The malarial parasites of Anolis species (Sauria: Iguanidae) in Panama

Lizards of the iguanid genus Anolis in Panama are parasitized by four species of Plasmodium. P.floridense occurs in A. limifrons, A. biporcatus, A. pentaprion and A. frenatus. The number of nuclei in mature schizonts is influenced by host species as is gametocyte shape but not gametocyte size. P. tropiduri parasitizes A. limifrons, A. pentaprion, A. biporcatus, A. frenatus, A. lionotus and A. poecilopus. The number of nuclei in schizonts varies according to host and type of blood cell parasitized. Gametocyte size varies slightly by host but shape remains relatively constant. Position of the parasite in the host cell may be affected by host species. Both schizonts and gametocytes are produced in white cells of all host species studied. P. balli occurs in A. limifrons, A. lionotus and A. poecilopus. Schizont and gametocyte size and shape are affected by host and blood cell type, with the parasite exhibiting different preferences for various blood cells in each host. P. minasense parasitizes A. limifrons, A. frenatus and A. capito, but its diagnosis in the last species may not be correct as gametocyte size and distribution of pigment differ considerably from other hosts. The mean number of nuclei in schizonts is not greatly affected by the host species. P. floridense is postulated to be of middle American origin in the genus Anolis, and to have reached Florida through the Caribbean.     

Size and shape variation in a Lesser Antillean anole, Anolis oculatus (Sauria: Iguanidae) in relation to habitat.

The anole fauna of the Lesser Antilles is depauperate in relation to that of the Greater Antilles, where complex communities characterized by adaptive specialization and convergent structure are present. Much of this adaptation is the result of changes in body size and shape, probably as a result of interspecific competition. Here we present data on variation in size and shape within a solitary Lesser Antillean species occupying an ecologically heterogenous island, and test the hypothesis that natural selection for varying environmental conditions is the cause of this variation. Univariate (analysis of variance), bivariate (analysis of covariance) and multivariate (multiple-group principal component analysis, canonical variate analysis) analysis showed that there is considerable geographic variation in size and shape within Anolis oculatus on Dominica. Partial Mantel tests rejected the null hypothesis of no association between size and shape and environmental variation. The possible proximate and evolutionary mechanisms responsible for these patterns are discussed. Despite these overall associations, a considerable amount of variation in shape appears to be unrelated to environmental variation.     

The Ontogeny of Display Behaviour in Sceloporus undulatus: (Sauria: Iguanidae)

A longitudinal study (from neonate to adult) was made of the display behaviour of 36 fence lizards from 8 clutches. A frame-by-frame analysis of 941 video-taped displays revealed that the hatchlings possessed almost all of their adult display patterns by the first two days of life. Of the total variance in the display behaviour, 7% or less was attributed to experience. Of the variance among lizards, approximately half came from between clutches and half from between clutchmates. Our data indicate that the visual communication signals (head bob displays) of this vertebrate species are almost totally innate.     

Ultrastructural analysis of spermiogenesis in Iguana iguana (Reptilia: Sauria: Iguanidae)

Spermiogenesis in the lizard, Iguana iguana, was studied by transmission and scanning electron microscopy. During this process, structures such as the acrosomal complex in the spermatid head and the axonemal complex in the mid and principal pieces of the flagellum are formed. The nuclear content is initially compacted into thick, longitudinal chromatin filaments. Nuclear shape is determined by further compaction and by the manchette, a layer of microtubules surrounding the head. The acrosomal complex originates from Golgi vesicles and the interaction between the proacrosomal vesicle and the nucleus. The midpiece consists of a pair of centrioles, surrounded by a fibrous sheath and rings of simple and modified mitochondria. The centrioles sustain the axoneme that appears at the end of the midpiece. The axoneme extends throughout the principal piece of the flagellum with the 9 + 2 pattern, still surrounded by the fibrous sheath. In the endpiece, the axoneme continues, surrounded only by the plasma membrane. In the lumen of seminiferous tubules, immature spermatozoa retain abundant residual cytoplasm.     

Foraging ecology in the lizard Anolis oculatus (Iguanidae) from Dominica, West Indies

