island endemic – Anole Annals

Hi!

Turns out grad school eats up a lot of your time some weeks. Who knew!

So here is a pretty cool Caribbean anole this week. Anolis acutus, the Sharp Anole is endemic to St. Croix. These anoles are tan to olive in colour. Their dewlaps are white with a large yellow-orange blotch closer to the body. Males have an average SVL of 67mm and females, about 49mm.

Photo: Brett, iNaturalist

They are territorial and maintain hierarchies within their habitats. If an individual is removed, they become slightly agitated until the territory is taken over by a new anole or the individual returns (Ruibal & Philibosian, 1974). The adults also tend to be sedentary and have a perch height hierarchy, but exclude juveniles from occupied trees leaving them to find and occupy empty ones or live on the ground (Ruibal & Philibosian, 1974).

St Croix anoles appear to be eurythermal, meaning they have a broad temperature range (McManus & Nellis, 1973).

Photo: nolafrog, iNaturalist

Photo: Delano Lewis, iNaturalist

This week’s anole, Anolis sabanus, can only be spotted on the island of Saba (Dutch W.I.).

Also called the Saban anole, this tan to pale grey coloured species is sexually dimorphic with males being covered with black spots/patches at an SVL of 29-72mm and females having a dorsal stripe and an SVL of 23-25mm. Their dewlaps are green or orange tinted.

Photo: Mark Yokoyama

In 2016, there was an introduction of the anole on the neighbouring island of Sint Eustatius. They belong to the bimaculatus series of anoles which includes other island endemics like Anolis oculatus (from my home island of Dominica).

Gina Zwicky, New Orleans based herper, is currently working on a study to see if there is a link between parasite pressure and the rise of immunity in generations of this anole, examining if evidence can be found of fluctuating selection in a natural population. Anoles are incredibly useful for research with their genomes being readily available for reference, how quickly they adapt and other factors. Island endemics especially are great research subjects due to their isolation which helps to eliminate certain other variables.

Photo: iNaturalist

Tag: island endemic

#DidYouAnole – Anolis acutus

#DidYouAnole – Anolis sabanus