The origins of Cuban species

August 24, 2016

The Caribbean islands form a natural laboratory for the study of evolution due to their unique biological and geological features. There has been heated discussion since the early 20th century on how species appeared on the islands.

The Cuban solenodon is a small, rare, endangered animal, belonging to the mammalian order Eulipotyphla. It is a mole-like nocturnal animal with a long snout that feeds on insects and is found in only a few fragmented locations in Cuba. Its evolutionary origins have been widely contested and have remained relatively elusive because they have been so difficult to capture and examine.

In 2012, a team of researchers successfully captured seven living Cuban solenodons and collected DNA samples before releasing them. They analysed five specific protein-coding genes and compared them to the same genes in another 35 species belonging to the same order.

While another research group had suggested that solenodons lived with dinosaurs in the Cretaceous period, this team found that the solenodon family evolved from its ancestor around 59 million years ago, long after the dinosaur extinction. The team's analysis also revealed that the Cuban solenodon and the Hispaniolan solenodon (the other existing solenodon species) diverged from each other in the Early Pliocene Epoch (3.7 to 4.8 million years ago), while the previous study set the divergence at 25 million years ago. Hispaniola is the second largest island in the Caribbean and is currently home to the Dominican Republic and Haiti.

The team now suggests that a much-later divergence time in addition to information on ocean-current patterns in the area indicate that the Cuban solenodon travelled over water (on floating plants or rafts, for example) to Cuba from Hispaniola, rather than evolutionarily diverging from them due to the much-earlier geological separation of the islands.

Together with results from other studies, the researchers believe that smaller invertebrates and some vertebrates (like butterflies and toads respectively) originated in the Caribbean islands via a land bridge between them and South America some 34 million years ago. On the other hand, many of the larger vertebrates, who would have been more capable of surviving the high-risk passage, may have originated in the islands via over-water travel.

The team's research is published in the August 8 edition of the journal Scientific Reports.
-end-


Hokkaido University

Related Dinosaurs Articles from Brightsurf:

Ireland's only dinosaurs discovered in antrim
The only dinosaur bones ever found on the island of Ireland have been formally confirmed for the first time by a team of experts from the University of Portsmouth and Queen's University Belfast, led by Dr Mike Simms, a curator and palaeontologist at National Museums NI.

Baby dinosaurs were 'little adults'
Paleontologists at the University of Bonn (Germany) have described for the first time an almost complete skeleton of a juvenile Plateosaurus and discovered that it looked very similar to its parents even at a young age.

Bat-winged dinosaurs that could glide
Despite having bat-like wings, two small dinosaurs, Yi and Ambopteryx, struggled to fly, only managing to glide clumsily between the trees where they lived, according to a new study led by an international team of researchers, including McGill University Professor Hans Larsson.

Some dinosaurs could fly before they were birds
New research using the most comprehensive study of feathered dinosaurs and early birds has revised the evolutionary relationships of dinosaurs at the origin of birds.

Tracking Australia's gigantic carnivorous dinosaurs
North America had the T. rex, South America had the Giganotosaurus and Africa the Spinosaurus - now evidence shows Australia had gigantic predatory dinosaurs.

Ancient crocodiles walked on two legs like dinosaurs
An international research team has been stunned to discover that some species of ancient crocodiles walked on their two hind legs like dinosaurs and measured over three metres in length.

Finding a genus home for Alaska's dinosaurs
A re-analysis of dinosaur skulls from northern Alaska suggests they belong to a genus Edmontosaurus, and not to the genus recently proposed by scientists in 2015.

Can we really tell male and female dinosaurs apart?
Scientists worldwide have long debated our ability to identify male and female dinosaurs.

In death of dinosaurs, it was all about the asteroid -- not volcanoes
Volcanic activity did not play a direct role in the mass extinction event that killed the dinosaurs, according to an international, Yale-led team of researchers.

Discriminating diets of meat-eating dinosaurs
A big problem with dinosaurs is that there seem to be too many meat-eaters.

Read More: Dinosaurs News and Dinosaurs Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.