Scincella Research Articles

Comparison of Mitochondrial Genome Expression Differences among Four Skink Species Distributed at Different Latitudes under Low-Temperature Stress.

Continual climate change strongly influences temperature conditions worldwide, making ectothermic animals as suitable species for studying the potential impact of climate change on global biodiversity. However, the study of how lizards distributed at different latitudes respond to climate change at the transcriptome level is still insufficient. According to the Climatic Variability Hypothesis (CVH), the range of climate fluctuations experienced by terrestrial animals throughout the year increases with latitude, so individuals at higher latitudes should exhibit greater thermal plasticity to cope with fluctuating environments. Mitochondria, as the energy center of vertebrate cells, may indicate species' plasticity through the sensitivity of gene expression. In this study, we focused on the changes in transcript levels of liver mitochondrial protein-coding genes (PCGs) in skinks from the genus Plestiodon (P. capito and P. elegans) and the genus Scincella (S. modesta and S. reevesii) under low-temperature conditions of 8 °C, compared to the control group at 25 °C. Species within the same genus of skinks exhibit different latitudinal distribution patterns. We found that the two Plestiodon species, P. elegans and P. capito, employ a metabolic depression strategy (decreased transcript levels) to cope with low temperatures. In contrast, the two Scincella species show markedly different patterns: S. modesta exhibits significant increases in the transcript levels of six genes (metabolic compensation), while in S. reevesii, only two mitochondrial genes are downregulated (metabolic depression) compared to the control group. We also found that P. capito and S. modesta, which live at mid-to-high latitudes, exhibit stronger adaptive responses and plasticity at the mitochondrial gene level compared to P. elegans and S. reevesii, which live at lower latitudes. We suggest that this enhanced adaptability corresponds to more significant changes in a greater number of genes (plasticity genes).

A new species of the genus Scincella Mittleman, 1950 (Squamata: Scincidae) from Sichuan Province, Southwest China

A new species of the genus Scincella Mittleman, 1950 (Squamata: Scincidae) from Sichuan Province, Southwest China

A new skink of the genus Scincella Mittleman, 1950 (Squamata: Scincidae) from Hoa Binh Province, northern Vietnam

A new species of the genus Scincella Mittleman, 1950 is described from northern Vietnam based on morphological and molecular evidence. Scincella ouboteri sp. nov. is characterized by a combination of the following characters: Size medium (SVL up to 58.6 mm); primary temporals 2; external ear opening present, with 3 or 4 lobules on anterior margin; loreals 2; supralabials 7; infralabials 6 or 7; nuchals in 2–4 pairs; midbody scales in 30–32 rows; dorsal scales smooth, in 6 rows across the back; paravertebral scales 65–73, not widened; ventral scales in 65–71 rows; 10–12 smooth lamellae beneath finger IV and 18–20 beneath toe IV; toes overlapping fingers when limbs adpressed along body; dorsal surface of body and tail bronze-brown with a black vertebral stripe, in width of two dorsal scales, two bright dorsolateral stripes extending from behind the head to middle of tail, a dark stripe running from nostril to eye and extending from posterior margin of eye along upper part of flank and tail. In phylogenetic analyses, the new species and S. ochracea form an independent lineage sister to all other congeners included in the study.

Effect of climate change on fossorial species: a case study comparing species of the genus Scincella

Abstract For species that have a fossorial habit or that spend most of their time under leaf litter, correlative models may not be sufficient to model their potential risk in the face of climate change; this is the case for the species examined here. In the present study, we compared three different models (maximum entropy correlative models, mechanistic models based on species thermal tolerance, and habitat cover) applied to three lizards of the genus Scincella (S. gemmingeri, S. lateralis and S. silvicola). Models were proposed for current climate scenario, and for 2050 at three SSPs greenhouse gas concentrations, assessing sites with suitable climate and habitat cover, optimum temperature for species survival, and to selecting the best predictive model. Current and future correlative models indicate areas with little climatic suitability within the thermal range that these lizards can tolerate; however, it was possible to corroborate the presence of populations of S. gemmingeri and S. silvicola in areas that do not have climatic suitability, but do have habitat coverage. These results support the hypothesis that the habitat and microhabitat structures protect these species against possible adverse climatic conditions. It may be that it is also necessary to measure physiological variables (to obtain the thermal range of each species), as well to include both habitat type and habitat structure in spatial analysis.

