Species Of Cnemidophorus Research Articles

Social display in the Curaçao Whiptail (Cnemidophorus murinus Laurenti)

Three teiid species (Squamata: Teiidae) are endemic to the ABC islands (Aruba, Bonaire, and Curaçao) of the former Netherlands Antilles: the Aruba Whiptail (Cnemidophorus arubensis) of Aruba, the Bonaire Whiptail (C. ruthveni) of Bonaire and Klein-Bonaire, and the Curaçao Whiptail (C. murinus) of Curaçao and Klein-Curaçao. Before now, social displays have been described only for one of these three species: C. ruthveni (Baird et al. 2003). All three species engage in an arm-waving display that involves forelimb circumduction (Baird et al. 2003; van Buurt 2005; van Buurt 2011), which conveys social signals to conspecifics in some iguanian and lacertid lizard species (Carpenter et al. 1970; Verbeek 1972; Mitchell 1973). However, this behavior in the ABC island species of Cnemidophorus has not been shown to have a social function (Baird et al. 2003). Instead, experimental evidence demonstrates that in C. ruthveni it functions as a pursuit deterrent display that is performed in response to approaching humans, whom the lizard may view as potential predators (Cooper et al. 2004), although there are not yet any published reports of C. ruthveni performing the display in response to the approach of a non-human predator. My observations and those of others (van Buurt 2011) also confirm that in C. arubensis the display is performed in response to approaching humans.

Cryptic diversity in South American Teiinae (Squamata, Teiidae) lizards

Based on phylogenetic and molecular dating analyses of several species of Cnemidophorus and Ameiva, representing major groups of species of these two genera, we uncover a previously unrecognized Ameiva lineage, which includes described Cnemidophorus parecis from south‐western Amazonia. We discuss the diagnosis of Ameiva and Cnemidophorus and the implications of the new taxonomic rearrangement of genera from Teiidae for the monophyly of Ameiva. Based on the conclusion of our analyses, we provide description of a new species named Ameiva jacuba from the central Brazilian Cerrado and a detailed diagnosis for the relocation of C. parecis to Ameiva. We do not adopt here recent taxonomic changes proposed for Teiidae and provide a discussion about them. Finally, based on molecular dating and the distribution of living species, we propose an evolutionary scenario for the origins of South American cis‐Andean Ameiva lineages, associated with the topographic subdivision of the Cerrado region during Miocene marine introgressions.

Two new species of Cnemidophorus (Squamata: Teiidae) of the C. ocellifer group, from Bahia, Brazil

Two new species of Cnemidophorus (Squamata: Teiidae) of the C. ocellifer group, from Bahia, Brazil

Two new species of Cnemidophorus (Squamata: Teiidae) from the Caatinga, Northwest Brazil

Two new species of Cnemidophorus (Squamata: Teiidae) from the Caatinga, Northwest Brazil

Two new species of Cnemidophorus (Squamata: Teiidae) of the C. ocellifer group, from Bahia, Brazil

Two new species of Cnemidophorus are described from the right bank of the São Francisco river, in the northwestern part of state of Bahia, Brazil. Both species are assigned to the Cnemidophorus ocellifer group and are distinguished from all other congeners on the basis of lepidosis and color pattern. One of them, Cnemidophorus cyanurus, shares with the species of the subgroup of C. littoralis (C. abaetensis, C. littoralis and C. venetacaudus), a bluish green tail, spurs on the heels of males, 6–7 supraciliaries, a high number of femoral pores (27–45), a row of enlarged scales in the dorsal part of the humerus, and 8 to 10 rows of ventral scales. The second species, Cnemidophorus nigrigula, shares with the C. ocellifer subgroup (composed of C. ocellifer, C. mumbuca, C. jalapensis and C. confusionibus) a low number of femoral pores (14– 21), enlarged scales in the temporal region posterior to the third subocular, 5 supraciliaries, 6 to 8 rows of ventral scales, and a brown tail color. It is also characterized by males being conspicuously larger than females and by females retaining the juvenile color pattern, which is lost in adult males. The latter characteristic has not been reported in any species of the C. ocellifer group before now. The two new species occur sympatrically at Santo Inácio.

