with a segmented body, jointed appendages, and a chitinous exoskeleton. Thylacocephalans are classified within this larger animal group.
Predation: An interaction in which one organism captures and consumes another organism. Their specialized grasping limbs support interpretations of a predatory feeding mode.
Fossil: Preserved remains, traces, or impressions of organisms from past geological ages. Thylacocephalans are known from fossil remains rather than living representatives.
Dollocaris ingens: A large Jurassic thylacocephalan known from exceptionally preserved fossils in the Solnhofen Limestone. Its fossils preserve conspicuous eyes and appendages used to interpret the group's anatomy.
Phylogenetics: The study of evolutionary relationships among organisms using shared traits and genetic evidence. Their precise position within arthropods remains difficult to resolve from fossil anatomy.
Carapace: A hard protective covering over part or all of an animal's body. Their most conspicuous feature is a large, two-valved carapace.
Swimming: Locomotion through water by generating thrust with body movements or appendages. Their streamlined carapace and appendages invite reconstructions of aquatic locomotion.
Arthropod systematics: The classification and evolutionary relationships of arthropods. Debates over their affinities center on where they fit within arthropod evolution.
Ostenocaris cypriformis: A fossil thylacocephalan species described from Jurassic marine deposits. It provides a named example of the group's distinctive body form.
Convergent evolution: The independent evolution of similar traits in distantly related lineages. Similarities to other arthropods may reflect function rather than close ancestry.