Plasmodium spp. (Apicomplexa: Plasmodiidae) of the flying lizardDraco volans (Agamidae)

The agamid lizardDraco volans from Palawan, Republic of the Philippines, was found to be parasitised by threePlasmodium species:P. draconis n. sp.,P. volans n. sp. andP. vastator, Laird 1960. BothP. draconis andP. volans, but notP. vastator, were also present inD. volans from Sarawak. The species are readily distinguished by schizont size, merozoite number, and gametocyte size and shape.P. volans has schizonts approximately one-half the size of those ofP. draconis and produces 4–6 merozoites in comparison to 4–16 in the larger species. Gametocytes of both new species are predominantly oval in the Palawan sample and elongate in that from Sarawak.P. draconis gametocytes are approximately twice the size ofP. volans gametocytes, but on average no more than one-half the size of gametocytes ofP. vastator.     

The cost of living large: comparative gliding performance in flying lizards (Agamidae: Draco)

Despite exhibiting considerable interspecific variation in body mass, flying lizards of the genus Draco are isometric in their area-mass scaling relationships and exhibit no significant compensatory variation in wing aspect ratio. Thus, larger species are expected to be relatively poor gliders, in lieu of behavioral or physiological compensation, when compared with smaller congeners. Here we tested this hypothesis by conducting gliding performance trials for 11 Draco species spanning virtually the entire size range of the genus. We considered three primary performance variables: maximum velocity adjusted for wind conditions, height lost over a standard horizontal glide distance, and glide angle. Comparative analysis confirmed that larger species are relatively poor gliders and do not compensate substantially for their higher wing loadings via either behavioral or physiological mechanisms. Flying lizards were found to exhibit substantial context-dependent variation in glide performance, with smaller species often exhibiting extensive variation in height lost and glide angle between trials. Variation also was observed in empirically derived velocity profiles, with only a subset of individuals appearing to perform equilibrium glides. Such size-dependent variation in performance has important consequences for the ecology and evolution of flying lizards and other glissant taxa.     

Additional Fallisia spp. (Apicomplexa: Plasmodiidae) of Neotropical lizards

Fallisia biporcati n. sp. parasitises thrombocytes and lymphocytes of Anolis biporcatus and A. lionotus in Panama. Round or oval schizonts average 13.3 × 11.5 (10.5–16 × 9–13) m, with LW 153.8 (94–208) m², and produce 38.3 (28–60) merozoites. Gametocytes are variably shaped, from round or oval to nearly triangular or rectangular, and average 12.6 × 9.0 (10–15 × 6–12) m, with LW 113.1 (82–150) m² and L/W ratio 1.43 (1.0–2.2). Thrombocytes and lymphocytes of A. poecilopus in Panama are parasitised by F. poecilopi n. sp. Schizonts, oval to elongate in shape, 7.7 × 4.7 (5.5–9 × 3–6) m, with LW 36.5 (22–54) m², are filled with 31.0 (20–51) tiny nuclei or merozoites. Gametocytes are 10.1 × 8.0 (7.5–14 × 6–11) m, with LW 82.0 (45–132) m², round to elongate with L/W ratio 1.27 (1.0–1.6). F. thecadactyli n. sp. parasitises thrombocytes and lymphocytes of Thecadactylus rapicaudus in Panama and Venezuela. Oval, oblong, or triangular schizonts average 10.3 × 8.0 (7–13 × 5–12) m, with LW 86.6 (37–156) m², and produce 40.2 (26–61) merozoites. Gametocytes are round, oval, triangular or elongate, 10.4 × 7.0 (7–15 × 5–11) m, with LW 74.8 (40–154) m² and L/W ratio 1.51 (1.1–2.2). F. dominicensis n. sp. parasitises thrombocytes of A. cybotes on Hispaniola. Schizonts, 6.0 × 4.8 (4–8 × 3–7) m, with LW 29.1 (12–56) m², round, oval, elongate, oblong or lentiform in shape, produce 12.4 (8–22) merozoites. Gametocytes are 6.6 × 5.0 (5–9 × 4–7) m , with LW 33.8 (20–56) m², round, oval or elongate, and L/W ratio of 1.34 (1.1–2.0).     

