RIO DE JANEIRO — The stately national museum, once home to Brazil’s royal family, was still smoldering at sunrise on Monday when scores of researchers, museum workers and anthropologists began gathering outside, dressed in black.

Some sobbed as they began taking stock of the irreplaceable losses: Thousands, perhaps millions, of significant artifacts had been reduced to ashes Sunday night in a devastating fire. The hall that held a 12,000-year-old skeleton known as Luzia, the oldest human remains discovered in the Americas, was destroyed.

Hundreds of residents joined them beneath an overcast sky that matched the national mood. They had come not only to mourn but also to protest Brazil’s near-abandonment of museums and other basic public services. Many saw the fire as a symbol for a city, and nation, in distress.

“It’s a moment of intense pain,” Maurilio Oliveira, who has worked as a paleoartist at the National Museum of Brazil for 19 years, said as he stood in front of the ravaged building. “We can only hope to recover our history from the ashes. Now, we cry and get to work.”