A new species of iguana has been identified in the Caribbean after scientists analysed the DNA of individuals thought to be an introduced South American variety.
The Southern Antilles iguana, which lives on St Lucia, St Vincent and the Grenadines, was shown to form a distinct genetic group.
Known to humans for centuries, it was also found to have unique bodily features including horns on its nose, a high crest and dark brown eyes.
It is the fourth iguana type to be identified in the region in two years, as zoologists tear up the rule-book from previous research, which had classified each as the common green iguana.
Southern Antilles iguana: The species has been identified from two other varieties - or subspecies. Pictured above is a very rare Saint Lucia iguana, identified by its black bands. This has been named a subspecies of the new species.
Southern Antilles iguana: This is an older individual in the new species. It is also part of a subspecies, the Grenadines pink rhino iguana, Iguana insularis unsularis, which turns a pinkish white in old age
Fauna & Flora International (FFI), which announced the discovery, said work was already underway to protect the 'new' reptiles.
Two types identified last year, the very rare Saint Lucia iguana and Grenadines pink rhino iguana, have been named as variations of this species - or subspecies.
The former is identified by broad black bands across its body while the latter turns pinkish white in old age.
Zoologists think they may have overlooked the species previously as their juveniles are bright green, just like those of the invasive species, making them 'virtually indistinguishable' until they reach adulthood.
FFI senior conservation biologist Dr Jenny Daltry heralded the find as a breakthrough, but said more action must be taken to protect the reptiles.
'Caribbean iguanas are in grave danger because of invasive alien species, habitat loss and over-hunting for bushmeat and the pet trade,' she said. 'We know what needs to be done.'
Lesser Antillean iguana: It was initially thought only two iguanas lived in the Caribbean. One, the Lesser Antillean iguana, or Iguana delicatissima, is pictured above
Scientists think they may have missed the species as they look identical to the invasive common green iguana, Iguana iguana, when they are juveniles