Bkm probe hybridization to Pst I-treated genomic DNA of Podarcis sicula and Lacerta vivipara shows the same pattern both in males and females. In situ hybridization of the same probe to Lacerta vivipara chromosomes shows no preferential localization of this DNA sequence. The results obtained clearly exclude the possible involvement of Bkm in sex-chromosome differentiation in the species investigated.
Femurs of 73 Gallotia galloti caught in different localities and belonging to two subspecies living in Tenerife Canary Islands were analysed by skeletochronology. The bones possessed annual rings like in many other lizards. For a high percentage of individuals, a remnant of the embryonic bone and a birth line of arrested growth remained present throughout life because cortical resorption never completely removed the first annual rings.
Thus the age of an individual can be directly calculated from the number of lines of arrested growth. In the sample studies here, the oldest lizards were at least 8 or 9 years old. They reached sexual maturity during their second or third year of life. Vera, L. Carretero, M. Interpopulation variation but not environmental mirroring in the ecophysiology of a temperate lizard.
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Diaz, J. I studies the thermoregulatory behavior of a field population of the Canarian lizard Gallotia galloti, using null hypothesis based on 1 the measurement of operative temperatures available in full sun and in the shade Te , and 2 the distribution of randomly positioned models with respect to sun and shade. The activity curve of the lizard population was unimodal, with a pronounced peak in the morning and lower though roughly constant levels at later times of day.
Activity levels were positively correlated with the difference between Te in the sund and Te in the shade, but negatively correlated with Te in the shade. The distribution of lizards into sun-shade categories was highly selective relative to paper models, with an overall daily selectivity pattern that was symmetrical around midday selection of sunlit perches early and late in the day, shade seeking at midday, and random distribution at intermediate hours. The low dispersion of hourly mean operative temperatures at lizard perching sites relative to random locations of models average values calculated weighting mean Tes with frequencies of sun-shade use and sun-shade availability suggested a high degree of thermoregulatory precision.
Diaz, M. Universidad de La Laguna. Plasma concentrations of aldosterone, sodium and potassium were measured in the lizard Gallotia galloti. Aldosterone concentrations in control animals were Peripheral sodium and postassium concentrations were Plasma aldosterone and sodium were negatively correlated. A positive relationship could be established between potassium concentration and aldosterone levels. Acute or chronic administration of exogenous aldosterone increased the circulating levels of this hormone, being maximal in chronically treated animals.
However, although plasma concentrations of aldosterone were augmented by acute administration, the sodium concentration in the plasma was only elevated by chronic treatment. No further changes to potassium concentration could be observed under primary hyperaldosteronism conditions. The extent to which aldosterone may be implicated in the regulation of sodium and potassium transport in reptiles and its possible action on postrenal structures of electrolyte transport are discussed.
The effects of D-aldosterone on the electrical properties and ionic transport have been analysed in vitro in the colonic epithelium of the lizard, Gallotia galloti. The injection of 30 g of D-aldosterone induced a significant rise of plasma aldosterone concentration, sustained for 4 hr after administration. Intraperitoneal injections of D-aldosterone caused a slight reduction of transmural potential difference PD and short-circuit current Isc. Cl- absorption was increased in treated lizards. Addition of mucosal barium to treated tissues brought about a sustained increase of PD and Isc.
The absorption of fluid in normal lizards was reversed to fluid secretion in treated lizards. The effects of D-aldosterone on lizard colon are compared with those reported for the colon of mammals and birds. Diaz Herrero, E. Dubois, A. Therefore, the designation by Boulenger of a third specimen MNHN as lectotype of the species is not valid, and the designation by Bischoff of the specimen MNHN as lectotype, although posterior to that of Boulenger , is valid.
Font, E. Perera eds. Evolutionary and Ecological Perspectives. Recerca, 8: Bright colors and conspicuous visual displays have been described in many lacertid species. In this study we use UV photography and reflectance spectrophotometry to document the presence and distribution of UV reflectance in color patches of Gallotia lizards from the Canary Islands. We found considerable reflection of UV light in blue, yellow, and green color patches of different Gallotia species. Fore example, the lateral and ventro-lateral blue patches of G.
The blue, UV-reflecting patches are present in lizards of either sex. However, These are differences in the spectral shape of blue patches from male and female lizards, particularly in the UV range. We conclude that G. Furthermore, we found large interindividual differences in the reflectance of blue patches in lizards from the same sex and population. These differences are again most marked in the UV region of the spectrum. We discuss possible functions of UV-reflecting patches in sex recognition, male-male contests, and mutual mate choice.
Fossi, M. Diaz-Diaz, R. Gomez, T. In the search for properties of the Kindling effect in the lizard Gallotia galloti and after testing about animals, one of them produced a very high density of recurrent electrographic seizures without previous application of any epileptogenic treatment. Ten percent of the recorded time four days, continuous recording was spent in seizures of variable morphology. Gonzales, J. The ratio between heating and cooling thermal time constants shows no dependence on body weight and its value was 0.
During heating the core and subcutaneous body regions heat at the same rate, while during cooling the core cools more slowly than the subcutaneous area. The increased heart activity during heating appears to be a physiologically controlled response, as opposed to the decreased heart activity during cooling, which appears to be a passive response.
