Venomous mammal species may have lived with dinosaurs

This endangered Hispaniolan solenodon may have ancestors who knew dinosaurs.

Story highlights

  • The origins of a venomous mammal predate the extinction of the dinosaurs, scientists believe
  • Researchers sequenced DNA of Hispaniolan solenodon, completing a branch of the tree of life

(CNN)A creature about the size of a very large shrew may have been around when a dinosaur-killing asteroid struck Earth millions of years ago — and it survived.

Scientists discovered that the Hispaniolan solenodon, a venomous mammal that lives in the Dominican Republic and Haiti, diverged from all other mammals 78 million years ago, long before Earth's largest dinosaurs died off, according to new research published Monday in the journal of Mitochondrial DNA.
    "It's just impressive it's survived this long," Adam Brandt, a postdoctoral researcher at the University of Illinois, said in a press release. "It survived the asteroid; it survived human colonization and the rats and mice humans brought with them that wiped out the solenodon's closest relatives."
    Researchers from the University of Illinois and University of Puerto Rico made the discovery after successfully sequencing the animal's mitochondrial DNA, completing a missing part on the tree of life.
    Mitochondrial DNA is important because it is passed down from mothers to their babies without changing. It creates a genetic tree that helps scientists trace back the origins of creatures.
    It wasn't easy getting this information. Because solenodons are endangered animals, scientists had to collaborate with international researchers to track down the creatures to sample their DNA.
    The findings correlate with some theories about how the reddish rodent-like animal ended up calling the island of Hispaniola, about 870 miles from Florida, home. Some geologists believe the island was once part of Mexico, but 75 million years ago it started drifting away from the Yucatan Peninsula.
    "Whether they got on the island when the West Indies ran into Mexico 75 million years ago, or whether they floated over on driftwood or whatever else much later is not very clear," lead researcher Alfred Roca, a professor of animal sciences and member of the Carl R. Woese Institute for Genomic Biology, said in a statement.
    Although their ancestors are long gone, the solenodons are carrying on a prehistoric lineage. But they may not be around for long.
    Since the animal evolved in an ecosystem long absent of predators, it now faces threats from pets, people and habitat loss.