Scientists have sequenced the genome of a small isolated mammal, proving that it survived the asteroid impact that wiped out the dinosaurs 65 million years ago.
Called Hispaniolan solenodon (Solenodon paradoxus), the genome sequencing was carried out by a team led by Dr Taras Oleksyk from the University of Puerto Rico at Mayagüez. The research is available in the journal GigaScience.
The animal is one of the only living mammals that are venomous, with its venomous saliva flowing from modified salivary glands on its teeth that can kill a mouse in minutes. It also has large claws, a flexible snout, and teats positioned on their rear – all unusual traits for a mammal.
Solenodon measures about 49 to 72 centimeters (19 to 28 inches) in length and weighs almost 1 kilogram (2.2 pounds). They are social animals that spend their days in tunnel networks. At night, they head to the surface and hunt both small and large invertebrates.
The animal is highly endangered, and lives only in a few remote locations on Cuba and the island of Hispaniola. This made it particularly difficult to sequence its DNA, not least because having lived for tens of millions of years in isolation, it is extremely inbred.
Despite this, they were able to make some interesting findings. They were able to prove that the animal did indeed survive the asteroid impact that killed the dinosaurs, something that wasn’t clear before, having diverged from other mammals 73.6 million years ago.
"We have confirmed the early speciation date for solenodons, weighing in on the ongoing debate on whether the solenodons have indeed survived the demise of dinosaurs after the asteroid impact in the Caribbean," Dr Oleksyk said in a statement.
While the Chicxulub impact at the end of the Cretaceous wiped out 75 percent of life on Earth, some animals were able to survive – and mammals subsequently thrived in the absence of the dinosaurs.
The researchers also found that there was a subspecies split at least 300,000 years ago, suggesting that the northern and southern populations of solenodons may need independent breeding strategies for conservation.
“It may now be imperative to study conservation genomics of solenodons, whose extinction would extirpate an entire evolutionary lineage whose antiquity goes back to the age of dinosaurs,” the team write in their paper.
“S. paradoxus survived in spectacular island isolation despite the devastating human impact to biodiversity in recent centuries. Nevertheless, survival of this species is now threatened by deforestation, increasing human activity, and predation by introduced dogs, cats, and mongooses.”