Harris, D. In recent years there has been an exponential increase in the amount of published DNA sequences, as it has become one of the most popular sources of data for reconstructing phylogenies. A number of studies have attempted to resolve the relationships of groups of lacertids using mitochondrial DNA sequence data, in particular Podarcis and Gallotia e.
Reassessment of these data suggest some alternative phylogenies to those previously published, and also highlight possible problems. By combining these essentially congruent data sets, and reanalysing levels of support for the phylogenies produced, a more complete estimate of relationships across the family is produced. Reasons for discrepencies are discussed, as are the relative advantages and disadvantages of the different sources of phylogenetic inference. Hecke, A. Herrel, A.
Huyghe, K. Morphological characteristics snout—vent length, badge area, mass, limb and head measures and whole-animal performance capacities sprint speed, acceleration capacity, stamina and bite force were measured in male lizards, Gallotia galloti. These males were also tested in paired staged contests to assess relative fighting capacity and to link these results to morphology and performance.
A multivariate analysis of the four performance features revealed a clear difference between the physiological capacities of winners vs losers, with bite force being the most important predictor of the outcome of fights. The finding that bite performance is linked to dominance fits in with the high sexual dimorphism in head size in this species, as head size is a predictor of bite force performance. Winners of contests also tended to have larger total areas of blue patches on their sides, suggesting that these badges convey information on the social status of the males.
However, since no correlation was found between bite force and badge size, the patches seem to contain information on a component of fighting capacity other than bite force. Kober, I. Lacerta Gallotia galloti. Comparison of genetic variability between ten populations of Canarian lizards Gallotia galloti complex sampled on four islands, shows the existence of two well differentiated lineages.
The first one groups the populations from the islands of Hierro and Gomera G. The analysis of allelic frequencies, the projection of the individuals on the two princepal axes of factorial analysis of correspondences, and the very low viability of offspring support the idea of a differenciation at the specific level between the two lineages Gallotia galloti s. Martin, A. Matuschka, F. In search for the final host of Sarcocystis gallotiae, sarcocysts of naturally infected Canarian lizards, Gallotia galloti, were fed to vertebrate predators of the lizard.
Repeated transmission experiments remained negative. Routine check of the feces of the wild G. The sporocysts were administered to small vertebrates, which may function as prey for G. The transmission experiments remained negative. The observation of a high intraspecific aggression of G.
Sarcocysts of S. Oral inoculation of two laboratory-bred G. The sarcocysts were identified as S. In epithelial cells of the intestine of G. We suggest that the life cycle of S. The genus Sarcocystis seems to be more flexible in its biologic adaptability to utilize autotomy and cannibalism for completing its cycle than had heretofore been assumed. Medina, L. For a better insight into general and derived traits of developmental aspects of catecholaminergic CA systems in amniotes, we have studied the development of these systems in the brain of a lizard, Gallotia galloti, with tyrosine hydroxylase TH - and dopamine DA immunohistochemical techniques.
Two main groups of TH-immunoreactive THi perikarya appear very early in development: one group in the midbrain which gives rise to the future ventral tegmental area, substantia nigra and retrorubral cell groups, and another group in the tuberomammillary hypothalamus. CA cell groups that appear rather late in development include the cells in the olfactory bulb, the locus coeruleus and the caudal brainstem.
As expected, the development of immunoreactive fibers stays behind that of the cell bodies, but reaches the adult-like pattern just prior to hatching. Catecholamine cells in the midbrain and tuberomammillary hypothalamus are still migrating, immature absence of dendrites and express only TH immunoreactivity at the time of first detection. Cells which appear at later developmental stages lie already further away from the ventricle, possess two or more dendritic processes, and generally express both TH- and DA immunoreactivity. Mertens, R. From the study of behaviour of the lizard Gallotia galloti in a natural population of the Northwest of Tenerife Canary Islands some behaviour patterns, which had not been previously discovered could be described in detail.
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The lizards were observed through binoculars from a hide during several days per week of April, May and June. The presently described behaviour patterns contribute to enlarge the behavioural catalogue of the studied species and some of them are cited as lacertid lizards for the first time. The possible function of the patterns is also discussed. The alimentary habits of lizard specimens are described from behavioral observations of a natural population of the species Gallotia galloti.
The results showed that the cited population had a mainly vegetable diet, principally Opuntia fruits and Launaea arborescens flowers, although it also fed on some insects. On the other hand, the temporal distribution of different eating behaviours was influenced by the weather, being more sommon in hours near middaxy. Overlapping spatial distribution of eating behaviours for the different animals was observed. Within and between-population variation differences in size andcolor pattern traits are described for the lizards Gallotia galloti eisentrauti and G.
Snout-vent length and HL were greater in G. Adult male to adult female SVL ratio, a measure of body size dimorphism, was 1. For most animals. Lateral patch color was in the 5 PB purple-blue step of the Munsell System Chart, and value and chroma were and 6, respectively. The data are discussed in relation to information on male intrasexual competition.
