Agama Stellio Research Articles

Agama stellio

This datasheet on Agama stellio covers Identity, Distribution.

Blood parasites of amphibians and reptiles in Israel

ABSTRACT A survey of 196 amphibians and reptiles (39 species) from Israel, conducted between June and November, 1984, revealed the following blood parasites: Rana ridibunda, 3 species of Trypanosoma, including T. rotatorium and 2 unidentified species, and 2 unidentified species of Haemogregarina. In lizards and snakes, only haemogregarines were seen, probably Hepatozoon spp. Two species were observed in Agama stellio, probably 2 species in Acanthodactylus boskianus and one species in Varanus griseus. Among the snakes, gamonts of morphologically similar haemogregarines were recorded from Coluber rhodorachis, Malpolon moilensis and Cerastes cerastes. These parasites resembled Hepatozoon aegypti which occurred in 2 specimens of Spalerosophis diadema. A different haemogregarine was observed in Walterinnesia aegyptia. A haemogregarine was recorded from the Caspian terrapin, Mauremys caspica rivulata. Localities and prevalence data are presented and potential vectors for the parasites are discussed.

ENERGY CONTENT OF EGGS AND BODIES AND THE MEASUREMENT OF RELATIVE CLUTCH MASS IN THE LIZARD AGAMA STELLIO STELLIO

ABSTRACT Energy content of eggs and bodies and the relative clutch mass (RCM) in the lizard Agama stellio stellio was investigated. There was a positive correlation between “ra” (rostrum—anus) length and clutch mass (both wet and dry), as well as between “ra” length and clutch calories, suggesting that RCM increases with age. There was no correlation between “ra” length and mean dry egg weight or mean egg calories. There was a positive correlation between dry clutch/dry body mass and clutch calories/body calories ratios. The relatively high RCM may reflect the foraging mode of the lizard.

Purification and kinetic properties of skeletal muscle lactate dehydrogenase from the lizard Agama stellio stellio.

Lactate dehydrogenase isoenzyme LDH-5 (M4) was purified to homogeneity from the skeletal muscle of lizard Agama stellio stellio as a poikilothermic animal, using colchicine-Sepharose chromatography and heat inactivation. The purified enzyme showed a single band after SDS-PAGE, corresponding to a molecular weight of 36 kD. The Km values for pyruvate, NADH, lactate, and NAD+ were 0.020, 0.040, 8.1, and 0.02 mM, respectively. Pyruvate showed maximum activity at about 180 microM, with a decline at higher concentrations. The enzyme was stable at 70 degrees C for 30 min, but was rapidly inactivated at 90 degrees C. The optimum pH for the forward reaction (pyruvate to lactate) was 7.5, and for the reverse reaction (lactate to pyruvate) was 9.2. Oxalate, glutamate, Cu2+, Co2+, Mn2+, and Mg2+ were inhibitory in both forward and reverse reactions.

Ultrastructure of developmental stages of Hemolivia mariae (Apicomplexa: Haemogregarinidae), natural parasite of the Australian sleepy lizard, in experimentally infected deviant hosts.

Mabuya vitatta (Olivier) (Scincidae) and Agama stellio (L.) (Agamidae) were infected with Hemolivia mariae Smallridge et Paperna, 1997 by ingestion of tick viscera from Amblyomma limbatum Neumann, fed as nymphs on naturally infected Australian sleepy lizards, Tiliqua rugosa Gray. The unnatural infection apparently interfered with the developmental schedule of the parasites. Transmission electron microscopic images of merogonic stages were obtained, as well as images of early developing gametocytes. Tissue and intraerythrocytic meronts were bound by a hardened wall. Intraerythrocytic gametocytes were lodged in a parasitophorous vacuole, which was filled with granular material, and were bound by a two-membrane wall. Small and large osmiophilic bodies were located in a sub-pellicular position. With differentiation, the wall membranes tightened with the parasitophorous vacuole wall, and the osmiophilic bodies disappeared. The outer parasite membrane consolidated into a thick encasing with distinct sutures. Late infection in A. stellio comprised gametocytes only.

Heavy Metal Contamination in a Lizard, Agama stellio stellio, Compared in Urban, High Altitude and Agricultural, Low Altitude Areas of North Greece

Contamination from heavy metals is a serious problem recognized In most countries of the world. Direct methods of metal detection are applied to soil and water; Indirect methods use plants and animals as bioindicators. Reptiles have not been used as bioindicators for various reasons: difficulty in sampling, ancient fears, little economic Importance, difficulty in the laboratory etc. Since Invertebrates are the prey of most lizards, the uptake of metals through invertebrates is an important pathway. Heavy metals accumulate through food ingestion and by incidental soil ingestion of soil. Reptiles have recently started to be used as bioindicators of pesticides entering the environment, with great success. The environment in Greece has a burden of heavy metals. The purpose of this paper is to ascertain whether reptiles, especially lizards, can be used as bioindicators of heavy metal pollution by compacting indirectly the level of pollution of two areas differing to some extent ecologically In the vicinity of a large city and in the vicinity of cultivated areas. The bioindicator species was the lizard Agama stellio stellio. 28 refs., 1 tab.

