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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 (SO1 and SOII), fast open (FO), fast close (FC), and slow close-power stroke (SC/PS). The SO1 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 SO11 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 (( 19881 J. Morphol. 196:157-171), and show some striking similarities with muscle activity patterns during the strike in chameleons (Wainwright and Bennett ( 1992al J. Exp. Biol. 168:l-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. B 1995 Wiley-Liss, Inc. Lizards capture prey by means of lingual or jaw prehension (Smith, '84, '88). Some authors argue that jaw-mediated prey cap- ture might be the primitive condition in squa- mates (Bels and Goosse, '90; referring to the plesiomorphic condition of jaw prehension in Amphibia, Thexton et al., '77; Lauder and ShafTer, '88; Findeis and Bemis, '90; Nishi- kawa and Cannatella, '91; Anderson, '931, but lingual prey capture is considered by most authors to be more primitive than jaw capture (Schwenk, '88; Schwenk and Bell, '88; Schwenk and Throckmorton, '89). Most functional morphological studies con- cerning prey capture in lizards have empha- sized a few groups belonging to the Iguania (Agamidae: Schwenk and Throckmorton, '89; Kraklau, '91; Iguanidae: Schwenk and Throckmorton, '89; Bels, '90; Bels and Go- osse, '90; Delheusy and Bels, '92; and Cha- maeleonidae: Gnanamuthu, '30; Zoond, '33; Bels and Baltus, '87; Bell, '89, '90; Wain

A study aimed at testing the contested validity of the subspecies Laudakia stellio daani yielded novel insights into the essence of subspecies. We examined morphologically museum specimens from Greece, Aegean islands, and Anatolia (n = 118; not all could be used in all analyses). Beyond the conventional mensural, meristic and qualitative characters we quantified 14 coloration characters, thus totalling 34 characters (including sex). Biometry was statistically analysed within and between the two geographically defined presumed subspecies, L. s. daani and L. s. stellio. Excluding or including broken‐tailed specimens changed the outcome of tests. Significant minor directional asymmetry occurred in one of four character‐taxon combinations. Phenetic cluster analysis poorly separated the two presumed subspecies when all characters, including those with discordant variation, were included; after selection of characters, the separation improved. Some biometric characters distinguish the two presumed subspecies, c...

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.

Resting oxygen consumption (VO2) rates of two desert agamid lizards, Phrynocephalus arabicus and Agama [Stellio] stellio brachydactyla, were determined in relation to ambient temperatures ranging from 10 to 40°C using a double-chambered, volumetric, closed system. Both species show relatively similar activity and preferred body temperature (PBT) ranges. Thermal dependence co-efficient (Q10) value shifts reflect that A. s. brachydactyla has a slightly lower mean PBT than that of P. arabicus. However, the metabolic rate-temperature (M-T) curves display the enhanced body mass-specific VO2 compared with the resultant obscured effect of the cooler microhabitats that A. s. brachydactyla seeks and adapts to.

SOME authors consider the lateral processes of sacral vertebrae in Lacertilia to be fused sacral ribs. Others deny this view and consider them to be nothing but well-developed transverse processes. While investigating the vertebral column of several individuals of the lizard, Agama stellio, I found one of them which supports the first view.

Agama stellio picea Parker, 1935, was clearly defined as a black lizard, with the female dotted with orange, from the Transjordan lava desert. Three later collections confirmed this. While the subspecies appears to be endemic to Jordan, its name has been erroneously applied to other A. stellio populations in adjacent countries.

The running speed of Agama stellio stellio was 2.1 ± 0.3 m s−1 at preferred body temperature (Tb, 30°C). To account for sprint locomotion, we meaured two mechanical parameters and examined the ultrastructural features of a major locomotory muscle in normal walking and running locomotion, the iliofibularis muscle, which is considered to act as an extensor of the lower hind limb. The time to peak isometric twitch tension and time to half relaxation were 52 ± 7 ms and 76 ± 5 ms, respectively. The comparative ultrastructure of the fast and slow fibes provides structure-to-function correlation. The sarcoplasmic reticulum and T-tubules system are abundant in fast fibres which serve to transmit Ca2+ and spread the excitatory impulse intracellularly with great rapidity. In contrast, the membranous system of slow fibres is relatively poor and this indicates slow impulse propagation. Thus, these results show that the fast locomotion of Agama stellio stellio can, in part, be explained by the physiology and ultrastructure of the fibres of the locomotory muscles.

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.