In this paper, we present the first record of the presence of a young Gallotia galloti F. Lacertidae inside a stomach of Rana perezi F. Pasteur, G. Proteinloci von 36 Eidechsen der Art Gallotia galloti aus Teneriffa wurden untersucht. Porcell, L. Richard, M. Population phylogeographic studies are generally based solely on mtDNA without corroboration, from an independent segregating unit i. This paper attempts to evaluate the utility of microsatellites for this process by use of the Western Canary Island lacertid Gallotia galloti as a model. The geological times of island eruptions are known, and well-supported mtDNA phylogenies exist corroborated as the organismal phylogeny rather than just a gene tree by nuclear random amplified polymorphic DNAs RAPDs.
The allelic variation in 12 populations from four islands representing five haplotype lineages was investigated in five unlinked microsatellite loci. Analysis of molecular variance showed this data to be highly structured. A series of genetic distances among populations was computed based on both the variance in allele frequency i. The genetic distances based on the former were more highly correlated with the mtDNA genetic distances than those based on the latter. This was achieved despite theoretical problems posed by the use of few loci, suspected bottlenecks, and large population sizes.
The finer details were less consistently represented. Nevertheless, this study demonstrates that even a small number of microsatellites can be useful in corroborating the deeper divisions of a population phylogeny. Romero Aleman, M. Some variants of the Golgi techniques have been used to study the possible origin and developmental sequence of astroglial cells in the lizard Gallotia galloti.
Apparently, glioblasts also evolve into astroblasts that, in turn could develop into immature protoplasmic or fibrous astrocytes, precursors of mature protoplasmic and fibrous astrocytes, respectively. The present study confirms our previous ultrastructural and immunohistochemical studies on the same animal. Sanchez, J. Even though, from Darwin onwards, interisland evolution has been a cornerstone of evolutionary theory it has not been possible to determine to what extent this geographic variation reflects the phylogeny e.
Using the morphology of western Canary Island lacertids Gallotia galloti as an example, a procedure is explored that gives a preliminary answer to this problem when there are a limited number of islands. The phylogenetic component represented by patristic distances derived from mitochondrial DNA [mtDNA] base pairs can be separated from two potential ecogenetic factors environmental richness and climate by partial Mantel tests. The former two correlations may be due to ecogenetic adaptation to current ecological conditions, wheras the latter reflects historical processes. Microgeographic variation of the vegetarian lizard Gallotia galloti within the island of Tenerife is described using univariate analysis, correlation, multiple group principal component analysis, canonical analysis, transects, and contours.
The scalation scale and femoral pore counts has two facets to its geographic variation, both of which are incongruent with the primary variation in the size and shape. The scalation shows categorical variation stepped cline between northern and southern populations and also a strong clinal relationship with altitude.
The possible causes of this variation are considered and adaptation to current ecological conditions appears to be implicated for at least the altitudinal variation, although the pertinent factors are not obvious.
Similar authors to follow
It is apparent that vertebrate populations distributed across small islands do not necessarily offer the advantage of a discrete homogeneous unit for evolutionary studies but can offer the opportunity for studying microgeographic variation. Previous studies using partial regression Mantel tests of matrix correspondence on within-island geographic variation in the color pattern of the Tenerife Canary Islands lacertid lizard Gallotia galloti support natural selection for different north-south climatically determined biotopes but do not support any historical cause.
However, tests on the DNA phylogeny based primarily on population data from 57 localities on Tenerife support the hypothesis that there were populations on two putative precursor islands that have come into secondary contact and introgressed after these islands were joined to form Tenerife by the eruption of the Canadas edifice. Subsequent partial Mantel tests continue to support the hypothesis that color pattern is adapted to the climatic biotopes even when this phylogenetic information is taken into account by 1 testing for color pattern adaptation separately within each lineage and 2 testing for color pattern adaptation across the entire island and simultaneously considering the molecular phylogenetic relationships as representing an alternative explanation.
Selection has largely expunged any trace of the geological history from current morphological variation, and the introgression of these island populations after an estimated 0. This study of the microgeographic variation in the colour pattern of the lizard, Gallotia galloti, within Tenerife has three facets. One, an analysis of the population distribution and density in relation to physical conditions; two, univariate and multivariate descriptions of the pattern of geographic variation; and three, formal testing of a range of causal hypotheses for these geographic patterns.
The range is not divided into separate allotheses high- and low-altitude populations by a inaptitude ring of ground-level cloud although there is a drop in population-density in the middle altitudes. Multiple regression indicates that, or the factors measured, this is primarily due to a decrease in insolation. The pattern of geographic variation in the six independent colour pattern characters is portrayed by contouring the 67 locality means.
There is generally good congruence among these patterns and a canonical analysis indicates that the generalized pattern of geographic variation is largely unidimensional and can therefore be represented adequately by and portrayed by contouring the first canonical variate. Seven causal hypotheses, from a range of possible and previously suggested causes, are considered. The procedure for testing these hypotheses should depend on their dimensionality and that of the observed pattern. Since all the observed and hypothesized patterns are basically unidimensional the seven hypothesized patterns were simultaneously tested against each observed pattern individual characters and canonical variate by partial correlation.
The hypotheses that the geographic variation in the colour pattern is caused by the topographically determined climate cannot be rejected. The relationship between an endemic lizard Gallotia galloti and plants with fleshy fruits was examined in a xeric habitat on the island of Tenerife, Canary Islands. Fruits of seven plant species were found in the droppings: Rubia fruticosa, Neochamaelea pulverulenta, Withania aristata, Lycium intricatum, Atriplex semibaccata, Opuntia dillenii and Scilla cf.