In general, populations of Anolis lizards on West Indian islands face few predators, are at high density and are thought to be limited by food. This paper describes how the foraging ecology of Anolis oculatus , a solitary species confined to the island of Dominica, Lesser Antilles, varies with habitat and season in relation to the quantity and quality of available food.
Availability of invertebrate food (determined using pitfall traps and sticky traps) was greater in a dry scrub woodland site, Cabrits National Park (CNP), compared with a montane rainforest site, Palmiste Ridge. In the former, there were general increases in abundance, volumes of softbodied prey and sizes of invertebrates from dry season to wet season. Concomitant dietary changes, as determined principally by stomach flushing, included an increase (by volume) in the proportion of soft-bodied prey. Dietary analyses confirmed the importance of ants (Formicidae) in the diet of A. oculatus , although for large individuals (mainly adult males) at the rainforest site, soft-bodied prey such as Oligochaeta and Orthoptera were, in volumetric terms, more important. Prey capture observations showed that large A. oculatus fed mainly above ground. Anolis oculatus at the montane rainforest site used higher perch heights than those in dry scrub woodland, although in both habitats, small individuals (mainly juveniles) fed mainly at ground level on ants. In the dry season in CNP, the diet (in volumetric terms) of smaller Anolis was dominated by hardbodied prey such as ants, springtails (Collembola), barklice (Psocoptera) and beetles (Coleoptera). large Anolis used springtails and barklice to a lesser extent, resulting in relatively low food niche overlap values between size classes and a reduced potential for intraspecific competition compared with the wet season.     

Functional morphology of dewlap extension in the lizard Anolis equestris (Iguanidae)

The dewlap is an extendible flap of skin ordinarily folded under the throat. Lizards, particularly those in the genus Anolis, extend their dewlaps during interactions with conspecifics, other lizards, and potential predators. Dewlap extension is effected by movements of elements of the hyoid apparatus. This paper describes the anatomy of the hyoid and associated musculature in Anolis equestris, a large arboreal lizard with a prominent dewlap. A mechanism for dewlap extension is proposed based on results of morphological and experimental techniques. Specializations of the hyoid skeleton for dewlap extension include elongated second ceratobranchials and highly movable joints between the ceratohyals and the hypohyals and between the first ceratobranchials and the body of the hyoid. A well developed M. ceratohyoideus extends between the ceratohyals and the first ceratobranchials of the hyoid apparatus. During dewlap extension, the hyoid apparatus acts as a first order lever. Contraction of M. ceratohyoideus pulls the ceratohyals posteriorly causing the hypohyals and the body of the hyoid to rotate dorsally around the first ceratobranchial/body joints. This movement results in the second ceratobranchials swinging forward and down, unfolding the dewlap. The relative immobility of the first ceratobranchials provides stability to the hyoid apparatus during dewlap extension. A comparison is made of dewlap extension and other hyoid displays.     

A new species of dactyloid anole (Iguanidae, Polychrotinae, Anolis) from the southeastern slopes of the Andes of Ecuador

We describe a new species of Anolis from the southeastern slopes of the Andes of Ecuador, province of Zamora-Chinchipe, Parque Nacional Podocarpus. It belongs to (1) the aequatorialis species-group by being of moderate to large size with narrow toe lamellae, and (2) the eulaemus sub-group by having a typical Anolis digit, in which the distal lamellae of phalanx II distinctly overlap the proximal scales of phalanx I. The new species is most similar morphologically to Anolis fitchi but differs from it mainly by having a dewlap with longitudinal rows of 2-5 granular, minute scales separated by naked skin (longitudinal rows of one or two keeled, large scales separated by naked skin in Anolis fitchi) and a vertically shorter dewlap (longer dewlap in Anolis fitchi).     

Africana telfordi n. sp. (Nematoda: Heterakidae) from the lizard,Enyalioides heterolepsis (Sauria: Iguanidae) from Panama

Africana telfordi n. sp. (Nematoda: Heterakidae) from the large intestine of the lizard Enyalioides heterolepsis collected in Panama is described and illustrated. Africana telfordi n. sp. represents the seventh species assigned to the genus and the second from the Neotropical Realm. It is distinguished from the other neotropical species, A. chabaudi, by the size and shape of the spicules. The spicules of A. telfordi are robust, analate, and 366-458 microm in length; those of A. chabaudi are narrow, alate, and 644-869 microm in length.     

Ethotypic Variation of Prey Recognition in Juvenile Anolis lineatopus (Reptilia: Iguanidae)

Among prey-naive Anolis lineatopus from Jamaica, individuals reject ants most commonly, crickets less commonly, and waxmoth larvae almost never. This study investigates the individual differences in the mechanism underlying prey perception in two of many ethotypes found, i.e., cricket-rejectors and cricket-acceptors. In one experiment artificially coloured live waxmoth larvae, crickets and ants were presented, in another experiment crickets and waxmoth larvae were moved passively with different speeds. Ethotypes differ in their evaluation of the interaction of prey key stimuli. Cricket-rejectors and cricket-acceptors differ in their responses to both crickets and waxmoth larvae that were either unicoloured yellow or black, but not in their responses to two types of ants of either colouration. Both ethotypes also differ in their preferences for artificially moved crickets and waxmoth larvae as a function of the interaction of prey type and velocity. In all but two prey items there is interaction in the perceptual pathways concerned. The first presentation in ontogeny of an ant inhibits attack on a cricket presented the next day. Some results suggest that ethotypes differ but gradually in their evaluation of stimuli presented, with cricket-rejectors having a higher threshold for attack. However, other results suggest that cricket-rejectors evaluate certain prey in a way qualitatively different from that of acceptors. At present there is little evidence for an understanding of the ethotypic differences of prey selection at a neural level, probably because neuroethologists have failed to look at individual differences of prey recognition; this failure is discussed in some detail.     