Phylogenetic systematics of Southeast Asian flying lizards (Iguania: Agamidae: Draco) as inferred from mitochondrial DNA sequence data

Phylogenetic analysis of mitochondrial DNA sequence data using maximum parsimony, minimum evolution (of log-determinant distances), and maximum-likelihood optimality criteria provided a robust estimate of Draco phylogenetic relationships. Although the analyses based on alternative optimality criteria were not entirely congruent, non-parametric bootstrap analyses identified many well-supported clades that were common to the analyses under the three altrenative criteria. Relationships within the major clades are generally well resolved and strongly supported, although this is not the case for the Philippine volans subclade. The hypothesis that a clade composed primarily of Philippine species represents a rapid radiation could not be rejected. A revised taxonomy for Draco is provided.     

Microbial digestion in the herbivorous lizard Uromastyx aegyptius (Agamidae)

The utilization of a diet rich in plant cell walls was studied in a large, desert-dwelling, herbivorous lizard, Uromastyx aegyptius (Agamidae). The diet eaten by U. aegyptius in spring in the 'Arava Valley, Israel, consisted almost entirely of leaves and fruits of short-lived annual plant species. The leaves contained only moderate levels of fibre compared with grasses and tree leaves, but those fruits eaten were markedly higher in fibre and lignin. All items had notably high contents of ash.
Following oral doses of [¹⁴C] cellulose, ¹⁴CO₂ was detected in respired air from U. aegyptius , demonstrating that the cellulose was digested and that the lizards gained oxidative energy from cellulose degradation. The hind gut was the principal site of microbial activity and the apparent digestibility of the cell-wall fraction was 69%. Similarly, the caecum/proximal colon had the highest concentrations of SCFA (76–120 mM).
The mean rate of SCFA production at 40 C in vitro was 31 mmol/1 h^-1. Assuming that this is representative of daily production rate, 69 kJ/kg d^-1 would be made available to the animal. This is 47% of the mean digestible energy intake estimated in free-living animals. Microbial fermentation contributes an important part of the energy budget of U. aegyptius but the effects of variation in body temperature on digestion and fermentation need further consideration.     

Two malaria parasites (Apicomplexa: Plasmodiidae) of the Australian skink Egernia stokesii

The Australian skink Egernia stokesii is parasitized uncommonly by Plasmodium circularis n. sp. and by Plasmodium mackerrasae. Plasmodium circularis is distinguished from all other plasmodiids by immature schizonts that encircle host cell nuclei, forming an unbroken ring from apparent fusion of the attenuated ends. Mature schizonts contract into halteridial or dumbbell-shaped forms 15.6 x 4.3 microm, LW 66.2 microm2, with 19-52 nuclei. Rounded or oval gametocytes are 9.0 x 7.3 microm, LW 66.9 microm2, and L/W 1.24. Gametocyte LW is 2.63 x host erythrocyte nucleus size and 1.79X uninfected erythrocyte nuclei. Plasmodium mackerrasae occurs in high prevalence and often massive parasitemia in E. stokesii. Schizonts, often oblong, elongate, or oval, are 5.1 x 3.7 microm, LW 19.8 microm2, with 7.2 merozoites. Immature gametocytes, elongate with terminal nucleus, may produce multiple infections of 6 or more parasites. Mature gametocytes, usually rounded, are 5.8 x 4.6 microm, LW 26.7 microm2, and L/W 1.29. Gametocyte size is 0.98 x host erythrocyte nucleus size and 1.03 x uninfected erythrocyte nuclei. Phanerozoites, in endothelium or connective tissue of most organs, may appear in large numbers in circulating blood as seemingly intact bodies of regular form, similar to or larger than phanerozoites seen in sections. Previously unreported phenomena for hemosporidian parasites include extremely large, highly irregular exoerythrocytic schizonts, in circulating blood, perhaps torn from endothelial lining of blood vessels and sinuses, and a visible flooding of free merozoites into the blood stream.     

Ultrastructural aspects of Fallisia effusa (Haemosporina: Garniidae) in thrombocytes of the lizard Neusticurus bicarinatus (Reptilia: Teiidae)

The fine structure of the different stages of the Fallisia effusa (Haemosporina: Garniidae), infecting the thrombocytes of the semi-aquatic Amazonian lizard Neusticurus bicarinatus (Reptilia: Teiidae) is described. Gametocytes, meronts, and merozoites of Fallisia effusa were found within a parasitophorous vacuole (PV). Multiple infections of micro- and macrogametocytes were observed. A circumferential coil of microtubules was seen in the cytoplasm of the infected host cell and this microtubule array was pronounced in cells harboring gametocytes. A deep invagination of the inner membrane complex of gametocytes may be involved in nutrition. The non-pigmented parasites underwent both merogony and gametogony in thrombocytes of the peripheral blood. No infection of the erythrocytes was observed. These observations confirm that Fallisia effusa displays characteristic features distinguishing it from other members of the Haemosporidian families, and that it has the ability to modulate microtubule assembly.     