Hepatozoon kisrae n. sp. a ete decouvert chez Agama stellio dans une localite du sud-est de la Samarie (Palestine). Ces Lezards sont egalemant les hotes de Hyalomma cf. aegyptium. Il est demontre que cet lxodide est le vecteur de l'Hemogregarine. Le cycle ne s'effectue que dans une zone precise : les Tiques d'une region voisine sont indemnes. Les micro et macromerontes se trouvent essentiellement dans les poumons, alors que les kystes (la plupart contenant deux cystozoites) siegent dans le foie. Les gametocytes intraerythrocytaires murs, de forme trapue, sont encapsules. Le developpement depuis l'oocyste jusqu'au sporocyste, qui a lieu dans l'hemocele de la Tique, a ete etudie en microscopie electronique. Les Lezards s'infectent par ingestion, soit de Tiques infectees de sporocystes, soit de visceres de Lezards infectes. Les Tiques s'infectent par repas sur Lezards infectes; la sporogonie est achevee 40 jours apres la fixation de la nymphe, lorque le stade adulte est atteint.

Normal serum from the lizard, Agama stellio, contains a variety of haemagglutinins specific for human, rat and mouse erythrocytes. These natural heterohaemagglutinins are not obviously inhibited by simple sugars, do not require calcium ions for their activity and can act as haemolysins in a specific, complement-dependent manner. They are, moreover, sensitive to 2-mercaptoethanol treatment and can be eluted from the γ-globulin region on cellulose acetate electrophoresis. These results suggest that natural heterohaemagglutinins of A. stellio (Reptilia) have properties similar to those of natural antibodies of advanced vertebrates (birds and mammals).

Abstract The ovarian cycle of Agama stellio stellio was investigated. Oocytes present in the ovary are largest in May. Yolk deposition is completed in 5-6 weeks. Oviducal females were present over a 40 days period. The mean clutch size is 8.1 eggs. The number of clutces produced per year is 1 and rarely 2. There is no interuterine migration of eggs.

The gamogony stages of Schellackia cf. agamae (Laveran and Pettit 1909) in the gut of its host Agama stellio Hasselq. and Linn. 1757, were studied by transmission electron microscopy. The ultrastructure of both microgamonts and macrogamonts conformed in most details with that of Eimeria species. The characteristic features of the microgamonts were a large crystalline body and a mitochondrial complex. The macrogamont had large organelles located within cisterna which were morphologically similar to type 2 eimerian wallforming bodies but which differed in number and location. These organelles were seen in various stages of disaggregation and did not seem to contribute to oocyst wall formation.

The lizard Agama stellio (L) of the Western Desert of Egypt has lower blood glucose concentration, higher glycogen content of the liver and gastrocnemius muscle, and higher serum esterified fatty acids in winter than in summer. The increase in the muscle glycogen content is not significant. There is no significant difference in total serum protein, serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) between lizards in summer and in winter. It is concluded that in winter, when food is scarce, energy is obtained from fat reserves.

The 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.

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.

In this study, the breeding biology of the lizard Agama stellio stellio was investigated. Adult testis weight changes markedly during the year, reaching maximum size in spring and minimum in summer. Seminiferous tubule diameter has its maximum level in spring and minimum in summer. Spermatogenesis is initiated in mid August and terminated in early July. Spermiogenesis is generally restricted to the period following hibernation. In July and August there is a complete spermatogenetic stasis. Epididymal tubules have their maximum diameter and epithelial cell height in spring. They are secretory during this season.

The agamid lizard Stellio stellio L. accelerates quickly and reaches maximum speed over short distances. Maximum speed on the level is proportional to body mass to the power. This relation differs from predictions based on an interspecific scaling model of “geometric” similarity (M0) and is intermediate between predictions based on interspecific scaling models of “elastic” similarity and of “static stress” similarity . Maximum speed was also measured on slopes ranging from –15° to + 60°. The effect of slope on speed varies with body mass. The maximum speed of large lizards decreases on steep slopes, but that of small lizards is remarkably independent of slope.

Meront stages of Schellackia cf. agamae (Laveran and Petit, 1909) were obtained from the anterior intestine mucosal epithelium of experimentally infected Agama stellio Hasselq. and Linn., 1757. Infection was recovered 5, 7, 10 and 15 days after feeding on blood and liver containing sporozoites from naturally infected A. stellio. The parasitophorous vacuole wall consisted of one bilaminate and one single unit membranes apposed at regular intervals. Following nuclear division merozoites differentiated by exogenuous budding. The ultrastructure of the meronts, the merozoite and the merogonous process conformed in all details with that of species of Eimeria.

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.

1. 1.|In Gerbillus, Streptopelia and Agama cold exposure produced variable changes in NE levels, while heat exposure provoked a general increase in the NE and DA levels, in some brain regions. 2. 2.|A single heat dose decreased markedly both NE and DA levels in Gerbillus brain, but increased them in Streptopelia brain. Two heat doses increased the two amines in Gerbillus and increased DA in the Streptopelia four brain regions. 3. 3.|Exposure of Agama to a single heat dose or to two heat doses caused a fall in the NE levels and an increase in those of DA. 4. 4.|It is concluded that the storage and release of NE and DA in the CNS may vary with changing ambient temperatures.

