Patterns of girdle shape and their correlates in Australian limb-reduced skinks.

The evolution of limb reduction in squamates is a classic example of convergence, but the skeletal morphological patterns associated with it are underexplored. To provide insights on the biomechanical and developmental consequences of transitions to limb reduction, we use geometric morphometrics to examine the morphology of pectoral and pelvic girdles in 90 species of limb-reduced skinks and their fully limbed relatives. Clavicle shapes converge towards an acute anterior bend when forelimbs are lost but hindlimbs are retained-a morphology typical of sand-swimmers. This may either indicate functional adaptations to locomotion in fine substrates, or a developmental consequence of complete limb loss. The shape of limb-bearing elements of both girdles (coracoid and pelvis) instead closely mirrors limb reduction, becoming more simplified as undulation replaces limbed locomotion. Integration between girdles decreases in taxa lacking elements of the forelimbs but not hindlimbs, indicating differential selection on each girdle in response to distinct locomotory strategies. However, this pattern becomes less clear when considering phylogenetic history, perhaps because it is limited to one specific clade (Lerista). We show how the functional demands of locomotion can induce changes at different levels of organismal organization, including both external and internal structures.

Redescription of Thubunaea schukurovi Annaev, 1973 from Ablepharus chernovi, with notes on the members of Thubunaea (Spirurida: Physalopteridae) from the Palaearctic and Indomalayan realms.

The spirurid nematode Thubunaea schukurovi Annaev, 1973 (Physalopteridae) is redescribed by means of light microscopy and scanning electron microscopy from Ablepharus chernovi collected in Çamliyayla, Turkey. This is the first record of the species from this host and the first record of the genus Thubunaea from Turkey. The taxonomic status of the species of the genus Thubunaea from the Palaeacrtic and Indomalayan realms is reviewed based on their original morphological descriptions; as a result, Thubunaea dessetae Barus & Tenora, 1976, a parasite of Saara hardwickii (Gray) (Agamidae) in Afghanistan, is transferred to the genus Pseudabbreviata as Pseudabbreviata dessetae (Barus & Tenora, 1976) n. comb. Several species described in India, that is, Thubunaea singhi Deshmukh, 1969 and Thubunaea brooki Deshmukh, 1969, both from Hemidactylus brookii Gray (Gekkonidae), and Thubunaea aurangabadensis Deshmukh, 1969 and Thubunaea syedi Deshmukh, 1969, both from Hemidactylus giganteus Stoliczka, are considered members of the genus Physalopteroides; therefore, the following new combinations are proposed: Physalopteroides singhi, Physalopteroides brooki, Physalopteroides aurangabadensis and Physalopteroides syedi. Thubunaea hemidactylae Oshmarin & Demshin, 1972 from Hemidactylus frenatus Duméril & Bibron in Vietnam is considered a member of the genus Physalopteroides as P. hemidactylae (Oshmarin & Demshin, 1972) n. comb.

Activity patterns and reproductive behavior of the Critically Endangered Bermuda skink (Plestiodon longirostris).

The study of rare or cryptic species in zoos can provide insights into natural history and behavior that would be difficult to obtain in the field. Such information can then be used to refine population assessment protocols and conservation management. The Bermuda skink (Plestiodon longirostris) is an endemic Critically Endangered lizard. Chester Zoo's successful conservation breeding program is working to safeguard, increase and reinforce skink populations in the wild. A key aim of this program is to develop our understanding of the behavior of this species. In this study, using 24 h video recordings, we examined the daily activity patterns, basking behavior and food preferences of four pairs of Bermuda skinks. The skinks displayed a bimodal pattern of activity and basking, which may have evolved to avoid the strength of the midday sun in exposed habitats in Bermuda. Captive Bermuda skinks appear to prefer a fruit-based diet to orthopteran prey. We also documented their reproductive behavior and compared it against two closely related species. Although there were many similarities between the courtship and mating behaviors of the three species, there was a significantly shorter period of cloacal contact in the Bermuda skink. Oophagia was also documented for the first time in this species. This knowledge has enabled the evaluation of the current ex-situ management practices of this species, filled gaps in knowledge that would be challenging to obtain in the field, and enabled the enhancement of both animal husbandry and reproductive success for the conservation breeding program.

