Sphaerodactylus Research Articles

Population genetic structure and species delimitation of a widespread, Neotropical dwarf gecko

Amazonia harbors the greatest biological diversity on Earth. One trend that spans Amazonian taxa is that most taxonomic groups either exhibit broad geographic ranges or small restricted ranges. This is likely because many traits that determine a species range size, such as dispersal ability or body size, are autocorrelated. As such, it is rare to find groups that exhibit both large and small ranges. Once identified, however, these groups provide a powerful system for isolating specific traits that influence species distributions. One group of terrestrial vertebrates, gecko lizards, tends to exhibit small geographic ranges. Despite one exception, this applies to the Neotropical dwarf geckos of the genus Gonatodes. This exception, Gonatodes humeralis, has a geographic distribution almost 1,000,000 km2 larger than the combined ranges of its 30 congeners. As the smallest member of its genus and a gecko lizard more generally, G. humeralis is an unlikely candidate to be a wide-ranged Amazonian taxon. To test whether or not G. humeralis is one or more species, we generated molecular genetic data using restriction-site associated sequencing (RADseq) and traditional Sanger methods for samples from across its range and conducted a phylogeographic study. We conclude that G. humeralis is, in fact, a single species across its contiguous range in South America. Thus, Gonatodes is a unique clade among Neotropical taxa, containing both wide-ranged and range-restricted taxa, which provides empiricists with a powerful model system to correlate complex species traits and distributions. Additionally, we provide evidence to support species-level divergence of the allopatric population from Trinidad and we resurrect the name Gonatodes ferrugineus from synonymy for this population.

XX/XY Sex Chromosomes in the South American Dwarf Gecko (Gonatodes humeralis).

Sex-specific genetic markers identified using restriction site-associated DNA sequencing, or RADseq, permits the recognition of a species' sex chromosome system in cases where standard cytogenetic methods fail. Thus, species with male-specific RAD markers have an XX/XY sex chromosome system (male heterogamety) while species with female-specific RAD markers have a ZZ/ZW sex chromosome (female heterogamety). Here, we use RADseq data from 5 male and 5 female South American dwarf geckos (Gonatodes humeralis) to identify an XX/XY sex chromosome system. This is the first confidently known sex chromosome system in a Gonatodes species. We used a low-coverage de novo G. humeralis genome assembly to design PCR primers to validate the male-specificity of a subset of the sex-specific RADseq markers and describe how even modest genome assemblies can facilitate the design of sex-specific PCR primers in species with diverse sex chromosome systems.

Geographic variation in Sphaerodactylus notatus Baird

Seven nominal species of geckos of the genus Sphaerodactylus are known form the Bahama Islands. Of these, two ( decoratus Garman and anthrocinus Cope) differ from the remaining five in having combinations of characters which differentiate them from the balance of the species, all of which have a certain community of characters. The affinities of anthracinus are with Hispaniolan and Cuban members of the genus (SCHWARTZ, 9), whereas decoratus has two Cuban subspecies (SCHWARTZ, 8). The remaining five forms ( notatus Baird, corticolus Garman, mariguanae Cochran, inaguae Noble and Klingel, caicosensis Cochran) are alike in that they all possess large, keeled, imbricating dorsals and smooth ventrals; corticolus , mariguanae , and caicosensis have keeled gular scales while notatus and inaguae have these scales smooth. At least mariguanae and corticolus are large forms (snout-vent lengths up to 40 mm); caicosensis is somewhat smaller (snout-vent length 31 mm). Of the seven Bahaman species, I have collected all but corticolus , and through the efforts of Dennis R. Paulson, I have seen specimens of this species very freshly preserved. The present paper will deal exclusively with the two species notatus and inaguae , which have keeled and imbricating dorsals, smooth gulars, and smooth ventrals.

Defensive Strategies of Puerto Rican Dwarf Geckos (Sphaerodactylus macrolepis) Against Invasive Fire Ants

Abstract: Invasive species present challenges to native organisms and offer unique opportunities to examine adaptations to novel stressors. We studied behavioral responses to invasive Red Imported Fire Ants (Solenopsis invicta) in native Puerto Rican Dwarf Geckos (Sphaerodactylus macrolepis) on Guana Island, British Virgin Islands. Geckos were exposed to no fire ants, few fire ants, or many fire ants. Solenopsis invicta was aggressive toward the geckos and the foraging ants frequently stung Dwarf Geckos, even when far from the mound. Dwarf Geckos displayed an array of anti-ant behaviors including consuming fire ants, flicking ants away with their limbs and/or tail, and rapidly fleeing attacking ants. These behaviors were elicited more frequently when more fire ants were encountered. Despite being stung often and by as many as nine fire ants, none of the tiny geckos died. Future research could usefully explore potentially delayed effects of fire ant envenomation and the impacts of fire ants on these geckos...