Thermal ecology of five Cnemidophorus species (Squamata: Teiidae) in east coast of Brazil

In this study we compared the body temperature of 16 populations belonging to five species of the genus Cnemidophorus from restinga habitats along the eastern coast of Brazil in order to evaluate the importance of how some environmental factors affect lizard body temperatures. Cloacal body temperatures ( T b) were taken immediately after capture with a quick-reading thermometer (Schultheis). Substrate temperatures ( T s) and air temperatures ( T a; approximately 1 cm above the substrate) were taken as close as possible to the point when each lizard was initially sighted. Most of the mean body temperatures in activity of the different populations and species of Cnemidophorus along the coast of Brazil ranged from 36.5 to 39.3 °C, except for Cnemidophorus lacertoides ( T b=35.2 °C) in the restinga of Joaquina, SC and for Cnemidophorus ocellifer ( T b=34.8 °C ) in the restinga of Praia do Porto, SE. Some studies show that the body temperature of lizards is more related to phylogenetic than ecological factors, suggesting that species of the same genus tend to have similar body temperatures even occurring in different types of environments. In general, regardless of the locality and latitude along the eastern coast of Brazil, the different species of lizards of the genus Cnemidophorus and their respective populations have similar body temperatures in activity and the apparent differences result from the influence of the local thermal environment of each restinga.

Two new species of Cnemidophorus (Squamata: Teiidae) from the Caatinga, Northwest Brazil

Two syntopic species of Cnemidophorus are described from the Caatingas of the Parque Nacional da Serra das Confusões (PNSC), located in the Southwestern region of the state of Piauí in Brazil. Both species are assigned to the ocellifer group, differing from all other members of the group by their distinct color pattern and lepidosis. Besides these differences, both new species share a number of particular features with other members of the group. One of them, C. venetacaudus, shares with C. abaetensis and C. littoralis the presence of spurs in the heels of males, six supraciliar scales, a high number of femoral pores (from 21–45), a row of enlarged scales in the dorsal region of the arm, 8–10 rows of ventral scales, and a bright bluish-green tail, while the other species, C. confusionibus, shares with C. ocellifer, C. mumbuca, and C. jalapensis a low number of femoral pores, enlarged scales in the temporal region (posterior to third subocular), 5 supraciliar scales, and 6–8 rows of ventral scales. Based on these comparisons, we suggest that the ocellifer group is more complex than previously admitted, being composed by at least two morphologically recognizable species subgroups.

Two New Species of Cnemidophorus (Squamata: Teiidae) from Islands of the Northeastern Coast of Venezuela

We describe two new whiptail lizard species, previously assigned to Cnemidophorus lemniscatus, from islands of the state of Nueva Esparta and Los Frailes Archipelago, off the northeastern coast of Venezuela. The two new species differ from C. lemniscatus in color, pattern, and squamation. The species from the islands of Margarita and Cubagua can be distinguished from the one of Los Frailes Archipelago in having the circumorbital semicircles extending further anteriorly, more scales between supraocular and supraciliaries, and a larger number of scales of a smaller size between the preanal shield and anal spurs. The two new species also differ conspicuously in color and pattern of both sexes and all age classes. Additionally, we comment on the status of the population of Cnemidophorus of Los Testigos Archipelago, discuss the morphological and color variation observed in C. lemniscatus from northern Venezuela and restrict the distribution of the latter species in the country to the mainland.