Enhanced short-wavelength sensitivity in the blue-tongued skink Tiliqua rugosa.

Despite lizards using a wide range of colour signals, the limited variation in photoreceptor spectral sensitivities across lizards suggests only weak selection for species-specific, spectral tuning of photoreceptors. Some species, however, have enhanced short-wavelength sensitivity, which probably helps with the detection of signals rich in ultraviolet and short wavelengths. In this study, we examined the visual system of Tiliqua rugosa, which has an ultraviolet/blue tongue, to gain insight into this species' visual ecology. We used electroretinograms, opsin sequencing and immunohistochemical labelling to characterize whole-eye spectral sensitivity and the elements that shape it. Our findings reveal that T. rugosa expresses all five opsins typically found in lizards (SWS1, SWS2, RH1, RH2 and LWS) but possesses greatly enhanced short-wavelength sensitivity compared with other diurnal lizards. This enhanced short-wavelength sensitivity is characterized by a broadening of the spectral sensitivity curve of the eye towards shorter wavelengths while the peak sensitivity of the eye at longer wavelengths (560 nm) remains similar to that of other diurnal lizards. While an increased abundance of SWS1 photoreceptors is thought to mediate elevated ultraviolet sensitivity in a couple of other lizard species, SWS1 photoreceptor abundance remains low in this species. Instead, our findings suggest that short-wavelength sensitivity is driven by multiple factors which include a potentially red-shifted SWS1 photoreceptor and the absence of short-wavelength-absorbing oil droplets. Examining the coincidence of enhanced short-wavelength sensitivity with blue tongues among lizards of this genus will provide further insight into the co-evolution of conspecific signals and whole-eye spectral sensitivity.

New host and locality records of helminths' infection of seven lizards from Morocco.

Morocco has a great diversity of reptiles; more than 26% of the herpetofauna species are considered to be endemic. Nevertheless, there is little information available on helminth parasites of Moroccan lizards. The purpose of this article is to establish a helminth list using non-invasive methods for natural populations of seven lizard species: Acanthodactylus maculatus, Chalcides mionecton, Chalcides montanus, Chalcides polylepis, Quedenfeldtia moerens, Quedenfeldtia trachyblepharus, and Tarentola mauritanica. For each species, prevalence and intensity of infection were given as well as their relationship to some determinant parameters (sex, age class, size, altitude, and seasons). Four species of nematodes, Parapharyngodon micipsae, Pharyngodon mamillatus, Spauligodon auziensis, Thelandros alatus, and unassigned Spauligodon were found. Mean helminth intensity for the seven lizard species was 7.3 ± 16.2 SD (range = 1-92 in infected lizards), with total infection prevalence of 5.6%. Mixed infections were observed in Chalcides montanus and Chalcides polylepis co-infected by Pharyngodon mamillatus and Spauligodon sp. Furthermore, the intensity of infection by nematodes were significantly different among the seven studied species. The nematode infection in Chalcides mionecton were related to sex, host size, and altitude; in Chalcides polylepis to the host age; in Quedenfeldtia trachyblepharus to elevation, age, and host size; and in Tarentola Mauritanica to age, body size, seasons, and altitude. In conclusion, our study provides data about nine new host and locality records and the effect of some determinant factors on host parasitism.

Elevation is a stronger predictor of morphological trait divergence than competition in a radiation of tropical lizards.

Adaptations for efficient performance are expected to shape animal morphology based on selection for microhabitat use and ecological forces. The presence of competitor species is predicted to cause niches to contract and enhance trait divergence. Therefore, increased species richness is expected to lead to greater trait divergence, and to result in reduced overlap and similarity between morphologies of sympatric species. We examined patterns of morphospace occupancy and partitioning in the skink fauna of New Guinea, the world's largest tropical island. Because skink species richness is largely decoupled from elevation in New Guinea, we could examine the effects of both factors (as proxies for competition and abiotic conditions), on morphospace occupancy and partitioning. We measured 1,860 specimens from 79 species of skinks throughout Papua New Guinea, and examined their morphospace occupancy in a spatial context. We calculated, for each assemblage within equal-area cells, the volume of morphospace occupied by all skinks, the mean volume occupied per species, and the mean distance and overlap between all species pairs. We then examined whether these metrics are related to species richness and elevation. Elevation is a stronger predictor of morphospace occupancy than species richness. As elevation increases, intraspecific variation decreases and morphologies become more similar to each other such that overall morphospace occupancy decreases. Highland skinks are, on average, smaller, thinner and shorter limbed than lowland species. We hypothesise that harsh climates in the New Guinea highland habitats impose strong selection on skinks to occupy specific areas of morphospace that facilitate efficient thermoregulation in suboptimal thermal conditions. We conclude that the effect of competition on trait divergence on a community and assemblage scale is eclipsed by abiotic selection pressures in these harsh environments.