Kinematics of prey capture and chewing in the lizard Agama agama (squamata: Agamidae)

High speed video recordings (200 fields per second) of prey capture and food processing in Agama agama permit the identification of strikes, chews and transport movements. Ten variables from strike movements and seven variables from chewing sequences are digitized; transport movements are inspected only. Univariate and multivariate statistical analyses disclose significant interindividual differences for three variables (maximum gape distance, maximum head angle, and maximum throat distance); but neither these nor principal components analysis show differences between strikes and chews for any of the gape change and hyoid depression variables. However, strikes and chews obviously differ in tongue protrusion and body movements. Chewing may be divided into four stages, comparable to those of transport cycles of other lizards and the generalized tetrapod model. Transport differs from chewing by having a shorter power stroke and relatively more cranial and less jaw movement. The kinematics of feeding in Agama agama are compared with those of other lizards studied previously.     

Function and evolution of the frill of the frillneck lizard, Chlamydosaurus kingii (Sauria: Agamidae)

Relative to body size, the frill of the Australian agamid lizard Chlamydosaurus kingii is one of the largest and most spectacular display structures seen in any animal species. More than 300 hours observation of free-ranging lizards, combined with data on museum specimens, revealed that the frill is used primarily for intraspecific communication and predator deterrence. Earlier hypotheses on alternative uses for the frill (gliding, food storage, thermoregulation or auditory enhancement) are not supported. The folded frill may also enhance camouflage, but this is probably a fortuitous effect rather than an adaptation.
Male frillnecks frequently display and fight during the mating season. Male displays are highly stereotyped, and involve repeated partial erection of the frill, head-bobbing, tail-lashing, and waving of forelimbs. Both males and females erect the frill during social encounters, and in response to potential predators. Males grow larger than females and have larger heads than do females at the same body size, but no dimorphism is apparent in the relative size of the frill. The extreme development of the display structure in this species may be due to general allometric relationships, as well as to ecological features that have intensified the action of sexual selection in Chlamydosaurus.     

The role of prostaglandins and the hypothalamus in thermoregulation in the lizard, Phrynocephalus przewalskii (Agamidae)

Typically, small lizards rely heavily on behavioral thermoregulation rather than physiological mechanisms to control their rates of warming and cooling. We tested the hypothesis that prostaglandins participate in mediating the cardiovascular response to heating and cooling and temperature regulating neurons in the hypothalamus of the small lizard Phrynocephalus przewalskii. In vivo and in vitro treatments, heart rates (HRs) were all found to be higher during heating than during cooling, hysteresis was distinct below 30 and 26°C, respectively. In vivo, as administration of COX inhibitor, there were no differences in HR between heating and cooling at any body temperature and administration of agonist prostaglandins only produced a significant effect on HR below 25°C. Single-unit activity was recorded extracellularly in vitro with microelectrodes, found the firing rate of the continuous unit increased 23% when the temperature of the artificial cerebrospinal fluid dropped from 30–20°C. We conclude that prostaglandins appear to play only a limited role in modulating heart activity in Phrynocephalus przewalskii and suggest that cold-sensitive neurons in the preoptic and anterior hypothalamus (PO/AH) are involved in thermoregulatory control during heating or cooling.     

Cladogenesis and phylogeography of the lizard Phrynocephalus vlangalii (Agamidae) on the Tibetan plateau

Phrynocephalus vlangalii is restricted to dry sand or Gobi desert highlands between major mountain ranges in the Qinghai (Tibetan) Plateau. Mitochondrial DNA (mtDNA) sequence (partial ND2, tRNA(Trp) and partial tRNA(Ala)) was obtained from 293 Phrynocephalus sampled from 34 sites across the plateau. Partitioned Bayesian and maximum parsimony phylogenetic analyses revealed that P. vlangalii and two other proposed species (P. erythrus and P. putjatia) together form a monophyletic mtDNA clade which, in contrast with previous studies, does not include P. theobaldi and P. zetangensis. The main P. vlangalli clade comprises seven well-supported lineages that correspond to distinct geographical areas with little or no overlap, and share a most recent common ancestor at 5.06 +/- 0.68 million years ago (mya). This is much older than intraspecific lineages in other Tibetan animal groups. Analyses of molecular variance indicated that most of the observed genetic variation occurred among populations/regions implying long-term interruption of maternal gene flow. A combined approach based on tests of population expansion, estimation of node dates, and significance tests on clade areas indicated that phylogeographical structuring has been primarily shaped by three main periods of plateau uplift during the Pliocene and Pleistocene, specifically 3.4 mya, 2.5 mya and 1.7 mya. These periods corresponded to the appearance of several mountain ranges that formed physical barriers between lineages. Populations from the Qaidam Basin are shown to have undergone major demographic and range expansions in the early Pleistocene, consistent with colonization of areas previously covered by the huge Qaidam palaeolake, which desiccated at this time. The study represents one of the most detailed phylogeographical analyses of the Qinghai Plateau to date and shows how geological events have shaped current patterns of diversity.     