Cryptic species, taxonomic inflation, or a bit of both? New species phenomenon in Sri Lanka as suggested by a phylogeny of dwarf geckos (Reptilia, Squamata, Gekkonidae, Cnemaspis)

We evaluated the status of 16 of 22 recognized Sri Lankan Cnemaspis Strauch species, and flagged overlooked diversity with two mitochondrial (cyt b & ND2) and two nuclear markers (RAG1 & PDC) totalling 2829 base pairs. A fossil-calibrated timetree and sampling of other South Asian Cnemaspis provide insights into the diversification of the genus in peninsular India and Sri Lanka. Phylogenetic analyses consistently inferred two broad clades within South Asian Cnemaspis, with Sri Lankan species in two clades, which we call the podihuna and kandiana clades. Each Sri Lankan clade as a whole is sister to Indian taxa and nested within Indian lineages. Cnemaspis modigliani Das from Indonesia is a member of the kandiana clade. This suggests a minimum of two dispersal events between India and Sri Lanka and one between Sri Lanka/India and South-east Asia. South Asian Cnemaspis date back to at least the Eocene, in Sri Lanka to the early Miocene, with late Miocene diversification in the kandiana clade. All but one of the named species we sampled is likely to be valid, and 10 divergent unnamed lineages may warrant specific recognition. A resolution of Sri Lankan Cnemaspis taxonomy will require thorough sampling and the use of both morphological and molecular data.

A new species of the genus Microgecko Nikolsky, 1907 (Sauria: Gekkonidae)from southern Iran.

The dwarf geckos of the recently revived genus Microgecko Nikolsky, 1907 comprise four species, ranging from western Iran to northwestern India. Iran hosts three species of the four recognized species of the genus Microgecko. Here, we describe a new species of this genus based on two and single specimens from southeastern and southern Iran, respectively. Combinations of scalation characters and distinct morphology, coloration and habitat peculiarities in calcareous mountains distinguish Microgecko chabaharensis sp. nov. from its congeners. Detailed information and an updated identification key for the genus Microgecko are also presented.

Microgecko helenae helenae Nikolsky, 1907 (Sauria: Gekkonidae) Extends Its Range to the Southern Zagros Mountains, South of Iran

During herpetological field work on the dwarf geckos of the Zagros Mountains in Fars Province, ten specimens of Microgecko helenae helenae were collected from two new habitats in western and southwestern parts of this province in the southern Zagros Mountains. The new locality in the Varavi Mountain is the southernmost record for this gecko in Iran. All of the collected specimens have a uniform dorsal pattern with two dorsolateral series of white spots. As a unique morphological character, the regenerated portion of tail in specimens with autotomized tail is uniformly yellow. Detailed morphology of the new specimens was compared with those of previous studies. Distribution, habitat types and taxonomy of M. h. helenae in the Zagros Mountains are also discussed.

A molecular phylogeny of Afromontane dwarf geckos (Lygodactylus) reveals a single radiation and increased species diversity in a South African montane center of endemism

Afromontane habitats throughout eastern sub-Saharan Africa support remarkable levels of microendemism. However, despite being the subject of decades of research interest, biogeographical patterns of diversification throughout this disjunct montane system still remain largely unknown. We examined the evolutionary relationships of diurnal dwarf geckos (Lygodactylus) from several Afromontane regions throughout southeastern Africa, focusing primarily on two species groups (rex and bonsi groups). Using both mitochondrial and nuclear markers, we generate a molecular phylogeny containing all members of the rex and bonsi groups, to evaluate the monophyly of these groups along with previous biogeographic hypotheses suggesting independent southward invasions into the greater Drakensberg Afromontane center of endemism in northeastern South Africa by each group. Our results provide no support for these taxonomic and biogeographic hypotheses, and instead reveal geographically circumscribed patterns of diversification. One clade is restricted to the highlands of southern Malawi and northern Mozambique and the other to the greater Drakensberg region of northeastern South Africa and Swaziland. Interestingly, L. bernardi from the Nyanga Highlands of eastern Zimbabwe is nested within the primarily savanna-dwelling capensis group. We use Bayesian species delimitation methods to evaluate species limits within the greater Drakensberg clade, which support the elevation of the subspecies of L. ocellatus and L. nigropunctatus, thus bringing the total to eight species within a relatively confined geographic area. These results further highlight the greater Drakensberg Afromontane region as both an important center of endemism, as well as a center of diversification contributing to the accumulation of southern Africa’s rich species diversity.

