Answer Monday

A fossil!It’s Cloudina hartmannae! The genus is named for the legendary paleontologist Preston Cloud Jr. (1912–1991), a pioneer in the study of the Precambrian, while the species is named for the polychaete specialist Olga Hartman (1900–1974). As Andrew H. Knoll writes in Life on a Young Planet (2003), “Cloudina is important because it shows that animals learned how to build mineralized skeletons well before the Cambrian Period began.” Cloudina thus receives a chapter of its own in Donald R. Prothero’s excellent new book The Story of Life in 25 Fossils (2015). Congratulations to Dan Phelps for his correct identification of C. hartmannae—and for correctly guessing that the genus is named for Preston Cloud—and a tip of the cloudy ha(r)t to Steve Newton for the photograph.