Complete mitochondrial genome of a blue-tailed skink Plestiodon capito (Reptilia, Squamata, Scincidae) and comparison with other Scincidae lizards.

Vertebrate mitochondrial genomes (mitogenomes) are valuable for studying phylogeny, evolutionary genetics and genomics. To date, however, compared to other vertebrate groups, our knowledge about the mitogenomes of skinks (the family Scincidae), even of reptile, has been relatively limited. In the present study, we determined the complete mitogenome of a blue-tailed skink Plestiodon capito for the first time, and compared it with other skinks available in GenBank. The circular genome is 17,344 bp long, showing a typical vertebrate pattern with 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes and one control region (CR). The gene organization, nucleotide composition, and codon usage are similar to those from skinks previously published. Twelve out of 13 PCGs initiates with canonical start codon (ATG), while COX1 starts with GTG. The codon usage analysis revealed a preferential use of the LeuCUN (Leu1), Pro, and Thr codons with the A/U ending. All tRNAs in P. capito were predicted to fold into typical clover-leaf secondary structure, except tRNA-Ser AGY. The secondary structures of 12S rRNA and 16S rRNA comprises 34 helices and 56 helices, respectively. The alignment of the Plesitodon species CRs exhibited high genetic variability and rich A + T content. Besides, variable types and numbers of tandem repeat units were also identified in the CR of Plestiodon. Phylogenetic analyses recovered P. capito as the sister species to P. tunganus; monophyly of the Scincidae is well supported. Our results will help to better understand structure and evolution of the mitochondrial DNA control region in reptiles as well as the evolutionary status of P. capito, and to lay foundation for further phylogenetic study of skinks in a mitogenomic framework.

Plasma estradiol and progesterone concentrations during the female reproductive cycle in a highly placentotrophic viviparous lizard, Mabuya sp.

The neotropical genus Mabuya are obligate placentotrophic viviparous lizards, which have a short vitellogenesis that produces microlecithal oocytes and a prolonged time of gestation (9 to 10 months). The hormonal control of female reproductive activity during follicular growth and pregnancy has not been studied, although it is known that the corpus luteum can produce progesterone, but regresses early in pregnancy, being replaced in this function by the placenta. Through enzyme immunoassay (EIA) we measured the plasma concentrations of estradiol (E2) and progesterone (P4) in females of a population of Mabuya sp at different stages of their reproductive cycle. Previously, we confirmed the presence of P4 in plasma by high-performance liquid chromatography methods with diode-array detector ultraviolet (HPLC-DAD-UV). The average concentration values of E2 and P4 were compared among reproductive stages and their dynamics were related to what is known in other oviparous and viviparous amniotes. The plasma E2 concentrations of Mabuya sp. are below the levels found in other viviparous reptiles, probably related to the substantial reduction of its follicular growth phase. Its highest concentration was detected during vitellogenesis, related to its function in the growth and maturation of the ovarian follicles and oviduct preparation for pregnancy; lower levels were observed during pregnancy, but they increase at the end when a new vitellogenesis event begins and massive placental maternal-fetal nutrient transfer occurs. High concentrations of P4 were found during pregnancy, related to its function in the maintenance of the developing embryos within the oviduct. The highest levels of P4 were found at early gestation, then they descend from mid-gestation to the end of gestation. Although some characteristics of hormonal control related to the high level of placentotrophy were observed in this species, the changes in plasma sex steroid concentrations during the reproductive cycle in females of Mabuya sp. follow patterns seen in other viviparous amniotes.

The mathematics of thermal sub-optimality: Nonlinear regression characterization of thermal performance of reptile metabolic rates.