The embryology of the retinal pigmented epithelium in dwarf geckos (Gekkota: Sphaerodactylinae): a unique developmental pattern.

BackgroundThe retinal pigmented epithelium (RPE) is a rounded shaped structure in almost all lizards. In the New World dwarf geckos, this structure shows an unusual morphology. In addition to this ocular character, we describe notable differences in the development of these geckos in comparison with available developmental staging tables for other geckos and squamate reptiles.ResultsWe identified two main patterns of development of the RPE for squamates. These patterns were mapped onto a metatree of concordant hypotheses of squamates based on molecular data. During post-ovopositional stages the representative species of sphaerodactyls exhibit a RPE layer that transforms gradually from an ovoid form into the generalized spherical form. Sphaerodactyls are the only group of squamates in which this pattern is known.ConclusionsThis transition might be circumstantial evidence that the accessory RPE plays a role in providing additional protection for their apomorphic concaviclivate temporal fovea. We also report the presence of conjunctival papillae in a developmental stage prior to the formation of scleral ossicles. This developmental progression is similar to that of birds and turtles.

Does dichromatism variation affect sex recognition in dwarf geckos?

As visual signals play a role in sex recognition among dwarf geckos (Sphaerodactylus), behavioral adaptations may counterbalance the lack of visual recognition cues in monochromatic species. Data from social interactions in captivity of 10 species were analyzed to evaluate a qualitative model, developed to explain the influences of dichromatism variation on behaviors related to sex recognition. The model, based on recognition theory, aimed to link the changes in behavioral mecanisms triggered by loss of recognition cues with the fitness consequences of different tactics to approach a conspecific of unknown sex; it suggested that uncertainty about conspecifics’ sex in monochromatic species could favor the display of ambivalent signals due to multiple potential advantages: assisting recognition by eliciting homotypical behaviors in social partners, solving fitness-reducing conflicts faster, reaping the benefits when meeting conspecifics of opposite sex, reducing cost associated with courtship displays and benefiting females by providing a reliable male quality indicator. In agreement with the model, males used courtship and threat signals unequivocally in dichromatic species, ambivalently in monochromatic species, and conditionally on opponent phenotype in species with two male morphs. Loss of visual recognition cues is suggested as an important and probably widespread source for the origin of similarity between sexual and aggressive signals.

Range extension of the least gecko, Sphaerodactylus glaucus Cope, 1865 (Squamata: Sphaerodactylidae) in Oaxaca, Mexico

An adult Collared Dwarf Gecko, Sphaerodactylus glaucus, was found in Parque Nacional Lagunas de Chacahua, Cerro Hermoso, municipality of San Pedro Tututepec, Oaxaca, Mexico, at an elevation of 72 m. This specimen represents a new municipality record and the westernmost distribution of the species on the Pacific Coast of Mexico.

Current Status of Mammals and Reptiles at Hub Dam Area, Sindh / Balochistan, Pakistan

During the present study in 2012, a total of twenty four mammalian species were recorded belonging to 5 orders and 10 families; out of these, 8 species are less common, 2 species are rare, while 14 species are common in Hub Dam area. Twenty five reptilian species belonging to 3 orders and 12 families were also recorded from the area. Three species of mammalian Urial (Ovis vignei), Chinkara/Indian Gazelle (Gazella bennettii) and Jungle Cat (Felis chaus), one reptilian species Common Krait (Bungarus caeruleus) were recorded as rare from the study area during 2012. During the present study, nine mammalian species Wild Goat/Sindh Ibex (Capra aegagrus), Urial (Ovis vignei), Chinkara/Indian Gazelle (Gazella bennettii), Indian Hedgehog (Paraechinus micropus), Cape Hare (Lepus capensis), Little Indian Field Mouse (Mus booduga), House Shrew (Sorex thibetanus), Balochistan Gerbil (Gerbillus nanus) and Indian Gerbil (Tatera indica) and two reptilian Warty Rock Gecko (Cyrtodactylus kachhensis kachhensis) and Banded Dwarf Gecko (Tropiocolotes helenae) were recorded from the area. As regards threats to mammals and reptiles, these are affected by disturbance. Efforts are being made to conserve the important mammals and reptiles particularly in the protected area especially at Hub Dam.