A New Species of Cnemidophorus from the Jalapão Region, in the Central Brazilian Cerrado

The Cerrado is one of the richest tropical savannas and is considered a biodiversity “hotspot.” It is estimated that, at the current rate of loss, the ecosystem will disappear by the year 2030. The number of new species being discovered in the Cerrado has increased linearly, especially over the last 50 years. We describe a new species of Cnemidophorus from the Jalapão region, in the northern Cerrado biome, Brazil. Linear discriminant analyses and a naïve Bayesian model indicated that a combination of meristic counts (femoral pores, scales around tail, prefemorals, dorsals, and supralabials) and categorical variables derived from pholidosis and coloration clearly distinguish the new species from its congeners. The new species is apparently parapatric with C. mumbuca, the two species occurring on opposite banks of the Novo River. The two species are ecologically and morphologically similar, sharing a small body size, a fixed clutch size of a single egg, and a small number of femoral pores. The new species is apparently endemic to the Jalapão region, in the northern portion of the Cerrado biome. Its small size and restricted geographic range are consistent with findings from Cerrado anurans that undescribed species tend to be small and have reduced ranges. These results highlight the urgency of biotic surveys in Cerrado in face of its accelerated pace of destruction.

Steroidogenic enzyme gene expression in the brain of the parthenogenetic whiptail lizard, Cnemidophorus uniparens

The steroidogenic enzyme CYP17 is responsible for catalyzing the production of androgenic precursors, while CYP19 converts testosterone to estradiol. De novo neurosteroidogenesis in specific brain regions influences steroid hormone dependent behaviors. In the all-female lizard species Cnemidophorus uniparens, individuals alternately display both male-like mounting and female-like receptivity. Mounting is associated with high circulating concentrations of progesterone following ovulation (PostOv), while receptivity is correlated with estrogen preceding it (PreOv). At a neuroanatomical level, the preoptic area (POA) and ventromedial nucleus of the hypothalamus (VMN) are the foci of the male-typical mounting and female-typical receptivity, respectively. In this study, we indirectly test the hypothesis that the whiptail lizard brain is capable of de novo neurosteroidogenesis by cloning fragments of the genes encoding two steroidogenic enzymes, CYP17 and CYP19, and examining their expression patterns in the C. uniparens brain. Our data indicate that these genes are expressed in the C. uniparens brain, and more importantly in the POA and VMN. Using radioactive in situ hybridization, we measured higher CYP17 mRNA levels in the POA of PostOv lizards compared to receptive PreOv animals; CYP19 mRNA levels in the VMN did not change across the ovarian cycle. To our knowledge, these are the first data suggesting that the reptilian brain is capable of de novo steroidogenesis. This study also supports the idea that non-gonadal sources of steroid hormones locally produced in behaviorally relevant brain loci are central to the mediation of behavioral output.

PHYLOGEOGRAPHY AND GENETIC STRUCTURE IN THE CNEMIDOPHORUS LONGICAUDA COMPLEX (SQUAMATA, TEIIDAE)

Cnemidophorus longicauda is a poorly-studied species of whiptail lizard distributed in the Monte Desert region of Argentina. Some variation in dorsal color pattern has been observed between northern and southern populations along the latitudinal range of the species. Recently, a new species of Cnemidophorus (C. tergolaevigatus) previously considered as C. longicauda has been described, although no comparative morphological study has been conducted. In this study we use the mitochondrial ND4 gene region to examine the phylogeography and genetic structure of this species complex. Phylogenetic reconstruction, Nested Clade Phylogeographic Analysis, and AMOVA reveal deep genetic divergence between northern and southern populations that are geographically separated by the Famatina-Sanogasta Mountains. Because most of the localities of C. tergolaevigatus are from the general region of the ''northern group'' recovered in this study, there is general concordance between geographic patterns of mtDNA and morphological (color pattern) variation, and thus support for the recognition of this species. We discuss this genetic break and the phylogenetic/phylogeographic history of the Cnemidophorus in the context of other lizard species with similar distributions, and the implications for understanding the evolutionary history of the temperate South American biota.