Quantitative analysis of jaw and hyolingual muscle activity during feeding in the lizard Agama stellio

The activity of jaw and hyolingual muscles during the entire feeding sequence is examined in the lizard Agama stellio, with special focus on the intraoral transport and swallowing stages. Correlation of electromyography (EMG) data with kinematics shows that the kinematic phases (slow opening, SO; fast opening, FO; fast closing, FC; slow closing/power stroke, SC/PS) are characterised by distinct activities in the jaw and hyolingual muscles. The SO phase is clearly the result of tongue protraction (upon protraction, the tongue is pulled against the prey and consequently the lower jaw is pushed down), whereas the FO phase is caused by activity in the jaw opener and dorsal cervical muscles. Both the FC and SC/PS phases are characterised by pronounced activity in the jaw adductor muscles. Tongue retraction is produced by activity in the hyoid and tongue retractor muscles. A quantitative analysis of time-related EMG data shows that, in accordance with the kinematic analyses, three different stages can be recognised as components of the feeding cycle: prey capture, intraoral transport and swallowing. However, analysis of intensity-related data allowed a fourth stage, crushing, to be detected. Whereas there are indications that prey capture, intraoral transport and swallowing are controlled by different motor patterns, the differences between crushing and transport are likely to be caused by feedback mechanisms. Our results show the importance of including intensity-related data in quantitative analyses of EMG recordings in order to discriminate between feeding stages. Additionally, it is shown that both the jaw and the hyolingual muscles play crucial roles during feeding. During all stages, movements of the hyolingual apparatus are an essential part of the feeding cycle. Thus, when examining lizard feeding mechanisms, the activity patterns of the hyolingual muscles should not be neglected.

Kinematics of feeding in the lizard Agama stellio

The kinematics of prey capture, intraoral transport and swallowing in lizards of the species Agama stellio (Agamidae) were investigated using cineradiography (50 frames s-1) and high-speed video recordings (500 frames s-1). Small metal markers were inserted into different parts of the upper and lower jaw and the tongue. Video and cineradiographic images were digitized, and displacements of the body, head, upper and lower jaw and the tongue were quantified. Twenty additional variables depicting displacements and timing of events were calculated. A factor analysis performed on the kinematic data separates prey capture and swallowing cycles from intraoral transport bites. However, the intraoral transport stage cannot be separated into chewing (reduction) and transport bites. The effect of prey type and size on the feeding kinematics of intraoral transport and swallowing cycles was investigated. During the intraoral transport stage, distinct aspects (e.g. durations, maximal excursions) of the gape and tongue cycle are modulated in response to both the size and type of the prey item. The results for A. stellio generally agree with a previous model, although it is the entire slow opening phase rather than solely the duration of the second part of this phase that is affected by the size of the prey. The intraoral transport cycles in A. stellio show the two synapomorphic characteristics of tetrapods (tongue-based terrestrial intraoral prey transport and the existence of a long preparatory period of prey compression). However, not all five characters of the feeding cycle previously proposed for amniotes are present in A. stellio. One major difference is that in A. stellio the recovery of the hyolingual apparatus does not take place during the slow opening phase but during the slow closing/powerstroke phase.

Chromosomal Studies of Four Egyptian Lizards of the Families Agamidae and Scincidae.

Chromosomal analysis of the four Egyptian species, Agama savignii, Agama stellio, Utomastix aegyptius (Family Agamidae) and Eumeces schneideri (Family Scincidae) have been studied. The diploid chromosome number and fundamental number (FN) of A. savignii is 2n = 46 and FN = 46. The karyotype of this species have 12 pairs of uniarmed macrochromosomes and 11 pairs of microchromosomes. The diploid chromosome number and FN of A. stellio and U. aegyptius are 2n = 36, FN = 48 and 2n = 34, FN = 46, respectively. The karyotype of each species is composed of 6 pairs of biarmed macrochromosomes and either 12 pairs of microchromosomes as in A. stellio or 11 pairs of U. aegyptius. The diploid chromosome number and FN of E. schneideri is 2n = 32 and FN = 46. The karyotype consists of 10 pairs of biarmed macrochromosomes, 2 pairs of acrocentric macrochromosomes and 4 pairs of microchromosomes. No clear differences were observed in the sex chromosomes of both sexes. Comparison of the karyotypic data of these species had been discussed.

Prey capture in the lizard Agama stellio.