Colonization of islands in the Mona Passage by endemic dwarf geckoes (genus Sphaerodactylus) reconstructed with mitochondrial phylogeny

Little is known about the natural history of the Sphaerodactylus species endemic to the three islands located in the Mona Passage separating the Greater Antillean islands of Hispaniola and Puerto Rico. In this study, parts of two mitochondrial genes, 16S rRNA and 12S rRNA, were sequenced to determine the relationships between the sphaerodactylids that live in the Mona Passage and other Caribbean species from the same genus. While the main goal was to identify the biogeographical origin of these species, we also identified a genetically distinct type of dwarf gecko that warrants future evaluation as a possible new species. According to the reconstructed phylogenies, we propose a stepwise model of colonization wherein S. nicholsi from southwestern Puerto Rico or a very close ancestor gave rise through a founder event to Sphaerodactylus monensis on Mona Island. In a similar fashion, S. monensis or a very close ancestor on Mona Island gave rise to S. levinsi on Desecheo Island. This study also suggests that the most recent common ancestor between the species from the islands in the Mona Passage and Puerto Rico existed approximately 3 MYA.

A new species of Lygodactylus (Squamata: Gekkonidae) endemic to Mount Namuli, an isolated 'sky island' of northern Mozambique.

A new species of high elevation dwarf gecko (Gekkonidae: Lygodactylus) is described from Mount Namuli, northern Mozambique. This new species is distinguished from other closely related species in the genus Lygodactylus by body size, scalation, and color, and is genetically divergent from congeners. The species is most similar genetically and morphologically to Lygodactylus rex, the King Dwarf Gecko, which is endemic to Mount Mulanje, Malawi. Mount Mulanje and Mount Namuli are two of several understudied inselbergs forming the southern limit of the Afromontane archipelago in Malawi and Mozambique. The sister taxon relationship of the dwarf gecko species on Mount Mulanje and Mount Namuli illustrates the historical biogeographic connections between these inselbergs, a pattern which is emerging with continued work in this region. The discovery of this new species adds to a growing list of species unique to Mount Namuli, and further establishes this montane region as a conservation priority.

Social behavior of dwarf geckos (Sphaerodactylus): a comparative repertoire

Variation in sexual dichromatism of dwarf geckos may affect the ability to use visual signals in sex recognition. Social interactions of nine species of dwarf geckos, covering the range of color pattern variation, were staged and videotaped in captivity. Sequential and nonsequential behavioral data allowed comparing species repertoires, uncovering associations between behavioral traits and variation in dichromatism, exploring potential sex recognition cues, and exploring potential functions of the most common courtship and threat signals. Males and females shared a similar social behavioral repertoire but some homotypical behaviors and different behavioral profiles were common to all species. A correlation between the use of threat signals and variation in sexual dichromatism was the most noticeable behavioral correlate among species. Whereas males from dimorphic species restricted the use of threat signals to agonistic contexts, males from monochromatic species displayed threat signals in agonistic and sexual contexts. All species seemed able to recognize conspecifics' sex through visual cues, but semiochemicals seemed to provide the most reliable sex recognition cues. Contextual and sequential data reinforced the previous suggestion that headbobs and stiff are the main courtship and threat signals, respectively. Stiff in monochromatic species, however, may have been co-opted to play a role in courtship as well.

Westernmost Record of Khuzestan Dwarf Gecko Tropiocolotes helenae helenae (Nikolsky, 1907) (Sauria: Gekkonidae) from Kermanshah Province, Western Iran

Based on extensive and long-term field work in western regions of the Iranian Plateau from March 2008 to April 2010, five specimens of Tropiocolotes helenae helenae (Nikolsky, 1907) were collected from stony hills around Qasr-e-Shirin and Sarpol-e-Zahab, in Kermanshah Province. The collected specimens were examined based on metric, meristic and pholidotic characters and compared with other specimens of this taxon from Lorestan and Ilam Provinces. Furthermore, the presence of two pores in basal, ventral part of the tail in both sexes in T. helenae was noticed and their possible adaptive value discussed.