Serotonergic modulation of male-like pseudocopulatory behavior in the parthenogenetic whiptail lizard, Cnemidophorus uniparens

Hormone–neurotransmitter interactions form an important link through which hormones influence a variety of behavioral processes. Typically, sexual behavior is dimorphic with males mounting receptive females. In the all-female lizard species Cnemidophorus uniparens, individuals display both male-like pseudocopulation and female-like receptivity. These respective behavioral states are correlated with high circulating concentrations of progesterone following ovulation and of estrogen preceding it. In sexual species, serotonin is involved in male-typical mounting, and, as reported here, in male-like pseudosexual behavior in this unisexual species. In the first study, C. uniparens were ovariectomized and treated systemically with exogenous androgen, a hormonal regimen that results in individuals displaying only male-like pseudosexual behavior. An increase in serotonin levels in the preoptic area coupled with the suppression of male-like pseudocopulation was observed in androgen-treated lizards injected with 5-hydroxytryptophan (the precursor of serotonin) and clorgyline (a monoamine oxidase inhibitor) compared to vehicle-treated controls. Our second experiment involved ovariectomizing lizards and either injecting them with estradiol or implanting them with either an empty (Blank) or a progesterone- or testosterone-containing Silastic capsule. Treatment with para-chlorophenylalanine (an inhibitor of tryptophan hydroxylase) facilitated male-like pseudosexual behavior depending on the circulating hormonal milieu and decreased serotonin levels in the preoptic area. Our data suggest that serotonin is inhibitory to male-like pseudosexual behavior in C. uniparens but more importantly that the hormonal environment modulates the serotonin system at the level of the preoptic area, with the serotonergic system then establishing behavioral thresholds that allow for this behavior to be “gated”.

The nitric oxide synthase inhibitor l-NAME suppresses androgen-induced male-like pseudocopulatory behavior in whiptail lizards

The synthesis of nitric oxide by the enzyme nitric oxide synthase (NOS) is involved in the androgen-dependent gating of male-typical copulatory behavior, both centrally, particularly in the preoptic area, and peripherally, notably through its role in penile erection. In the all-female whiptail lizard species Cnemidophorus uniparens, individuals display copulatory behaviors indistinguishable from males of similar species if gonadectomized and treated with testosterone. In this experiment, androgenized individuals were treated with a NOS inhibitor, which eliminated male-like behavior in half the individuals, suggesting that the central role of nitric oxide synthesis is conserved in this species. The deficit was principally in mounting, suggesting that sexual motivational systems were affected, rather than consummatory mechanisms.

A new species of Cnemidophorus (Squamata: Teiidae) from western Argentina

AbstractA new species of whiptail lizard of the genus Cnemidophorus (Teiidae) is described from La Rioja province, western Argentina. The species is characterized by a broad light brown-grayish middorsal pattern, the lack of vertebral and paravertebral stripes, alternating white and brown stripes from dorsolateral to flanks, pointed snout, postnasal scale usually longer than loreal scale, and 10 longitudinal rows of ventral scales. The previous and current states of knowledge on southern South American Cnemidophorus species are discussed.

Geographical Variation in the Ecology of Populations of Some Brazilian Species of Cnemidophorus (Squamata, Teiidae)

We investigated geographical variation in ecological parameters among populations of Cnemidophorus cryptus, Cnemidophorus gramivagus, Cnemidophorus lemniscatus, Cnemidophorus ocellifer, and Cnemidophorus parecis, from three Brazilian biomes (Cerrado, Caatinga, and Amazonian Savannas). Lizards used mainly the open ground, with a high similarity in microhabitat use among populations. Differences in microhabitat use probably resulted from the availability of microhabitats and not from microhabitat preferences. Body temperatures were high and little influenced by environmental temperatures, there being no differences among populations. There were significant differences in diet among populations, with C. ocellifer from Caatinga and Cerrado consuming large quantities of termites, whereas Amazonian Savanna species used primarily ants and insect larvae. The data on reproductive seasonality indicated cyclical reproduction in seasonal biomes and continuous reproduction in unpredictable climate regions. We found significant differences in mean clutch size among populations, independent of body size, with C. lemniscatus having the smallest clutch size (1.50) and C. ocellifer from Cerrado the largest (2.10). There were fewer differences in clutch size among species from Amazonian Savannas, than between populations of C. ocellifer from Caatinga and Cerrado. Apparently, populations under seasonal climates concentrate their reproductive effort during the short reproductive season, producing larger clutches, whereas those under more stable or unpredictable climates reproduce continuously, yielding smaller clutches, corroborating the hypothesis that environmental conditions exert an important influence upon life-history parameters. There were significant differences in body shape among populations, but most of the variation was related to sex. We also observed significant differences in body size among populations, seemingly unrelated to differences in community structure, but the highly conservative morphology of Cnemidophorus species suggests the presence of historical constraints.

