For nearly a century after its first description in 1892, Anomalocaris was treated as a museum specimen of minor interest rather than a serious biological question. The fossil had been split, accidentally, into three separate species: the segmented body was filed under one genus as a shrimp-like crustacean, the circular mouthparts were catalogued as a jellyfish, and the grasping frontal appendages were named as a third creature entirely. Each piece, considered alone, seemed unremarkable; together, they would have implied an animal whose proportions and ecology no one was prepared to accept.
The reassembly, carried out by Whittington and Briggs in the 1980s, corrected an error rather than uncovering something wholly new. What emerged was a meter-long active swimmer with stalked compound eyes and predatory mouthparts. This configuration forced paleontologists to revise the standing view of Cambrian seas as a low-energy setting populated chiefly by small grazers and filter-feeders. Subsequent finds of bitten and partially healed trilobite shells, long dismissed as meaningless damage from the fossilization process, were re-examined and, in many cases, reinterpreted as predation traces consistent with jaws the size of Anomalocaris.
The episode is often retold as a triumph of patient morphology, but its main lesson concerns method. The fragmentation was not a failure of observation; the original describers saw the specimens clearly. The failure lay in the prior assumption that Cambrian ecosystems lacked apex predators, an assumption that made the reassembled animal seem implausible and therefore not worth pursuing. Once that assumption was relaxed, partly under pressure from new Burgess Shale material and partly from independent work on trace fossils, the pieces were quickly reconciled. On this reading, caution about ecological assumptions is at least as productive a discipline as caution about morphological description.
The passage is primarily organized to do which of the following?