1. Introduction

The brown anole is a small Neotropical lizard that has been recently introduced to Singapore in 2012 (Tan & Lim, 2012). It is native to Cuba and the Bahamas but has since been widely introduced and established around the world: Florida, Hawaii, Taiwan, Grand Cayman, Grenada, and Jamaica and recently, Singapore. Not all introduced populations come from their native source populations. In fact, brown anoles found in Grand Cayman, Grenada, Hawaii and Taiwan were brought in through secondary introductions from well-established populations in Florida (Kolbe et al., 2007). It is highly invasive in many countries but whether this exotic species will threaten the local Singapore biodiversity is yet to be determined.

2. Description

2.1 Coloration

The lizard’s skin color is controlled by melanophores and changes rapidly, often spanning their entire range of possible colors in only a few minutes, depending on the temperature, time of day, level of territorial aggression, or reproductive activity (Campbell, 2000). An example of how the anole changes coloration is that the lizard appears pale brown when warm, and darker brown to almost black when cool. This is because these ectothermic reptiles use darker colors to help absorb more heat from the sun when they are basking (Dailykos, 2013). The belly and throat are white and the edges of their eyelids are light beige (Norval et al., 2002).

Male color ranges from light gray to nearly jet-black, and plain-colored to covered dorsally with irregular dark patches or chevrons and a network of light lines. Mature females show a great change in colour as well, but usually possess a white dorsal stripe along the midline of their back. Along both sides of the line, black triangles fuse to form a diamond or zig-zag pattern that males lack (Campbell, 2001). Juveniles resemble females and it is difficult to distinguish between juvenile males and adult females.

3. Diagnosis

4. Distribution

4.1 Native & introduced regions

4.2 Invasion Pathways

5. Habitat

5.1 Trunk-ground ecomorphs

6. Biology

7. Alien species

7.1 Reasons for Invasiveness

7.1.1 Habitat generalist
7.1.2 Females can store sperms
7.1.3 Small numbers can establish large populations
7.1.4 Disperse across water
7.1.5 Strong hindlimbs

8. Negative impacts on native species

8.1 Reduced Arthropod Diversity in Taiwan

8.2 Altered Ant Community Structure in Southern Taiwan

8.3 Displacement of A. carolinensis in Florida

8.4 Competition-induced Habitat Shifts on A. conspersus in Grand Cayman

9. Taxonavigation

Order: Squamata
Family: Polychrotidae
Genus: Norops
Species: Norops sagrei
Synonyms: Anolis sagrei

9.2 Subspecies

10. Phylogenetic Tree