Tiny honeycomb-like colonies from southern China have opened a long-running gap in the story of animal life. For decades, bryozoans seemed oddly absent from the Cambrian explosion, the burst of diversification that filled ancient seas with most major animal groups. These fossils suggest they were there all along. The new material comes from the early Cambrian Xiannüdong Formation in Shaanxi Province and dates to about 520 million years ago. In Nature, an international team describes new specimens of Protomelission gatehousei and a newly named species, Dayingomelission hexaclitia, preserved in unusual detail. That matters because bryozoans, tiny filter-feeding invertebrates that live in colonies, have long posed an evolutionary problem. Their fossil record seemed to begin much later, in the Ordovician, even though molecular analyses had pointed to a much earlier origin. Nearly every other major animal phylum had a Cambrian representative. Bryozoans appeared to be the exception. “Bryozoa has been the elephant in the room of Cambrian palaeontology for a long time.” said co-author Dr Timothy Topper of Northwest University and the Swedish Museum of Natural …