Seasonal change in liver and fat body masses of Agama stellio stellio are described. Females have significantly heavier liver and fat bodies than males. In both sexes the liver undergoes an autumnal hypertrophy. It has the lowest mass in August. The liver of immatures of both sexes shows no apparent change. In both sexes fat bodies have their maximal mass in summer. In males, fat body mass decreases continuously from August to June. In females, a relatively similar August to April pattern of changes is followed by an abrupt decrease in April and May, when vitellogenesis takes place. The pattern of changes in fat bodies of immatures is roughly similar to that of adult males. It is concluded that in males liver and fat bodies are used primarily for maintenance. The role of the female liver is not so clear, while fat bodies are used for both maintenance and reproduction.

Scanning electron microscope observations of the frontal papillae and peribuccal cuticle of four species of raillietiellid pentastomids have shown an array of sensilla which are grouped in characteristic patterns. The arrangement of sensilla is remarkably uniform within the species studied and it cannot be used in specific diagnosis. Possible functions are suggested.

The relationship between electrolytes, glucose, and urate in the blood and the adrenocortical tissue were studied by inhibition of corticosteroid secretion. Although several methods for surgical adrenalectomy were devised, none of them succeeded. As a basis for comparison of the effects of drugs, the normal histology of the adrenals was studied. Metopirone and o,p -DDD caused severe histological damage to the adrenal, whereas dexamethasone and overdoses of ACTH had no apparent effect. Despite the obvious damage seen in the adrenal tissue, no changes were detected in blood, electrolytes, or hematocrit.

Kinetics of radioiodine incorporation and disappearance under standard conditions of housing and maintenance were undertaken in Agama stellio, the commonest of the Israel lizards. Quantitative and qualitative measurements of radioactive iodine incorporation were made by: (1) periodic measurements of radioactivity over the thyroid area, using a collimated scintillation counter; (2) periodic scannings of the whole body using an isotopic scanner and (3) assay of tissues for radioactivity. Although there was activity almost immediately after 131I injection over the thyroid, it was not the site of the exclusive iodine accumulation. Most of the radioiodine was concentrated from the first moment after injection in the stomach, which apparently acted as a reservoir for the 131I. It was subsequently released into the circulation and taken up by the thyroid. Maximum thyroid uptake was found 5–7 days after 131I injection, followed by a plateau of 6–7 days and a gradual decline. Labeled MIT, DIT, T4 and in some cases small amounts of T3, were found in the glands by thin-layer chromatography. Labeled T4 reached a maximum of 20% of the total radioiodine within 7 days.

1. 1. Oxygen consumption and lactate production above resting levels, and selected body temperatures, were measured in the lizard Agama stellio . 2. 2. Active and resting V O 2 have low Q 10 (1.7, 2.0) in the activity range 30–37°C and higher 4.0) below this. 3. 3. A correlation was found between published resting and active V O 2 of lizards, and between V O 2 and lifestyle. Four types were recognized, in order of increasing V O 2 : (a) fossorial; (b) sit-and-wait (in A. stellio ): (c) cruising, and (d) widely foraging. 4. 4. A. stellio has a high capacity for lactate production, correlated with its short but rapid bursts of activity. This accounts for 80–90% of the energy used during 30 sec maximal activity.

Es wurde das gehaufte, geographisch begrenzte Auftreten multipler Allele fur LDH-H, das bei den bisher untersuchten Organismen nur selten Varianten zeigt, nachgewiesen. Ebenso gelang die Identifizierung von elektrophoretischen Varianten in Abhangigkeit vom pH.

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.

1. 1. Polyacrylamide gel electrophoresis of 98 hemolysates of the lizard Agama stellio from 10 Greek islands, revealed a constant electrophoretic pattern consisting of two slow hemoglobin bands. 2. 2. Aging of hemolysates produced a diffuse electrophoretic profile that was restored to normal by reduction and alkylation. 3. 3. Rabbit antisera against Agama stellio hemolysates from three islands gave a continuous precipitin line in Ouchterlony plates with hemolysates from several islands.

(1951). XCIX.—A new subspecies of Agama stellio (L.) from Southern Israel (Negev), Agama stellio brachydactyla, subsp. nov. Annals and Magazine of Natural History: Vol. 4, No. 46, pp. 1052-1053.

Brygoofilaria agamae gen. et sp. n. (Filarioidea: Onchocercidae) is described from the periesophageal and peritracheal connective tissue, from lymph spaces in the intestinal mesentery and the pericardial cavity of Agama stellio in Lebanon. It differs from other genera in the subfamily Splendidofilariinae parasitic in reptiles in various characters including vulvar position, morphology of the esophagus, and size of microfilariae.