The number of fruit species consumed at each area by G. Seed Viability did not differ between control seeds and seeds from the droppings, except for N. The gut passage of seeds significantly reduced the germination of R. This should produce a non-random seed shadow in the habitats, potentially affecting the distribution of species with fleshy fruits.
Omnivorous lizards on islands can act as important seed dispersers over short distances for plant species with fleshy fruits, actively influencing both their relative abundance and vegetation structure in xeric habitats. We analyzed the frugivorous diet of the lizard Gallotia galloti, a Canary Island endemic, in relation to season and fruit availability in a xeric habitat from Tenerife.
Variation in fleshy fruit consumption was associated with seasonal patterns of fruits availability. A total of seeds were found in droppings analyzed during the entire year corresponding the majority to Rubia fruticosa and Plocama pendula Rubiaceae. These results contrast with the majority of continental lacertids that are insectivorous. Vogel, P. Wevers Jr. Howard, C. Aggressive encounters ranged from only throat extension to escalated fights with biting and rolling over. Winners were heavier, had longer heads, and performed tongue-flicking, throat extension and biting at a higher rate than losers.
The rate of aggressive behaviour increased with decreasing difference in snout-to-vent length, head length and head width of the contestants. The results are in agreement with some predictions of the sequential assessment game model in that probability of victory increased with the difference in fighting ability and that the rate of aggressive behaviour was higher in contests between animals of similar size.
Rodriguez-Dominguez, M. Zimmermann, H. Lebensraum, Verhalten, Fortpflanzung. Grossmann, W. In order to contribute to a comparative view on lacertids, the effect of pinealectomy on the freerunning activity displayed under constant darkness and temperature Animals showed an entrained motor activity rhythm under an initial light-dark hours routine and freerunning circadian periods ranging between After pinealectomy, most animals showed no significant circadian rhythm, their locomotor activity becoming diffuse throughout the whole 24 h period.
Thus, the pineal gland seems to play an important role as a main pacemaker regulating the endogenous activity rhythm under constant conditions. This result contrasts with that found in Podarcis sicula where after pinealectomy only changes in length of the freerunning period were found. Musters, R. Canary island lizards are very aggresive animals.
Kept indoors the lizards arc very shy. Adult animals lose their shyness in an outdoor ter- rarium. If kept together the young animals may fight or even kill each other. My conclusion is to keep the juveniles in separate containers. The fe- males lay about seven eggs in July, and at an incu- bation temperature of 28 to 31o C the eggs hatch after 63 to 68 days.
Bravo, T. Castillo, C. Die weitgehende Erhaltung des Schuppenkleides gestattet zum erstenmal eine genauerer Beschreibung der ausgestorbenen Art Gallotia goliath. Auch Konkurrenz zwischen juvenilen G. Gasc, J. Izquierdo, I. A new deposit of giant lacertids is described from a volcanic cave in the western part of El Hierro island. On the basis of an analysis of the pieces found in this deposit, using both the literature and osteological material from Tenerife and El Hierro, it is concluded that three different species are represented: Gallotia goliath Mertens , now extinct in the Canary Islands, Gallotia simonyi Stein.
The two last species are still present on the island. The presence of G. Maca-Meyer, N. Contrary to recent opinion, it is phylogenetically distinct, within the G. It may be the sister taxon of either all the other members of the G. The phylogenetic distinctness of G. Gallotia shows great community differences on other islands in the Canaries, two having a single small species, one a single giant, and three a giant and a medium-sized form.
Marrero Rodriguez, A. Et Pet, Pertenece a la familia del lagarto gigante de El Hierro. Diario de Avisos. In June of the senior author discovered a new form of lizard in the Teno Massif, the westernmost part of Tenerife Island, which is very similar to the Giant lizard of El Hierro Gallotia simonyi. The new lizard differs from the latter by its smaller size, morphological characters, and its very different pattern of coloration.
To the present, only G. In this article, the recently discovered lizards and their habitat are briefly presented. Furthermore, the present knowledge of the status of the population and problems concerning the endangerment of these extremely rare reptiles are discussed. Arano, B. Cytogenetic analysis and the patterns of alloenzyme migration were used to analyse the possible endogamic depression caused by the scarce number of specimens of the lizard still in existence. There would appear to be no chromosomic definition for sex nor do variations appear in the layout of C bands over the various individuals.
Protein electrophoresis has shown that all individuals are monomorphous over the 32 loci analysed. This fact reveals absence of heterocygosity and polymorphism. From the results, we discuss the possibility of total loss of genetic diversity and the application of other techniques towards confirming this extreme analysis of mini- and macro-satellites.
An optimisation of the present cross breeding system used for the specimens in captivity is proposed in order to palliate the high rates of endogamy. The study of two speimens of Gallotia simonyi, that were captured on Roque de Fuera Anaga, Tenerife , has confirmed the presence, up to fairly recent times, of the last population of this species on the island of Tenerife. The mentioned population has been completely exterminated within the last 50 years by man.