Prey capture in Agama stellio was recorded by high-speed video in combination with the electrical activity of both jaw and hyolingual muscles. Quantification of kinematics and muscle activity patterns facilitated their correlation during kinematic phases. Changes in angular velocity of the gape let the strike be subdivided into four kinematic phases: slow open (SOI and SOII), fast open (FO), fast close (FC), and slow close-power stroke (SC/PS). The SOI phase is marked by initial activity in the tongue protractor, the hyoid protractor, and the ring muscle. These muscles project the tongue beyond the anterior margin of the jaw. During the SOII phase, a low level of activity in the jaw closers correlates with a decline of the jaw-opening velocity. Next, bilateral activity in the jaw openers defines the start of the FO phase. This activity ends at maximal gape. Simultaneously, the hyoid retractor and the hyoglossus become active, causing tongue retraction during the FO phase. At maximal gape, the jaw closers contract simultaneously, initiating the FC phase. After a short pause, they contract again and the prey is crushed during the SC/PS phase. Our results support the hypothesis of tongue projection in agamids by Smith ([1988] J. Morphol. 196:157-171), and show some striking similarities with muscle activity patterns during the strike in chameleons (Wainwright and Bennett [1992a] J. Exp. Biol. 168:1-21). Differences are in the activation pattern of the hyoglossus. The agamid tongue projection mechanism appears to be an ideal mechanical precursor for the ballistic tongue projection mechanism of chameleonids; the key derived feature in the chameleon tongue projection mechanism most likely lies in the changed motor pattern controlling the hyoglossus muscle. © 1995 Wiley-Liss, Inc.

Structure and histochemical organization of the spleen of Agama stellio (Sauria: Agamidae) and Chalcides ocellatus (Sauria: Scincidae).

The spleen of Agama stellio is composed mainly of red pulp; the white pulp is poorly developed, and its clusters are scattered throughout the organ and contain lymphocytes, reticular cells, and some plasma cells. The red pulp consists of clear reticular cells intermingled with blood cells, sinusoids, and pigment cells. The spleen of Chalcides ocellatus is encapsulated by connective tissue and is composed of white and red pulp. The white pulp consists of lymphoid tissue that surrounds the central arterioles, forming the periarteriolar lymphocyte sheath (PALS). The red pulp is composed of a system of venous sinuses and cords. The results of various histochemical procedures designed to demonstrate mucosubstances, proteins, and nucleic acids indicate that the spleen in these species resembles the mammalian spleen. © 1993 Wiley-Liss, Inc.

Ultrastructural studies on oocysts, sporulation and sporozoites of Schellackia cf. agamae from the intestine of the starred lizard Agama stellio

Young intracellular oocysts of Schellackia cf. agamae in the gut epithelium of Agama stellio were bound by several fine membranes. Later-stage oocysts and sporoblasts in the lamina propria were intercellular and were bound by a thin but firm tri-layered wall. Oocysts had a large central refractile body which, during sporulation, sent extensions into the developing sporozoites. Sporozoites escaped into the gut tissue, leaving a large oocyst residuum with the remains of a refractile body. These sporozoites invaded a variety of connective tissue cells, endothelial cells and circulatory leucocytes in the lamina propria. Sporozoites caused lysis of the host cell cytoplasm at their perimeter and multiple sporozoite infections led to complete degradation of the host cell.

Activity of sarafotoxin/endothelin peptides in the heart and brain of lower vertebrates

The effects of sarafotoxin-b (SRTX-b) and endothelin-1 (ET-1) were tested in the fish tilapia ( Ore niloticus × O. aureus hybrids) and torpedo ( Torpedo ocellata), the toad ( Bufo viridis), the agama lizard ( Agama stellio) and water snake ( Natrix tessellata). In isolated heart preparations of the fish and agama, peptide doses of 0.05–0.5 μg/ml induced positive inotropic effects, reduction of the contraction rate and arrhythmia, leading to cardiac arrest. In the toad, a negative inotropic effect and a reduction of the contraction rate were observed, whereas the water snake was hardly affected by either SRTX-b or ET-1. In the agama, an i.v. injection of 15 μg of SRTX-b caused changes in the ECG, culminating in A-V block that led to cardiac arrest, while in the toad an injection of 45 μg induced only transient disturbances in the ECG. Binding studies with 125I-SRTX-b revealed specific binding sites for SRTX-b and ET-1 in the heart and brain preparations of fish (tilapia and torpedo) and agama, whereas no specific binding could be demonstrated in the toad or in the snake. These results suggest that most vertebrates tested are sensitive to SRTX/ET, while the snake may possess receptors that are of a different structure.

Food consumption of the lizard Agama stellio stellio

Food consumption in the lizard Agama stellio stellio was measured by calibrated production of faeces and urates. There was no difference between daily food consumption in spring and in summer. This non-seasonal pattern in A. stellio from a temperate arid habitat thus falls between the spring/summer pattern found in other lizards from warm temperature climates, and the wet/dry season pattern found in arid environments. Estimated consumption was close to that predicted for a 66 g lizard, and slightly higher than that of the tropical Agama agama. Occupation of a temperate climate has not reduced energy intake in A. stellio, but may have consequences for its time budget.

