Geckolepis | |
---|---|
Geckolepis megalepis | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Squamata |
Family: | Gekkonidae |
Subfamily: | Uroplatinae |
Genus: | Geckolepis Grandidier, 1867 [1] |
Type species | |
Geckolepis typica Grandidier, 1867 [1] | |
Geckolepis is a genus of geckos, commonly referred to as fish scale geckos, which are endemic to Madagascar and the Comoro Islands. They are nocturnal, arboreal, insectivorous lizards, found in primary and secondary forest, as well as degraded habitats. They are best known for their ability to lose their skin and scales when grasped by a predator.
The scales of Geckolepis are imbricated (overlapping) and ossified. Histological studies on the scales were performed as early as 1911 by Wilhelm Josef Schmidt. [2] Schmidt noted the heterogeneity and imbrication of the scales, [2] which makes meristics difficult on Geckolepis. [3] Schmidt noted that the imbrication of the scales was a result of their folding, essentially being bilayered rather than monolayered. He showed also that the scale centres are ossified, formed from irregular crystals, which he illustrated in some detail. [2] In their micro-CT scans, Scherz et al. [3] found that the scales of G. megalepis and other species have the same degree of x-ray attenuation as bone, and concluded that this suggested the presence of osteoderm as well. They noted that, like in Schmidt's illustrations, a zone toward the tip of the scales lacks ossifications as visible in micro-CT scans. [3] Paluh et al. [4] studied the osteoderm of Geckolepis cf. maculata using micro-CT and histology, and compared it to other geckos known to have osteoderm, namely Gekko gecko and Tarentola mauritanica . [5] They found that the osteoderms differ strongly from those of the other gecko species that possess them, and represent a third independent convergent derivation of osteoderm in geckos. The osteoderm of Geckolepis somewhat resembles that of the Gerrhosauridae or 'plated lizards'.
The scales of Geckolepis were known to come off already in the 19th century; Alfred Voeltzkow in 1983 described capturing specimens with bundles of cotton to avoid the scales coming off. [6] Once lost, scales are regenerated, and eventually the regenerated scales are indistinguishable from original ones. [3] [7] The mechanism for this scale autotomy and the subsequent regeneration is not well understood, but was studied by C. Schubert and colleagues. [8] [7] These studies showed that it is not only the scales that are shed in the 'dermolytic autotomy' of Geckolepis, but rather, there is a preformed splitting zone between the integument and the underlying connective tissue. They also showed that the dermolytic process is an active one, wherein a network of myofibroblasts in the splitting zone probably contract, followed by vasoconstriction to minimise blood loss. [8] Their findings were questioned by Aaron M. Bauer and colleagues, but only based on comparative evidence from other geckos, which all have splitting zones within the integument, and not below it. [9] [10] Indeed, no subsequent studies have yet looked at this mechanism again, but there have been repeated calls for such investigation, especially as the regenerative properties may have relevance for human medicine. [3] [4]
The genus Geckolepis has difficult taxonomy due to variable pholidosis. [11] [12] Recent taxonomic and genetic investigation have shown that several cryptic species are present in this genus. [11] [13] In 2016, Hawlitschek et al. resurrected G. humbloti from synonymy with G. maculata , as a species endemic to the Comoro Islands. [14] In 2017, Scherz et al. (2017) described G. megalepis from the limestone pinnacle karst formations of Ankarana National Park—this species has larger scales than all other members of the genus, but it was also identified based on its osteology. [3] The taxonomic identity of G. maculata remains uncertain. [3]
The following five species are recognized: [14] [15]
Lygodactylus is a genus of diurnal geckos with 82 species. They are commonly referred to as dwarf geckos. They are mainly found in Africa and Madagascar although two species are found in South America. Lygodactylus picturatus, the best known species, is found in Kenya and commonly known as the white-headed dwarf gecko. Recently, illegal importation from Tanzania of brightly colored, Lygodactylus williamsi, known as electric blue geckos, has been gaining attention for Lygodactylus geckos in the reptile trade.