Copepod parasites of a commercial clam (Meretrix meretrix) from Phuket,Thailand

Three species of copepods are reported from hard clams, Meretrix meretrix (L.), obtained from the market in Phuket, Thailand. They are: Conchyliurus bombasticus Reddiah (Clausidiidae), Ostrincola portonoviensis Reddiah (Myicolidae), and Lichomolgus similis Ho & Kim (Lichomolgidae). The first two species are redescribed based on the newly collected material. Conchyliurus fragilis Reddiah is proposed to be relegated to a synonym of C. bombasticus. L. similis is recorded for the first time from the Indian Ocean.     

A new Haemocystidium (Apicomplexa: Plasmodiidae) species of the dhub lizard, Uromastyx aegyptia microlepis , in Abu Dhabi, distinguished by the absence of pigment

The spiny-tailed lizard, Uromastyx aegyptia microlepis , in Abu Dhabi is parasitized by Haemocystidium apigmentada n. sp., and 2 species of Hepatozoon . The elongate gametocytes of H. apigmentada are 13-19 × 6-9 μm, with length × width (LW) 90-133 μm(2), and L/W ratio 1.56-3.17. Gametocyte dimensions do not differ by sex. Gametocytes are unpigmented. Hepatozoon species 1 has gamonts with a consistently terminal nucleus, with dimensions of 13-16 × 4.5-7 μm, LW of 58-104 μm(2), and L/W ratio of 2.00-3.22. Hepatozoon species 2 gamonts have a broad nucleus at the midbody, and dimensions of 13-15.5 × 5-7 μm, LW of 71-109 μm(2), and L/W ratio of 1.93-3.00.     

Haematozoan parasites of the lizard Ameiva ameiva (Teiidae) from Amazonian Brazil: a preliminary note

Three different haematozoan parasites are described in the blood of the teiid lizard Ameiva ameiva Linn. from North Brazil: one in the monocytes and the other two in erythrocytes. The leucocytic parasite is probably a species of Lainsonia Landau, 1973 (Lankesterellidae) as suggested by the presence of sporogonic stages in the internal organs, morphology of the blood forms (sporozoites), and their survival and accumulation in macrophages of the liver. One of the erythrocytic parasites produces encapsulated, stain-resistant forms in the peripheral blood, very similar to gametocytes of Hemolivia Petit et al., 1990. The other is morphologically very different and characteristically adheres to the host-cell nucleus. None of the parasites underwent development in the mosquitoes Culex quinquefasciatus and Aedes aegypti and their behaviour in other haematophagous hosts is under investigation. Mixed infections of the parasites commonly occur and this often creates difficulties in relating the tissue stages in the internal organs to the forms seen in the blood. Concomitant infections with a Plasmodium tropiduri-like malaria parasite were seen and were sometimes extremely heavy.     

The language of lizards: interpreting the function of visual displays of the Indian rock lizard, Psammophilus dorsalis (Agamidae)

The first step in understanding any communication system is to document signal diversity relative to the context of signalling (e.g. sex of the signaller and audience). Observation of 30 free-ranging rock lizards (Psammophilus dorsalis) on rock outcrops in southern India over a period of 18 months revealed that these lizards produce a complex array of ritualized signals involving push-ups (head-bobbing), dorsal flattening, extension of the legs or gular region, and tail-raising. Push-ups were performed by both sexes, usually after moving from one location to another. Push-ups were rarely accompanied by other postural modifications, and seem to function as non-directed signals. Dorsal flattening was elicited by birds flying overhead, and seems to make the lizard less conspicuous to predators. There was, nonetheless, a strong sex difference in the frequency of this behaviour, because the habitats used by males (open rocks) exposed them to more birds. Males displayed to females by extending their gular folds and arching their backs; other animals (e.g. squirrels, monkeys) also elicited the latter posture from both sexes. Leg extension was observed for both males and females, but in different contexts—males in response to conspecifics, females in response to other animals. Females raised their tails in response to encountering a male. Thus, these lizards have a complex repertoire of postures for predator evasion, for interaction with other species and with conspecifics, and for communicating sex-specific social information about gender (tail-raise) or dominance status (gular extension, leg extension).     

