24 new lizard species identified in the Caribbean
A suite of lizards called skinks has just slipped into science books, with researchers discovering 24 new species of reptiles from the Caribbean islands.
Many species of skinks have been identified from museum specimens, and now researchers say half of the debutants could be extinct or near extinction, with the rest threatened with extinction, said the lead researcher of the study Blair Hedges, professor of biology at Penn State. University.
The researchers examined the specimens using the animals’ DNA and appearance, including the number and shape of their scales, to identify them. Of the 39 species they identified in the Caribbean, six were already known and nine had been named long ago but were not considered valid until now.
New World skinks, like those identified, arrived in the Americas about 18 million years ago from Africa, possibly floating on mats of vegetation. Their fame comes from their ability to produce a human placenta, the organ that connects growing offspring to the mother’s essential nutrients.
“Although there are other lizards that give birth, only a fraction of the lizards known as skinks produce a placenta and gestating offspring for up to a year,” Hedges said in a statement.
As pregnancy can slow an animal down, this long gestation period may have given skink predators a competitive advantage; they think that the little Indian mongoose (Urva auropunctata) – an invasive species introduced by farmers in the 19th century to control rats in sugar cane fields – is responsible for the disappearance of many skink species. [Infographic: How Long Are Animals Pregnant?]
“Our data show that the mongoose, which was introduced from India in 1872 and spread around the islands over the next three decades, nearly wiped out all of this reptile fauna, which had gone largely unnoticed by scientists and conservationists so far,” Hedges said.
In fact, data show a sharp decline in skink populations soon after the mongoose was introduced.
As to why so many skink species have gone unnoticed for so many years, Hedges offered two explanations. “First, Caribbean skinks were already nearly extinct by the start of the 20th century, so people since that time have rarely encountered them and therefore been less likely to study them,” he said.
Also, some key features that distinguish the species have been overlooked, he said. These included various features of body proportion, scale as well as coloring and patterning.
The research, funded by the National Science Foundation, is detailed in today’s (April 30) issue of the journal Zootaxa.