Apicomplexa: Sarcocystidae from the endangered Hierro giant lizard Gallotia simonyi Reptilia: Lacertidae. Wild-caught specimens of the highly endangered giant lizard Gallotia simonyi, which is endemic to the Canary Island of Hierro, were examined for sarcosporidian parasites. Feeding of these sarcocysts to a laboratory-reared G. Following experimental transmission. I used light and electron microscopy and identified this parasite as Sarcocastis simonyi sp. Bender, C. Bings, W. The cliff of Fuga de Gorreta on Hierro ist the last retreat of Gallotia simonyi. During a visit of the island in the author followefd old and new hints at the present and former occurrence of the lizard.
However, it was not possible to document the present existence of the species outside the Fuga de Gorreta. In addition caves and concheros of the Guanches were investigated with respect to skeletal material. Several remains of lizards were found, some dentalia indicating a considerable size of the lizards. The findings also indicate that the lizards were eaten by the aboriginals. Wie bei den anderen kanarischen Lacerten, gibt es auch bei L. Bemerkenswert sind zahlreiche Eidechsenknochen, unter denen sich auch Reste der heute fast ausgestorbenen Gallotia simonyi befinden, und die die einst weitere Verbreitung dieser Art auf der Insel belegen.
Dies ging bisher nur aus mittelalterlicher Berichten hervor. Zu dieser Jahreszeit hat die Vegetation gerade begonnen, sich zu entwickeln. In dieser Zeit erscheinen die Tiere of lethargisch, und sie sind sehr scheu. Die Eiablage findet in der untersuchten Gegend zwischen dem Mai und Juli statt. Ein Weibchen zeitigte zwei Gelege in einem Jahr, wovon das 2. Das 1. Caetano, A. Since , the insular, endangered Hierro Giant Lizard Gallotia simonyi machadoi: Lacertidae has been subjected to captive breeding for conservation purposes at El Hierro Canary Islands.
Due to the lack of a reintroduction plan, presently the captive stock probably outnumbers the wild population of the species, which only occurs at a steep cliff within the island. For the first time, two adult males, fitted with radiocollars, were freed in the wild. The lizards were released at La Dehesa, a pre-selected sit devoid of current populations of the species, but belonging to its historic range as evidenced by plenty of subfossil remains.
The study was aimed to test whether the captive reared lizards are good subjects for a reintroduction program, and whether the selected area still suits well their ecological requirements. For months, both lizards stayed close to the release plot, dug burrows and found food. Body weight losses during the dry season were overcome in the following humid seasons, as food availabity improved.
Activity cycles and feeding were favoured by better thermal conditions than those experienced by the wild and captive populations. Adter days, one of the lizards was killed by a feral cat, as has been shown to happen in the wild population. Our results shows that the extant wild population of G.
A reintroduction of captive reared lizards in well preserved habitats of the islands in both recommendable and feasible, provided that a feral cat control program is undertaken. We studied the thermal sensitivity of sprint speed in the captive population of the endangered lizard Gallotia simonyi Lacertidae on El Hierro island and in G. Among adults, lizards of both species were faster than adults of other lacertids. The sprint performance curves for both species had a flat upper plateau, and the obtained values for performance breadth were high, indicating that species attained near maximum sprint speeds over a wide range of body temperatures.
Gallotia stehlini was significantly faster than G. Juveniles of G. The lower sprint speed of G. Juveniles rather than adults from the captive population of G. The giant lizard of El Hierro, Gallotia simonyi, is perilously close to extinction. Here we describe 51 categories of resenzia for this endangered species grouped in five classes; maintenance, locomotory, feeding, social and reproductive.
Reproductive behaviour showed peculiar patterns involved on plant material consumption. However, even under resenzia conditions, Gallotia simonyi exhibited low levels of lovomotor activity and decreased levels of aggressiveness compared to other Gallotia species in the Canary archipelago. Agonistic behaviour was only observed in juvenile individuals. These observations are consistent with the mild temperament of Gallotia simonyi, which may be related to the prolongued captivity of the adults.
Avian predation is likely to be a relevant pressure on the populations of lizards of El Hierro Canary Islands , particularly if we consider that kestrel Falco tinnunculus is extremely abundant on the island. We investigate the potential predation pressure on G. We also address the question of wheather there is a size refugium for large lizards in relation to avian predators. Lizards are a substantial portion of the diet of the kestrel although predation pressure upon models was not high.
The only site where high predation pressure was detected in the plasticine models is the natural habitat of the relictual extant population of G. In this habitat however, models of large lizards were attacked significantly less than models of small lizards. A study of the diet of F. We report selected body temperatures Tb and thermal set-points ranges Tset of males, females and juveniles of Gallotia simonyi. This information may contribute to improving captive population conditions and to select reintroduction areas of this endangered species.
We also report thermal requirements of sympatric G. Mean body temperature of G. The lizards from the Island of El Hierro appear to be more thermophylous than the other two species. Cheylan, M. Corbett, K. Corti, C. Feral cats are introduced predators spread all over the canary archipelago. Their possible role in the extinction processes undergone by the endemic fauna was investigated by comparing the impact of cat predation on Gallotia simonyi, a big sized, endemic lacertid lizard close to extinction, whith that experienced by other native and introduced species at two sites on El Hierro island.