A CRITICALLY ENDANGERED NEW SPECIES OF CNEMIDOPHORUS (SQUAMATA, TEIIDAE) FROM A CERRADO ENCLAVE IN SOUTHWESTERN AMAZONIA, BRAZIL

We describe a new species of Cnemidophorus from a Cerrado enclave in southwestern Amazonia, Rondônia state, Brazil. This species is apparently endemic to Cerrado enclaves in the vicinity of the city of Vilhena, a region under intensive anthropic pressure due to the expansion of soybean plantations. A discriminant analysis indicated that femoral pores and scales around the tail are the best discriminators among Brazilian species of Cnemidophorus. A naïve Bayesian network constructed with categorical (mostly coloration) variables indicated that the new species had high conditional probabilities of dorsolateral fields absent, vertebral field spotted, and paravertebral lines absent. The analyses revealed clear distinctions between species of Cnemidophorus that range north and south of the the Amazon River. The new species may have evolved as a result of vicariance, following the isolation of peripheral enclaves of Cerrado in southwestern Amazonia after the late Pleniglacial. The restricted range in small areas, under extreme human pressure around Vilhena, makes this species one of the most critically endangered elements of the Brazilian herpetofauna.

Genetic homogeneity based on skin histocompatibility and the evolution and systematics of parthenogenetic Cnemidophorus laredoensis (Sauria: Teiidae)

The parthenogenetic whiptail lizard Cnemidophorus laredoensis of Texas and México was derived from one or more hybrids between the gonochoristic species Cnemidophorus gularis and Cnemidophorus sexlineatus. We analyzed clonal structure in C. laredoensis on the basis of histocompatibility reactions to reciprocal skin grafting. Individuals of C. laredoensis rejected skin grafts from both parental species and from a hybrid between C. gularis and an undescribed parthenogenetic species. One lizard initially identified as C. laredoensis was found to be a triploid C. laredoensis × C. gularis hybrid, based on its histocompatibility reactions. The hybrid accepted grafts from individuals of C. laredoensis; however, C. laredoensis rejected grafts from this and a second hybrid. Seventeen individuals of C. laredoensis from six sites located throughout the range of the species in Texas were fully histocompatible, based on a large number of reciprocal skin grafts. Only three individuals of C. laredoensis from three sites donated grafts to other individuals of the species, but they were unable to host all or most of the reciprocal grafts. The skin histo compatibility among 17 individuals of C. laredoensis from six widely separated geographic sites points to a high level of genetic homogeneity in the species due to clonal descent from one parthenogenetic C. gularis × C. sexlineatus hybrid. Unidirectional rejection of skin grafts by three lizards could be a result of postformational mutations within this lineage, though this suggestion is open to question. The name C. laredoensis should be restricted to populations in Texas and México that are diagnostically identical with the parthenogenetic species described from two sites in Laredo, Webb County, Texas, in 1973.

Sexual dimorphism in physiological performance of whiptail lizards (genus Cnemidophorus).