First Record of Forelimb and Hindlimb Abnormalities in the Genus Scincella (Squamata: Scincidae)

Observations of the osteological features of malformations in lizards are currently limited. In examinations of ca. 1,300 Scincella specimens, one Scincella lateralis specimen and three S. boettgeri specimens were observed to have malformed digits, i.e., ectrodactyly. Each of these specimens had a malformation in only one limb. One S. lateralis specimen lacked digits I–III of manus, and three S. boettgeri specimens lacked digits I, II, or I and II of pedes. Micro-computed tomography scanning revealed that the phalanges and metacarpals of digits I–III were absent in the malformed S. lateralis specimen, whereas the malformed S. boettgeri specimens lacked all phalanges for externally absent toes but had five metatarsals, despite these being shorter in the absent toes than those in normal toes. Although malformed limbs have been reported previously in lizards, this is the first report based on osteological descriptions. Some genera of Scincidae include species that have undergone phylogenetic reduction of their digits. In such species, the developmental order of the phalanges and metacarpals/metatarsals is well-known from embryological studies. With reference to this developmental mechanism, we also discuss the assumed development of the malformed specimens observed in this study.

A new species of the genus Scincella (Squamata: Scincidae) from Yonagunijima Island, Southern Ryukyus, Japan

We performed a molecular phylogenetic analysis for the ground skink populations of the genus Scincella Mittleman, 1950 on Yonagunijima Island, Southern Ryukyus and representative samples of Scincella species known from other islands of the East Asian Archipelago. Partial mitochondrial cytochrome c oxidase subunit I and cytochrome b sequence data were used. Additionally, we examined the nuclear genetic variation between the Yonagunijima samples and those of closely related species. The genetic distances were largely equivalent between the Yonagunijima population and the two closest species, S. boettgeri from other southern Ryukyu Islands and S. formosensis from Taiwan. Moreover, there were nuclear haplotypes unique to the Yonagunijima population. We thus recognize the Yonagunijima population as a distinct species and describe it as Scincella dunan sp. nov. Morphologically, S. dunan sp. nov. is similar to S. boettgeri, but differs in some morphometric and meristic characters, and dorsolateral stripe pattern. These findings further support the biogeographically unique status of Yonagunijima Island among the southern Ryukyus islands.

Ground Skink (Scincella lateralis) Tails Found in Carolina Wren (Thryothorus ludovicianus) Nests

Thryothorus ludovicianus (Carolina Wren) have rarely been reported to eat lizards. We found Scincella lateralis (Ground Skink) tails in 3 nests of Carolina Wrens occupying nest boxes in residential areas of Huntsville, TX, in 2017. The most likely explanation is that the wrens had been feeding the skinks or their tail sections to their nestlings.

De novo Assembly, Annotation, and Analysis of Transcriptome Data of the Ladakh Ground Skink Provide Genetic Information on High-Altitude Adaptation

The Himalayan Arc is recognized as a global biodiversity hotspot. Among its numerous cryptic and undiscovered organisms, this composite high-mountain ecosystem harbors many taxa with adaptations to life in high elevations. However, evolutionary patterns and genomic features have been relatively rarely studied in Himalayan vertebrates. Here, we provide the first well-annotated transcriptome of a Greater Himalayan reptile species, the Ladakh Ground skink Asymblepharus ladacensis (Squamata: Scincidae). Based on tissues from the brain, an embryonic disc, and pooled organ material, using pair-end Illumina NextSeq 500 RNAseq, we assembled ~77,000 transcripts, which were annotated using seven functional databases. We tested ~1600 genes, known to be under positive selection in anurans and reptiles adapted to high elevations, and potentially detected positive selection for 114 of these genes in Asymblepharus. Even though the strength of these results is limited due to the single-animal approach, our transcriptome resource may be valuable data for further studies on squamate reptile evolution in the Himalayas as a hotspot of biodiversity.