The sympatric, small and widespread G. A general approach to food habits, spatial patterns and activity patterns of feral cats was devised to achieve conclusions. Ecological and social adjustments were similar to those described in other feral populations previously studied. Cats showed a strong dependence on the availability of rabbits. Evidence was found that cats also selected Gallotia lizards as preferred prey, irrespective of their aboundance. Nearly extinction of G. Hence, feral cat control is invoked as a necessary measure to save the giant lizard from extinction, and recover its former island-wide range.
Garcia Cruz, C. Llorente, G. The place chosen la Dehesa is situated in the west of El Hierro island.
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The vegetation is composed of Juniperus forest not much affected by human influence. Although the El Hierro Giant Lizard Gallotia simonyi is mainly a herbivorous species, its diet is completed by consuming preys, mainly arthropods. Monitoring throughout an annual cycle was carried out in order to evaluate in a reliable way the suitability of the area as a possible place for releasing lizards.
The evolution of trophic resources animal was analyzed by means of monthly biocenometers.
The results obtained show that the resources consumed by the natural population of El Hierro Giant Lizard are represented. Both, prey number and biomass available are scarce throughout the year but they are considered enough for fulfilling the trophic requirements of an introduced populations since they play a complementary role in its diet.
On the other hand, the size classes of the arthropods present fall within the range consumed by the lacertids of such body size. Paleontological and archaeological evidences coming from 39 sites of El Hierro Canary Islands show that the herbivorous, bog sized and endangered G. Sadly for conservation concerns, most of this landscape has been strongly perturbed by man.
The taphonomical traits of many subfossil findings strongly suggest for feral cats probably introduced after the resenzi conquest playing a role in these extinctions. Lavin, S. The objewct of this study was to examine the erythrocytes, leukocytes and thrombocytes of the giant lizard of El Hierro Gallotia simonyi by light and electron TEM microscopy, and cytochemical staining. Smears were prepared from blood from the ventral coccygeal vein of 10 healthy adult lizards five males and five females from the Giant Lizard of El Hierro Reproduction and Research Centre, Canary Islands, Spain.
Electron microscopy was also performed on all samples. Azurophil cytoplasm was vacuolated on TEM. The cytoplasm of lymphocytes contained many ribosomes and was positive for AP. Monocytes had a large nucleus and a vacualated cytoplasm but did not stain by any of the cytochemical methods used. Thrombocytes had a relatively large nucleus but little cytoplasm; they did not stein cytochemically. The blood cells of the giant lizards of El Hierro differ from those of other members of the Order Squamata both morphologically and cytochemically. The variation in cytochemical responses in the blood of reptiles makes it necessary to study species individually if meaningful clinical decisions are to be made.
Saco, M. Montori, A. In the present paper we present the results obtained during the first year of action within the recovery plan of the species designed and advanced by the Spanish Herpetological Society AHE and the Regional Government of the Canary Islands. Believed to be extinctand rediscoveredin , the Hierro Giant Lizard has at present only a small population of scarcely specimens livingin the area called Fugade Gorreta in the island of EI Hierro Canary Islands. To avoid its extinction, reproduction of captive specimens has been achieved, and the basic studies have been performed to contemplate its reintroduction in other suitable areas.
At present a number of animals born in captivity is available specimens , from which new population groups maybe established to allow the species to recolonize the areas it formerly occupied in the island. Naeslund Diaz, C. Roque Chico de Salmor Canary Islands surveys: 1. Band 6. Orrit, N. One of the places chosen La Dehesa is situated in the west of el Hierro island. The area was selected because of several reasons: the finding of fossil remains of giant lizards, its remote situation far from human influence, the good plant coverage and the present of potential shelters.
Monitoring was carried out in order to evaluate in a reliable way the suitability of the area as a possible place for releasing lizards.
The evolution of trophic resources vegetation was analyzed by means of monthly transects. The results allow to value this area positively as a zone for expanding the range of the lizard, since it resenz the necessary condition for supporting a lizard population.
The lack of water during the dry seasons is minimized by the water contained in the vegetation. The carrying capacity of La Dehesa expressed in minimum lizard density and calculated from the plant biomass available would vary between Endangered and close to resenzia , the giant lizard of El Hierro Gallotia simonyi is the subject of a recovery plan based on captive breeding and eventual reintroduction into native habitats.
This endemic species is largely herbivorous and in captivity bred resenzia o on a diet that was nutritious but not based on native foods. One goal was to change the dietary habits of a group of G. Thus, a controlled period of adaptation to the natural vegetation of the reintroduction area was established. In captivity they had received water ad libitum, but in the dry natural area water is only occasionally available as condensation or rain. Our results indicate that the animals can consume and do well on the native resources available in the reintroduction area, particularly fruits of Juniperus resenzia, which are produced throughout the year.
Lastly, we include dietary recommendations for lizards born in captivity which will ultimately be reintroduced into native habitats. Las Palmas de Gran Canaria. Paulo, O. Ziegler eds. Roca, V. Un Canario enapurlos. Superviviente del pasado. Revista de la Consejeria de Politica Territorial y Medio ambiente.