Although several approaches have been suggested, there is no broadly accepted single approach for quantitative characterization of thermal performance in ectotherms. I sought to identify the most appropriate non-linear function with which to represent thermal performance of ectothermic metabolic rate, and to interrogate the biological relevance of the thermal parameters of this function. I used published data for exercise-induced metabolic rates of eight species of reptile from a broad phylogenetic base and global distribution. Using an Akaike Information Criterion, I compared 12 different models proposed to characterize thermal performance adapted from a broad range of disciplines, finding that a beta-distribution model described the reptile metabolic rate data most parsimoniously. Using the beta-distribution model, unique functions were parameterized for each species. Four parameters were extracted from each species-specific fit: the temperature coincident with the peak of the thermal performance curve, Topt; the point at which the function intersected the x-axis, CTmax; and two points indicative of thermal breadth, Td(lower) and Td(upper). There was a positive relationship between the species' preferred body temperatures (Tpref) reported in the scientific literature and both Topt and Td(lower) extracted from the species-specific beta functions. While Td(lower) estimates were not different to published Tpref values, Topt estimates were statistically higher than Tpref. This is consistent with previous observations that the point of peak performance does not match Tpref. The predicted CTmax also correlated well with published values. The model in its current form was not able to estimate CTmin, and this parameter was not explored here, but should be in future research. By providing a quantitative description of the thermal performance, the beta-distribution function offers a new theoretical basis for thermal optimality. I contend that Tpref aligns with the mathematical threshold Td(lower), where metabolic rate is at its maximum prior to thermal inhibition.

Egernia stokesii (gidgee skink) MHC I positively selected sites lack concordance with HLA peptide binding regions.

Genes of the major histocompatibility complex (MHC) play an important role in vertebrate disease resistance, kin recognition and mate choice. Mammalian MHC is the most widely characterised of all vertebrates, and attention is often given to the peptide binding regions of the MHC because they are presumed to be under stronger selection than non-peptide binding regions. For vertebrates where the MHC is less well understood, researchers commonly use the amino acid positions of the peptide binding regions of the human leukocyte antigen (HLA) to infer the peptide binding regions within the MHC sequences of their taxon of interest. However, positively selected sites within MHC have been reported to lack correspondence with the HLA in fish, frogs, birds and reptiles including squamates. Despite squamate diversity, the MHC has been characterised in few snakes and lizards. The Egernia group of scincid lizards is appropriate for investigating mechanisms generating MHC variation, as their inclusion will add a new lineage (i.e. Scincidae) to studies of selection on the MHC. We aimed to identify positively selected sites within the MHC of Egernia stokesii and then determine if these sites corresponded with the peptide binding regions of the HLA. Six positively selected sites were identified within E. stokesii MHC I, only two were homologous with the HLA. E. stokesii positively selected sites corresponded more closely to non-lizard than other lizard taxa. The characterisation of the MHC of more intermediate taxa within the squamate order is necessary to understand the evolution of the MHC across all vertebrates.

Extended molecular phylogenetics and revised systematics of Malagasy scincine lizards.

Among the endemic biota of Madagascar, skinks are a diverse radiation of lizards that exhibit a striking ecomorphological variation, and could provide an interesting system to study body-form evolution in squamate reptiles. We provide a new phylogenetic hypothesis for Malagasy skinks of the subfamily Scincinae based on an extended molecular dataset comprising 8060bp from three mitochondrial and nine nuclear loci. Our analysis also increases taxon sampling of the genus Amphiglossus by including 16 out of 25 nominal species. Additionally, we examined whether the molecular phylogenetic patterns coincide with morphological differentiation in the species currently assigned to this genus. Various methods of inference recover a mostly strongly supported phylogeny with three main clades of Amphiglossus. However, relationships among these three clades and the limb-reduced genera Grandidierina, Voeltzkowia and Pygomeles remain uncertain. Supported by a variety of morphological differences (predominantly related to the degree of body elongation), but considering the remaining phylogenetic uncertainty, we propose a redefinition of Amphiglossus into three different genera (Amphiglossus sensu stricto, Flexiseps new genus, and Brachyseps new genus) to remove the non-monophyly of Amphiglossus sensu lato and to facilitate future studies on this fascinating group of lizards.

