Form and function in Thylacocephala, Conchyliocarida and Concavicarida (?Crustacea): a problem of interpretation

摘要: Differences in the preservation of Jurassic thylacocephalans and conchyliocarids have given rise to different interpretations form these fossils, thus their mode life. When evidence from two groups is combined with that derived Palaeozoic concavicarids, it becomes possible unify several this one group organisms, Thylacocephala. The ranges at least Silurian Cretaceous.A review how differences interpretation arisen, some resolution attempted. If thylacocephalan “anterior structure” reinterpreted by analogy hyperiid amphipods as a paired compound eye occupying most surface head, explains its bilobed nature position stomach within structure, but raises difficulty post-cephalic origin for carapace. simpler solution preferred regarding structure discrete eyes smooth cornea subjacent crystal cones.The raptorial appendages are post-oral post-adductor insertion. They therefore tentatively identified maxillae maxilliped, verification mandible's needed test this. postero-ventral battery “body somites” protopods abdominal limbs. A respiratory current deduced entered branchiostegal chamber ventrally, left posterodorsally. It speculated looped linear pattern intra-cuticular spheres Paraostenia photophores. large small interommatidial angles were probably used discern low contrast prey or carrion against dim background. By amphipods, suggested mesopelagic predators. may attained neutral buoyancy food substrate shark coleoids.