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Gobierno de Canarias, 6: Rodriguez, M. Romero-Bevia, M. We also observe a sex-ratio bias towards females, as well as a lower proportion of juveniles than expected. The possible causes of this population structure are discussed. Gallotia simonyi shows a clear sexual dimorphism in body size, as well as a significantly slower growth rate than other lacertid lizards of similar body size. We did not observe significant differences in the condition state of individuals from lower and higher altitudinal parts of the distribution area.
Rosa, H. Salvador, A. Siebenrock, F. Der Fund eines ca. Ein Appell zur Rettung von L. Carranza, S. Martinez Rica, J. This paper presents the first data on the ecology of the Giant Hierro Lizard Gallotia simonyi simonyi from Canary Islands; this animal was believed to be extinct until its recent finding, in The biotope, a very steep rocky cliff, almost inaccessible in many places, is described; the climate of the area is subdesertic and the plant cover, very sparse, is xerophytic; the vertebrate fauna is poor, but insects are abundant and diverse.
The colour of this lizard is almost black, with large dull grey patches at the sides in the adults, while in the youngs the colour is earthly brown with whitish dorsal stripes. Daily activity begins in young specimens when the sun reaches the area, while in the adult ones activity begins somewhat later, even at noon for the oldest animals. The diet consists entirely of plants, and includes lignified stems and other non-nourishing parts from several species Kleinia neriifolia, Lavandula abrotanoides, etc.
Obviously there exists a strong intraspecific competition for food. The number of animals was very low in September , about specimens, half of them or more being young. This number might have been increased by now through protective measures recently adopted. Nevertheless, the status of the population is still critical and the danger of its extinction is strong. Some recent plans to modify the area, building industrial facilities nearby, may have, of course, very bad effects on this lizard. Steindachner, F.
Undescribed behavior. Amat, F. Angel, M. Damit haben wir an dieser Stelle erst einmal genug zu dem Thema gesagt — dachten wir. Nun gibt es aber doch weitere erfreuliche Neuigkeiten vorzustellen. Luef, H. Santa Cruz de Tenerife. We describe the external morphology of a new giant lizard found alive on La Gomera Island Canarian Archipelago , which had been previously described from subfossil bones.
Adult size SVL mm is comparable with the two largest living species G. It differs from the other species of Gallotia in the low number of temporal scales , presence of one elongate interprefrontal scale linearly depressed in center that is very infrequent in most of its congeners small when it is present , having two distinctive lateral lines of small blue spots, and in having a blackish-brown dorsum and ventral parts ivory white.
According to subfossil data, based on tooth morphology and body size, this lizard seems to correspond to the putatively extinct subspecies G. This taxon is sufficiently distinct to be treated as a full species, G. After prospecting 70 localities in La Gomera, we only found a very small and threatened population of this species in Valle Gran Rey, in the western part of the island and living in an area of less than 1 ha. A small population size only six individuals are known and a large number of feral cats in their habitat makes this lizard the most endangered vertebrate of the Canaries and Europe and one of the most threatened in all the world.
The species is suspected to be on the brink of extinction, so conservation measures are urgently needed, including a captive breeding plan at Valle Gran Rey, close to the natural habitat. Rico, J. Geografica, Octubre Rodriguez-Luengo, J. Schuster, P. Scriba, D. Es wird ein kurzer Einblick in die verwandtschaftliche Stellung von Lacerta simonyi stehlini gegeben.
Einige Beobachtungen zur Nahrungsaufnahme und zum Verhalten im Terrarium gepflegter Exemplare werden beschrieben. Es wurden nacheinander zwei Gelege von sieben und elf Eiern gebracht. Ihr Aussehen, Wachstum und Verhalten in den ersten vier Lebensmonaten wird beschrieben. Heselhaus, R. Luft, A. Martin, J. Lagarto de Gran Canaria. Monografias de Herpetologia, no.
Mateo Miras, J. Richter, K. The transmission of Sarcocystis species via cannibalism seems to be common among lizards of the genus Gallotia that are endemic to the Canary Islands. Gran Canarian giant lizards, Gallotia stehlini, were screened for the presence of sarcosporidian parasites. In their feces the lizards passed sporocysts of 8.
A series of laboratory infections was carried out to shed light on the life cycle of Sarcocystis stehlinii n. Lacertidae as obtained from behaviour observations. Naranjo, J. Perez-Santana, L. The retinotectal projection of reptiles is largely crossed. The intertectal commissure is an important pathway that interconnects directly the two sides of the optic tectum. The rostrocaudal topography of intertectal commissural fibers at the dorsal midplane was examined by means of the in vitro horseradish peroxidase HRP labelling technique in the lizard Gallotia stehlini.
Unilateral large deposits of tracer in the optic tectum as well as smaller deposits restricted to one quadrant were used to map the intertectal fibers anterogradely. Most commissural axons reached the contralateral side grouped into a dense bundle at the transition between two structurally distinct parts of the midbrain dorsal midline.
The smaller rostral zone relates laterally to the griseum tectale, whereas the larger caudal zone relates to the tectum. The intertectal fibers seem to converge on the rostralmost part of the latter midline region, even though they originate throughout the optic tectum. A rough rostrocaudal tectotopic order was detected at the midline. Retrogradely labelled neurons were best obtained by depositing HRP directly within the compact commissure at the midline.
