Kentropyx calcarata (Teiidae) and Mabuya nigropunctata (Scincidae) occur together in lowland tropical forest of the Amazon near the Rio Curuá-Una of Brazil. During the wet season of 1995 these lizards were common at forest edge along narrow roads that transect forest, in treefalls and along streams where sun reaches the ground. Both species are heliothermic, basking to gain heat. Their association with open patches results from high activity temperature requirements in an environment where sun availability is low. Null temperature distributions from forest and treefalls showed that forest does not offer opportunities for heat gain similar to treefalls. Moreover, the large proportion of time spent basking by both species indicates the importance of these patches for thermoregulation. K. calcarata is slightly larger in body length and heavier at a given body length than M. nigropunctata. Both species are active foragers that seek out prey while moving through the habitat, feeding on orthopterans, roaches and spiders. M. nigropunctata also eat significant numbers of insects that occur on vegetation, such as hemipterans. Prey size is larger in K. calcarata and associated with lizard body size. Prey size does not vary with body size in M. nigropunctata and prey are typically relatively small.

Many of the ecological differences between these two lowland forest species appear to be historical: the ecology of K. calcarata is very similar to that of other species of Kentropyx and teiids in general and the ecology of M. nigropunctata is most similar to that of other studied species of south American Mabuya.

Studies of niche overlap within communities of lizards have shown that separation may be along the three major dimensions of space, time and food. Space is usually the most important dimension where a range of habitats are involved; there is less information on the importance of microhabitat separation within a single habitat type. This study investigated microhabitat relationships of small diurnal lizard species occupying granitic rock habitat in Zimbabwe. There was statistically significant niche separation among all species in both the type of rock occupied (size, shape, number of cracks, closeness to other rocks, and vegetation cover) and the position of the lizard in the microhabitat (height on rock, slope angle, and distance to cover). Overlap of microhabitat was lowest between the generalist terrestrial skink Mabuya varia and all other species. The arboreal skink Mabuya striata was found on rocks at one site where the more saxicolous Mabuya quinquetaeniata was absent, due to competitor release. Overlap of microhabitat among rock specialists was lowest between the sit-and-wait foragers Agama kirkii and Platysaurus intermedius, as in other tropical lizard communities. The high degree of microhabitat separation was attributed to the high structural complexity of the granitic rock habitat.

Examination of Giemsa stained smears made from the peripheral blood, liver and spleen of hand-caught lizards from West Pokot area showed the presence of seven out of the nine Plasmodium species of lizards which have been previously described in Africa. These species are redescribed using a set of biological characters and procedure which enabled a large quantity of each stage of any species to be studied, measured and compared. The utilization of these characters and procedure was a reaction to the multiple infections in individual lizards and a wide host range of each species among lizard species. The adoption of the criteria is recommended for future taxonomie work on lizard Plasmodia in Africa.

A key which brings together all the previously described species of lizard Plasmodia and the new species encountered in the present investigation is presented. The key is simplified so that it can be of use to epidemiologists and pathologists who may work on saurian malaria in Africa.

During investigations on the malaria parasites of lizards in the West Pokot district of Kenya, haemoproteids, haemogregarines, pirhemocyton-like and anaplasma-like organisms were found in the blood. Microscopic examination showed that some of these are new species and they are described in this paper. The new described species are Haemoproteus mungutii (haemoproteid), Karyolysus poleensis, Schellakia mabuyai (haemogregarines), Pirhemocyton kongelai, Haematractidium omogoi, Sauroplasma kachelibaensis (Pirhemocyton-like organisms), Eperythrozoon ngokai and Aegyptianella elgonensis (anaplasma-like organisms). K. poleensis and S. mabuyai are regarded as the first report of the genera in lizards in Africa while A. elgonensis is regarded as the first report of the genus Aegyptianella in lizards.

During investigations into the epidemiology of malaria of lizards in Kenya, Giemsa-stained smears made from the peripheral blood, liver and spleen of hand-caught lizards from West Pokot district were examined for the presence of Plasmodium species. Ten new species were found and described. These are Plasmodium sapaaensis, P. kyaii, P. kachelibaensis, P. icipeensis, P. gloriai, P. odhiamboi, P. bowiei, P. kaninii, P. kadogoi and P. adunyinkai.

P. sapaaensis was found to be related to P. mabuiae, P. kadogoi to P. rhadinurum, P. kaninii to P. minasense (s. Telford) and P. adunyinkai to P. maculilabre. P. kyaii and P. kachelibaensis have distinct characteristics which distinguish them from the Plasmodium species in the tropiduri group reported so far.

Four species i.e. P. icipeensis, P. odhiamboi, P. gloriai and P. bowiei, exhibited peculiar characteristics most especially their effect on the white cells. They were therefore constituted into the “Kenyan” group.