Numerous studies have examined sexual dimorphism in the morphology and behavior of vertebrates; very few, however, have explicitly investigated the possibility of gender differences in physiological performance, despite the observations of such differences in humans. In this study, I investigated physiological sexual dimorphism in the lizard genus Cnemidophorus by measuring five whole-animal traits, all of which are likely to influence fitness in these species: burst speed, endurance, maximal exertion capacity, standard metabolic rate, and evaporative water loss rate. Because at least some of these traits are known to be strongly influenced by body size, I tested for dimorphism using both absolute and size-corrected trait values. An examination of six Cnemidophorus species and subspecies revealed a strong trend toward higher absolute trait values in males for all variables except endurance. Most of the dimorphism in standard metabolic rate and evaporative water loss rate could be explained by differences in body mass between males and females; for the locomotor traits, however, body size explained only a small fraction of the overall sexual dimorphism. The portion of trait differences not explained by body size was likely due to gender differences in physiology, such as differences in relative muscularity and fat content.

Cnemidophorus neomexicanus-Cnemidophorus perplexus Nomenclatural Problem (Sauria: Teiidae) and Its Resolution

For the past 44 yr, populations of the parthenogenetic New Mexico whiptail lizard have been allocated to either Cnemidophorus perplexus Baird and Girard 1852 or Cnemidophorus neomexicanus Lowe and Zweifel 1952. The latter name has been in general use for the past 30 yr based on an opinion that the lectotype of C. perplexus, United States National Museum (USNM) 3060, was a triploid hybrid derived from insemination of a normally parthenogenetic individual of C. neomexicanus by a male of C. inornatus. Questions concerning the genealogy of the lectotype have recently resurfaced. Therefore, we used canonical variate (CVA) and principal components analyses (PCA) of nine meristic characters and snout-vent length to test the hypothesis that the lectotype of C. perplexus is a hybrid. Because C. neomexicanus and C. inornatus are sympatric at the type locality of the former, this also provided an opportunity to verify that the type of C. neomexicanus is not a hybrid. Our reference material included two sets of geographically paired samples of the presumptive parental species, C. neomexicanus (n = 77) and C. inornatus (n = 105) from the vicinity of the restricted type locality of C. perplexus. Of 23 specimens presumed from morphological features to be C. neomexicanus x C. inornatus hybrids, 13 that were syntopic with one of the reference sets were used as our hybrid reference group. The type specimens of C. perplexus and C. neomexicanus were included in the CVA as unknowns for assignment to the hybrid group or taxon with which each shared the greatest multivariate similarity. The CVA assigned the holotype of C. neomexicanus to C. neomexicanus (Set 1: P = 0.642; Set 2: P = 0.358), and the lectotype of C. perplexus was assigned to C. neomexicanus as well (Set 2: P = 0.789; Set 1: P = 0.211). Projections of scores for both types in a principal components analysis of all specimens supported both assignments. In addition, the color pattern of the lectotype resembles C. neomexicanus and none of the 23 hybrids, and meristic scores of the lectotype are within the range limits of our reference samples of C. neomexicanus. Our analyses indicate that the lectotype of C. perplexus was misidentified as a hybrid by previous workers. However, there are two compelling reasons why we shall petition the ICZN to suppress perplexus as an available name for a species of Cnemidophorus: (1) ambiguity concerning the type locality; and (2) controversy as to whether the name C. perplexus should be associated with specimen USNM 3060. Approval of the petition will bring the issue to closure and extend the 30yr use of the name C. neomexicanus for the New Mexico whiptail.

Temperature selection and thermoregulatory precision of bisexual and parthenogenetic Cnemidophorus lizards from southern Texas, U.S.A.

1. 1. Temperature selection and thermoregulatory precision of male and female Cnemidophorus gularis and females of two clonal complexes of the parthenogenetic species Cnemidophorus laredoensis (LAR-A and LAR-B) in a linear thigmothermal gradient were measured over a 24-h period. 2. 2. All four groups of Cnemidophorus selected similar mean T b s over the 24-h period. 3. 3. Male and female C. gularis and LAR-A selected higher T b s during some hours of photophase than during some hours of scotophase. 4. 4. The pattern of temperature selection during photophase by LAR-A and LAR-B differed in ways that parallel the differences in the diel activity cycle of these two parthenogens. 5. 5. Cnemidophorus gularis is a more precise thermoregulator than either clonal complex of C. laredoensis.