Life cycle and transmission of Schellackia cf. agamae, a parasite of the starred lizard Agama stellio

Patent infections with Schellackia cf. agamae were established in the starred lizard Agama stellio by feeding blood or liver or by injection of blood from A. stellio infected with sporozoite stages. Mosquitoes, Aedes aegypti and Culex molestus, and larval ticks of Hyalomma aegyptium were fed on sporozoite infected A. stellio and themselves gave rise to patent infections after ingestion by uninfected A. stellio. Merogony in the duodenal epithelium usually lasted to the 14th day post-infection (d.p.i.), while in some lizards it persisted until 18 d.p.i. Microgamonts, macrogamonts and zygotes occurred 11–14 d.p.i. Oocysts migrated into the lamina propria before sporulation. Sporulation had terminated by 18 d.p.i., when sporozoites first appeared in the liver and the blood. Small, young sporozoites invaded hepatocytes and liver macrophages, while a few occurred in the erythrocytes. Sporozoites which occurred from 25 d.p.i. were larger and had invaded erythrocytes and aggregated in melanin-containing liver macrophages. Parasitaemias of medium and high levels as well as hepatic sporozoites persisted in some experimentally infected lizards for 357–370 d.p.i. Lizards could not be reinfected while a parasitaemia was detectable in them. Reptiles other than A. stellio could not be infected with S. cf. agamae.

Ultrastructural studies on sporozoite stages of Schellackia cf. agamae from liver and blood of the starred lizard agama stellio

Ultrastructural studies on sporozoite stages of Schellackia cf. agamae from liver and blood of the starred lizard Agama stellio. International Journal for Parasitology 19: 13–19. Sporozoite stage infection of Schellackia cf. agamae (Laveran & Petitt, 1909, Bulletin de la Société de Pathologie Éxotique 2: 511–512) was studied in naturally and experimentally infected Agama stellio. Infection in the liver coincided with infection in erythrocytes. In the liver sporozoites occurred in hepatocytes as well as in macrophages. Infection resulted in extreme vacuolization of the host cell, parasites were located in a common large enclave formed by the collapse of individual parasitophorous vacuoles. Sporozoites aggregated in melanin-containing macrophages in the liver in advanced stage of infection were causing only limited damage to the host cell cytoplasm. Progressive erosion of the cytoplasm also characterized infected erythrocytes.

On the distribution of four species of agama (Agamidae) in Turkey

Abstract The distribution of the Hardun, Agama stellio, the Caucasian Agama, Agama caucasia, the Syrian Agama, Agama ruderata, and Phrynocephalus helioscopus, in Turkey is presented with dot maps A. stellio and A. caucasia are sharply separated both horizontally and vertically. The area of A. stellio is defined by the March isotherm of 8°C and the July and August isotherms of 24°C. A. ruderata occurs in the large steppe areas of Inner and South-east Anatolia, but not in those of Eastern Anatolia.

Electron microscopic study of sperm head differentiation in the lizard Agama stellio

Early differentiation of the spermatid of Agama stellio is demonstrated by two anterior nuclear depressions, occupied by two proacrosomal vesicles, which fuse to form one vesicle. Later, this vesicle exhibits an acrosomal granule in its midposterior portion. The space between the posterior acrosomal membrane and the nuclear envelope is occupied by a subacrosomal fibrous layer which later exhibits a subacrosomal granule posterior to the acrosomal granule. The acrosomal vesicle and the nuclear depression flatten and later elongate. The acrosomal granule spreads and assumes the inverted V shape of the acrosomal vesicle, and the subacrosomal material assumes a feathery shape capping the nuclear prolongation. The subacrosomal granule on top of this feathery material forms a long, cross-striated subacrosomal rod which extends towards the tip of the acrosome. The chromatin material undergoes condensation into spirally oriented fibers, which eventually become homogeneous and dense. This process is accompanied by a change in the orientation of the manchette microtubules, which initially occur as rings around the nucleus and are eventually found parallel to the longitudinal axis of the nucleus.

Lipid Storage and Utilization in the Lizard Agama stellio stellio

Lipid Storage and Utilization in the Lizard Agama stellio stellio

The tail of the lizard Agama stellio stellio: Energetics, significance and comments on its regeneration

AbstractThe percentage of Agama s. stellio with broken tails is low compared to other lizards, and is higher in males than in females. The tail has a low energy content. Agama s. stellio has a tail retention adaptation as do other lizards which use the tail for climbing. The tail regenerates little or not at all, possibly because breaks occur intervertebrally, intravertebral fracture planes not being present.