Paroedura is a genus of geckos, endemic to Madagascar and the Comoros. These geckos are typically terrestrial, though the young of most species can climb until they are too heavy for their feet to support.
Uroplatus is a genus of geckos, commonly referred to as leaf-tail geckos or flat-tailed geckos, which are endemic to Madagascar and its coastal islands, such as Nosy Be. They are nocturnal, insectivorous lizards found exclusively in primary and secondary forest.
Blaesodactylus is a genus of six species of lizards, endemic to Madagascar, commonly known as velvet geckos, and formerly considered part of the genus Homopholis.
Paragehyra is a genus of lizards in the family Gekkonidae (geckos). The genus is endemic to Madagascar.
Calumma is a genus of chameleons, highly adapted and specialised lizards, in the family Chamaeleonidae. The genus is endemic to the island of Madagascar. One species, formerly known as Calumma tigris, was transferred to the genus Archaius in 2010, upon the discovery of its closer relation to Rieppeleon—one of several genera referred to collectively as "leaf" or "pygmy" chameleons—rather than to Calumma. The earliest known fossil of the genus is of Calumma benovskyi, from early Miocene Kenya, showing that the genus likely originated on mainland East Africa. The genus includes one of the heaviest and longest chameleon species, the Parson's chameleon.
Stumpffia is a genus of microhylid frogs that are endemic to Madagascar. They are mostly brown frogs that typically live among leaf litter. S. contumelia has a snout–vent length of about 8–9 mm (0.31–0.35 in), making it one of the world's smallest frogs, and several others in the genus are only slightly larger. The largest species is no more than 28 mm (1.1 in).
Xenotyphlops grandidieri is a species of blind snake in the family Xenotyphlopidae. The species is endemic to Madagascar. There are no subspecies that are recognized as being valid.
Uroplatus sikorae, commonly referred to as the mossy leaf-tailed gecko or the southern flat-tail gecko, is a species of lizard in the family Gekkonidae. The species is endemic to Madagascar. It is a CITES II protected animal due to habitat loss.
Geckolepis megalepis is a species of gecko found in the limestone karst formations of northern Madagascar. It is the first addition to the Geckolepis genus since 1942. This species of gecko has the largest scales of any known gecko and can detach them as a defence mechanism when a predator attacks, leaving the predator with a mouthful of scales rather than itself; a character it shares with all other members of the genus Geckolepis. Its scales were reported to come away with greater ease than its congeners.
Geckolepis humbloti, commonly known as the Comoran fish scale gecko, is a nocturnal species of lizard in the family Gekkonidae. It is endemic to Grande Comore in the Comoros.
Grandidier's gecko is a species of lizard in the family Gekkonidae. It is endemic to Madagascar.
Grandidier's dwarf gecko is a species of lizard in the family Gekkonidae. The species is endemic to Madagascar.
The Ibity ground gecko is a species of lizard in the family Gekkonidae. Though initially described in 1998 as a subspecies of the Mocquard's Madagascar ground gecko, it has been recognized as a distinct species within the species complex since 2008. It is endemic to Ibity and Itremo in the Central Highlands of Madagascar, and is named after Mount Ibity where it was first discovered.
Uroplatus pietschmanni, known commonly as the cork-bark leaf-tail gecko, the cork bark leaftail gecko, and the spiny leaf-tailed gecko, is a species of lizard in the family Gekkonidae. The species is endemic to Madagascar.
Andolalao Rakotoarison is a Malagasy herpetologist.
Paroedura guibeae, Guibé's ground gecko, is a species of lizard in the family Gekkonidae. The species was formerly synonymized with Paroedura bastardi, but a study in 2021 found that it represents a separate species within the species complex. It is endemic to Madagascar.
Paroedura rennerae is a species of lizards in the family of the Gekkonidae. Members of this species were formerly assigned to Paroedura bastardi, but a study in 2021 found that they represent a separate species within the species complex. It is endemic to Madagascar, where it occurs in a variety of habitats.
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