The role of ecological factors in determining phylogeographic and population genetic structure of two sympatric island skinks (Plestiodon kishinouyei and P. stimpsonii).

We conducted comparative phylogeographic and population genetic analyses of Plestiodon kishinouyei and P. stimpsonii, two sympatric skinks endemic to islands in the southern Ryukyus, to explore different factors that have influenced population structure. Previous phylogenetic studies using partial mitochondrial DNA indicate similar divergence times from their respective closest relatives, suggesting that differences in population structure are driven by intrinsic attributes of either species rather than the common set of extrinsic factors that both presumably have been exposed to throughout their history. In this study, analysis of mtDNA sequences and microsatellite polymorphism demonstrate contrasting patterns of phylogeography and population structure: P. kishinouyei exhibits a lower genetic variability and lower genetic differentiation among islands than P. stimpsonii, consistent with recent population expansion. However, historical demographic analyses indicate that the relatively high genetic uniformity in P. kishinouyei is not attributable to recent expansion. We detected significant isolation-by-distance patterns among P. kishinouyei populations on the land bridge islands, but not among P. stimpsonii populations occurring on those same islands. Our results suggest that P. kishinouyei populations have maintained gene flows across islands until recently, probably via ephemeral Quaternary land bridges. The lower genetic variability in P. kishinouyei may also indicate smaller effective population sizes on average than that of P. stimpsonii. We interpret these differences as a consequence of ecological divergence between the two species, primarily in trophic level and habitat preference.

Allelic expression of mammalian imprinted genes in a matrotrophic lizard, Pseudemoia entrecasteauxii.

Genomic imprinting is a process that results in the differential expression of genes depending on their parent of origin. It occurs in both plants and live-bearing mammals, with imprinted genes typically regulating the ability of an embryo to manipulate the maternal provision of nutrients. Genomic imprinting increases the potential for selection to act separately on paternally and maternally expressed genes, which increases the number of opportunities that selection can facilitate embryonic control over maternal nutrient provision. By looking for imprinting in an independent matrotrophic lineage, the viviparous lizard Pseudemoia entrecasteauxii (Scincidae), we test the hypothesis that genomic imprinting facilitates the evolution of substantial placental nutrient transport to embryos (matrotrophy). We sequenced transcriptomes from the embryonic component of lizard placentae to determine whether there are parent-of-origin differences in expression of genes that are imprinted in mammals. Of these genes, 19 had sufficiently high expression in the lizard to identify polymorphisms in transcribed sequences. We identified bi-allelic expression in 17 genes (including insulin-like growth factor 2), indicating that neither allele was imprinted. These data suggest that either genomic imprinting has not evolved in this matrotrophic skink or, if it has, it has evolved in different genes to mammals. We outline how these hypotheses can be tested. This study highlights important differences between mammalian and reptile pregnancy and the absence of any shared imprinting genes reflects fundamental differences in the way that pregnancy has evolved in these two lineages.

Geographic variation in hybridization and ecological differentiation between three syntopic, morphologically similar species of montane lizards.

To understand factors shaping species boundaries in closely related taxa, a powerful approach is to compare levels of genetic admixture at multiple points of contact and determine how this relates to intrinsic and extrinsic factors, such as genetic, morphological and ecological differentiation. In the Australian Alps, the threatened alpine bog skink Pseudemoia cryodroma co-occurs with two morphologically and ecologically similar congeners, P. entrecasteauxii and P. pagenstecheri, and all three species are suspected to hybridize. We predicted that the frequency of hybridization should be negatively correlated with genetic divergence, morphological differentiation and microhabitat separation. We tested this hypothesis using a mitochondrial locus, 13 microsatellite loci, morphological and microhabitat data and compared results across three geographically isolated sites. Despite strong genetic structure between species, we detected hybridization between all species pairs, including evidence of backcrossed individuals at the two sites where all three species are syntopic. Hybridization frequencies were not consistently associated with genetic, morphological or ecological differentiation. Furthermore, P. entrecasteauxii and P. pagenstecheri only hybridized at the two sites where they are syntopic with P. cryodroma, but not at the largest site where P. cryodroma was not recorded, suggesting that P. cryodroma may serve as a bridging species. This study reveals the complex dynamics within a three species hybrid zone and provides a baseline for assessing the impact of climate change and anthropogenic habitat modification on future hybridization frequencies.

