The skink (Trachylepis Maculata)

May 23, 2010 Features / Columnists, Interesting Creatures in Guyana

A skink on the prowlA skink on the prowl

Trachylepis maculata is a species of skink in the genus Trachylepis recorded from Demerara in Guyana, northern South America. It is placed in the genus Trachylepis, which is otherwise mostly restricted to Africa, and its type locality may be in error. It is an unstriped, olive-brown, greyish animal, with dark spots all over the body. Its taxonomic history is complex due to confusion with Trachylepis atlantica from the Atlantic Ocean island of Fernando de Noronha and doubts regarding its type locality.
T. maculata was first described, as Tiliqua maculata, by Gray in 1839 on the basis of three specimens said to be from Demerara, Guyana. On the same page, Gray described Tiliqua punctata from the island of Fernando de Noronha off Brazil. In 1887, the two names were considered by Boulenger to pertain to the same species, which was initially named Mabuya punctata but renamed Mabuya maculata by Anderson in 1900, because the latter name was preoccupied by an older name. In 1935, Dunn disputed that the two were identical, and reinstated Mabuya punctata as the name for the Noronha species, apparently unaware that the name is preoccupied, and considered maculata to be the same as Mabuya mabouya.
In 1946, Travassos again synonymized the two, naming the Noronha skink as Mabuya maculata. In the early 2000s, the matter was revisited by Mausfeld and Vrcibradic, who noted that the type specimens of punctata differs from maculata in having five instead of three keels on the dorsal scales; generally fewer scales; parietal scales separated, not in contact as in punctata; and fewer subdigital lamellae below the fourth finger and toe. Consequently, they regarded the two as representing distinct species and recommended that the Fernando de Noronha species be named Mabuya atlantica and the Guyana one Mabuya maculata. In 2002, it was realized that the genus Mabuya was not a natural grouping and a mainly African group of species which also includes the Fernando de Noronha skink was transferred to a separate genus, first named Euprepis and later Trachylepis. Since then, this species has been known as Trachylepis atlantica.
In 2009, Miralles and coworkers again considered the taxonomy of maculata, referring it to Trachylepis instead of Mabuya because the third supraocular and frontal are in contact, as in other species of Trachylepis. It also has auricular lobules and heavy keels on the dorsal scales. They were the first to use the current name combination, Trachylepis maculata.
The origin and nature of T. maculata are still unclear. The collection from Demerara which included T. maculata included various species that have not been found in Guyana again, including some restricted to Caribbean islands or to other parts of South America. Consequently, Mausfeld and Vrcibradic suggested that T. maculata may be the same as similarly coloured Caribbean Mabuya species or the Venezuelan Mabuya falconensis, but these differ from T. maculata in a number of characters, indicating their membership in Mabuya instead of Trachylepis. T. maculata may in fact have come from Guyana, perhaps inadvertently introduced into Guyana from Africa, and subsequently become extinct; alternatively, the three known specimens may have been collected in Africa. Among African Trachylepis, Trachylepis perrotettii is regarded as most similar to T. Maculata.
Skinks in general are said to be the most diverse group of lizards. They make up the family Scincidae which shares the superfamily or infraorder Scincomorpha with several other lizard families, including Lacertidae (the “true” or wall lizards). Scincidae is the largest of the lizard families with about 1200 species.
Skinks look roughly like true lizards, but most species have no pronounced neck and sport relatively small legs. Several genera (e.g., Typhlosaurus) have no limbs at all, others, such as Neoseps, have only reduced limbs. Often, their way of moving resembles that of snakes more than that of other lizards. The longer the digits, the more arboreal the species is.
A biological ratio exists that can determine the ecological niche of a given skink species. The SENI (Scincidae Ecological Niche Index) is a ratio based on anterior foot length at the junction of the ulna/radius-carpal bones to the longest digit divided by the snout-to-vent length (SVL). Skinks usually have long, tapering tails that can be shed and regenerated.
Most skink are medium sized with a length from the snout to the vent of up to 12 cm (4.7 in), although there are a few that grow to larger sizes, such as the Corucia, which can reach 35 cm (13.8″) from snout-to-vent. They are generally carnivorous and largely eat insects, including crickets, grasshoppers, beetles, and caterpillars. They also eat earthworms, snails, slugs, isopods, other lizards, and small rodents. Some species, particularly those favoured as home pets, have a more varied diet and can be maintained on a regimen of roughly 60 percent vegetables/leaves/fruit and 40 percent meat (Insects and Rodents).
Skinks are found in a variety of habitats worldwide, ranging from deserts to grasslands. Some species are endangered, such as the Chevron Skink in New Zealand, with less than 100 reports since first being identified in 1906.
Many species are good burrowers. There are more terrestrial or fossorial (burying) species than arboreal (tree-climbing) or aquatic species. Some are “sand swimmers”, especially the desert species, such as the mole skink in Florida. Most skinks are diurnal (day-active) and typically bask on rocks or logs during the day.
Approximately 45 percent of skink species are viviparous. Many are ovoviviparous (hatching eggs internally and giving birth to live offspring). Some, such as the Genus: Tiliqua and Corucia, give birth to live young through a mammal-like placenta attached to the female – viviparous matrotrophy. The approximately 55 percent of skink species are oviparous (egg-laying) give birth in small clutches.
Raccoons, foxes, possums, snakes, coatis, crows, cats, dogs, herons and hawks all are predators of skinks.
(Source: Wikipedia – The Free Online Encyclopedia)