In a single new scientific publication, 24 new species of lizards known as skinks（小蜥蜴） , all from islands in the Caribbean, have been discovered and scientifically named. According to Blair Hedges, professor of biology at Penn State University and the leader of the research team, half of the newly added skink species already may be extinct or close to extinction, and all of the others on the Caribbean islands are threatened with extinction. The researchers found that the loss of many skink species can be attributed primarily to predation（捕食） by the mongoose（猫鼬） -- an invasive predatory mammal that was introduced by farmers to control rats in sugarcane（甘蔗） fields during the late 19th century. The research team reports on the newly discovered skinks in a 245-page article published April 30 in the journal Zootaxa.

About 130 species of reptiles from all over the world are added to the global species count each year in dozens of scientific articles. However, not since the 1800s have more than 20 reptile species been added at one time. Primarily through examination of museum specimens, the team identified a total of 39 species of skinks from the Caribbean islands, including six species currently recognized, and another nine named long ago but considered invalid until now. Hedges and his team also used DNA sequences, but most of the taxonomic（分类的） information, such as counts and shapes of scales, came from examination of the animals themselves.

"Now, one of the smallest groups of lizards in this region of the world has become one of the largest groups," Hedges said. "We were completely surprised to find what amounts to a new fauna（动物群） , with co-occurring species and different ecological types."

He said some of the new species are six times larger in body size than other species in the new fauna.

Hedges also explained that these New World skinks, which arrived in the Americas about 18 million years ago from Africa by floating on mats of vegetation, are unique among lizards in that they produce a human-like placenta, which is an organ that directly connects the growing offspring to the maternal tissues that provide nutrients.

"While there are other lizards that give live birth, only a fraction of the lizards known as skinks make a placenta and gestate offspring for up to one year," Hedges said.