Autotomy, tail regeneration and jumping ability in Cape dwarf geckos (Lygodactylus capensis) (Gekkonidae)

Many studies have examined the effect of caudal autotomy on speed and behaviour of lizards escaping over horizontal surfaces, but there have been few studies on lizards escaping over vertical surfaces and, in particular, species that jump between surfaces. We examined jumping by the Cape dwarf gecko (Lygodactylus capensis) in terms of individuals’ varying states of tail autotomy and regeneration. Although longer jumps were less likely to be successful (i.e. the animal would not successfully grip the surface and fell to the ground), there was no difference in the distance over which animals with full and partial tails would attempt to jump. Both recently autotomized individuals and individuals with intact tails successfully jumped up to nine times their body length (snout–vent length). The jumping ability of L. capensis was therefore clearly not negatively impaired by tail loss, presumably because the geckos are using their hind legs to propel their jump. Their tails may, however, be important to control their landing as well as their locomotion on vertical surfaces. The high observed frequency of tail loss, coupled with rapid and complete regeneration (including the scansorial tail tip), suggests that caudal autotomy is an important survival tactic in this species.

Autotomy, Tail Regeneration and Jumping ability in Cape Dwarf Geckos (Lygodactylus capensis) (Gekkonidae)

Many studies have examined the effect of caudal autotomy on speed and behaviour of lizards escaping over horizontal surfaces, but there have been few studies on lizards escaping over vertical surfaces and, in particular, species that jump between surfaces. We examined jumping by the Cape dwarf gecko (Lygodactylus capensis) in terms of individuals’ varying states of tail autotomy and regeneration. Although longer jumps were less likely to be successful (i.e. the animal would not successfully grip the surface and fell to the ground), there was no difference in the distance over which animals with full and partial tails would attempt to jump. Both recently autotomized individuals and individuals with intact tails successfully jumped up to nine times their body length (snout–vent length). The jumping ability of L. capensis was therefore clearly not negatively impaired by tail loss, presumably because the geckos are using their hind legs to propel their jump. Their tails may, however, be important to control their landing as well as their locomotion on vertical surfaces. The high observed frequency of tail loss, coupled with rapid and complete regeneration (including the scansorial tail tip), suggests that caudal autotomy is an important survival tactic in this species.

The Microanatomy of Regenerated Bristled Receptors of Two Gecko Species, Cyrtopodion fedtschenkoi and Sphaerodactylus roosevelti (Reptilia: Gekkonidae)

The microanatomy of regenerated cutaneous bristled receptors of two geckos, Cyrtopodion fedtschenkoi and Sphaerodactylus roosevelti , were described and compared with the same data on the iguanian lizards. The small receptors of the geckos examined (13 – 19 μm in diameter) consist of a dermal papilla and one or two modified germinative cells. Every receptor has up to three very thin bristles of an acellular structure. Comparison of the size, microanatomy and histochemistry of regenerated bristles in the receptors of agamids, Madegascan iguanas, and geckos makes it possible to assume the independent origin of the bristled receptors in the lizard groups listed.

Nic Bishop Lizards (review)

Reviewed by: Nic Bishop Lizards Deborah Stevenson Bishop, Nic. Nic Bishop Lizards; written and illus. with photographs by Nic Bishop. Scholastic, 2010. 48p. ISBN 978-0-545-20634-1 $17.99 R* Gr. 3-6. Lizards: they're scaly, they're cold-blooded, and, in the hands of master nature documentarian Bishop, they're both gorgeous and fascinating. You'd think the continued excellence of the Nic Bishop photoessay series (Nic Bishop Butterflies and Moths, BCCB 5/09, etc.) would have made it hard for new entries to impress, but this one is just as absorbing and gasp-worthy as the first. The text is confiding and stylish, with a personal approach that's hard to resist: the dwarf gecko "is small enough to curl up on your thumbnail.… In fact, it has most of the same organs as you." Not only is the prose rich with just such telling detail, it manages to answer key reader questions just as the reader formulates them, covering an amazing amount of lizard-inhabited ground in its modest page count. Bishop's already stunning photographs are helped by a layout that's particularly thoughtfully crafted, so that poses vary pleasingly from spread to spread and background colors are chosen with meticulous care, setting each photograph like a jewel. Even veteran viewers of the arresting grotesquerie of the lizard world will see some new and fresh images. Several photographs of chameleons display some of their lesser-snapped color phases: an elegant veiled chameleon, zapping his tongue out unerringly for cricket collection, is tastefully patterned in muted Santa Fe colors; a panther chameleon frontin' for his lady glows with sunset orange. In a magical, slightly comical foldout sequence, a basilisk bipedally scampers across the water surface with the haste, inclined posture, and intent focus of a commuter chasing after a departing bus. As with the rest of this series, this title will sell itself—just silently show off a few pages of lizardy goodness and you won't be able to keep the book on the shelf. A closing note offers some intriguing detail about Bishop's photograpy process; an index, a brief list of further reading, and a short glossary are also included. Copyright © 2010 The Board of Trustees of the University of Illinois