These belong to pyriform cells in the periventricular layers 3 and 5. Axons labelled from the tectum did not enter the posterior commissure nor the intervening commissural region related to the griseum tectale. Rogner, M. Carrascal, L. Museo Nacional de Ciencias Naturales, Madrid.
Humboldt-Universität zu Berlin
Schifter, H. The lacertid lizard Gallotia stehlini , an endemic of Gran Canaria, shows no visually obvious geographic variation, yet all seven scalation characters that were examined exhibit significant geographic variation. The number of collar scales, scales along the ventral trunk and femoral pores are correlated with habitat type, while the number of femoral pores is correlated negatively with altitude. Mantel tests were used to compare simultaneously an observed pattern with three hypothesized patterns habitat type, altitude and proximity. They indicate that, while several individual characters are significantly associated with the putative causal factors of habitat type and altitude, there is no association between an overall scalation distance matrix and habitat type, or altitude when the effect of proximity is removed.
Consequently, one should consider the individual characters as well as the multivariate generalized distances. Some of the observed patterns of geographic variation in scalation are very similar to those of the small scincid lizard Chalcides sexlineatus on Gran Canaria and also parallel the altitudinal and latitudinal variation in the scalation of the Tenerife lacertid Galotia galloti. The low level of congruence in patterns of geographic variation in individual characters i.
Wijffels, L. Zapatero, C. Pharyngodonid nematodes Oxyuroidea belonging to the genus Alaeuris Thapar, , were collected from the posterior gut of Gallotia stehlini Lacertidae from Grand Canary Island. Two species Alaeuris stehlini n. The new species is described in which the long thin males are characterized by narrow caudal alae, a rounded first pair of adanal papillae non pedunculate, the second pair attached and elongate, the three pair teated; a short narrow V plate and a relatively long caudal appendage.
The females are also long and thin with a slightly salient vulva, a conical pointed caudal appendage, oesophageal length approximately one third of body, excretory pore below the oesophageal bulb. The new subspecies most closely resembles Alaeuris numidica numidica. Seurat, Petter, and Alaeuris numidica madagascariensis Petter, Menne, H. Busack, S. The lacertid lizard Psammodromus algirus has been considered a uniform species across its distribution area in North Africa and southwestern Europe. Coloration data and discriminant function analysis of morphological data corroborate mitochondrial DNA and allozyme data to indicate northern and southern Iberian populations represent unknown species that are described here.
Additional work is needed to fully understand bio-geography and variation in this species complex. Blanc, C. Habitat selection of Psammodromus algirus and P. The two species select areas with a high cover of herbs and bushes at ground level and at a height of 10 cm above ground. Whereas P. Therefore, and despite their coincidence in the centre of the habitat gradient and hence their high overlap in habitat use, both species appear to be segregated, with P. The observed differences in habitat selection are discussed in the light of differences in morphology, reproductive constraints and predator avoidance.
We conclude that interspecific competition plays a negligible role in the habitat segregation of the two species. Aguilar, F. The basic anatomy of the lacertid hemipenis intromittent organ and methods for its investigation are described. In many members of the Lacertidae, the hemipenis has a structure quite unlike that of other squamate reptiles: the distal lobes of the retracted organ are complexly folded and there is a well-defined supporting structure of dense connective tissue, the armature.
This incorporates blood sinuses and has an intramuscular portion embedded in the m. Unarmatured hemipenes occur in some lacertids and, like those of other squamates, possess sac-like lobes in the retracted state, but they are singular in having the lobes invested by the m. These articles can be cited using the expression "in press". For example: Smith, J. Article Title. Journal Title. Articles marked with this shopping trolley icon are available for purchase - click on the icon to send an email request to purchase.
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We employed a qualitative case study design to explore potential factors affecting microblogging integration in a hybrid course. Using the technology acceptance model TAM model as an umbrella framework, we examined through in-depth interviews with 18 participants the impact of microblogging integration into instruction that affected students' reported use and perceptions of their microblogging-supported learning experiences.
We found that individual differences, system characteristics, social influence, and facilitating conditions all have impact on student participation and engagement in microblogging integration to varying degrees. We identified more granular factors within each of the four dimensions. Additionally, we proposed a Twitter user taxonomy based on perceived usefulness and usage behavior and discussed its broad implications in higher education learning environments.
Finally, we identified several pedagogical implications pertaining to strategies of microblogging integration under the context of a hybrid course, and offered pertinent recommendations for future research. Keywords : computer-mediated communication; social media; technology acceptance model TAM ; microblogging; Twitter. Adding hashtags to tweets allows users to connect with previously unknown others around areas of common interest and provides opportunities to examine these connections. This study explored how open education is discussed on Twitter around the openeducation hashtag through a scalable mixed methods content analysis model useful for the multi-pronged analyse of hashtag discourse.
Researchers analysed a convenience sample of tweets using the openeducation hashtag and grouped the results into themes. Thirty-two themes emerged, which were grouped into eight categories. To extend the research model, a questionnaire developed from the themes was piloted with a subset of active hashtag users. The results provide insight into the major discourse on open education, as well as a scalable means to analyse discourse on Twitter, identify active participants, and probe further about ties people have to a topic of interest. Keywords : content analysis; Twitter; social media; open education.
DOI: The study adopted survey approach. The sampling method adopted for the purpose of this study was simple random sampling techniques.