The biology of gliding in flying lizards (genus Draco) and their fossil and extant analogs

The flying lizards of the genus Draco are among the most remarkable and successful clades of gliding vertebrates. Here, we evaluate the evolution of gliding in Draco and other lizards, describe the suite of morphological innovations that characterize Draco, discuss the ecological context of gliding in this genus, describe functions of their patagial membranes that are not related to gliding, and summarize the interspecific allometry of the Draco gliding apparatus, as well as the corresponding consequences for their now empirically quantified gliding performance. Several fossil reptilian lineages had morphologies similar to that of modern Draco, with patagial membranes supported by elongated ribs or rib-like dermal structures. Using Draco's snout-vent length/mass relationships, we provide improved estimates of wing loading for three of these fossil gliders (Icarosaurus seifkeri, Kuehneosaurus sp., Coelurosauravus elivensis) and then estimate absolute gliding performance for each taxon by extrapolating from Draco's wing loading/glide performance relationship. We find that I. seifkeri likely represented the best nonflapping terrestrial vertebrate glider yet described, whereas the larger Kuehneosaurus and Coelurosauravus probably required high descent velocities to achieve sufficient lift for gliding, with commensurately greater height loss with each glide.     

Morphological and histochemical investigations of esophagogastric tract of a lizard, Laudakia stellio (Agamidae, Linnaeus 1758)

Histological structures of esophagus and stomach tissue samples of Lacerta stellio have been studied, and glycosaminoglycan (GAG) distribution has been histochemically determined. Histologically, esophagus and stomach of L. stellio are composed of four layers: mucosa, submucosa, muscularis mucosae and serosa. Mucosa of esophagus is covered by simple columnar ciliated epithelium with many mucous secreting goblet cells and contains branched tubular glands.Stomach of L. stellio is composed of fundus (oral and aboral) and pylorus regions. Mucosa is covered by columnar epithelium. Fundic glands are branched tubular glands while pyloric glands are usually simple tubular glands. In both regions of the stomach, glands are subdivided into three areas as base, neck and isthmus. Both in the esophagus and stomach, muscular layer is in the form of smooth muscle having inner circular and outer longitudinal layers.According to the results obtained by Alcian Blue (pH 5.8)/Periodic Acid Schiff staining, stomach is similar to esophagus in that neutral mucins and hyaluronic acid (HA) are dominant in isthmus and neck regions of gland tissue of stomach. In the base of the stomach, only neutral mucins have been observed. HA has been observed to be dominant in all other regions of both stomach and esophagus, along with some but not much sulphated GAGs.     

Some coccidial parasites of the lizard Amphisbaena alba (Reptilia: Amphisbaenia: Amphisbaenidae)

Five parasites are described in the lizard Amphisbaena alba (Amphisbaenidae) from the state of Par , North Brazil. Mature oocysts of Choleoeimeria amphisbaenae n. sp., are passed already mature in the faeces. They are ellipsoidal-cylindrical, average 33.7 x 22.8 m and are devoid of micropyle, oocyst residuum or polar body. The colourless wall is smooth and of 2 layers. The 4 dizoic sporocysts have no Stieda body and average 13 x 9.3 m. Endogenous stages develop in the epithelial cells of the gall-bladder in the manner described for the genus and may cause extensive tissue damage. Sporulation of Isospora capanemaensis n. sp., is completed 3 days after the oocysts are voided in the faeces. They average 14.8 x 14.5 m and have no micropyle, oocyst residuum or polar body. The 2 tetrazoic sporocysts are pear-shaped, average 8.6 x 6.6 and have an inconspicuous Stieda body. Endogenous development is in the epithelial cells of the ileum, and heavy infections cause considerable tissue destruction. Multisporocystic oocysts passed in the faeces of one A. alba possibly originated from an invertebrate host ingested by the lizard. A globidium-like cyst in the digestive tract of A. alba measured 105 x 85 m and contained many hundreds of merozoites. A stained kidney smear of the same lizard revealed the presence of an unidentified parasite producing multinucleate cyst-like stages.