Teiidae Research Articles

Christina Theodoris: Scientific Artist.

Christina Theodoris earned her BS in Biology at the California Institute of Technology and is currently pursuing her MD/PhD at the University of California, San Francisco, in Developmental and Stem Cell Biology. She is a student researcher at the Deepak Srivastava laboratory at Gladstone Institutes, focusing on gene regulatory networks and their disruption in cardiac disease to identify targets for network-correcting therapies. As an artist and a scientist, Christina endeavors to strike a balance between her 2 passions, using her experiences in art to move forward through the setbacks and missteps that are an accepted part of the scientific process as, after all, “there are no mistakes in art.” I was born and raised in Atlanta, where my parents immigrated from Greece. My parents initially came to the United States for graduate school—my father in electrical engineering and my mother in physical therapy. Growing up in Georgia, I always loved playing with my sister in the forest and really enjoyed nature and art. My sister and I were always excited for the daily math puzzle my dad would give us to figure out on the drive to school, and I was inspired by my mother’s compassion for her patients. For high school, I went to a public magnet school for art and science. Thanks to the mentorship of my extraordinary teachers, I was fortunate to be selected for the national Marie Walsh Sharpe art program, where I studied with artists Susanna Coffey and Chuck Forsman, and the national Earthwatch Institute program, where I researched signal detection theory with whiptail lizards in the Arizona desert. Experiences like these set me on the trajectory to pursue my passions in art and science. Christina Theodoris When I went to college, I knew I wanted to pursue a career in medicine; I loved pediatrics …

Female Brazilian whiptail lizards (Cnemidophorus ocellifer) prefer males with high ultraviolet ornament reflectance

Conspicuous colouration is an important way of social communication in many taxa. The role of ultraviolet (UV) signals in intraspecific communication has only recently been studied in lizards, and there is not a general understanding of the adaptive role of UV colouration. Colour ornaments can signal male quality in mate choice and are therefore suitable for reliably predicting the outcome of female preference. Here, we tested the potential role of UV colouration in female spatial preference in a non-territorial teiid lizard, Cnemidophorus ocellifer. We experimentally manipulated the UV reflectance of size-matched male pairs and tested the effects of our treatment on females’ spatial distribution. We found that females associated with males of higher UV reflectance, suggesting that UV colour can be an important clue during mate preference decisions. Our results provide the first empirical evidence for the importance of UV colouration in female preference in a mutually ornamented lizard species.

Projections of Future Suitable Bioclimatic Conditions of Parthenogenetic Whiptails

This paper highlights the results of bioclimatic-envelope modeling of whiptail lizards belonging to the Aspidoscelis tesselata species group and related species. We utilized five species distribution models (SDM) including Generalized Linear Model, Random Forest, Boosted Regression Tree, Maxent and Multivariate Adaptive Regression Splines to develop the present day distributions of the species based on climate-driven models alone. We then projected future distributions of whiptails using data from four climate models run according to two greenhouse gas concentration scenarios (RCP 4.5 and RCP 8.5). Results of A. tesselata species group suggested that climate change will negatively affect the bioclimatic habitat and distribution of some species, while projecting gains in suitability for others. Furthermore, when the species group was analyzed together, climate projections changed for some species compared to when they were analyzed alone, suggesting significant loss of syntopic areas where suitable climatic conditions for more than two species would persist. In other words, syntopy within members of the species group will be drastically reduced according to future bioclimatic suitability projections in this study.

Injured Salvator merianae (Teiidae) regenerates six tails in central Argentina

Lizards have the ability of regenerate many tissues like nerve cells, part of the mandible, parts of the limb, and most of them can regenerate the tail. Tail autotomy followed by tail regeneration is a strategy widely used in lizards to escape from predators. In some cases tail breaks but it does not detaches completely from the body, leading to a regenerated tail with multiple tips. Here we report the finding of a young individual of Salvator merianae from central Argentina which regenerated six tails after being injured.

Differential repetitive DNA composition in the centromeric region of chromosomes of Amazonian lizard species in the family Teiidae.