Observation of Tick Parasitism on Scincella lateralis in Texas

Cases of Ixodes scapularis (Blacklegged Tick or Deer Tick) are known to infest a variety of lizard species including Scincella lateralis (Ground Skink). We report the finding of 1 Ground Skink with an attached immature tick, later identified as an engorged Blacklegged Tick nymph, in a population with a low rate of tick infestation. Of the 151 Ground Skinks we collected at the Piney Woods Environmental Laboratory, only 1 was parasitized by any tick species. We extracted whole-body tick DNA and tested for various bacterial pathogens, including Anaplasma phagocytophilum, Ehrlichia spp., Borrelia spp., and Rickettsia spp. PCR tests for these pathogens were negative except for Rickettsia spp. Within our sampling region of Walker County, TX, in the East Texas Piney Woods, we estimated the infestation prevalence of Blacklegged Ticks utilizing Ground Skinks as a host at 0.66%, much lower than previous estimations in Oklahoma.

A new skink of the genus Scincella Mittleman, 1950 (Squamata: Scincidae) from southern Vietnam.

A new skink of the genus Scincella Mittleman, 1950, from Binh Phuoc Province, southern Vietnam is described based on morphological data, including hemipenial characters, and nucleotide sequences from COI. The following morphological characters diagnose Scincella baraensis sp. nov.: relatively small size in adults (snout-vent length up to 49.2 mm); when limbs adpressed, toes do not or just reach fingers; 30 smooth midbody scale rows and dorsal scales not enlarged; 66-70 paravertebral scales; 64-66 ventral scale rows; 7 supralabials, the fifth and sixth below the center of the eye; enlarged temporal scales 1+2; nuchals present; ear with small auricular lobules; 18-20 smooth lamellae beneath toe IV; hemipenis smooth, short, and unforked; dorsum with faint black dots. The new species differs from its congeners by an uncorrected p-distance in COI sequences of at least 16.2%.

First Photographic Record of Reeve’s Ground Skink ( Scincella reevesii Gray, 1838) (Reptilia: Sauria: Scincidae) from India

This is the first record of the Reeve's Ground Skink (Scincell reevesi) from India with a photographic record from Tripura State. Diagnostic features and colour of the specimen added for recognition.

Complete mitochondrial genome of Scincella modesta (Squamata: Scincidae) and phylogenetic analysis

We sequenced and annotated the complete mitochondrial genome (mitogenome) of Scincella modesta (Squamata: Scincidae). This mitogenome was 17,466 bp long and encoded 13 protein-coding genes (PCGs), 22 transfer RNA genes, 2 ribosomal RNA genes, and 2 non-coding regions. The overall nucleotide composition was 31.8% of A, 14.5% of G, 27.2% of T, and 26.5% of C. Phylogenetic analysis using Bayesian Inference (BI) validated the taxonomic status of S. modesta, exhibiting the close relationship with the other two species from the genus Scincella.

Complete mitochondrial genome of Scincella modesta (Squamata: Scincidae)

The first complete mitochondrial genome sequence was determined for an oviparous lizard, Scincella modesta (Scincella, Scincidae). The total length of the complete mitochondrial genome was 17,511 bp, encodes 13 protein-coding genes, 22 tRNAs, 2 rRNA genes, and 2 non-coding regions. The overall base composition of S. modesta is A: 31.9%, T: 27.2%, G: 14.5%, and C: 26.5%. Most of the S. modesta mitochondrial genes are encoded on the H-strand except for the ND6 gene and eight tRNA genes, which are encoded on the L-strand. Mrbayes and ML tree based on 13 protein-coding genes indicated that S. vandenburghi is the sister group of the S. modesta within the genus Scincella. The complete mitogenome sequence of S. modesta provided fundamental data for resolving phylogenetic and genetic problems related to genus Scincella.

Short-term response to season of burn by amphibians and reptiles in a Florida longleaf pine – wiregrass sandhill

We investigated how herpetofauna respond to burning and burn season in longleaf pine (Pinus palustris Mill.) sandhills by contrasting preburn species richness, diversity, and evenness and captures of six reptile and six amphibian species to the first (Y+1) or second (Y+2) year after burn or between dormant-season burns (DSB) and growing-season burns (GSB). Responses to burning overall or burn season were inconsistent among species; several showed no response, whereas others responded positively or negatively. Most responses were evident only in Y+1. Reptile species richness, diversity, and evenness responses were not detected. Amphibian richness increased after burning overall; diversity and evenness decreased more in GSB than in DSB in Y+1. Southern toad (Anaxyrus terrestris (Bonnaterre, 1789)) captures increased and Florida crowned snake (Tantilla relicta Telford, 1966) captures decreased following burns overall in Y+1. Ground skink (Scincella lateralis (Say in James, 1823)) captures increased more in DSB than GSB in Y+1. Florida gopher frog (Lithobates capito (LeConte, 1855)) and southeastern five-lined skink (Plestiodon inexpectatus; Taylor, 1932) captures increased, and oak toad (Anaxyrus quercicus (Holbrook, 1840)) decreased more in GSB than DSB in Y+2. Responses were likely due to changes in aboveground activity affecting captures or (for amphibians especially) annual variability in captures unrelated to burns. Our results indicated that reptiles and amphibians of sandhills are resilient to short-term effects of burning overall and burn season.