New species of Spauligodon (Nematoda: Pharyngodonidae) in Lepidodactylus novaeguineae (Sauria: Gekkonidae) from Papua New Guinea

Spauligodon zweifeli n. sp. (Nematoda: Pharyngodonidae) from the large intestines of a gecko, Lepidodactylus novaeguineae (Sauria: Gekkonidae), is described and illustrated. Prevalence of infection was 57% (mean intensity 8.5, range 1-23). Spauligodon zweifeli n. sp. is the 43rd species to be assigned to this genus and differs from other species in the genus by possessing asymmetrical fusiform eggs in which the ends are extended as digitiform processes. It is the second species to be described from the Australian biogeographical realm.     

New species of Skrjabinodon (Nematoda: Pharyngodonidae) in Uracentron flaviceps (Squamata: Iguanidae) from Ecuador and Peru

Skrjabinodon dixoni n. sp. from the large intestine of Uracentron flaviceps (Squamata: Iguanidae) from Peru is described and illustrated. It is also reported in the same host from Ecuador. Skrjabinodon dixoni n. sp. differs from other species assigned to Skrjabinodon by morphology of tail filament and number of tail filament spines.     

Ethotypic Variation of Prey Recognition in Juvenile Anolis lineatopus (Reptilia: Iguanidae) Revisited

A previous study (von Brockhusen -Holzer & Curio 1990) had led to the major conclusion that prey-naive Anolis lineatopus hatchlings differ in terms of a “hard-wired” perceptual mechanism underlying the recognition of cricket prey. We reconsider here one result leading to that conclusion since it rested on negative evidence in one treatment group as compared to another. A newly applied discriminant analysis utilizing the complete prey rejection/acceptance data of individuals in the two treatment groups, i.e. cricket-rejectors and prefed cricket-acceptors, again permits the repudiation of a motivation-based alternative hypothesis explaining the rejector-acceptor dichotomy. Thereby we reconfirm the original hypothesis of a “hard-wired”, preprogrammed polyethism underlying prey recognition.     

New species of Rhabdias (Nematoda: Rhabdiasidae) and other helminths from Norops capito (Sauria: Polychrotidae) from Nicaragua

Rhabdias nicaraguensis n. sp. (Rhabditida: Rhabditidae) from the lungs of Norops capito (Sauria: Polychrotidae) is described and illustrated. Rhabdias nicaraguensis n. sp. represents the 54th species assigned to the genus and the 12th from the Neotropical realm. Of the 12 Neotropical Rhabdias species, nicaraguensis is most similar to tobagoensis and vellardi. These 3 species have equatorial placement of the vulva, inflated cuticle, and 6 small circumoral lips. Rhabdias nicaraguensis is easily separated from R. tobagoensis by the shape of the buccal cavity and from R. vellardi by body size and shape of the tail. Rhabdias nicaraguensis differs from both species by host preference, the amount of inflated cuticle covering the body, and the phasmids situated posterior to the midpoint of the tail.     

Female response to filmed displays of Anolis nebulosus (Sauria,Iguanidae)

A film loop apparatus was devised to test a possible social function of the display of Anolis nebulosus. Films of a displaying male were projected onto translucent screens at both ends of an enclosure. One film loop portrayed the display typical of the lizard's population, while the other loop projected an altered version of the basic display. Female A. nebulosus were introduced singly into the centre of the enclosure. They gave a graded response to the film loops; an increasing proportion of females approached the ‘normal’ displaying image as the film loops of altered displays contained a greater number of changes. The various experimental techniques previously used to study the function of lizard displays are reviewed.     

Rhabdias anolis n. sp. (Nematoda: Rhabdiasidae) from the lizard,Anolis frenatus (Sauria: Polychrotidae), from Panama

Rhabdias anolis n. sp. from the lungs of Anolis frenatus collected in Panama is described and illustrated. Rhabdias anolis n. sp. represents the 45th species assigned to the genus and the ninth from the Notropical Realm. It is distinguished from all other Neotropical species by the presence of a pair of sessile lateral papillae on its tail.     

A new rhabdiasid species from Norops megapholidotus (Sauria: Polychrotidae) from Mexico

Rhabdias leonae n. sp., a parasite of the lungs of Norops megapholidotus, is described and illustrated. The Mexican taxon differs from the other species in the genus by a combination of characters: possession of 4 lips, corpus slightly inflated, slightly postequatorial vulva, and presence of swollen cuticle of anterior and posterior ends. This is the 12th species described in the Neotropical realm and the first species of Rhabdias described from an endemic Mexican lizard.