Differences in heterochromatin distribution patterns and its composition were observed in Amazonian teiid species. Studies have shown repetitive DNA harbors heterochromatic blocks which are located in centromeric and telomeric regions in Ameiva ameiva (Linnaeus, 1758), Kentropyx calcarata (Spix, 1825), Kentropyx pelviceps (Cope, 1868), and Tupinambis teguixin (Linnaeus, 1758). In Cnemidophorus sp.1, repetitive DNA has multiple signals along all chromosomes. The aim of this study was to characterize moderately and highly repetitive DNA sequences by Cot1-DNA from Ameiva ameiva and Cnemidophorus sp.1 genomes through cloning and DNA sequencing, as well as mapping them chromosomally to better understand its organization and genome dynamics. The results of sequencing of DNA libraries obtained by Cot1-DNA showed that different microsatellites, transposons, retrotransposons, and some gene families also comprise the fraction of repetitive DNA in the teiid species. FISH using Cot1-DNA probes isolated from both Ameiva ameiva and Cnemidophorus sp.1 showed these sequences mainly located in heterochromatic centromeric, and telomeric regions in Ameiva ameiva, Kentropyx calcarata, Kentropyx pelviceps, and Tupinambis teguixin chromosomes, indicating they play structural and functional roles in the genome of these species. In Cnemidophorus sp.1, Cot1-DNA probe isolated from Ameiva ameiva had multiple interstitial signals on chromosomes, whereas mapping of Cot1-DNA isolated from the Ameiva ameiva and Cnemidophorus sp.1 highlighted centromeric regions of some chromosomes. Thus, the data obtained showed that many repetitive DNA classes are part of the genome of Ameiva ameiva, Cnemidophorus sp.1, Kentroyx calcarata, Kentropyx pelviceps, and Tupinambis teguixin, and these sequences are shared among the analyzed teiid species, but they were not always allocated at the same chromosome position.

The Organization of Repetitive DNA in the Genomes of Amazonian Lizard Species in the Family Teiidae

Repetitive DNA is the largest fraction of the eukaryote genome and comprises tandem and dispersed sequences. It presents variations in relation to its composition, number of copies, distribution, dynamics, and genome organization, and participates in the evolutionary diversification of different vertebrate species. Repetitive sequences are usually located in the heterochromatin of centromeric and telomeric regions of chromosomes, contributing to chromosomal structures. Therefore, the aim of this study was to physically map repetitive DNA sequences (5S rDNA, telomeric sequences, tropomyosin gene 1, and retroelements Rex1 and SINE) of mitotic chromosomes of Amazonian species of teiids (Ameiva ameiva, Cnemidophorus sp. 1, Kentropyx calcarata, Kentropyx pelviceps, and Tupinambis teguixin) to understand their genome organization and karyotype evolution. The mapping of repetitive sequences revealed a distinct pattern in Cnemidophorus sp. 1, whereas the other species showed all sequences interspersed in the heterochromatic region. Physical mapping of the tropomyosin 1 gene was performed for the first time in lizards and showed that in addition to being functional, this gene has a structural function similar to the mapped repetitive elements as it is located preferentially in centromeric regions and termini of chromosomes.

Widespread failure to complete meiosis does not impair fecundity in parthenogenetic whiptail lizards.

Parthenogenetic species of whiptail lizards in the genus Aspidoscelis constitute a striking example of speciation by hybridization, in which first-generation hybrids instantly attain reproductive isolation and procreate as clonal all-female lineages. Production of eggs containing a full complement of chromosomes in the absence of fertilization involves genome duplication prior to the meiotic divisions. In these pseudo-tetraploid oocytes, pairing and recombination occur exclusively between identical chromosomes instead of homologs; a deviation from the normal meiotic program that maintains heterozygosity. Whether pseudo-tetraploid cells arise early in germ cell development or just prior to meiosis has remained unclear. We now show that in the obligate parthenogenetic species A. neomexicana the vast majority of oocytes enter meiosis as diploid cells. Telomere bouquet formation is normal, but synapsis fails and oocytes accumulate in large numbers at the pairing stage. Pseudo-tetraploid cells are exceedingly rare in early meiotic prophase, but they are the only cells that progress into diplotene. Despite the widespread failure to increase ploidy prior to entering meiosis, the fecundity of parthenogenetic A. neomexicana is similar to that of A. inornata, one of its bisexual ancestors.