Head shape variation among cryptic populations of ground skinks ( Scincella lateralis )

Head shape variation among cryptic populations of ground skinks ( <i>Scincella lateralis</i> )

A new skink of the genus Scincella Mittleman, 1950 (Squamata: Scincidae) from Ba Den Mountain, Tay Ninh Province, southern Vietnam.

Ba Den is an isolated mountain in southern Vietnam and home to two endemic species of lizards. Herein, we describe another endemic species, a new skink of the genus Scincella Mittleman, 1950, from the area based on morphological data, including hemipenial characters and nucleotide sequences of COI. The following morphological characters diagnose Scincella badenensis sp. nov.: medium size in adults (snout-vent length up to 64.4 mm); toes reach to fingers when limbs adpressed; midbody scale rows 32-36, smooth; paravertebral scales 67-71; dorsal scales not enlarged; ventral scale rows 68-74; supraoculars four; prefrontals in broad contact with one another; loreal scales two; tympanum deeply sunk, without auricular lobules; two enlarged anterior temporal scales; smooth lamellae beneath toe IV 18-20; pair of enlarged precloacal scales; hemipenes short, smooth and forked near the tip with two short lobes and two small terminal papillae; no dorsal pattern in males; and females with black interruptive vertebral line. The new species differs from its congeners by at least 10.4% uncorrected p-distance in COI sequences.

Morphological and Molecular Characterization of Post-Larval Pre-Tetrathyridia of Mesocestoides sp. (Cestoda: Cyclophyllidea) from Ground Skink, Scincella lateralis (SAURIA: SCINCIDAE), FROM SOUTHEASTERN OKLAHOMA.

Free pre-tetrathyridia of Mesocestoides sp. are described, for the first time, from samples obtained from the coelomic cavity of a ground skink, Scincella lateralis, from Oklahoma. Closer examination of these early-stage tapeworms revealed they were transitional metamorphosis stages between a post-hexacanth procercoid form to the full metacestode of Mesocestoides. A series of transitional stages was found that span the full period of sucker and apical organ development. However, we did not see any fully developed tetrathyridia, i.e., having classic Mesocestoides morphology but with the apical sucker absent following developmental atrophy. This is the first time that metamorphic pre-tetrathyridial stages of a Mesocestoides sp. have been reported in vivo from a natural infection. These observations corroborate earlier reports of such stages of Mesocestoides vogae developed in vitro, though the previously reported isolate of M. vogae is asexually proliferative, and the species from the present study showed no sign of asexual proliferation. The fact that these immediately post-hexacanth stages can occur in a single lizard intermediate host may suggest that Mesocestoides spp. might develop through a simple 2-host life cycle rather than an obligate 3-host cycle that has been speculated to occur by most previous authors. DNA sequence comparisons and phylogenetic analyses based on mitochondrial 12S, cox1, and nad1 genes have demonstrated that our specimens from S. lateralis represent a species clearly distinct from all previously sequenced Mesocestoides and closely related to 2 forms from domestic dogs and Channel Island fox in California previously published as Mesocestoides sp. C.

A new species of smooth skink (Squamata: Scincidae: Scincella) from Cambodia.