A single origin of extreme matrotrophy in African mabuyine skinks.

Most mammals and approximately 20% of squamates (lizards and snakes) are viviparous, whereas all crocodilians, birds and turtles are oviparous. Viviparity evolved greater than 100 times in squamates, including multiple times in Mabuyinae (Reptilia: Scincidae), making this group ideal for studying the evolution of nutritional patterns associated with viviparity. Previous studies suggest that extreme matrotrophy, the support of virtually all of embryonic development by maternal nutrients, evolved as many as three times in Mabuyinae: in Neotropical Mabuyinae (63 species), Eumecia (2 species; Africa) and Trachylepis ivensii (Africa). However, no explicit phylogenetic hypotheses exist for understanding the evolution of extreme matrotrophy. Using multilocus DNA data, we inferred a species tree for Mabuyinae that implies that T. ivensii (here assigned to the resurrected genus Lubuya) is sister to Eumecia, suggesting that extreme matrotrophy evolved only once in African mabuyine skinks.

When do species-tree and concatenated estimates disagree? An empirical analysis with higher-level scincid lizard phylogeny.

Simulation studies suggest that coalescent-based species-tree methods are generally more accurate than concatenated analyses. However, these species-tree methods remain impractical for many large datasets. Thus, a critical but unresolved issue is when and why concatenated and coalescent species-tree estimates will differ. We predict such differences for branches in concatenated trees that are short, weakly supported, and have conflicting gene trees. We test these predictions in Scincidae, the largest lizard family, with data from 10 nuclear genes for 17 ingroup taxa and 44 genes for 12 taxa. We support our initial predictions, andsuggest that simply considering uncertainty in concatenated trees may sometimes encompass the differences between these methods. We also found that relaxed-clock concatenated trees can be surprisingly similar to the species-tree estimate. Remarkably, the coalescent species-tree estimates had slightly lower support values when based on many more genes (44 vs. 10) and a small (∼30%) reduction in taxon sampling. Thus, taxon sampling may be more important than gene sampling when applying species-tree methods to deep phylogenetic questions. Finally, our coalescent species-tree estimates tentatively support division of Scincidae into three monophyletic subfamilies, a result otherwise found only in concatenated analyses with extensive species sampling.

Phylogenetic evidence of historic mitochondrial introgression and cryptic diversity in the genus Pseudemoia (Squamata: Scincidae).

The Australian scincid genus Pseudemoia comprises six morphologically similar species restricted to temperate south-eastern Australia. Due to the high degree of morphological conservatism, phylogenetic relationships and taxonomic status within the Pseudemoia entrecasteauxii complex (comprising the nominal species P. entrecasteauxii, P. cryodroma, and P. pagenstecheri) remains unresolved. To further investigate the phylogenetic relationships and taxonomic status of Pseudemoia spp., and to test the hypothesis that P. cryodroma evolved from hybridization between P. entrecasteauxii and P. pagenstecheri, we sequenced one mitochondrial locus (ND4) and five nuclear loci (ß-globin, LGMN, PRLR, Rhodopsin, RPS8). While we find strong support for the monophyly of the P. entrecasteauxii complex, there exists marked incongruence between the mitochondrial and nuclear markers, particularly in regards to the high altitude specialist, P. cryodroma. The most parsimonious explanation of this discordance is historic mitochondrial introgression, although a hybrid origin for P. cryodroma cannot be completely rejected. Within P. pagenstecheri sensu lato, we identified a strongly supported, highly divergent yet morphologically cryptic lineage restricted to northern New South Wales. Although more weakly supported by the nuDNA, we also identified a second geographically distinct lineage of P. pagenstecheri s.l., which may warrant separate conservation management. Our study reveals a more complex evolutionary history of the genus Pseudemoia than previously appreciated and contributes to our understanding of the biogeography and evolution of Australian mesic zone fauna.

Incubation temperature fluctuation does not affect incubation length and hatchling phenotype in the Chinese skink Plestiodon chinensis.