Stable isotope evidence for Turkey Vulture reliance on food subsidies from the sea

Turkey Vulture (Cathartes aura) reliance on marine subsidies in coastal Baja California peninsula was quantitatively assessed by analyzing carbon and nitrogen stable isotope ratios in its feathers. Feathers were collected in two separate roosts in a small farm, a small fishing village and an uninhabited beach. We compared among them the isotopic niches of the four populations and also with those of Yellow-footed Seagull (Larus livens), Brown Pelican (Pelecanus occidentalis) and Orange-throated Whiptail lizard (Aspidoscelis hyperythra), used as reference for sympatric marine and terrestrial species. The importance of nutrients of marine origin varied among local close subpopulations, suggesting some spatial segregation. Dominant individuals would be established near predictable sources of food (human settlements), having a mixed terrestrial–marine diet influenced by local human activities (isotopic signature of feathers also indicated the role of human-fed cattle as vulture food). Subordinate individuals would be relegated to wandering along the beaches searching for washed up food, having a diet almost exclusively marine.

Reptiles of Banco Chinchorro: Updated List, Life History Data, and Conservation

One of the most useful strategies for biological conservation is the creation of protected natural areas. In addition, periodic updates of management plans are necessary to modify or improve the information and make it accessible to future research. Banco Chinchorro Biosphere Reserve is a protected atoll situated 31 km eastward from the southern coast of Quintana Roo, Mexico. A management plan published in 2000 contains a list of reptiles inhabiting the four islands of the atoll, but concerns about errors contained on the list necessitated updates and corrections. Herein, we clarify and update this list and present new life-history data for some species. We used four approaches to improve the list: interviews with staff, fishermen, and professional visitors; literature review; scientific collections; and field work conducted from 2011 to 2013. Thirteen species (1 crocodilian, 4 marine turtles, 2 iguanas, 2 geckos, 2 anoles, 1 whiptail lizard, and 1 snake) were observed in comparison to 14 species previously recorded in the management plan. Of the 13 species currently noted, 9 (69%) species appear in the International Union for Conservation of Nature Red List (7 with a threatened status), 7 (54%) are in Convention on International Trade in Endangered Species of Wild Fauna and Flora Appendices, and 9 (69%) are protected by Mexican law. One invasive species (Anolis sagrei) seems to have adapted and found its niche; whereas another (Hemidactylus frenatus) represents a threat for another species (Aristelliger georgensis), and efforts to eradicate it are strongly recommended. Banco Chinchorro is the only site in Mexico where Anolis allisoni is present. It also hosts the most distant and isolated population of the parthenogenetic lizard Aspidoscelis maslini from the mainland. After this study, we promoted the inclusion of both species in the Mexican protected species list based on ecological and distribution information. Finally, we discuss considering the reptiles of the reserve as Evolutionarily Significant Units.

Diet and Foraging Behavior ofAmeivula ocellifera(Squamata: Teiidae) in the Brazilian Semiarid Caatinga

This study investigated the influence of seasonality on diet and foraging behavior of the whiptail lizard Ameivula (Cnemidophorus) ocellifera in the Caatinga of northeastern Brazil. Diet composition was identified through stomach analysis of lizards collected monthly by active search during 2009 (rainy and dry seasons) and half of 2010 (rainy season). Foraging behavior was investigated during one rainy and one dry month of 2012, allowing us to determine the percent of time spent moving (PTM), number of movements per minute (MPM), and number of successful attacks on prey by lizards during foraging activity. Analysis of stomach contents showed significant seasonal differences in diet: insect larvae, Coleoptera, and Orthoptera predominated during the two rainy seasons (2009 and 2010); insect larvae, Hemiptera, Araneae, and Orthoptera predominated in the dry season. Prey movement index was lower during rainy seasons, mainly because of more insect larvae consumed during those periods. Population niche breadth was broader in the dry season, but individual niches did not differ significantly between seasons. When foraging, the average PTM was 61.1 ± 15.1%; MPM was 2.03 ± 0.30; and prey items captured/min was 0.14 ± 0.14. PTM for A. ocellifera was similar to values found for North American whiptails (Aspidoscelis), but MPM was relatively higher. Seasonal differences were observed in PTM, which were significantly higher in the rainy season. This difference may represent a behavioral adjustment in response to differences in seasonal food availability.

