Field and laboratory work by a group of zoologists led by Omar Torres-Carvajal from Museo de Zoología QCAZ, Pontificia Universidad Católica del Ecuador, has resulted in the discovery of a new species of blunt-headed vine snake from the Chocoan forests in northwestern Ecuador. This region is part of the 274,597 km2 Tumbes-Chocó-Magdalena hotspot that lies west of the Andes. The study was published in the open access journal ZooKeys.
Blunt-headed vine snakes live in an area comprising Mexico and Argentina, and are different from all other New World snakes in having a very thin body, disproportionately slender neck, big eyes, and a blunt head. They live in trees and hunt frogs and lizards at night. The new species described by Torres-Carvajal and his collaborators was named Imantodes chocoensis and increases the number of species in this group of snakes to seven.
Snakes collected as far back as 1994 and deposited in several Ecuadorian and American natural history museums were also examined. The authors were soon surprised with an interesting discovery. Some individuals from the Ecuadorian Chocó lacked a big scale on their face that is present in all other blunt-headed vine snakes from the New World. Other features, as well as DNA evidence, indicate that these Chocoan snakes actually belong to a new species. DNA data also suggest that its closest relative is a species that inhabits the Amazon on the other side of the Andes.
'One possible explanation for the disjunct distribution between the new species and its closest relative is that the uplift of the Andes fragmented an ancestral population into two, each of which evolved into a different species, one in the Chocó region and the other in the Amazon' said Dr Torres-Carvajal.