Big-scaled Dwarf Gecko

Appearance

Additionally, the big-scaled dwarf gecko displays sexual dimorphism with males being larger than females. Furthermore, size, particularly snout vent length, differs depending on the location of the lizard. Those in Puerto Rico are larger than their US Virgin Island counterparts. The big-scaled dwarf gecko is commonly seen on the forest floor of the islands, in their preferred microhabitat of leaf litter. Additionally, the species also exhibits significant sexual dichromatism in which the male and females are unique in coloration. A main difference is the colored head found in males but is lacking in females.

Another notable characteristic of the big-scaled dwarf gecko is their preference for cooler environments due to their miniature size which increases their rate of desiccation. Their total evaporative water loss grows with temperature and so these lizards’ behaviors and location alters during the day in order to seek out appropriate microhabitats.

In terms of appearance, the big-scaled dwarf gecko has its notable imbricate dorsal scales, which overlap over each other. Located in the gular region, specifically the throat, the lizard displays keeled scales. As these scales travel down the length of the body, they become smooth at around the belly region as well as at the tail. It is worth mentioning that in addition to sexual dimorphism, big-scaled dwarf geckos are sexually dichromatic, with each sex displaying a separate set of colors. Males have less patterned markings, no rings around the gular area, and have a colored head, which can differ in shade. The head can be many different colors, from blue all the way to a brownish-orange. Unlike the males, the females never exhibit this sort of coloration on their head. Females, though, have distinct markings that males lack such as the canthal line that starts at their snout and ends at their neck.

Distribution

Big-scaled dwarf geckos are endemic to various islands in the Caribbean such as Puerto Rico and the US Virgin Islands. They prefer dry, arid climates like rocky outcroppings. Due to their water retention ability, they actually thrive in dry areas and environments.

The specific microhabitats that the S. macrolepis occupy are the beach vegetation and rain forest floors. These two microhabitats do dictate certain characteristics of the lizard, with those from the coastal region being more visual attuned to higher light levels than those from the forest floor. This distinction is made clearer in the Visual acuity section in physiology.

It is also noteworthy that the S. macrolepis occupy 90% of St. Croix, being a very common sight on the island. Compared to its relative, S. beattyi, who also lives on St. Croix, the S. macrolepis lives in wetter habitats since it is more prone to desiccation.

Status

Currently, the "Sphaerodactylus macrolepis" is classified as least concern by the IUCN. This classification was completed in 2015 in which the big-scaled dwarf gecko was found in stable population. They are common throughout the area around Puerto Rico and face no major threats to their existence.

Reproduction

Noting the small size of the big-scaled dwarf gecko, they are particularly prone to dehydration. Of the age groups, the young offspring and hatchlings are most affected by this problem. This issue can be circumvented by hatching in colder seasons.

Food

The diet of the big-scaled dwarf gecko is mostly tiny arthropods such as springtails. Additionally, they have been documented eating "drosophila" fly larvae and adults.

Predators

While predation on the islands that the big-scaled dwarf gecko occupies is not extremely high, they are still hunted by other organisms such as the "Anolis pelchullus", more commonly known as the Puerto Rican grass bush anole. The Puerto Rican grass bush anole is considered small by anole standards, with females measuring in at about 38mm. However, the S. macrolepis is even smaller, hence the title “dwarf”. In comparison, the average big-scaled dwarf gecko sits around 20mm and is still smaller than a “small” anole. As such, predation of this sort can occur.

Additionally, it has been documented that the big-scaled dwarf gecko in the Virgin Islands region  are also hunted by birds such as the bridled quail dove. This predator prey relationship arises from a shared area of foraging. Both species are present on the forest floor.

Another predator of the Sphaerodactylus macrolepis is the Alsophis portoricensis, the Puerto Rican racer snake. The snake reacts with caudal luring, a type of wriggling movement when approaching prey, in the presence of S. macrolepis. This reaction is unique to this type of lizard and several other species.