Speciation with gene flow in whiptail lizards from a Neotropical xeric biome

Two main hypotheses have been proposed to explain the diversification of the Caatinga biota. The riverine barrier hypothesis (RBH) claims that the São Francisco River (SFR) is a major biogeographic barrier to gene flow. The Pleistocene climatic fluctuation hypothesis (PCH) states that gene flow, geographic genetic structure and demographic signatures on endemic Caatinga taxa were influenced by Quaternary climate fluctuation cycles. Herein, we analyse genetic diversity and structure, phylogeographic history, and diversification of a widespread Caatinga lizard (Cnemidophorus ocellifer) based on large geographical sampling for multiple loci to test the predictions derived from the RBH and PCH. We inferred two well-delimited lineages (Northeast and Southwest) that have diverged along the Cerrado-Caatinga border during the Mid-Late Miocene (6-14 Ma) despite the presence of gene flow. We reject both major hypotheses proposed to explain diversification in the Caatinga. Surprisingly, our results revealed a striking complex diversification pattern where the Northeast lineage originated as a founder effect from a few individuals located along the edge of the Southwest lineage that eventually expanded throughout the Caatinga. The Southwest lineage is more diverse, older and associated with the Cerrado-Caatinga boundaries. Finally, we suggest that C. ocellifer from the Caatinga is composed of two distinct species. Our data support speciation in the presence of gene flow and highlight the role of environmental gradients in the diversification process.

Genetic structure of Tupinambis teguixin (Squamata: Teiidae), with emphasis on Venezuelan populations.

<p><em>Tupinambis teguixin</em> es la única especie registrada para Venezuela. Este teido se encuentra distribuido en diferentes bioregiones del Neotrópico, en algunos casos separadas por barreras geográficas que pueden estar restringiendo el flujo genético entre sus poblaciones. Para evaluar esta posibilidad, pusimos a prueba las Hipótesis Paleogeográfica y la Rivereña. Para ello evaluamos el grado de estructuración genética de seis poblaciones de <em>T. teguixin</em> de Venezuela, una de Brasil y una de Ecuador. Utilizamos dos bases de datos moleculares, una con las poblaciones de Venezuela (Base de datos Venezuela, 1 023 pb) y la segunda incluyendo las otras dos poblaciones (Base de datos Suramérica, 665 pb), con 93 y 102 secuencias concatenadas de citocromo b y ND4, y 38/37 haplotipos. En cuanto a la metodología, utilizamos tres medidas de diversidad genética: diversidad nucleotídica, diversidad haplotípica y número de sitios polimórficos. Estimamos el flujo genético mediante el estadístico <em>Φ</em><em><sub>ST</sub></em> y los valores de <em>F<sub>ST</sub></em> pareados. También construimos redes de haplotipos. Los resultados evidencian estructura poblacional, encontrándose (1) un <em>Φ</em><em><sub>ST</sub></em> global de 0.83, (2) <em>F<sub>ST</sub></em> pareados altos (0.54-0.94), (3) redes de haplotipos con un patrón geográfico definido, cada población con sus haplotipos agrupados (menos Delta), Zulia y Ecuador con redes separadas, y (4) un solo haplotipo compartido entre las poblaciones. Los análisis muestran que la estructura no es producto de la distancia geográfica entre las poblaciones (r = 0.282, p = 0.209), sino un efecto histórico biogeográfico de la Cordillera de Mérida y del río Orinoco (71.19 % variación molecular), como barreras geográficas. Consideramos la población del Zulia una unidad evolutiva significativa y proponemos que las otras poblaciones temporalmente sean consideradas unidades de manejo, hasta tanto se tenga más información. Las poblaciones del Delta y Guri conformarán una sola unidad de manejo por compartir un haplotipo.<strong></strong></p>

Cytogenetic analyses of five amazon lizard species of the subfamilies Teiinae and Tupinambinae and review of karyotyped diversity the family Teiidae.