Based on morphological and genetic evidence we evaluated the taxonomic status of a newly discovered forest-dwelling population of skink (genus Scincella) from the Keo Seima Wildlife Sanctuary, Mondulkiri Province, Cambodia. From phylogenetic analysis of a 668-bp fragment of the mtDNA COI and diagnostic morphological characters we allocate the newly discovered population to the Scincella reevesii–S. rufocaudata species complex and describe it as Scincella nigrofasciata sp. nov. The new skink species can be distinguished from all other Southeast Asian congeners by the following combination of morphological characters: snout-vent length (SVL) 40.0–52.6 mm; relative tail length (TaL/SVL ratio) 1.25–1.94; prefrontals in broad contact; infralabials 6; primary temporals 2; relative forelimb length (FIL/SVL ratio) 0.20–0.22; relative hindlimb length (HIL/SVL ratio) 0.30–0.33; relative forearm length (FoL/SVL ratio) 0.14–0.16; adpressed forelimbs and hind limbs either overlapping (0.4–2.2 mm) or separated (1.9–2.3 mm); midbody scale rows 32–33, paravertebral scales 69–74, vertebral scales 65–69; dorsal scales between dorsolateral stripes 8; comparatively slender fingers and toes, subdigital lamellae under fourth toe 15–17; dark discontinuous regular dorsal stripes 5–7; distinct black dorsolateral stripes, narrowing to lateral sides and extending to 52%–86% of total tail length. We provide additional information on the holotype of Scincella rufocaudata (Darevsky & Nguyen, 1983), and provide evidence for the species status of Scincella rupicola. Our discovery brings the number of Scincella species in Cambodia to five and emphasizes the incompleteness of knowledge on the herpetofaunal diversity of this country.

Prescribed Fire Impacts to Amphibians and Reptiles in Shelterwood-harvested Oak-dominated Forests

As part of a larger study examining the role of prescribed fire in regenerating upland oaks (Quercus spp.), seasonal prescribed burns (winter, spring, summer, and unburned control) were applied to first-stage shelterwood-harvested stands on Horsepen Wildlife Management Area in the Virginia Piedmont in 1995. Because fire impacts are poorly documented for herpetofaunal communities, we surveyed these stands in 1996 capturing 133 individuals of ten species during over 12,720 pitfall trapnights. We found no significant differences in relative abundance of Eastern Red-backed Salamanders (Plethodon cinereus) (P = 0.26), American Toads (Bufo americanus (P = 0.93), or all amphibians combined (P = 0.25) among unburned shelterwood stands and those treated with winter, spring, or summer burns. Three species of reptiles (Northern Fence Lizard [Sceloporus undulatus], Ground Skink [Scincella lateralis], and Southeastern Five-lined Skink [Eumeces inexpectatus]) combined were captured more frequently in burned versus unburned stands (P = 0.02). Based on a stepwise multiple regression model, Eastern Red-backed Salamander captures were more strongly influenced by landscape variables (P = 0.0320), including distance to permanent water and mesic (i.e., eastern-northern) aspects, than by fire treatments (P = 0.26). Similar landscape models were not significant (P < 0.05) for toads or reptiles. Based on these results, prescribed fire may not be detrimental to herpetofaunal communities in oak dominated forests in the Virginia Piedmont.

Effects of temperature and oxygen on growth and differentiation of embryos of the ground skink, Scincella lateralis.

Development of reptile embryos is dependent upon adequate oxygen availability to meet embryonic metabolic demand. Metabolic rate of embryos is temperature dependent, with oxygen consumption increasing exponentially as a function of temperature. Because metabolic rate is more temperature sensitive than diffusion, developmental processes are predicted to be oxygen-limited at high temperatures. We tested the hypothesis that the amount of development lizard embryos achieve in the oviduct is dependent upon both temperature and oxygen availability. We evaluated the effect of temperature (23, 33°C) and oxygen concentration (9%, 15%, 21% O2 ) on survival and development of embryos of the oviparous skink Scincella lateralis. We predicted that incubation at 33°C under hypoxic conditions would result in higher embryo mortality due to mismatch between embryo oxygen demand and oxygen supply compared to eggs incubated at 23°C under hypoxic conditions. Embryo mortality was highest at 33°C/9% O2 (86%) compared to 23°C/9% O2 (14%), however, mortality did not differ among any other oxygen-temperature treatment combination. Both temperature and oxygen affected differentiation, but the interaction between temperature and oxygen was not significant. Embryo growth in mass and hatchling mass were affected by oxygen concentration independent of temperature treatment. Differing responses of growth and differentiation to temperature and oxygen treatments suggests that somatic growth may be more sensitive to oxygen availability than differentiation. Results indicate that embryo mortality can occur both via the direct effect of high temperature on cellular function as well as indirectly through thermally induced oxygen diffusion limitation.