Studies examining the effects of incubation temperature fluctuation on the phenotype of hatchling reptiles have shown species variation. To examine whether incubation temperature fluctuation has a key role in influencing the phenotype of hatchling Chinese skinks (Plestiodon chinensis), we incubated eggs produced by 20 females under five thermal regimes (treatments). Eggs in three treatments were incubated in three incubators, one set constant at 27°C and two ramp-programmed at 27 ± 3°C and 27 ± 5°C on a cycle of 12h (+) and 12h (-). The remaining eggs were incubated in two chambers: one inside a room where temperatures varied from 23.0 to 31.1°C, with a mean of 27.0°C; the other outside the room where temperatures varied from 20.2 to 35.3°C, with a mean of 26.1°C. We found that: (1) for eggs at a given embryonic stage at ovipositon, the mean rather than the variance of incubation temperatures determined the length of incubation; (2) most (egg mass, embryonic stage at oviposition, incubation length and all examined hatchling traits except tail length and locomotor performance) of the examined variables were affected by clutch; and (3) body mass was the only hatchling trait that differed among the five treatments, but the differences were tiny. These findings suggest that incubation temperature fluctuation has no direct role in influencing incubation length and hatchling phenotype in P. chinensis.

The natural and human-mediated expansion of a human-commensal lizard into the fringes of Southeast Asia.

BACKGROUND: Human-commensal species often display deep ancestral genetic structure within their native range and founder-effects and/or evidence of multiple introductions and admixture in newly established areas. We investigated the phylogeography of Eutropis multifasciata, an abundant human-commensal scincid lizard that occurs across Southeast Asia, to determine the extent of its native range and to assess the sources and signatures of human introduction outside of the native range. We sequenced over 350 samples of E. multifasciata for the mitochondrial ND2 gene and reanalyzed a previous RADseq population genetic dataset in a phylogenetic framework. RESULTS: Nuclear and mitochondrial trees are concordant and show that E. multifasciata has retained high levels of genetic structure across Southeast Asia despite being frequently moved by humans. Lineage boundaries in the native range roughly correspond to several major biogeographic barriers, including Wallace's Line and the Isthmus of Kra. Islands at the outer fringe of the range show evidence of founder-effects and multiple introductions. CONCLUSIONS: Most of enormous range of E. multifasciata across Southeast Asia is native and it only displays signs of human-introduction or recent expansion along the eastern and northern fringe of its range. There were at least three events of human-introductions to Taiwan and offshore islands, and several oceanic islands in eastern Indonesia show a similar pattern. In Myanmar and Hainan, there is a founder-effect consistent with post-warming expansion after the last glacial maxima or human introduction.

A New Isosporan (Apicomplexa: Eimeriidae) from the Pacific Blue-Tailed Skink, Emoia caeruleocauda (Sauria: Scincidae: Eugongylinae), from Guam, U.S. Territory.

PURPOSE: Nothing is known about coccidians (Apicomplexa: Eimeriidae) from the Pacific blue-tailed skink, Emoia caeruleocauda. Here, we report mensural and morphometric data on a new species of Isospora from E. caeruleocauda from Guam, US Territory. METHODS: Feces from four E. caeruleocauda collected by hand in November 2023 were placed in individual vials containing 2.5% potassium dichromate. They were examined for sporulated oocysts after flotation in Sheather's sugar solution, measured, and photographed. RESULTS: A single (25%) E. caeruleocauda was found to be passing oocysts representing a new species of Isospora. Oocysts of Isospora guamensis n. sp. are ellipsoidal to ovoidal with a bi-layered wall, measure (L × W) 16.5 × 11.8 µm, and have a length/width (L/W) ratio of 1.4; a micropyle and an oocyst residuum were absent but a polar granule was present. Sporocysts are ovoidal and measure 9.4 × 6.5 µm, L/W 1.4; Stieda and sub-Stieda bodies were present but a para-Stieda body was absent. The sporocyst residuum is composed various-sized granules in a compact rounded or irregular mass, sometimes dispersed between the sporozoites. The new species can be differentiated from all other isosporans from skinks by possessing the smallest oocysts known from this host family. CONCLUSION: This is the first time an isosporan coccidian has been reported from E. caeruleocauda as well as the first report of a coccidian from a Guam-inhabiting skink.