Lizards of the family Teiidae (infraorder Scincomorpha) were formerly known as Macroteiidae. There are 13 species of such lizards in the Amazon, in the genera Ameiva (Meyer, 1795), Cnemidophorus (Wagler, 1830), Crocodilurus (Spix, 1825), Dracaena (Daudin, 1801), Kentropyx (Spix, 1825) and Tupinambis (Daudin, 1802). Cytogenetic studies of this group are restricted to karyotype macrostructure. Here we give a compilation of cytogenetic data of the family Teiidae, including classic and molecular cytogenetic analysis of Ameiva ameiva (Linnaeus, 1758), Cnemidophorus sp.1, Kentropyx calcarata (Spix, 1825), Kentropyx pelviceps (Cope, 1868) and Tupinambis teguixin (Linnaeus, 1758) collected in the state of Amazonas, Brazil. Ameiva ameiva, Kentropyx calcarata and Kentropyx pelviceps have 2n=50 chromosomes classified by a gradual series of acrocentric chromosomes. Cnemidophorus sp.1 has 2n=48 chromosomes with 2 biarmed chromosomes, 24 uniarmed chromosomes and 22 microchromosomes. Tupinambis teguixin has 2n=36 chromosomes, including 12 macrochromosomes and 24 microchromosomes. Constitutive heterochromatin was distributed in the centromeric and terminal regions in most chromosomes. The nucleolus organizer region was simple, varying in its position among the species, as evidenced both by AgNO3 impregnation and by hybridization with 18S rDNA probes. The data reveal a karyotype variation with respect to the diploid number, fundamental number and karyotype formula, which reinforces the importance of increasing chromosomal analyses in the Teiidae.

Multiyear Sampling Reveals an Increased Population Density of an Endemic Lizard after the Establishment of an Invasive Snake on Aruba

Abstract The island of Aruba is home to several endemic species, and has been colonized recently by the invasive boa, Boa constrictor. We present data for a multiple-year sampling effort on one of Aruba's endemic species, the Aruban Whiptail Lizard (Cnemidophorus arubensis). Our sampling began before the invasion of B. constrictor and ended after their firm establishment, thus affording us the unique opportunity to document the potential effects of this invasive snake on the endemic lizard. Additionally, we compare our data with earlier studies with an average lizard density of 235.1/ha (SE = 73.42, n = 11). After the invasion of the B. constrictor we calculated densities of C. arubensis as high as 2,185/ha. Although B. constrictor regularly preys upon C. arubensis, the relationship between B. constrictor and C. arubensis likely represents ecological facilitation of the lizard species. Herein, we further develop a hypothesis that may explain how the invasive B. constrictor has caused an increase in the po...

Comparative Chromosome Painting and NOR Distribution Suggest a Complex Hybrid Origin of Triploid Lepidodactylus lugubris (Gekkonidae).

Parthenogenesis, unisexuality and triploidy are interesting but poorly studied phenomena occurring in some reptile species. The mourning gecko (Lepidodactylus lugubris) represents a complex of diploid and triploid parthenogenetic mostly all-female populations (males occur quite rarely) widely distributed in coastal areas of the Indian and Pacific Oceans. Here, we study karyotypes of a male and two female L. lugubris (LLU) triploid individuals (3n = 66) using comparative painting with Gekko japonicus, Hemidactylus turcicus and H. platyurus chromosome specific probes to visualize the homologous regions and to reveal genus specific rearrangements. Also, we applied a 28S ribosomal DNA probe and Ag-staining to detect nucleolus organizer regions (NORs). Our results suggest that the karyotype of L. lugubris underwent a chromosome fission and a fusion after its divergence from a common ancestor of the Gekko-Hemidactylus group. The NORs were found to be located on one out of three homologs on each of LLU8, LLU15 and LLU18, thus further confirming a hybrid origin of triploid individuals. It seems that three different bisexual populations might have contributed to the origin of this triploid parthenogenetic population. We postulate that the heterozygosity in NOR localization is maintained in the triploid clone studied by the absence of recombination as described in whiptail lizards. The pattern of NOR localizations and homologous regions in males and females, as well as the absence of other detectable karyotypic differences, suggest that males arise spontaneously in all female populations and do not arise from independent hybridizations with different species.

