The fossil whorls were a mystery. In 1899, geologist Alexander Karpinsky described an odd spiral of teeth, the first known fossil of its kind, uncovered from the ancient rocks of Krasnoufimsk, Russia.
Whole skeleton of Dipterus, an extinct lungfish from the middle Devonian period. Specimen (UMMP 16140) from the University of Michigan Museum of Paleontology. ANN ARBOR—If you're reading this sentence ...