Neaves' Whiptail Lizard: The First Known Tetraploid Parthenogenetic Tetrapod (Reptilia: Squamata: Teiidae)

Abstract The first known tetraploid amniote that reproduces through parthenogenetic cloning by individual females is named and described. The species originated through hybridization between Aspidoscelis exsanguis (triploid parthenogen) × Aspidoscelis inornata (diploid bisexual or gonochoristic species) in the laboratory. We compared multivariate morphological variation between two lineages that arose from separate F1 hybrid zygotes in one clutch and among several generations in those lineages. The tetraploid species is also compared with its ancestral taxa, with two hybrids of A. exsanguis × A. inornata that were found in nature at two localities that are 100 km apart in southern New Mexico, and with three laboratory hybrid males. This will facilitate identification of field-caught tetraploids in the future.

Conservation and Management of Polytypic Species: The Little Striped Whiptail Complex (Aspidoscelis inornata) as a Case Study

Subspecies have most often been described qualitatively with small sample sizes as excerpted from geographic continua. They present a long-standing conflict with evolutionary and statistical principles as well as conservation planning that often relies upon a phylogenetic perspective. Herpetological subspecies have been recognized in the literature as exceeding numerical expectations and subsequent reevaluations during the last decade have decreased their numbers ∼50%, the exception being whiptail lizards (Aspidoscelis, family Teiidae). Here we used 842 base pairs of mitochondrial (mt) DNA to examine potential taxonomic and conservation boundaries among two putative species and four subspecies of the abundantly polytypic Aspidoscelis inornata (Little Striped Whiptail Complex, LSWC) of southwestern North America. Body coloration, but not mtDNA, distinguished two putative species inhabiting alkali deposits, whereas neither dataset could diagnose three paraphyletic subspecies. A trend to elevate putative subspecies following a more contemporary evaluation is premature for the LSWC: we suggest that two species (arizonae, pai) and three subspecies (gypsi, junipera, llanuras) lack molecular and morphological differentiation and thus should be rescinded in taxonomic rank. These uncertainties concerning the LSWC with regard to its distributions and relationships impinge upon conservation proposals that, for example, seek to list A. arizonae as ‘threatened’ under the Endangered Species Act.Frecuentemente las subespecies han sido descritas cualitativamente y con tamaños de muestra pequeños extraídos de un continum geográfico. Ellas representan un viejo conflicto con los principios evolutivos y estadísticos así como para desarrollar planes de conservación que frecuentemente dependen de una perspectiva filogenética. Las subespecies herpetológicas han sido reconocidas en la literatura como excediendo las expectativas numéricas y una reevaluación subsecuente durante la década pasada ha disminuido sus números en ∼50%, siendo la excepción los Huicos (Aspidoscelis, familia Teiidae). Aquí utilizamos 842 pares de ADN mitocondrial (mt) para examinar el potencial taxonómico y límites de conservación entre dos supuestas especies y cuatro subespecies de la abundante y politípica Aspidoscelis inornata (complejo del Huico Liso, CDHL) del suroeste de Norteamérica. El patrón de coloración, pero no el ADN mitocondrial, distingue a dos supuestas especies que habitan en los depósitos de álcali mientras que ningún conjunto de datos pudo diferenciar las tres subespecies parafiléticas. Elevar a estas supuestas subespecies siguiendo una evaluación más contemporánea es prematuro para CDHL: sugerimos que las dos especies (arizonae y pai) y las tres subespecies (gypsi, junipera, llanuras) carecen de diferenciación morfológica y molecular por lo que deben ser consideradas sin rango taxonómico. Esta incertidumbre con respecto a las CDHL en cuanto a sus relaciones y distribuciones impacta propuestas de conservación que, por ejemplo, buscan enlistar a A. arizonae como “amenazada” bajo la ley de especies en peligro de extinción.

Type of soil and temperature range explain the preferred habitat and current distribution of the endemic lizard Aspidoscelis hyperythra in southern Baja California peninsula

The Baja California peninsula herpetofauna is composed by more than 160 species, many of them endemic. In the last years the region is experiencing an accelerating population growth and land use change, specially in the lowlands and coastal areas. Based on GLM models we described and predicted the distribution patterns of the regional endemic whiptail lizard, Aspidoscelis hyperythra Cope, 1863 (Sauria: Teiidae). We verified the accuracy of the predictive occurrence map in the field and then we generated a final suitable habitat model for the species. The soil characteristics have a great influence on occurrence probability. The highest values correspond to sandy areas with low slope, temperatures between 18 and 22 °C, annual range temperature below 15 °C, NDVI values ranged 0.60–0.73, rainfall between 200 and 400 mm, and altitude lower than 800 m. Vegetation was also important; the establishment of the species requires woody plants that produce (a) plant litter where the lizards find prey; (b) burrowing sites for clutches, daily shelter, or hibernation and (c) open areas with light shade available for effective thermoregulation. These areas where natural tropical deciduous forest and sarcocaulescent scrub are stablished are also the most attractive to human settlements; so the conflict between conservation and development is stronger there.

Extreme variant of the triploid parthenogenetic lizardAspidoscelis exsanguis(Squamata: Teiidae) from New Mexico

Abstract Parthenogenetic reproduction in several all-female species of whiptail lizards (genus Aspidoscelis) does not preclude the occasional production of extreme variants. An adult lizard with a unique combination of dorsal color pattern, scutellation, and meristic characters captured 20 August 2013 approximately 200 m east of the Rio Grande in Bosque Farms, Valencia County, New Mexico, was inferred to be an extreme variant of triploid, hybrid-derived Aspidoscelis exsanguis which was also observed near the point of capture. There was no basis for identifying the specimen as a tetraploid hybrid because morphology did not reflect that origin and no gonochoristic species (e.g., Aspidoscelis marmorata or Aspidoscelis inornata) was known to occur at the site. Morphological analyses also ruled out the possibility that it could be an extreme variant of diploid parthenogenetic Aspidoscelis neomexicana, which is syntopic with A. exsanguis in Bosque Farms.

Temporal and ontogenetic variation in the escape response of Ameiva festiva (Squamata, Teiidae)

Several factors have been shown to affect lizard escape behavior (flight initiation distance or FID, the distance between predator and prey when the prey initiates escape). Patterns of daily activity, such as foraging or movement behavior, vary with respect to time of day, supporting that escape responses may vary temporally as well. However, there remains scant information regarding the effects of time of day on FID. During peak activity, FID may decrease due to increased cost of giving up resources (e.g., prey or potential mates). An alternative hypothesis is that FID may increase because lizard activity in general may serve to alert a predator in advance of its approach. A lizard in this scenario may be favored to flee sooner rather than later. Moreover, juvenile and adult lizards of multiple species may differ in behavioral, ecological, and morphological traits that could influence escape decisions. I tested the effects of time of day (in 30-min intervals) and age (juvenile or adult) on the FID of a tropical whiptail lizard, Ameiva festiva in Costa Rica. I found that A. festiva escape responses varied with time of day such that in general, their FID decreased throughout the day. In addition, I observed a peak in FID from mid to late-morning that matches published estimates of peak activity times for A. festiva. Overall, juvenile A. festiva initiated an escape response sooner than adults, which may be related to differences in perceived risk associated with differences in size and predator experience between the two age groups. I conclude that escape responses may be contingent on both the activity level of the animal at the time of approach and its age.